The Czech registry of renal biopsies. Occurrence of renal diseases in the years 1994-2000.

BACKGROUND: This report describes data collected by the Czech Registry of Renal Biopsies (CRRB). METHODS: Twenty-eight centres provided data on all biopsies of native kidneys performed in the Czech Republic (population 10.3 million) over the period 1994-2000. Data on serum creatinine concentration (sCr), 24 h proteinuria, haematuria, serum albumin level, arterial hypertension, diabetes mellitus, histological diagnosis and complications after renal biopsy were collected. RESULTS: Altogether 4004 biopsies in 3874 patients were performed (males 57.9%, children < or = 15 years 17.7%, elderly >60 years 14.3%). Microhaematuria was present in 65.9%, macrohaematuria in 9.2%, nephrotic proteinuria (> or = 3.5 g/24 h) in 39.3%, and low-grade proteinuria (<3.5 g/24 h) in 41.4%. Among adults, hypertension was present in 45.2%, mild renal insufficiency in 23% (sCr 111-200 micromol/l) and advanced renal insufficiency in 13.7% (sCr 201-400), while 11.5% of patients had sCr >400 micromol/l. The most frequent renal diseases were primary (59.8%) and secondary (25.4%) glomerulonephritis (GN). Tubulointerstitial nephritis (TIN) was observed in 4.4% and hypertensive nephroangiosclerosis in 3.4%. The samples were non-diagnostic in 4.6%. Among primary GNs, the most frequent diagnoses were: IgA nephropathy (IgAN) 34.5%, minimal change disease (MCD) 12.4%, non-IgA mesangioproliferative GN (MesGN) 11.3%, focal segmental glomerulosclerosis (FSGS) 10.8% and membranous GN (MGN) 9.3%. Among secondary GNs, systemic lupus erythematosus (SLE) represented 23.0%, necrotizing vasculitis (NV) 15.5%, Henoch-Schonlein purpura 5.7%, thin basement membrane glomerulopathy (TBN) 19.3%, Alport syndrome 6.9%, renal amyloidosis 9.9% and myeloma kidney 2.9%. Among children, the most common were IgAN (19.2%), MCD (17.6%) and TBM glomerulopathy (12.3%), while among the elderly the most common were MGN (11.0%), NV (10.7%) and amyloidosis (9.6%). The most common in patients with nephrotic proteinuria were MCD (50.5%) among children, but IgAN (24.6%) in adults aged 16-60 years and MGN (16.8%) among the elderly. IgAN (21.3%) and FSGS (8.3%) were the most common diagnoses among patients with mild renal insufficiency, but TIN (11.6%) and NV (11.3%) were the most common in more advanced renal insufficiency. Since 1999, diabetic patients represented 12.2% of adults, with mean proteinuria 8.9 g/24 h; diabetic glomerulosclerosis was found in 42.4% (with microhaematuria present in 66%) and non-diabetic renal diseases in 47.5% (IgAN in 17.5%, MGN and NAS in 11.1% and NV in 9.5%). The mean annual incidence (per million population) was: primary GN 32.4, secondary GN 13.8, IgAN 11.2, MCD 4.0, MesGN 3.7, FSGS 3.5, SLE 3.2, MGN 3.0, TBM 2.7, TIN 2.4 and NV 2.1. Ultrasound needle guidance was used in 56%, preferably in children (79%). The frequency of serious complications (gross haematuria, symptomatic haematoma, blood transfusion) remained at 3%. CONCLUSION: The CRRB provides important data on the epidemiology of GN based on a whole country population.

Soluble cytokine receptors in renal vasculitis and lupus nephritis.

BACKGROUND: The activation of various cytokines, e.g. TNFalpha, IL-1 and/or IL-6, may play an important role in the pathogenesis of renal vasculitis and lupus nephritis (LN). The systemic effect of these cytokines may be modulated by their circulating soluble receptors. The plasma levels of cytokine receptors may thus also be markers of the activation of these cytokines. MATERIAL/METHODS: The plasma levels of TNFalpha, its soluble receptor p75 (sTNF-RII), IL-6, and the soluble IL-6 receptor (sIL-6R) were measured using ELISA in 17 patients with ANCA-positive renal vasculitis (12 active - ANCA-A, 7 in remission ANCA-R), 9 patients with active lupus nephritis (LN), and 5 healthy subjects. RESULTS: Patients with LN had increased plasma levels of TNFalpha, sTNF-RII, IL-6 and sIL-6R in comparison with controls. Patients with ANCA-A also had increased plasma levels of TNFalpha, sTNF-RII and sIL-6R in comparison with controls, but the increase in the plasma level of IL-6 was not statistically significant, due to the large standard deviation. Patients with ANCA-R had increased plasma levels of sTNF-RII in comparison to controls, but the plasma levels of TNFalpha were significantly lower in ANCA-R than in ANCA-A. While the ratio of TNFalpha to sTNF-RII was significantly lower in all groups of patients than in the controls, the ratio of IL-6 to sIL-6R was significantly increased only in LN in comparison to controls. CONCLUSIONS: While increased plasma levels of TNFalpha may be a nonspecific marker of the activity of ANCA-positive renal vasculitis and LN, plasma levels of sTNF-RII are also increased in patients with ANCA-positive renal vasculitis in remission. Increased plasma levels of sTNF-RII may inhibit the systemic effects of TNFalpha, but may also prolong the half-life of its active form. Plasma levels of sIL-6R are increased both in ANCA-A and in LN, but their increase is much less pronounced than that of sTNF-RII and cannot effectively block the systemic effects of IL-6.