The role of T-lymphocytes in the reactivation of presumed ocular histoplasmosis scars.

The surprising finding of viable lymphocytes in clinically inactive scars gives more credence to the immunological theory regarding reactivation of histoplasmosis scars. We feel that the T-lymphocyte theory can explain the mechanism by which an inactive scar becomes active upon reintroduction of the antigen. The clinical course of the disease as well as the response to corticosteroid therapy and photocoagulation are also consistent with this hypothesis.