الفهرس 
AcknowledgementOnly 14 pages are availabe for public view
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Abstract
Human umbilical cord blood has proven to be a successful alternate source of hematopoietic stem cells for pediatric patients with major hematologic disorders. Toxoplasma gondii is a global opportunistic protozoan, which cause fatal complications in immunocompromised individuals. Our goal is to study the prevalence of toxoplasmosis in umbilical cord blood (UCB) and to assess the sensitivity of ELISA and PCR for Toxoplasma infection screening. One hundred cord blood samples were collected immediately after delivery. Anti-Toxoplasma IgG and IgM antibodies were determined using ELISA method; Toxoplasma DNA was detected using nested PCR technique. Total nucleated cells (TNC) and HB were also determined. Demographic data and risk factors data related to the transmission of toxoplasmosis, were collected from mothers. Among 100 cord blood samples, 36 samples (36%) were positive for anti- Toxoplasma IgG antibodies and 6 samples (6%) were positive for anti- Toxoplasma IgM antibodies. The nested PCR showed 11 (11%) samples containing Toxoplasma DNA from which, 6 (54.54%) samples were IgM positive. As rgard validity& reliability of ELISA IgM in detection of Toxoplasma cases in comparison to PCR results, it was found that sensitivity of ElISA IgM was 54.5%, specificity was 100%, positive predictive value was 100%, negative predictive value was 94.7% and accuracy was 95%.Regarding the diagnostic methods for toxoplasmosis, ELISA demonstrates a high sensitivity and specificity.There is a high agreement between ELISA IgM and PCR (p value less than 0.001 [highly significant]).There is a slight agreement between ELISA IgG and PCR (p value equal to 0.17[non-significant]).There is no significant association between positive anti-toxoplasma IgM and IgG (P value = 0.11).Regarding HB measurement and TNC estimation, there was no significant statistical difference between positive and negative samples for Toxoplasma infection by ELISA or PCR methods. In our study, there was no significant association between blood group and toxoplasma positivity by any of the three used methods.On analysis of the demographic data, our results showed no significant association between maternal age and toxoplasmosis positivity by any of the three used methods. Our study showed no significant association between genders of the babies whose cord blood was under investigation and toxoplasma seropositivity by any of the three used methods.Toxoplasma positivity by any of the three used methods was not significantly associated (p > 0.05) with residence of the mothers. The rate of abortion among mothers incorporated in our study was 14% (one case was IgM positive, 6 cases were IgG positive and one case was PCR positive) and the seroprevalence ratesof anti- T. gondii antibodies were 16.7% for either IgM or IgG. There was no significant association between risk factors like contact with cats and consumption of raw meat and cord blood positivity for toxoplasmosis. There was a high agreement between anti-Toxoplasma IgM ELISA and PCR, (p value < 0.001), but There was a slight agreement between anti-Toxoplasma IgG ELISA and PCR tests (p value=0.1). Screening of cord blood before transplantation for toxoplasmosisis essential by both serology and PCR.