Abstract: | Children free from infectious disease have been examined by indirect immunofluorescence for the presence of antibodies to the intracellular capsid antigen of Epstein-Barr virus (EBV). In the first year of life 46%, between 2 and 6 years of age 66%, and between 7 and 14 years 91%, of the children proved positive. The corresponding percentages for the presence of antibodies to cytomegalovirus (CMV) and herpes simplex virus were about 50%, irrespective of the children's age. Serum samples from 69 patients suffering from infectious mononucleosis (IM) were tested for anti-EBV antibodies. Of the 29 Paul-Bunnell-positive patients 22 had antibodies, 11 of them in high titres (greater than 1 : 80). Of the 40 Paul-Bunnell-negative cases only 21 had antibodies, 8 in high titres. Of the Paul-Bunnell-negative cases, 73% were found to have anti-CMV antibodies, 32% in high titre. The respective percentages for the Paul-Bunnell-positive cases were 42% and 10%. |