(A) Women in the STI Clinic. Of the women with a current, PCR-confirmed, Chlamydia infection in the STI clinic, the large majority (94%) had IgG antibodies and one-third (38%) had IgA antibodies in the serum, while only 10% of women without infection had IgG and 6% IgA in the serum. The gene discussed is CD79A; the disease is infection.