Analysis of T lymphocyte subsets in cytomegalovirus mononucleosis.

Lymphocyte proliferative responses to mitogens and herpes virus antigens are diminished during cytomegalovirus (CMV) mononucleosis. We analyzed peripheral blood T lymphocytes from patients in the acute and convalescent phases of CMV mononucleosis using monoclonal antibodies directed against the T helper and the T cytotoxic-suppressor cell subsets. Acute CMV infection is associated with a reversal in the normal ratio of helper to suppressor T lymphocytes with relative and absolute decreases in T helper cells and corresponding increases in T suppressor cells. These alterations in T lymphocyte subsets are accompanied by diminished lymphocyte responses to the mitogen concanavalin A (Con A). During convalescence, helper T lymphocytes increase, suppressor T lymphocytes decrease, and Con A responses return to normal.