Abstract
One hundred and fourteen biopsies from 91 cases of African Burkitt's lymphoma were examined by immunofluorescence methods for the presence of surface‐associated mu, gamma, delta, kappa and lambda chains, as well as for the Fc region of gamma chains and for β~ic.~ Only 5% of the biopsies were surface‐Ig‐negative; 18% were negative for mu chains and 61% for gamma chains. Delta chain staining was absent, or borderline in a few tumors. Mu chains, gamma chains in a few highly reactive tumors and, in many cases, the predominant light chain seemed to be clonal markers. They gave no convincing evidence of more than one cell clone, either within single tumors or within syn‐ or metachronous tumors in one individual. Gamma chains in moderately stained tumors, Fc and β~ic~ correlated with each other and the first two reactivities decreased after incubation at low pH, indicating that their presence resulted from outside coating of the cells. The results indicated that one clone of B cells is involved in Burkitt's lymphoma in the large majority of cases. This clone is in a state of differentiation at which surface delta chains are not expressed. No prognostic information resulted from the analysis of the markers studied.