Defective in vitro T Cell Colony Formation in Patients with Membranous Nephropathy

Koichi Matsumoto, MD, Department of Nephrology, Prince Henry’s Hospital, St. Kilda Road, Melbourne 3004 (Australia) Dear Sir, The etiology and pathogenesis of idiopathic membranous nephropathy (MN) is not fully understood, but immunological mechanisms are thought to be involved [1]. We have recently shown that MN patients with the nephrotic syndrome (NS) have an impaired response of cellmediated immunity (CMI) [2]. Our previous study [3, 4] also illustrated an alteration in concanavalin A-in-duced suppressor cell activity in the majority of MN patients with NS. The purpose ofthe present work was to assess the T lymphocyte colony formation in a selected group of MN in order to further elucidate the existence of a CMI disorder in this nephropathy (fig. 1). The T colony formation was studied in 9 adult patients with MN. Colony-forming assays were performed by a one-step culture method with some modifications [5]. In 13 normal subjects, the average number of T colonyforming cells (TCFC) was 551.5 ± 90.5 (SD). By contrast, in MN patients with NS, the mean number of TCFC was 388.5 + 151.9, a value significantly less than normals (p < 0.05). During complete remission, TCFC levels were similar to those of normal subjects. Compared with random determinations, serial studies of TCFC in individual patients were much more informative. Figure 2 shows the course of a 59-year-old woman who presented with NS. Her renal biopsy specimen showed MN. She showed persistently low TCFC during 3 months of the follow-up period, while the E rosetting 400 300 200 100 0 80 75 70 65 25 20 ÿ ‚ < u E î ■Ç O o 101 50,000 40,000 30,000 c « ■ < – 20,000