The bone marrow of two patients with y heavy-chain disease contained
a number of plasmacytes and lymphoid cells that showed intracytoplasmic
immunofluorescence when stained by anti-y but not by anti-light-chain re- agents. Surface staining of the bone marrow and blood cells showed a decrease
in Ig bearing lymphocytes but cells carrying y chains without light chains
could not be demonstrated. One of these patients was studied again during
a complete clinical remission when the abnormal protein was no longer
detectable in serum.25 At that time, the bone marrow contained a normal
number of plasma cells with a normal distribution of heavy and light chains
and the percentages of blood lymphocytes bearing the different heavy and
light chains were in the normal range.