Lymphocyte transformation in immunoproliferative disorders.

Lymphocyte transformation with phytohaemagglutinin (PHA) was studied in 30 patients with immunoproliferative disorders (lymphoproliferative and plasma cell disorders).Lymphocyte transformation at 3 days was reduced in the lymphoproliferative disorders (chronic lymphocytic leukaemia (CLL), well-differentiated (lymphocytic) follicular lymphoma (FLL) and Waldenström's macroglobulinaemia (WM)), and normal in the plasma cell disorders (myelomatosis, primary systemic amyloidosis, α-chain disease and benign monoclonal gammopathy) and in idiopathic cold haemagglutinin disease. A case of plasma-cell leukaemia with increased numbers of abnormal cells in the circulation also showed reduced transformation. It is suggested that the presence in the circulation of abnormal lymphocytes (or plasma cells) accounts for the results in CLL and FLL, WM and plasma-cell leukaemia. In WM a correlation was found between the activity of the disease (expressed by the levels of IgM paraprotein) and the degree of blast transformation.The long-term (28 days) in vitro survival of lymphocytes using subconcentrations of PHA was also studied in 7 patients. The cell populations (PHA-non-responsive) of CLL and FLL, but not of WM, had a good in vitro survival, resembling in this respect the normal PHA-responsive population of lymphocytes, but they remained PHA-non-responsive after 4 weeks' culture. It is speculated that in CLL the long survival in vitro of the PHA-non-responsive (leukaemic) population corresponds to their long life-span in vivo.