[Serum concentration and urinary excretion of soluble receptors for tumor necrosis factor in patients with primary glomerulonephritis].

In sera and urine of healthy and diseased patients two soluble types of TNF receptors--p55--sTNF RI and p75--sTNF RII have been detected. They can protect cells against excessive cytotoxic activity of TNF-alpha in vitro and in vivo. The aim of the study was to investigate the prognostic significance and role of sTNF R in various types of glomerular diseases. We studied 49 patients with primary glomerular diseases (5 minimal change--MC; 4 focal glomerulosclerosis--FSGN; 4 membranous nephropathy--MN; 12 mesangial proliferative GN--MSPGN; 18 IgA nephropathy--IgAN; and 6 membranoproliferative GN--MPGN) and 10 healthy persons. Renal biopsies were evaluated by light and immunofluorescence microscopy. STNF RI and sTNF RII concentrations were measured by ELISA (BIOSOURCE international kits). The treatment of patients consisted of 3 to 5 i.v. methylprednisolone pulses (1.0 g per single dose, average total 1.0 g/20 kg given alternate days) followed by oral prednisone 20 to 25 mg/day and six monthly i.v. cyclophosphamide 0.6 g/1 m2/month. The studied groups showed a significantly higher concentration of sTNF RI and sTNF RII in their sera and urine when compared with the control. In patient groups serum Cr showed significant correlations with volume of interstitial tissue in renal biopsy, correlation of serum Cr with serum sTNF RI, serum sTNF RI with serum sTNF RII and with urinary sTNF RI, serum sTNF RII with urinary sTNF RI and with urinary sTNF RII. The ratio of serum sTNF RI to serum sTNF RII in patients was unchanged compared to the controls but ratio of urinary sTNF RI to sTNF RII was higher in all patient groups except patients with MC. In patients with renal sufficiency (Cr < 1.3 mg/dl) and reduction of proteinuria > 50% after 1 year of therapy urinary secretion of sTNF RII was higher before treatment than in patients with protein reduction < 50%. In patients with renal insufficiency and reduction of proteinuria > 50% urinary excretion of sTNF RI was lower than in patients with lower reduction of proteinuria (< 50%) after 1 year of therapy. Our results suggest that serum sTNF R could be useful as indicator of clinical activity of the disease and urinary excretion of soluble receptors as a predictor of effectiveness of immunosuppressive therapy.