In vitro study of expression of interleukin-2 receptors in T-lymphocytes from patients with IgA nephropathy.

The present study was undertaken to examine the expression of interleukin-2 receptor (IL-2R)/CD25 antigen in cultured T-lymphocyte subsets in IgA nephropathy. Twenty-four IgA nephritic patients, 12 patients with chronic glomerulonephritis (non-IgA nephropathy), and 17 healthy controls were studied in an infection-free interval. T-cell subsets in peripheral blood mononuclear cells (PBMC) and activated T-lymphocyte subsets expressing IL-2R were determined by double immunofluorescence staining with fluorochromes conjugated to monoclonal antibodies against T-helper/inducer (CD4+) cell, T-suppressor/cytotoxic (CD8+) cell, B (CD20+) lymphocytes, and IL-2R. The percentages of CD4+ and CD8+ lymphocytes, CD4/CD8 ratio, and total activated lymphocytes (with IL-2R/CD25 antigen) did not differ between the IgA nephritic patients, patients with chronic glomerulonephritis, and healthy controls in freshly isolated, unstimulated lymphocytes or PBMC cultured with pokeweed mitogen. Following pokeweed mitogen stimulation for 5 days, 17.3 +/- 10.3%, 16.6 +/- 8.4%, and 16.7 +/- 9.4% of PBMC from IgA nephritic patients, patients with chronic glomerulonephritis, and controls respectively expressed IL-2R (p greater than 0.05). However, the individual T-cell subsets bearing IL-2R were distinctly different between the IgA nephritic patients and patients with chronic glomerulonephritis or healthy controls. IgA nephritic patients had increased activated CD4+ lymphocytes (with IL-2R) (p less than 0.025) and reduced activated CD8+ lymphocytes (p less than 0.025). Our study suggests a defective immunoregulation in IgA nephropathy with enhanced T-helper/inducer and reduced T-suppressor/cytotoxic activity when stimulated with mitogen and probably, during clinical exacerbation.