Decreased T-colony formation by lymphocytes from patients with focal glomerular sclerosis.

The T-colony-forming capacity was examined in 13 normal subjects and 8 patients with biopsy-proven focal glomerular sclerosis (FGS). Fifteen patients with chronic mesangial proliferative glomerulonephritis (CGN) without renal insufficiency were studied as a disease control. The two main assays used were the counting of T colonies formed by the patients' lymphocytes, and the measurement of T-colony-forming activity in conditioned medium from cultures of patients' lymphocytes. The levels of T-colony-forming cells (TCFC) and T-colony-stimulating factor (TCSF) were decreased in patients with FGS compared with those in normal controls and lower in FGS patients with the nephrotic syndrome (NS) than in those without NS. In contrast, these parameters in CGN patients with or without NS did not differ from normal subjects. TCSF activity for TCFC in both normal individuals and FGS patients was removed from media conditioned by phytohemagglutinin (PHA)-stimulated peripheral blood lymphocytes (PHA-LCM) with interleukin-2 (IL-2) receptor bearing cultured T cells. These in vitro findings suggest that IL-2 is the essential factor contained in PHA-LCM. Thus, depressed TCFC in FGS patients with NS may result in part from impaired generation of TCSF by lymphocytes.