Serum complement components in patients with trachoma.

Serum C1q, C3, C4, and C5 components of complement levels were measured in 56 healthy subjects and 98 patients with trachoma. Serum C1q and C3 levels were found to be significantly low in stages II and III. There was no change in serum C4 and C5 levels in any of the stages. The levels of C1q and C3 complement components in serum in stages II and III returned to normal as the disease resolved following the medical treatment.