Chronic lymphocytic leukaemia and the mixed lymphocyte reaction.

The lymphocytes from patients with chronic lymphocytic leukaemia  (CLL)  have been studied  in  the mixed lymphocyte reaction  (MLR)  using both  the  two-way  (both populations  viable)  and one-way (only  one viable  population)  systems. The  ABO antigens  were  matched  but  the  pairs  were  selected for at least two antigenic differences of the HL-A system. The lymphocytes  of  the  patients  were  as capable as normal cells of invoking a response in allogeneic normal lymphocytes.  Conversely, barely any response was produced when the lymphocytes of the patients were exposed to non-viable normal allogeneic cells. The failure of the leukaemic lymphocytes to respond adequately  in the MLR is correlated with a very poor response to phytohaemagglutinin  and  may  be contrasted  with  the  definite positive  responses obtained  with specific  antigens.