also occurred in vivo and was the reason for the mixed staining pattern.
These and other findings provided evidence of an actual anti-IgG activity in
the monoclonal surface 1gM.23 In contrast, in the two remaining patients with
similar mixed staining, the newly synthetized 1gM was not able to bind
normal IgG, and surface IgG and 1gM on freshly drawn cells showed an
independent behavior during the antibody-induced redistribution process. In
one of these two patients multiple auto-immune abnormalities were found,
including a high level of rheumatoid factor. In such cases we are presumably
dealing with the attachment of immune complexes to the B lymphocyte
surf ace.