Assessment of Humoral Immune Response as a Guide for Chlamydial Eye Infection Diagnosis Using Enzyme-Linked Immunosorbent and Micro-Immunofluorescence Assays

2 Abstract: In Egypt, the high prevalence of trachoma represents a major cause of blindness especially in rural areas. The aim of this study is to assess the humoral immune response in trachoma patients and to observe the change in immune response in acute and chronic stage to confirm the clinical diagnosis. This study was performed on 80 patients attending the outpatient clinic of Research Institute of Ophthalmology starting from December 2012 to December 2013; the first group included 50 patients clinically diagnosed as trachoma either in the acute or chronic stage of the disease, while the second group included 10 patients defined as controls in which they are diagnosed with conjunctivitis due to other cause than Chlamydia. Lastly, the third group included 20 patients in which were investigated as non-affected controls. Two tests were done for the detection of specific IgA and IgG, these are enzyme-linked Immunosorbent Assay (ELISA) and Micro Immuno-Fluorescence (MIF).The results demonstrated an increase in both specific anti-Chlamydia trachomatis (C.trachomatis) IgG and IgA. IgG was recorded to be more prevalent in patient's sera than IgA, accordingly, IgG show more sensitivity to the ELISA and MIF detection tests than for specific IgA (sensitivity by ELISA was 90% v.72% and by MIF was 92%v. 48% for IgG and IgA respectively). A significant agreement between ELISA and MIF for detection of specific IgG was also observed, however, this conformity was not significant for IgA. The combination of the two tests ELISA and MIF offer an absolute accuracy for the specific detection of IgG and IgA, when done, the sensitivity of the combined tests for specific IgG was higher than that for specific IgA (86% v.38% respectively). The combined two tested indicate the high prevalence and chronicity of the disease. Therefore it is suitable for screening clinically diagnosed trachoma patients in Egypt as both tests are rapid, simple and can be used to test large number of samples at once.