Transforming Growth Factor-β mRNA Expression in CD4+ T Cells from Patients with Primary Glomerulonephritides

Immunoreactivity to transforming growth factor-β (TGF-β) was detected in glomerular cells from patients with chronic glomerulonephritis, yet it remains uncertain whether the glomerular TGF-β deposits reflect TGF-β produced by the glomerular cells alone or from additional extrarenal origin. We examined the TGF-β messanger RNA (mRNA) expression in circulating CD4+ T cells from 45 patients with different primary glomerulonephritides. By semiquantitative polymerase chain reaction, the TGF-β mRNA expression was significantly raised in histopathologic entities characterized by increased mesangial proliferation or segmental sclerosis but not in histopathologic entities with little mesangial proliferation or sclerosis. These findings suggest that, other than TGF-β produced de novo, TGF-β from systemic source can also contribute to mesangial proliferation by binding to the glomerular cells after being filtered by the glomeruli. Increased TGF-β gene expression in CD4+ T cells in these patients may potentially enhance glomerular injury.