EBV serology: Simplicity through complexity

Transcription

1 EBV serology: Simplicity through complexity Georg Bauer Abteilung Virologie Universität Freiburg Germany

2 Specific EBV serology is required, as the symptoms of clinically apparent EBV infection may be overlapping with those of many other diseases.

3 The serological response to EBV infections is highly variable. Determination of the classical markers does not allow to draw the right conclusions in each individual case!

4 The next graphs demonstrate the problems of EBV serodiagnosis.

5 MISSING VCA-IGM MISSING ANTI-EBNA-1 PERSISTENT VCA-IGM

6 EBV serology using immunofluorescence in 3622 unselected cases Number of sera 3622 Seronegative 222 (6.1 %) Anticellular reactivity 151 (4.1 %) VCA-IgG positive 3245 Anti-EBNA-1 positive 284 (86.4 %) Anti-EBNA-1 negative 441 (13.6 %) acute EBV infections 239 past EBV infections with 22 missing or lost Anti-EBNA-1

7 PROBLEMS OF CLASSICAL EBV-SEROLOGY Acute infections without detectable VCA-IgM Persisting VCA-IgM (false positive result) Lack of Anti-EBNA-1 in 6 % of persons with past EBV infection Secondary loss of Anti-EBNA-1 during immunosuppression Problem of anticellular reactivity

8 The immunoblot with recombinant antigens (Mikrogen) represents a quantitative system

9 Immunoblot The with RecomLine recombinant assay antigen is suitable represents for a quantitation quantitative system

10 PROBLEM OF ANTICELLULAR REACTIVITY RESOLVED

11 p18-igg: A second late marker IgG antibodies against recombinant p18 from a specifically modified clone (patented by Mikrogen) become detectable late in infection and thus represent a second late marker (analogous to p72-igg). Detection of IgG against this modified p18 thus allows diagnosis of past EBV infections even in those cases that do not develop p72-igg (Anti-EBNA-1). p54-igg p18-igg p23-igg p138-igg p72-igg DAYS AFTER ONSET OF DISEASE

12 IMMUNOBLOT AND LINEASSAY ALLOW AVIDITY DETERMINATION

13 CLASSICAL SEROLOGY OF EBV INFECTIONS Abb. 4: Idealisierter Verlauf der IgG-Antwort DETERMINED bei a kute BY r EBV-Infektion THE EBV RECOMLINE ASSAY (MIKROGEN) c p72 p18 p23 p138 p54 Tage Woc hen Monate DAYS WEEKS MONTHS + + HS UREA + + HS UREA + + HSUREA + HS + UREA + HS + UREA + + HSUREA + + HSUREA

14 EBV INFECTION WITHOUT DEVELOPMENT OF P72-IgG: DIAGNOSIS THROUGH p18 - IgG Abb. 5: Idealisie rter Verlauf der IgG-Antwo rt AND bei akuter AVIDITY EBV-Infektion DETERMINATION ohne p72-igg-bildung c p72 p18 p23 p138 p54 Tage DAYS WEEKS MONTHS Woc hen Monate + UREA HS + UREA HS + UREA HS + + HSUREA + + HS UREA + UREA HS + UREA HS

15 RARE CASE OF EBV INFECTION WITHOUT BOTH LATE MARKERS Abb. 7: Seltener Fall: Ausbleiben beider später Marker (isoliertes p23-igg) c p72 p18 p23 p138 p54 DAYS WEEKS MONTHS Tage Woc hen Monate + + HS UREA + + HS UREA + UREA HS + + HS UREA + + HS UREA + + HS UREA

16 EBV INFECTION WITH DELAYED APPEARANCE OF LATE MARKERS Abb. 6: Idealisierter Verlauf der serologisc hen Antwort bei akuter EBV-Infektion mit verzögerter Entwicklung der späten Marker c p72 p18 p23 p138 p54 Tage DAYS WEEKS MONTHS Woc hen Monate + + HS UREA + + HS UREA + UREA + HS + + HS UREA + + HS UREA + + HSUREA + HS + UREA

17 THANK YOU VERY MUCH!

18 NOW IT IS YOUR TURN!

19 You will now see the optical density reading of several diagnostically interesting cases tested in the EBV RecomLine Assay (IgG). Please make your judgement. We then present the data of the avidity determination (urea treatment, columns marked in black) and the final serological diagnosis. High avidity: less than 5 % of p23- IgG and less than 4 % of p18-igg, p72-igg removed by urea. High avidity is typical for past infection, low avidity is indicative for acute infection.

20 ACUTE OR PAST? hov P72 P18 P23 P138 P54

21 2 PAST INFECTION! BOTH LATE MARKERS PRESENT, HIGH AVIDITY OF p72-, p18- AND p23-igg hov hovh P72 P18 P23 P138 P54

22 15 1 5? P72 P18 P23 P138 P54 G L

23 15 ACUTE EBV INFECTION! LATE MARKERS ARE MISSING AND p23-igg SHOWS LOW AVIDITY G L G LH 1 5 P72 P18 P23 P138 P54

24 ? 2 p72 p18 p23 p138 p54 BZLF-1 VCA-IgG 256 Anti-EBNA-1 negativ

25 PAST EBV INFECTION WITHOUT p72-igg. p18-igg INDICATES PAST INFECTION. CONFIRMATION BY HIGH AVIDITY OF p18- and p23-igg p72 p18 p23 p138 p54 BZLF-1 VCA-IgG 256

26 GUN? P72 P18 P23 P138 P54

27 PAST EBV INFECTION WITHOUT p18-igg. p72-igg INDICATES PAST INFECTION. CONFIRMATION BY HIGH AVIDITY OF p72- and p23-igg. 8 GUN 6 GUNH 4 2 P72 P18 P23 P138 P54

28 TEL VCA-IgG 124 VCA-IgM 6 Anti-EBNA-1 neg.? p72 p18 p23 p138 p54

29 RECENT EBV INFECTION! HIGH AVIDITY OF p23-igg, PRESENCE OF p18-igg WITH LOW AVIDITY VCA-IgG 124 VCA-IgM 6 Anti-EBNA-1 neg. TEL 15 KONTROLLE HARNSTOFF 1 5 p72 p18 p23 p138 p54

30 15 1 5? P72 P18 P23 P138 P54 MAZ

31 PAST INFECTION WITHOUT p72-igg P72 P18 P23 P138 P54 MAZ MAZH

32 SEL 18 Tage später 18 days later? p72 p18 p23 p138 p54 p72 p18 p23 p138 p54 VCA-IgG 512 AI.5 Anti-EBNA-1 neg. VCA-IgG 512 AI.5 Anti-EBNA-1 neg.

33 ACUTE EBV INFECTION WITH DELAYED OR MISSING LATE MARKERS SEL 18 Tage später 15 KONTROLLE CONTROL UR EA HARNSTOFF 15 CONTROL KONTROLLE UR EA HARNSTOFF p72 p18 p23 p138 p54 p72 p18 p23 p138 p54 VCA-IgG 512 AI.5 Anti-EBNA-1 neg. VCA-IgG 512 AI.5 Anti-EBNA-1 neg.

34 8 months later 2 2 haas haas8m p72 p18 p23 p138 p54 p72 p18 p23 p138 p54

35 PAST EBV INFECTION WITHOUT BOTH LATE MARKERS. FREQUENCY: 1 / haas haas8m 15 haash 15 haas8mh p72 p18 p23 p138 p54 p72 p18 p23 p138 p54

36 SUMMARY Immunoblot and Lineassay (using recombinant, purified antigens) : resolve the problems of anticellular reactivity represent quantitative tests, allowing avidity determination. Antibody profiles in acute, recent and past EBV infections: Basic pattern, complicated by stochastics. 2 % of past infections show aberrant serological profiles. The use of a second late marker (p18-igg, Mikrogen EBV RecomLine) resolves the problem of missing or lost Anti-EBNA-1. The use of the late markers p72- and p18-igg, together with p23-, p54- and p138-igg leads to clear serological results even in cases of aberrant serological response. Some cases require avidity determination for final determination.