372
P-0938
Poster Sessions / Parasitology International 47 (SuppL) (1998) 283-389 iMPROVEDDIAGNOSIS OF TOXOPLASMOSIS ACQUIRED DURING PREGNANCY BY DETERMINATION OF SPECIFIC IgG AVIDITY
Lo~a.r JTNovak-Antotie2,~ore A'* *Institute of Ivficrobiologyand Immunology, Medical Faculty, University of Ljubljmm, Slovenia **Department of C.o,naecoingy and Obstetrics, Medical Centre Ljubljana, Slovenia In esxly pregnancy, it is sometimes difficult to estimate the time of acquisition of toxopla~la infection. The toxoplasma specific IgM, IgA and high titer of indirect f l ~ t IgG antibody (HA) test may have been present before the start of pregnancy and consequently, the fetus is protected against infection. To either confu'm or exclude toxoplasma wimaw infection in early regnancy we tested additionaly all suspected acute toxopissma sera using the specific IgG avidity enzyme immuonassay (EIA). This method, introduced in 1989 by Hedman et al. is based on the strength of the binding of specific IgG to multivalent toxoplasma antigen. The binding strength, called IgG avidity, was found to be low in the firm phase atter primary infection but then to increase with time. Eighty-five results of the IgG IFA test, EIA Plateiia Toxo IgM and EIA Plateha Toxo IgA (Sanofi Pasteur) obtained in a period of 10 to 20 weeks of pregnancy were compared with those obtained in the same sera using EIA Toxo IgG avidity, kit BEIA by Bonty. Fourteen sera of pregnant women, 4 with seroconversion and 10 with a fourfold or greater inorease in IFA titer, IgM and/or IgA positive, showed low < 15 % IgG avidity (average of 7 %), indicating acute primary infection. Of 71 serum samples with high stable IFA titer (h>i024) and/or positive Ig~vi,lgA results, suggesting a possible recent toxoplasma infection in pregnancy, 52 (73.2 %) had an IgG avidity > 25% (average of 51%). The established high lgG avidity excluded the acquisition of primary toxoplamm infection in early pregnancy, indicating that the infection had occused more than 20 weeks earlier. An avidity of value between 15 to 25% (average of 19.6 %) found in 17 (23.9 %) sera suggested that primary infection may have occured within the previous 6 months. Only two of 71 (2.8%) sera showed low < 15 % (average of 11%) IgG avidity, indicating recent primary infection in pregnancy. This additional test makes it possible to distinguish primary infection and infection that oconred prior to pregnancy in many toxoplasma screened pregnant women who otherwise on the basis of hJgh IFA titer and a positive specific IgM, IgA results, would have been identified as having a recent infection. Thanks to the results of this test many of these women will avoid unnecesary further examinations, treatment and anxiety.
P-0940
Sluiters JF, Hofman D, Vogel M, Luijendijk A Department of Medical Microbiology and Infectious Diseases, Erasmus University Medical Center Rotterdam, Rotterdam, The Netherlands, E mail:
[email protected] From 1984 onwards 321 heart transplant recipients were monitored for Toxop/asma gondii infection. In addition to a combined use of an indirect ELISA for igG and IgM (on serum IgM fraction), an antibody capture ELISA for IgM, Western Blot to detect specific IgG, IgM and/or IgA was applied. Immunoblotting was carried out with reduced antigen and 13 % SDS-PAGE separating gel. Seronegative recipients of the heart of a Toxoplasma seropositive donor received pyrimethamine as prophylaxis. Eadier observations showed in about 74% of the recipients significant changes in antibody concentration, either by an increase in antibody titre or by seroconversion. However, clinical disease rarely developed in recipients already seropositive for Toxoplasma, but in these cases, amongst others, 6 kD igG antttoxoplasma antibodies did appear. 104 (32%) of the 321 recipients were seronegative by ELISA for T. gondii at the time of surgery. Outside documented pdmery infections also other seronegative recipients seroconverted. On the other hand, recipients with preexisting ELISA-IgG levels did drop below threshold values dunng vanabie periods of time. However, IgG antibody profiles consistently showed the presence of 33-35 kD antitoxoplasma antibodies. Immunoblotting revealed that seroconverstons are not necessadly an indication for pdmary infection. These observations did lead to a wider application of immunoblotting to detect an anti 6 kD and 33-35 kD response in sera of patients suspected for an active T. gondii infection.
P-0941
P-0939
PEROXIDASE ANTIPEROXIDASE AND SEROLOGY FOR DIAGNODSIS OF TOXOPLASMOSIS ASSOCIATED WITH LYMPHADENOPATHIES Safar ~ , Azab M**, Khalil H**, Farag-Allah N*, Mokhtar N *Research Institute of Ophthalmology, **Ain Shams University, Parasitology Department, and Cancer Institute Cairo University • Pathology Department, Egypt The aim of this study was to Iocalise Toxoplasmaantigen by Peroxidaze Antiperoxidaze (PAP) in various reactive and malignant lymphadenopathies in processed paraffin embedded biopsies. An attempt was made in some cases to correlate the resutls of PAP with IFAT IgG and IgM. Immunohistochemical staining by immunoperoxidaze method was done on paraffin embedded lymph node biopsies from 3 groups of patients, Hodgkin's lymphoma (HL), non Hodgkin'slymphoma (NHL), and reactive hyperplasia(RH), total ofg0 cases. Results revealed that the persentage positivity of PAP was 23% in (HL), and 33.3% in (3FILL) and (RH), while IFAT-IgG gave 80.0%, 81.8% and 52.4% positivity in the 3 groups of patients. On conclusion the sensitivity of PAP and serology for diagnosing associated Toxoplasma infection in HL, NHL and RH groups showed that serology proved more sensitive than PAP.
TOXOPLASMA GONDII INFECTIONS IN HEART TRANSPLANT RECIPIENTS: LONG-TERM FOLLOWUP BY IMMUNOBLO'I-FING
SERODIAGNOSIS OF ACUTE TOXOPLASMOSIS IN PREGNANT W O M E N IN M A C E D O N I A
Krsteva E.*, Hristovski N.**, Jankova O.*, Talevski R.***, Krstev e.~* * Institute for health protection o f Bitola, Macedonia, **Agricultural college - Bitola, ***Medical centre - Bitola, Macedonia The infection with T. gondii in pregnancy is important clinical problem. The earlier fetal infection occurs, the risk o f td~ortion and fetal damage is greater. The aim of this study is to determine the risk o f acute toxoplasmosis in pregnancy.Our research includes serological testing of 308 pregnant women in 2 years period (1996/97) w h o ' v e had abortion, premature birth or fetal damage. Specimens were tested in 4 methods: ELISA Ig M and l g Cr(Human), ISAGA(BioMerieux) and IFA (INEP). With ELISA Ig M were found positive 24(7,8%) specimens, negative 27,6(89,6%) and 8(2,6%) specimens with indetermined values (equivocal). Positive with l S A G A were found 19(6,2%) specimens (index>9), negativ 282 (91,5%) specimens (index<5) and 7(2,3%) specimens have had indetermined values (index 6-8). Positive with ELISA l g G were found 64(20,9°6) (>51U), negative 244(79,2%) specimens. With IFA were found 76(24,70,6) positive ( > h i 6 0 ) , 12(3,9%) specimens were with indetermined fitter (1:80) and 220(71,4%) specimens were negative (tittet<1:80). Positive titters only in Ig M antibodies, with the two methods in repetitive samples were found at 3(0,9%) women- recent infection. Positive fitter o f Ig M and Ig G antibodies at 21(6,8%)-pestacute phase in also 52(16,9OA) were found only Ig G antibodies what indicates the immune status to toxoplasmosis. The results indicate that the primary toxoplasmnsis in pregnancy is important reason for abortion, premature birth and fetal damage (7,8%).