Bone marrow biopsy in patients with hepatitis C virus infection: Spectrum of findings and diagnostic utility

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1 Research Article Bone marrow biopsy in patients with hepatitis C virus infection: Spectrum of findings and diagnostic utility Jeffery M. Klco, 1 Bob Geng, 2 Elizabeth M. Brunt, 1 Anjum Hassan, 1 Tu-Dung Nguyen, 1 Friederike H. Kreisel, 1 Mauricio Lisker-Melman, 2 and John L. Frater 1 * Patients with hepatitis C virus (HCV) infection develop a number of hematologic disorders, with benign and malignant B-cell proliferations being the most common. HCV-infected patients are also prone to developing peripheral cytopenias, the etiologies of which are multifactorial and include hypersplenism and/or antiviral medications. Some of these patients may undergo bone marrow biopsy but no study has systematically recorded the bone marrow findings in this patient group. Here, we report on the range of bone marrow findings in 47 adult HCV-infected patients. These patients, who lacked concurrent human immunodefiency virus (HIV) infection, most commonly presented for a bone marrow biopsy due to abnormal peripheral cell counts. The bone marrow biopsies displayed a range of findings. Dyserythropoiesis, present in 19% of the cases, was the most common finding. Patients with pancytopenia(n 5 6), as defined by current World Health Organization standards, were the most likely to have bone marrow abnormalities; two pancytopenic patients had acute myeloid leukemia, and one patient had a primary myelodysplastic syndrome. There was no correlation in bone marrow findings and antiviral medications, MELD score, cirrhosis or splenomegaly, suggesting that the degree of bone marrow dysfunction is independent of stage of HCV. The results of this study suggest that bone marrow biopsy in HCV-infected patients, even those with features of hypersplenism and/or documented antiviral therapy, can be a valid test for hematologic evaluation, especially for patients with severe pancytopenia and/or sudden alterations in peripheral cell counts. Am. J. Hematol. 85: , VC 2009 Wiley-Liss, Inc. Introduction Over 170 million individuals are infected with Hepatitis C virus (HCV) worldwide [1], with an estimated prevalence of 1.8% in the United States [2]. HCV is a single-stranded RNA virus that is transmitted primarily by parenteral routes and most commonly presents as a chronic hepatitis in infected patients [3]. Viral persistence, mainly within hepatocytes, involves a failure of both innate and adaptive immune responses to fully clear the virion and results in the known liver diseases associated with HCV, such as chronic hepatitis, progressive fibrosis with resultant cirrhosis and an increased risk of hepatocellular carcinoma [4]. HCV infection also has a well-documented association with a number of extrahepatic disease manifestations, such Type II/III mixed cryoglobulinemia and non-hodgkin B-cell lymphomas [5]. These two entities may be related as B-cell proliferation is a component of Type II mixed cryoglobulinemia [6]. Unlike hepatocytes, in which HCV is capable of infection and replication, it is thought that HCV is only capable of infecting B lymphocytes; B-cell proliferation in HCV-infected patients results from chronic antigenic stimulation [6,7]. Diffuse large B-cell lymphoma is the most common non-hodgkin lymphoma (NHL) associated with HCV infection, although many low-grade neoplasms, such as marginal zone lymphoma and lymphoplasmacytic lymphoma, are also frequently noted [8]. Further support of the association between HCV infection and B-cell lymphoproliferation are the observations that anti-hcv viral therapy can result in regression of splenic marginal zone lymphoma [9]. Patients with HCV infection also develop abnormalities in peripheral cell counts. A large study analyzing data collected in the third National Health and Nutrition Examination Survey (NHANES III) found that patients with HCV, as determined by the presence of anti-hcv antibodies, are more likely than those in the general public to have neutropenia and thrombocytopenia [10]. The mechanism of these VC 2009 Wiley-Liss, Inc. cytopenias is unclear, but has been proposed to involve hypersplenism or autoimmune processes [11]. In addition, many of the current antiviral medications, such as ribavirin and interferon gamma, are known to cause cytopenias [12 14]. Although there is speculation that HCV infection can itself cause cytopenias [15], no study to date has evaluated the bone marrow findings of patients with HCV infection. Here, we report on the spectrum of bone marrow histomorphologic features in 47 monoinfected patients with chronic hepatitis C infection in an institutional retrospective analysis. Methods Case selection and HCV documentation. This study was approved by the Washington University School of Medicine Institutional Review Board. A search of the database of the Division of Anatomic and Molecular Pathology at the Washington University School of Medicine was conducted for patients over the age of 18 with hepatitis C infection who underwent a bone marrow evaluation in a 10-year period from 1998 to early This generated a list of 71 patients. Exclusions were: (1) Additional supporting information may be found in the online version of this article. 1 Department of Pathology and Immunology, Washington University School of Medicine, Saint Louis, Missouri; 2 Department of Gastroenterology, Hepatology Division, Washington University School of Medicine, Saint Louis, Missouri Conflict of interest: Nothing to report. *Correspondence to: John L. Frater, Department of Pathology and Immunology, Washington University School of Medicine, Box South Euclid Avenue, St Louis 63110, MO. jfrater@wustl.edu Received for publication 22 September 2009; Revised 12 November 2009; Accepted 13 November 2009 Am. J. Hematol. 85: , Published online in 1 December 2009 Wiley InterScience ( wiley.com). DOI: /ajh American Journal of Hematology 106

2 no documented history of hepatitis C infection; (2) coinfection with human immunodeficiency virus (HIV); (3) evidence of acute hepatitis B infection with seropositivity to HB S antigen or HB core IgM; (4) positive IgM hepatitis A antibody; (5) lack of suitable bone marrow material for evaluation. Using these criteria, 47 patients were identified with documented anti-hcv antibodies (n 5 42) and/or HCV-RNA detected by PCR (n 5 34). Laboratory parameters. Complete blood count (CBC) values were available for all but one patient and all reported CBC values were obtained within one week of the bone marrow biopsy. Additional laboratory values were also obtained within 2 weeks of the bone marrow biopsy. The MELD score, or Model for End-Stage Liver Disease, was calculated at According to records, no patient underwent dialysis within 2 weeks of bone marrow biopsy. Bone marrow analysis. Thirty-nine of the 47 patients had both a bone marrow core biopsy and aspirate smear for diagnostic interpretation; two had only a suitable aspirate and six had only a core biopsy. The cases were blinded and reviewed by two pathologists (JMK and JLF). Each case was evaluated for cellularity, dysplasia, malignancy, lymphocytosis, plasmacytosis, and myeloid:erythroid ratio. A complete cellular differential (500 cells) was performed on each case in which an aspirate was available. A diagnosis of dysplasia was made when signs of dyspoiesis in the erythroid lineage (nuclear irregularities, nuclear budding, internuclear bridging), myeloid lineage (abnormal lobation and/or granulation), and/or megakaryocytic lineage (small hypolobated forms, multinucleated forms) were present in greater than 10% of cells within each lineage, in accordance with current World Health Organization criteria [16,17]. A Prussian blue iron stain was available on the aspirate smears in 24 cases. These smears were blinded and reviewed by JMK and JLF. Iron stores were graded according to the method of Rath and Finch and aspirate smears were deemed adequate if greater than seven particles were present for evaluation [18,19]. Statistical analysis. Statistical significance was assessed using the student t-test with a two-tailed distribution for numeric clinical values. Two-by-two contingency tables and Fisher s exact test, two tailed, were used for categorical variables. Results The 47 eligible patients (M:27; F:20) were predominantly Caucasian (n 5 35); the remainder were African-American (n 5 11) or Hispanic (n 5 1). The mean patient age at the time of bone marrow biopsy was 51 years (range: years). According to the clinical history provided at the time of bone marrow biopsy, the most common indication for bone marrow evaluation was an abnormality in one or more cell lineages with 39 patients having at least an isolated cytopenia. Five patients presented for lymphoma workup, three of whom underwent a bone marrow biopsy for staging of a previously diagnosed non-hodgkin lymphoma (follicular lymphoma, marginal zone lymphoma, and chronic lymphocytic leukemia/ small lymphocytic lymphoma) while the other two had clinical concern for lymphoma. Lastly, three patients were being evaluated for a plasma cell neoplasm due to elevated globulin levels or lytic bone lesions. Laboratory parameters CBCs were available for 46 of the 47 patients and the mean values are present in Table I. Twenty-four (53%) patients presented with leukopenia (WBC < /L) while four had a leukocytosis (WBC > /L). Eighteen patients had an absolute neutrophil count (ANC) under /L. Thirty-eight (83%) patients were anemic based on our institutional range (hemoglobin < 12.1 g/dl) and 26 patients (57%) had hemoglobin levels of less than 10 g/dl. Thirty-two (70%) patients were thrombocytopenic based on our institutional range (platelet count < /L); 29 (63%) had a platelet count under /L and 16 (35%) had a platelet count under /L. For the purpose of this study and in accordance with World Health Organization (WHO) standards [16], cytopenias are TABLE I. Clinical and Laboratory Features (Mean Values) of 47 HCV Patients Who Underwent a Bone Marrow Biopsy for Hematologic Evaluation Age (years, mean) 51.2 Cirrhosis (n 5 40) 26 Antiviral therapy 7 Splenomegaly (n 5 39) 30 Hepatic function, mean values Bilirubin-Total (mg/dl) 1.6 Alk.Phosphatase (IntUnits/L) ALT (IntUnits/L) 50.3 INR 1.3 MELD 12.1 Hematologic parameters, mean values WBC (310 9 /L) 5.0 Neutrophils (310 9 /L) 3.3 Lymphocytes (310 9 /L) 1.1 Monocytes (310 9 /L) 0.5 RBC (310 6 /L) 3.2 Hemoglobin (g/dl) 10.1 MCV (fl) 92.0 Platelet (310 9 /L) research article ALT, alanine aminotransferase; INR, international normalized ratio; MELD, model for end-stage liver disease; WBC, white blood cell count; RBC, red blood cell; MCV, mean corpuscular volume. defined as a hemoglobin under 10 g/dl, a platelet count under /L and/or an absolute neutrophil count under /L [20]. Using these standards, six patients had pancytopenia, 21 had a bicytopenia, and 14 had an isolated cytopenia at the time of bone marrow biopsy. Serologic markers of liver function and the MELD score are also listed in Table I. Cryoglobulin levels, viral loads, and HCV genotype were only available for a small subset of the patients, precluding a thorough evaluation. Antiviral treatment occurred within 6 months of bone marrow biopsy in seven patients. Six were taking combined interferon-ribavirin, and the seventh was on interferon monotherapy. The presence or absence of organomegaly was determined by abdominal imaging, as only a subset of patients had documented liver biopsies. Thirty of the 39 patients with a radiographic assessment of spleen size had evidence of splenomegaly, with the largest spleen measuring over 23 cm in greatest dimension. Twenty-six of the 40 patients with liver imaging studies demonstrated findings of cirrhosis. Twelve patients had a liver biopsy and five patients underwent an orthotopic liver transplant for endstage liver disease; hepatocellular carcinoma was documented in one case. Material from 11 patients was available for independent review and strong correlation was present with the radiographic findings. Bone marrow findings Two patients presented with acute myeloid leukemia (AML), not otherwise specified (Figure 1). A third patient, also diagnosed with AML, had a history of myelodysplastic syndrome (MDS) and demonstrated significant multilineage dysplasia in the aspirate smear in addition to increased blasts; this AML is best classified as an acute myeloid leukemia with myelodysplasia-related changes. Two patients had involvement by a clonal plasmacytosis involving 16% and 22% of the bone marrow with diagnoses of asymptomatic (smouldering) plasma cell myeloma and POEMS syndrome, respectively. Another patient had extensive involvement by previously diagnosed chronic lymphocytic leukemia/small lymphocytic lymphoma (CLL/SLL), which was supported by flow cytometry. Two patients had confirmed myelodysplastic syndromes refractory anemia with excess blasts-1 (RAEB-1) and myelodysplastic syndrome, unclassifiable (MDS-U). The latter patient had persistent pancytope- American Journal of Hematology 107

3 research article TABLE II. Spectrum of Bone Marrow Findings in 47 HCV-Infected Patients Bone marrow findings Cellularity (n 5 45, mean) 50.5% Erythroid hyperplasia 12 Megakaryocytic hyperplasia 4 Lymphoid aggregates (n 5 45) 14 Hemophagocytosis 1 Acute myeloid leukemia 3 RAEB-1 1 MDS-U 1 CMML 1 Clonal lymphocytosis 2 Plasma cell neoplasm 2 Dyserythropoiesis 10 Multilineage dysplasia 4 Aplastic anemia 0 Anemia of chronic disease 4 RAEB-1, refractory anemia with excess blasts-1; CMML, chronic myelomonocytic leukemia; MDS-U, myelodysplastic syndrome, unclassifiable. Dysplasia is defined by current WHO criteria (>10% of precursors). TABLE III. Results of Available Bone Marrow Cytogenetic Studies of HCV-Infected Patients with Bone Marrow Abnormalities Patient Conventional cytogenetics Bone marrow diagnosis Figure 1. Spectrum of bone marrow findings in patients with HCV. A: multiple lymphoid aggregates with immunophenotype consistent with CLL/SLL (hematoxylin and eosin, original magnification 3200); (B) plasma cell dyscrasia (Wright-Giemsa, original magnification 31000); (C) hemophagocytosis with multilineage dysplasia (Wright- Giemsa, original magnification 31000); (D) refractory anemia with excessive blasts (RAEB-1) (Wright-Giemsa, original magnification 31000); (E) acute myeloid leukemia (FAB-M5a) (hematoxylin and eosin, original magnification 3400); (F) bone marrow dyserythropoiesis (Wright-Giemsa, original magnification 31000). [Color figure can be viewed in the online issue, which is available at 35/M 42 46,XY,i(7)(q10)[cp4]/43 46,XY, Acute myeloid leukemia i(7)(q10), 1 20[cp8]/46,XY [8] 63/M 48, XY, 23, 1der (9)t(5;9)(q13;p24) Acute myeloid leukemia der(12)t(?;12)(?;p13),111, 114 [11]/46,XY[9] 20/M 42 43,XY,del(2)(p13),add(2)(q33),23, 25,add(15)(p13), 217,der(20)t(17;20) (p12;q12) [2] Acute myeloid leukemia with myelodysplasia related changes 56/M 43 46,XY,del (4)(q22q27) [20] Chronic myelomonocytic leukemia 38/M 46,XY [20] Multilineage dysplasia and hemophagocytosis 45/F 46,XX,der(1;15)(q10;q10) [2]/46,XX [13] Myelodysplastic syndrome, unclassifiable 52/M 46,XY [20] Dyserythropoiesis 47/M 46,XY [20] Refractory anemia with excess blasts-1 61/F 46,XX [20] Multilineage dysplasia nia, isolated dyserythropoiesis and a cytogenetics study demonstrating der(1;15)(q10;q10), a rare abnormality that has been observed in myeloid neoplasias, including MDS [21]. See Table II for summary of the bone marrow findings and Table III for full cytogenetic details. Another patient with multilineage dysplasia had marrow monocytosis with a history of a prolonged peripheral monocytosis, consistent with chronic myelomonocytic leukemia (CMML). This patient also had involvement by clonal B-cell population (approximately 2% of marrow cellularity), suggestive of a concurrent lowgrade B-cell lymphoproliferative disorder. Evaluation of the remaining 38 specimens showed a mean bone marrow cellularity of 48% (range 20 80%). Twelve patients had erythroid hyperplasia, as defined by greater than 35% nucleated red blood cell precursors in bone marrow. Only four patients had megakaryocytic hyperplasia. The megakaryocytes in these cases demonstrated a mild increase in immature forms along with no significant megakaryocyte clustering. Five patients had a marrow lymphocytosis (greater than or equal to 15% marrow lymphocytes). Significant fibrosis was not observed and reticulin stains were not routinely performed. Dyserythropoiesis, as defined by morphologic changes in at least 10% of the erythroid precursors, was present in six additional patients without evidence of a cytogenetic abnormality or increased blasts. Thus 10 patients in total, including the previously mentioned patient with AML with myelodysplasia-related changes, demonstrated significant dyserythropoiesis. Interestingly, dyserythropoiesis at lower levels (between 5 and 10% of precursors) was present in an additional seven patients. Thus, 17 of the 47 patients (36.0%) had morphologic abnormalities in the erythroid lineage. Two of the six patients with unexplained dyspoiesis had resolution of their peripheral cell count abnormalities over time, which is inconsistent with a primary MDS. One of these patients originally present with multilineage dysplasia, pancytopenia and marked hemophagocytosis and his counts normalized after starting antiviral therapy. A third patient presented with isolated thrombocytopenia and had a bone marrow study notable for isolated dyserythropoiesis and megakaryocyte hyperplasia. The patient clinically had moderate splenomegaly and we favor his thrombocytopenia is likely secondary to hypersplenism rather than a clonal bone marrow disorder. The remaining three patients had complete blood cell counts performed at least a year after the bone marrow study without resolution of their cytopenias. Fourteen of the 45 (31%) bone marrow core biopsies had lymphoid aggregates, eight of which demonstrated a polyclonal B cell population by flow cytometry. In total, with the exception of the aforementioned two cases demonstrating clonal B cell populations (patients with CMML and CLL/ SLL), flow cytometry demonstrated a polytypic pattern in 15 cases. Of the five cases that had a lymphocytosis by manual differential without a diagnosis of lymphoma, the morphologic and/or immunophenotypic features were consistent with a reactive lymphocytosis. In addition, flow cytometry demonstrated plasma cell clonality in the two aforementioned cases with a plasma cell neoplasm while 108 American Journal of Hematology

4 two additional cases with a mild plasmacytosis had polytypic plasma cell populations. Bone marrow examination: Prussian blue iron stain Seven of the 24 patients with an available iron stain had decreased iron stores (score of 0 or 1); however, one of these smears was inadequate due to fewer than seven particles present for evaluation. Six patients had increased storage iron (score of 4 or greater) and the rest of the aspirates showed normal bone marrow iron stores. Four of the six patients with increased bone marrow storage iron had serum iron levels less than 50 mcg/dl and ferritin levels greater than 400 ng/ml, consistent with anemia of chronic disease (Supporting Information Table I) [22]. These four patients lacked significant bone marrow dysplasia. Ringed sideroblasts were prominent in one additional case; however, this case lacked bone marrow dysplasia and the underlying etiology of the ringed sideroblasts in this case is unclear. TABLE IV. Clinical Features of HCV-Infected Patients with and Without Bone Marrow Dysplasia Without dysplasia (n 5 32) With dysplasia (n 5 9) P value Age, mean (years) Cirrhosis 17/26 (65%) 5/8 (63%) Antiviral therapy 4/31 (13%) 2/9 (22%) Splenomegaly 21/26 (81%) 5/8 (63%) Hematologic parameters, mean values WBC (310 9 /L) Neutrophils (310 9 /L) Lymphocytes (310 9 /L) Monocytes (310 9 /L) RBC (310 6 /L) Hemoglobin (g/dl) MCV (fl) Platelets (310 9 /L) Bone marrow parameters, mean values (range) Bone marrow cellularity (%) 46.6 (20 70) 57.8 (20 90) Blasts (%) 0.6 (0 2) 1.3 (0 8) Promyelocytes (%) 4.3 (0 8) 4.6 (0 10) Myelocytes (%) 9.6 (4 20) 12.6 (1 21) Metamyelocytes (%) 10.7 (6 21) 9.6 (1 17) Bands/PMNs (%) 26.2 (9 44) 12.3 (3 29) <0.001 Erythroids (%) 32.4 (15 54) 49.3 (27 82) Lymphocytes (%) 8.4 (3 21) 6.5 (2 10) Plasma cells (%) 2.2 (0 7) 1.9 (0 6) Hepatic function, mean values Bilirubin-total (mg/dl) Alk.Phosphatase (IU/L) ALT (IU/L) INR MELD WBC, white blood cell count; RBC, red blood cell; MCV, mean corpuscular volume; PMNs, neutrophils; ALT, alanine aminotransferase; INR, international normalized ratio; MELD, model for end-stage liver disease. Patients with involvement by leukemia, lymphoma, or a plasma cell neoplasm were excluded from analysis. Dysplasia is defined by current WHO criteria (>10% of precursors). research article Association of clinical/laboratory findings and bone marrow findings Of the six patients with pancytopenia, two had AML and another had MDS-U. No patients had aplastic anemia. No significant differences in the peripheral cell counts, bone marrow cellularity or markers of chronic liver disease were observed (Table IV) when comparing the patients with dysplasia (n 5 9) to those patients whose bone marrow biopsy showed no significant dysplasia (n 5 32). The six patients with AML, CLL/SLL or a plasma cell neoplasm were excluded from this analysis. Manual 500-cell differential counts on the bone marrow aspirates demonstrated a significant decrease in the myeloid to erythroid ratio in the patients with dysplasia. The patients with dysplasia also had higher mean corpuscular volume (98.0 fl versus 88.8 fl; P ), likely a result of megaloblastoid changes. No significant differences were appreciated in the patients with and without splenomegaly (Table V). In addition, the seven patients with confirmed antiviral therapy did not show a difference in peripheral cell counts or in bone marrow dysplasia relative to those without antiviral treatment. Interestingly, seven patients without splenomegaly or documented antiviral medication were identified; one patient had multilineage dysplasia, one had AML and another had POEMS syndrome. Lastly, no differences in the hematologic parameters or bone marrow findings were present when separating patients on their MELD score, or Model for End-Stage Liver Disease, which is an assessment of the extent of liver disease based on biochemical data [23 25] (Supporting Information Table II). Discussion Patients with HCV infection can develop peripheral blood cell count abnormalities that are commonly attributed to hypersplenism, antiviral therapy, decreased thrombopoietin levels, and/or autoimmune mechanisms [11,26 28]. Some of these patients may undergo a bone marrow biopsy for hematologic evaluation, yet to our knowledge the effects of HCV infection on the bone marrow have not been systematically evaluated. Here, we present the first study to investigate the spectrum of bone marrow findings in a large cohort of patients with HCV infection that lack concurrent HIV infection. A wide range of hematologic abnormalities was noted in this group, with dyserythropoiesis being the most common. The bone marrow findings in this selected cohort of HCV patients are present irrespective of splenomegaly, antiviral medications, and MELD score. As shown in this study, cytopenias occurring in the absence of splenomegaly and/ or antiviral medications may be explained by bone marrow abnormalities, establishing a bone marrow biopsy as a viable tool to evaluate marked or unexplained pancytopenias in patients with known HCV infection. The results of this study also suggest that bone marrow dysfunction is independent of the stage or extent of liver fibrosis. However, TABLE V. Hematologic Findings of HCV-Infected Patients: Influence of Splenomegaly and Antiviral Medications Splenomegaly (n 5 30) No Splenomegaly (n 5 9) P Antiviral Therapy (n 5 7) No Antiviral Therapy (n 5 40) P WBC, mean (310 9 /L) Neutrophils, mean (310 9 /L) Lymphocytes, mean (310 9 /L) Monocytes, mean (310 9 /L) Hemoglobin, mean (g/dl) Platelets, mean (310 9 /L) Bone marrow dysplasia 6/30 (20%) 2/9 (22%) /7 (29%) 8/40 (20%) Table includes all 47 patients included in this study. Dysplasia is defined by current WHO criteria (>10% of precursors). American Journal of Hematology 109

5 research article due to the paucity of liver biopsies in this cohort due to the majority of the cases having irrefutable clinical evidence of cirrhosis, an association or lack thereof between bone marrow abnormalities and grade of necroinflammation in the liver cannot be assessed. Although the association between HCV and B-cell lymphomas is well known, it is unclear from this study if HCVinfected patients are more prone to develop myelodysplasia, as only a small percentage of these patients undergo a bone marrow biopsy (Lisker, unpublished results). Thus, the patient population in this study is not representative of all HCV-infected patients and inferences on the incidence of bone marrow neoplasms, including MDS, in HCVinfected patients is not possible. In addition, the possibility remains that the morphologic changes seen in these cases, especially those with low levels of dysplasia or those that lack increased blasts or cytogenetic abnormalities, may be due to a non-neoplastic response to chronic infection rather than a bone marrow neoplasm. This concern is supported by two lines of evidence: (1) dyspoiesis is also a common finding in the bone marrow of patients with other viral infections, such as HIV [29 32] and (2) three of the six patients in this study with significant dysplasia either had peripheral cell count resolution over time or isolated cytopenias clinically explained by hypersplenism. The remaining three patients represent a challenging group of patients in which an underlying myelodysplastic syndrome cannot be definitely ruled out. Another possibility is that HCV infection directly leads to dysmyelopoiesis, considering that HCV virion has been detected in the bone marrow of chronically infected HCV patients [33,34] as well as in peripheral circulating mononuclear cells [35,36]. Unfortunately, techniques for investigating HCV infection and replication from formalin fixed paraffin-embedded tissue are not universally accepted and are not part of routine clinical practice. Here, we present a retrospective review of bone marrow findings of 47 adult patients with hepatitis C virus infection. Our cohort of HCV-infected individuals frequently displayed varying degrees of bone marrow dysplasia, similar to that seen in other chronic viral infections. The bone marrow findings are independent of the degree of liver fibrosis and cirrhosis, splenomegaly, MELD score, and antiviral medications. These findings suggest that the bone marrow dysfunction is likely an additional factor for clinicians to consider when evaluating a HCV-infected individual with abnormal peripheral cell counts. Acknowledgments The authors thank Brent Tetri MD and Julie Gutierrez for their assistance in obtaining clinical history important for this study. References 1. Baldo V, Baldovin T, Trivello R, Floreani A. Epidemiology of HCV infection. Curr Pharm Des 2008;14: Alter MJ, Kruszon-Moran D, Nainan OV, et al. The prevalence of hepatitis C virus infection in the United States, 1988 through N Engl J Med 1999; 341: Choo QL, Kuo G, Weiner AJ, et al. Isolation of a cdna clone derived from a blood-borne non-a, non-b viral hepatitis genome. Science 1989;244: Chang KM. Immunopathogenesis of hepatitis C virus infection. Clin Liver Dis 2003;7: Mehta S, Levey JM, Bonkovsky HL. Extrahepatic manifestations of infection with hepatitis C virus. Clin Liver Dis 2001;5: De Re V, De Vita S, Marzotto A, et al. Pre-malignant and malignant lymphoproliferations in an HCV-infected type II mixed cryoglobulinemic patient are sequential phases of an antigen-driven pathological process. Int J Cancer 2000;87: Ivanovski M, Silvestri F, Pozzato G, et al. Somatic hypermutation, clonal diversity, and preferential expression of the VH 51p1/VL kv325 immunoglobulin gene combination in hepatitis C virus-associated immunocytomas. Blood 1998;91: Nieters A, Kallinowski B, Brennan P, et al. Hepatitis C and risk of lymphoma: results of the European multicenter case-control study EPILYMPH. Gastroenterology 2006;131: Hermine O, Lefrere F, Bronowicki JP, et al. Regression of splenic lymphoma with villous lymphocytes after treatment of hepatitis C virus infection. N Engl J Med 2002;347: Streiff MB, Mehta S, Thomas DL. Peripheral blood count abnormalities among patients with hepatitis C in the United States. Hepatology (Baltimore, MD) 2002;35: Afdhal N, Mchutchison J, Brown R, et al. Thrombocytopenia associated with chronic liver disease. J Hepatol 2008;48: Fried MW, Shiffman ML, Reddy KR, et al. Peginterferon alfa-2a plus ribavirin for chronic hepatitis C virus infection. N Engl J Med 2002;347: Maddrey WC. Safety of combination interferon alfa-2b/ribavirin therapy in chronic hepatitis C-relapsed and treatment-naive patients. Semin Liver Dis 1999;19 (Suppl 1) Manns MP, Mchutchison JG, Gordon SC, et al. Peginterferon alfa-2b plus ribavirin compared with interferon alfa-2b plus ribavirin for initial treatment of chronic hepatitis C: a randomised trial. Lancet 2001;358: Dieterich DT, Spivak JL. Hematologic disorders associated with hepatitis C virus infection and their management. Clin Infect Dis 2003;37: Swerdlow SH,Campo E,Harris NL,Jaffe ES,Pileri SA,Stein H,Thiele J, editors.. WHO classification of tumours of the haematopoietic and lymphoid tissues. Lyon: IARC; Rosati S, Mick R, Xu F, et al. Refractory cytopenia with multilineage dysplasia: Further characterization of an unclassifiable myelodysplastic syndrome. Leukemia 1996;10: Barron BA, Hoyer JD, Tefferi A. A bone marrow report of absent stainable iron is not diagnostic of iron deficiency. Ann Hematol 2001;80: Hughes DA, Stuart-Smith SE, Bain BJ. How should stainable iron in bone marrow films be assessed? J Clin Pathol 2004;57: Greenberg P, Cox C, Lebeau MM, et al. International scoring system for evaluating prognosis in myelodysplastic syndromes. Blood 1997;89: Wong KF, Hayes KJ, Glassman AB. Der(1;15)(q10;10): A nonrandom chromosomal abnormality of myeloid neoplasia. Cancer Genet Cytogenet 1995;83: Means RT, Krantz SB. Progress in understanding the pathogenesis of the anemia of chronic disease. Blood 1992;80: Kamath PS, Wiesner RH, Malinchoc M, et al. A model to predict survival in patients with end-stage liver disease. Hepatology (Baltimore, MD) 2001;33: Malinchoc M, Kamath PS, Gordon FD, et al. A model to predict poor survival in patients undergoing transjugular intrahepatic portosystemic shunts. Hepatology (Baltimore, MD) 2000;31: Wiesner R, Edwards E, Freeman R, et al. Model for end-stage liver disease (MELD) and allocation of donor livers. Gastroenterology 2003;124: Zhang W, Nardi MA, Borkowsky W, Li Z, Karpatkin S. Role of molecular mimicry of hepatitis C virus protein with platelet GPIIIa in hepatitis C-related immunologic thrombocytopenia. Blood 2009;113: Garcia-Suarez J, Burgaleta C, Hernanz N, et al. HCV-associated thrombocytopenia: clinical characteristics and platelet response after recombinant alpha2b-interferon therapy. Br J Haematol 2000;110: Adinolfi LE, Giordano MG, Andreana A, et al. Hepatic fibrosis plays a central role in the pathogenesis of thrombocytopenia in patients with chronic viral hepatitis. Br J Haematol 2001;113: Harris CE, Biggs JC, Concannon AJ, Dodds AJ. Peripheral blood and bone marrow findings in patients with acquired immune deficiency syndrome. Pathology 1990;22: Mir N, Costello C, Luckit J, Lindley R. HIV-disease and bone marrow changes: A study of 60 cases. Eur J Haematol 1989;42: Schneider DR, Picker LJ. Myelodysplasia in the acquired immune deficiency syndrome. Am J Clin Pathol 1985;84: Sun NC, Shapshak P, Lachant NA, et al. Bone marrow examination in patients with AIDS and AIDS-related complex (ARC). Morphologic and in situ hybridization studies. Am J Clin Pathol 1989;92: Lerat H, Rumin S, Habersetzer F, et al. In vivo tropism of hepatitis C virus genomic sequences in hematopoietic cells: Influence of viral load, viral genotype, and cell phenotype. Blood 1998;91: Sansonno D, Iacobelli AR, Cornacchiulo V, et al. Detection of hepatitis C virus (HCV) proteins by immunofluorescence and HCV RNA genomic sequences by non-isotopic in situ hybridization in bone marrow and peripheral blood mononuclear cells of chronically HCV-infected patients. Clin Exp Immunol 1996;103: Gowans EJ. Distribution of markers of hepatitis C virus infection throughout the body. Semin Liver Dis 2000;20: Tian D, Yang D, Wang W, et al. Extrahepatic and intrahepatic replication and expression of hepatitis C virus. J Tongji Med Univ 1998;18: American Journal of Hematology