[Detection of Epstein-Barr virus in the tonsils in infectious mononucleosis].

Tonsils of 50 patients with infectious mononucleosis were examined for the presence of Epstein-Barr virus nuclear antigens (EBNA) and in 11 cases for the presence of Epstein-Barr virus (EBV) nucleic acid sequences. In tonsillar tissue of 42 patients less than 1 to 40 per cent EBNA-positive cells could be demonstrated by anticomplement immunofluorescence. 10 out of 11 tonsils examined by in situ hybridization contained less than 1 to 50 per cent cells with EBV nucleic acid sequences. The histological examination indicated that cells labelled by in situ hybridisation are in the majority proliferating B-lymphocytes and to a small extent cells of tonsillar epithelium.