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Earliest possible diagnosis of seroconversion for toxoplasmosis in pregnancy

Abstract number: P942

Meroni V., Genco F., Lanzarini P., Stronati M., Ciardelli L., Garofoli F., Bollani L.

The early and definitive detection of a recently acquired infection is critical for the clinical management of the mother and her foetus. IgG antibodies are often absent in early phases of infections and IgM antibodies may be non specific and disappear at the end of pregnancy. Therapy usually given as early as possible could affect antibody production. To distinguish early infection from non-specific antibody response we evaluated two routine tests for IgG and for IGM two new confirmation immunoblots and mmunological tests in 39 pregnant women with suspected seroconversion.39 pregnant women negative for anti-Toxoplasma IgG (LIAISON Toxo IgG II DIASORIN Italy, VIDAS toxo IgG II Biomerieux France)and positive for IgM with at least one of the two tests routinely used(LIAISON TOXO IgM DIASORIN Toxo IgM ISAGA BIOMERIEUX)were followed weekly to detect the production of anti-Toxoplasma IgG. Spiramicyn was given at the first positive IgM test. All samples were also tested with LDBIO TOXOII IgG and LDBIO TOXOII IgM the latter being not commercially available (LDBIO DIAGNOSTICS France). In 12 out of 39 women lymphocyte stimulation was performed using Toxoplasma antigen (DIASORIN)and CD25 and Stimulation Index were evaluated.10 women resulted IgM ISAGA and type II WB negative in all these cases no seroconversion was recorded even after therapy interruption. IgM ISAGA and LDBIO TOXO II IgM was positive in 29 women. For 13 patients the seroconversion was proved with the appearance of specific anti-Toxoplasma IgG during the follow-up. In 4 they were already present in the first sample by LDBIO TOXOII IgG in 9 IgG antibodies were detected on subsequent samples earlier with LDBIO TOXOII IgG and with LIAISON Toxo IgG assay.9 were also positive in lymphocyte stimulation.13 women were LDBIO TOXOII IgM negative and no IgG was detected with all the tests on later samples even after the treatment was discontinued. In 5 cases lymphocyte stimulation confirmed these results.

Conclusions: In 36 patients an early and correct diagnosis was reached with LDBIO TOXO II IgM. LDBIO TOXO II IgG and LIAISON Toxo IgG II were positive earlier and confirmed the seroconversion several weeks before the other IgG test. In all negative cases it was possible to stop safely the therapy and to reassure the women. No infected woman was missed, all positive women were given the appropriate therapy and prenatal diagnosis was offered. We had three false positive results at IgM (one also with lymphocyte stimulation).

Session Details

Date: 19/04/2008
Time: 00:00-00:00
Session name: 18th European Congress of Clinical Microbiology and Infectious Diseases
Subject:
Location: Barcelona, Spain
Presentation type:
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