Cell surface localized IgM-kappa immunoglobulin reactivity in a case of chronic lymphocytic leukaemia.

The cell surface of peripheral lymphocytes from a patient with chronic lymphocytic leukaemia reacted strongly with fluorescein conjugated anti-IgM and kappa serum. Moreover in the presence of complement anti-IgM serum was cytotoxic. This patient was unusually resistant to various therapeutic measures. Serum immunoglobulin levels were slightly subnormal. The reactivity described differs from other chronic lymphocytic leukaemias studied but could be found in a number of Burkitt cases. The leukaemia cells may represent the malignant transformation of a normal lymphoid cell specialized to carry immunoglobulin on its cell membrane.