B lymphocyte markers in multiple myeloma and related plasma cell dyscrasias.

Multiple myeloma and benign monoclonal gammopathies are regarded as monoclonal B cell proliferations in which B lymphocyte maturation is blocked in the final stages of the differentiation cycle. "Blocked" cells accumulate in the body and produce large quantities of immunoglobulins. These are monoclonal, because they come from a monoclonal cell stock.

Relationships between cell-cell interactions, cAMP, and gene expression in a developmental mutant of Dictyostelium discoideum.

Previous work has led us to propose that close cell-cell associations during D. discoideum development serve as a signal to deactivate expression of discoidin I mRNA, and that intracellular cAMP serves as a mediator of this regulatory pathway. This model is based in part on the failure of a morphogenetic mutant, EB-21, to deactivate discoidin I expression under conditions where these cells fail to acquire cell-cell cohesiveness and hence remain as single cells, unlike the wild type strain which forms multicellular aggregates.

Distinct developmental regulation and properties of the responsiveness of different genes to cyclic AMP in Dictyostelium discoideum.

Cyclic AMP (cAMP) is known to be an important mediator of gene expression in eukaryotic cells. At present, little is known about the developmental events which render specific genes responsive to cAMP in distinct cell types, or about the biochemical mechanisms by which cAMP exerts these regulatory effects. By examining the effects of cAMP treatment on specific mRNA levels in Dictyostelium discoideum cells with different 'developmental histories', we defined the developmental states in which specific genes display responsiveness to cAMP.

Immunological studies on the origin of the precursor cells in Waldenström's macroglobulinemia.

Preliminary results obtained with OK anti-T and FMC anti-B monoclonal antibodies in a study of peripheral blood lymphocytes from eight patients with Waldenström's macroglobulinemia and of bone marrow lymphocytes from three patients, are reported. Endocytoplasmic immunofluorescence revealed a 1 to 3% marrow plasma cell fraction in all three cases, together with an approximately 10% increase in the monoclonal precursor compartment. Displacement of the peripheral blood helper: suppressor ratio was also observed using anti-T-lymphocyte monoclonal antibodies.