The absence of B-cell antigen B2 from leukaemia cells and lymphoblastoid cell lines

60 leukaemia patients with acute mylogenous leukaemia, chronic myelocytic leukaemia, acute lymphatic leukaemia, and chronic lymphocytic leukaemia were tested for five specificities of the new B-lymphocyte alloantigenic system. Two specificities of the first B-cell locus were significantly lower in frequency than in B lymphocytes from 105 controls. B-cell group 1 was found in 18% of leukaemia patients vs. 48% of controls (p less than 0.025) and B-cell group 2 was found in 0% of leukaemia patients vs 23% of controls (p less than 0.025). Group 2 was also absent in 37 cultured lymphoblastoid lines. It is suggested that resistance to B-cell leukaemia and to Epstein-Barr virus transformation in vitro may be linked to a B-lymphocyte specificity on the first B-lymphocyte locus.