Detection of antichlamydial antibodies in tears: a diagnostic aid?

The antibody response in sera and tears of 167 patients with suspected chlamydial conjunctivitis was compared with the antibody response in sera and tears of 45 patients with symptoms of urogenital chlamydial infection to discover whether and which type of antichlamydial antibody detected in tears may be of diagnostic help in chlamydial conjunctivitis.

Diagnosis was based on chlamydial antigen detection from the conjunctiva and urogenital tract, done by a direct immunofluorescence assay, McCoy cell culture, and polymerase chain reaction. Additionally, antichlamydial immunoglobulin A (IgA) and immunoglobulin G (IgG) were determined in sera and tears of all patients by an immunoperoxidase assay.

Two hundred twelve patients were examined--167 with conjunctivitis, 45 with symptoms of urogenital chlamydial infection. Cell culture, direct immunofluorescence assay, and polymerase chain reaction brought identical results. Conjunctival specimens taken from 33 (20%) of the patients with conjunctivitis were Chlamydia antigen positive; specimens taken from 134 (80%) were negative. Antichlamydial antibodies were found in tears of 29 (88%) of the patients with conjunctivitis whose specimens were Chlamydia antigen positive. Fifty-four (40%) of the patients with conjunctivitis whose specimens were Chlamydia antigen negative had antichlamydial antibodies in their tears. Twenty-five patients with urethritis (56%) were Chlamydia antigen positive in urethral swabs; 20 (44%) were negative. Antichlamydial antibodies were found in the tears of eight (32%) of the Chlamydia antigen-positive and two (10%) of the Chlamydia antigen-negative patients with urethritis. In contrast to patients with conjunctivitis, findings for patients with urethritis always were negative for antichlamydial IgG in the tears.

Antichlamydial antibodies in tears were seen significantly more often in patients with conjunctivitis than in those with urethritis (P < or = 0.05). Antichlamydial IgG was found only in tears of patients with conjunctivitis. Therefore, the authors conclude that the detection of antichlamydial IgG in the tears might be helpful for diagnosis in patients with suspected chlamydial conjunctivitis who have antigen-negative conjunctival swabs.