Possible Cellular Expression of IFN- in Women with Abortion Infected with Toxoplasma Gondii

This study included one hundred and twenty six women with spontaneous abortion (6 of them with induced abortion). Venous blood was collected from these women, and serum was obtained for the performance of the ELISA test for the detection of anti-Toxoplasma IgM to indicate the acute T. gondii infection. Paraffin embedded blocks of the trophoblastic tissue obtained from each patient were prepared. The trophoblastic tissue was investigated for the presence of T. gondii antigen by using immunohistochemical analysis, using specific monoclonal antibodies for T. gondii. According to the immunohistochemical analysis, the patients were divided into three groups, (group 1) 26 positive for Toxoplasma, (group 2) 26 negative for Toxoplasma, and (group 3) 6 negative for Toxoplasma (induced abortion group).
The results indicated a high frequency of the T. gondii infection among women with abortion, 23 of 120 women (19.17%) have IgM Abs against T. gondii by ELISA test. The use of ELISA test for the detection of anti-Toxoplasma IgM was highly specific (100%) but not highly sensitive (88.46%). This could explain the use of more sensitive techniques for the detection of T. gondii infection like immunohistochemical analysis. The results of the IHC revealed that 26 of 120 women (21.66%) had Toxoplasma antigen within the trophoblastic tissue. The sensitivity and specificity of IHC were 100%, 96.91%, respectively.
The current study showed that there was no significant difference between the mean age of positive and negative groups, while there was a highly significant difference between the mean age of positive and induced abortion groups. Similarly, the mean age between negative and induced abortion groups showed a highly significant difference.
In this protocol, the majority of patients within the positive and negative groups were found to have no previous abortions, while patients with previous abortions constituted a less percent. Among the induced abortion group, it has been found that all the six cases had no previous abortions.
The mean gestational age among the three groups was compared in this study, where it revealed a highly significant difference between the positive and induced abortion groups. The same result was found between the mean gestational age of negative and induced abortion groups. In addition, it revealed the lack of significant difference between the mean gestational age of positive and negative groups. The majority of abortions within the positive group for T. gondii fall in the period of 12 weeks (41%) followed by 8 (15%) and 10 (12%) weeks of gestational age.
Levels of IFN- were investigated by using immunohistochemical analysis. The results revealed a highly significant difference regarding the mean percent of IFN- when compared between the positive and negative groups. In this work, t-test revealed a highly significant difference regarding the mean percent of IFN- between positive and induced abortion groups. Similarly, a significant difference was found when the mean percent of IFN- was compared between the negative and induced abortion groups. The results of immunohistochemical analysis of IFN- within positive group showed that there were negative and highly significant correlations with gestational age but not with number of previous abortions.
In conclusion, the data of this study strengthen the possibility that IFN- may explain the role of type 1 cytokines in the pathogenicity of abortion in the positive group for T.gondii.