The twelfth patient with a monoclonal serum IgG (of the A type) is of
special interest. Small crystalline inclusions were found in 10%-15% of blood
lymphocytes and were shown by intracytoplasmic staining to be positive for
p. and A chains (Fig. 3). By electron microscopy these crystals were seen tp be
surrounded by ergatoplasmic membranes. In addition 1% of the blood lymphocytes
and a few plasma cells contained IgG A. Double labeling experiments
for cytoplasmic and membrane staining showed the presence of p. and A chains
on those lymphocytes which contained the crystals whereas ‘y determinants
were not found on these cells. Surface immunofluorescence staining was performed
twice