H. Nagase et al., Mechanism of hypergammaglobulinemia by HIV infection: Circulating memory B-cell reduction with plasmacytosis, CLIN IMMUNO, 100(2), 2001, pp. 250-259
The mechanism of hypergammaglobulinemia in patients infected with HIV has r
emained unclear in spite of the identification of a reduction of CD4(+) T c
ells. The amounts of CD27(+) memory B cells were remarkably reduced in the
peripheral blood and immunoglobulin (Ig) production was diminished in HIV-i
nfected patients. Some of the freshly isolated patients' T cells expressed
the CD70 (CD27 ligand) on the surface and the CD70 expression on both of th
e CD4(+) and CD8(+) T cells was greatly enhanced by various stimuli. It was
also striking that plasmacytosis was observed in patients' bone marrow. Th
us, our findings suggest that CD70 expressed spontaneously or by activation
on T cells of HIV-infected patients stimulates memory B cells via CD27 and
promotes their differentiation into plasma cells, resulting in the elevati
on of serum Ig levels and the elimination of circulating memory B cells in
HIV-infected patients. (C) 2001 Academic Press.