Our data provide evidence that the proliferative process affects B lymphocytes
in W.M. and related conditions, and in most if not all cases of CLL
Indeed, lymphocyte populations characterized by S.Ig markers were found
in all W.M. and in 70 of 73 CLL patients. This finding correlates with several
other observations. Phytohemagglutinin responsiveness is presently considered
as a T cell property27 and most CLL and W.M. patients show a
poor and/or delayed response when the blood lymphocytes are reacted with
this mitogen. There is some correlation between phytohemagglutinin unresponsiveness
and lymphocyte counts. Similarly the present data show a
correlation between lymphocyte counts and the percentages of S.Ig bearing
cells. The normal phytohemagglutinin responses which have been observed
in treated patients with normal lymphocyte counts28 may be related to the
low percentages of S.Ig bearing cells which were found in such patients.