[Infections mononucleosis with pleural effusion].

A 24-year-old man was admitted to our hospital for further examination of pleural effusion. On physical examination, he had a temperature of 39 degrees C, the pharynx was painful and liver and spleen were enlarged. The leukocyte count was 5,700/microliters (atypical lymphocyte 6%). The serum LDH, GOT, GPT, ALP and gamma-GTP levels were elevated, and antibodies to Epstein-Barr viral capsid, early, and nuclear antigens were diagnostic of a primary Epstein-Barr virus infection. The CD4/CD8 ratio of peripheral blood lymphocyte was decreased to 0.2. The pleural effusion was exudate, and infiltration of mononuclear cells was noted. The CD4/CD8 ratio of lymphocytes in the effusion also was decreased to 1.1. The result of pleural biopsy showed a perivascular infiltration of mononuclear cells and immunological stain showed that the infiltrated cells were dominantly T-lymphocytes (about 90%). These findings suggested that the pathogenesis of pleural effusion in infectious mononucleosis was a pleulitis due to the infiltration of T-lymphocytes. Pleural effusion is known as a rare complication of infectious mononucleosis.