Immunoregulatory studies in patients with IgA nephropathy.

Numerous studies have evaluated T cell subsets and in vitro IgA synthesis in patients with IgA nephropathy. These reports have resulted in the hypothesis that defective regulation of IgA synthesis is important in the pathogenesis of IgA nephropathy. Baseline immunologic measurements were performed in a clinically well characterized group of 19 pediatric and 13 adult (greater than or equal to 18 years) patients with no macrohematuria or intercurrent infection at the time of study.

Characterization of mononuclear cell-derived histamine release enhancing factor.

Histamine release enhancing factor (HREF) is a product of phytohemagglutinin-stimulated mononuclear cells that substantially augments in vitro IgE-mediated basophil histamine release. The factor is stable at 56 degrees C and has a molecular weight in the 10,000 to 30,000 dalton range. The magnitude of HREF activity produced is dependent on the concentration of mononuclear cells cultured and the final concentration of HREF during basophil challenge.

Characteristics of diatrizoate-induced basophil histamine release.

Factors influencing the release of histamine by basophils exposed to the radiocontrast agent diatrizoate were investigated in vitro by use of cells from healthy adult subjects with no history of radiocontrast reactions. Diatrizoate-induced release shared similarities with calcium ionophore-induced release. The response to both agents is dose dependent, enhanced by deuterium oxide, optimal at 37 degrees C, calcium dependent, and enhanced with longer reaction times.

Evaluation of T lymphocyte subpopulations in children with nephrotic syndrome.

We have evaluated lymphocyte subsets both quantitatively and functionally in children with nephrotic syndrome. Ten children had minimal change nephrotic syndrome (MCNS), seven had focal segmental glomerular sclerosis (FSGS) and four had recovered from MCNS. Two patients with FSGS had decreased OKT4+ cells and a decreased T4/T8 ratio.