THE IMPORTANCE OF THE DETECTION OF ANTI-P-30 IGA ANTIBODIES IN ACQUIRED TOXOPLASMOSIS

The study was undertaken to find out whether the detection of the IgA antibodies against T. gondii is a better serological marker of the acu te phase of toxoplasmosis than the detection of IgM. Eighty four serum samples from 70 patients with acquired toxoplasmosis were tested. The duration of the T. gondii invasion was from one week to over one year . IgA antibodies against P30 (SAG1), a major surface protein of T. gon dii, were tested using CLONATEC TOXO A Ab EIA assay. Among 84 sera, th e specific IgM antibodies were found in 82 cases (97.6%) but the IgA a ntibodies were detected in 42 cases (50%), which suggest that they are more time specific. The IgA antibodies start to appear in the sera be tween 2-4 weeks after invasion, i.e. later than those of IgM, and conc omitantly or shortly after IgG. In 65% of cases of very recent infecti ons (less than 4 weeks) IgA antibodies were not detected. The highest values for IgA were found in samples collected 2-3 months after invasi on and disappeared between 5-9 months. IgA antibodies were frequently found in patients with high IgG antibody titers (91%), but were not de tected when IgG titers were decreasing. There were no IgA antibodies p resent in the patients one year after invasion, however, in some patie nts the IgM antibodies were still present (''residual'' IgM antibodies ). Detection of the IgA specific antibodies is a valuable marker of th e acute phase of toxoplasmosis between 4 weeks and 4 months, however, their presence has to be interpreted together with other serological t ests examining IgG and IgM.