IMMUNE-RESPONSES TO CHLAMYDIA-PNEUMONIAE IN TWINS IN RELATION TO GENDER AND SMOKING

This study investigated whether gender or smoking has an impact on imm une responses to Chlamydia pneumoniae in generally healthy adults. A t otal of 129 twins (46 twin pairs and 37 single twins) from the Finnish Twin Cohort who had previously reported the highest discordance for s moking with their co-twins participated. C. pneumoniae-specific serum IgA and IgG antibody levels were measured by the micro-immunofluoresce nce test (micro-IF) at admission and 3 months later if the IgA level i n the first sample was elevated. Cell-mediated immune (CMI) responses to C. pneumoniae and control antigens from heparinised blood samples w ere assessed by the lymphoproliferation (LP) assay. When all the subje cts were pooled and analysed by gender and smoking status, marked diff erences in the humoral immune response between the genders were observ ed, irrespective of smoking status. When twin pairs solely were analys ed, significantly elevated IgA antibody levels suggestive of persisten t infection were found among the currently or formerly smoking men com pared to their non-smoking co-twins. The CMI response showed a recipro cal trend with respect to humoral immunity. In conclusion, specific an tibody levels were found to be higher in men than in women irrespectiv e of smoking status, although smoking may further enhance the humoral response and depress the CMI response in men.