Humoral immune response in Epstein-Barr virus infections. II. IgG subclass distribution in African patients with Burkitt's lymphoma and nasopharyngeal carcinoma.

Native Burkitt's lymphoma (BL) and nasopharyngeal carcinoma (NPC) patients from Kenya were examined with regard to the serum concentrations and distribution of the four IgG subclasses, total IgG, and antibody activities to Epstein-Barr (EB) virus associated antigens. The results were compared with corresponding data of an African control group. As revealed by indirect immunofluorescence techniques, the patients displayed a pattern of IgG and IgA antibodies to EB virus associated antigens which is characteristic for these diseases. No significant differences could be detected between the total IgG levels of the diagnostic groups. The mean total IgG concentrations of our Kenyan patients were two to three times as high as those found in four different groups of Europeans, which is consistent with results of previous studies on Gambian, Nigerian, and Congolese Bantu populations. Quantitative determination of the four IgG subclasses by radial immunodiffusion revealed a unique pattern in the BL group which was characterized by a decreased proportion of IgG2 and significantly lower absolute IgG2 values as compared with the controls. The IgG subclass distribution pattern in the African NPC sera was essentially identical with that of European NPC and African control sera. The pathogenetic implications of these findings are discussed.