Chlamydial antibodies in semen: search for "silent" chlamydial infections in asymptomatic andrological patients.

The importance of a serological diagnostic workup in male genitourinary infections with Chlamydia trachomatis and its relevance for male infertility is still under debate. In a prospective study, antichlamydial serum and seminal plasma antibodies of 131 consecutive patients (mean age 31: 20-57) without evidence of acute urethritis and with negative urethral chlamydial culture were investigated. The antibody determination was carried out with a genus specific rELISA. In patients with positive seminal plasma IgA, chlamydial genome was evaluated by polymerase chain reaction (PCR). The results were associated with standard semen parameters according to evaluated WHO guidelines. Specific serum IgG antibodies were found in 51 patients (38.9%), IgA in 39 (29.7%); both antibodies were present in 25 patients (19%). Seminal plasma IgG was demonstrable in seven patients (5.3%), IgA in 26 (19.9%), and five patients were positive for both antibody classes (3.8%). Of the 26 men positive for specific seminal plasma IgA antibodies 12 did not demonstrate a serum antibody reaction. Only two patients with positive IgA titers in their seminal plasma showed a positive chlamydial genome reaction in PCR (8%). Men with antichlamydial seminal plasma IgA and/or IgG did not differ significantly in any of the standard semen sperm parameters from men testing negative for antibodies, with the exception of peroxidase positive leukocytes (p < 0.01), nor was there an association between any of the ejaculate parameters and any of the antibody titers. The data of about 40% antichlamydial serum antibody findings without a significant association with seminal plasma antibodies and no clinical signs of infection seem to reflect a history of urogenital infection. The unique presence of seminal plasma IgA in 12 of 26 cases may be caused by a local antibody response due to a "silent" infection. Thus, seminal plasma IgA was associated with signs of inflammation, whereas, there was no association with genome or pathogen demonstration. Therefore, it appears to be necessary to reevaluate genus-specific seminal plasma IgA antibodies with a species-specific microimmunofluorescence test and to compare these results with a genome screening using PCR or in situ hybridization.