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Background. Renalinvolvementremainsamajordeter-minant in antineutrophil cytoplasmic autoantibody-associated small vessel vasculitis (AASV). While somepatients may develop persistent renal damage, othershave a favourable outcome.Methods. To identify patients at risk for poor renaloutcome, we evaluated 95 renal biopsies (67 initialbiopsies and 28 repeat biopsies) of 67 patients withAASV for the presence and extent of active (AI)and chronic (CI) lesions, retrospectively. AI, CI, levelsof proteinuria and dose of cyclophosphamide (CYC)were related to renal outcome.Results. Recovery of renal function in patients ini-tially dialysis dependent was associated with a lowerCI compared with patients who remained on dialysis(P

Mycophenolate mofetil (MMF), being effectively used as immunosuppressant in transplant medicine, has recently attracted interest as therapeutic agent for autoimmune diseases (AID). For these patients, no pharmacokinetic (PK) data are available. This study is an investigation of single-dose concentration-time profiles of 1 g off MMF in 16 patients with AID, including 10 patients with ANCA-associated vasculitis and 6 patients with systemic lupus erythematosus, and compares them with profiles of 16 renal transplant recipients (RTX). Mycophenolic acid (MPA) blood levels were measured by both HPLC and EMIT, and MPA-glucuronide was determined by HPLC. In AID, mean MPA concentrations at 12 h were significantly higher compared with RTX (4.1 +/- 3.27 versus 1.8 +/- 1.15 mg/L; P = 0.018), whereas peak concentrations were lower (P = 0.017). However, mean MPA-AUC at 12 h as well as at 24 h were comparable between both groups. In contrast to RTX, there was an association in AID between MPA trough levels at 12 h and at 24 h with AUC(0-12) (P < 0.05 and P < 0.01). MPA trough concentrations at 24 h provided an estimation of AUC(0-24 h) in both patient groups (P < 0.001 and P < 0.01; AID and RTX, respectively). Compared with RTX, MPA-PK seems to be less affected in AID by renal function. Inter-individual variability of PK parameters was high in both groups. These data indicate that there are differences of MPA-PK between RTX and AID. The use of therapeutic drug monitoring in patients with AID appears to be clinically practicable and may be valuable to optimize individual immunosuppressive therapy.

Background. In small vessel vasculitis and its renallimited form, idiopathic crescentic glomerulonephritis, renal damage is characterized by pauci-immune necrotizing crescentic glomerulonephritis (CGN) without histological evidence of immunoglobulin (Ig) deposition. In some patients, however, significant amounts of immune deposits may be detected. Therefore, we evaluated the clinical significance of these immune deposits in anti-neutrophil cytoplasmic autoantibody (ANCA)-associated pauci-immune CGN. Methods. Renal biopsies of 45 consecutive patients with new onset of Wegener’s granulomatosis, microscopic polyangiitis and idiopathic CGN were retrospectively evaluated by light microscopy, immunohistochemistry and electron microscopy and the findings compared with renal function and outcome. Results. Typical pauci-immune CGN was found in 37 patients (group I). In eight patients (18%; group II), however, histopathological examination revealed substantial deposition of Ig in the mesangium anduor along the glomerular basement membrane. Five of these eight patients were cANCA positive; two initially had pANCA and developed a cANCA pattern and one was pANCA positive. There were no differences between groups in age, gender, renal function or extrarenal organ involvement at the time of biopsy. However, patients in group II had significantly more proteinuria (5.4"3.1 vs 1.3"1.0 gu24 h; Ps0.016). We also observed a trend for a worse outcome with respect to renal function and mortality in group II patients; however, the differences did not reach significance. Conclusions. Our results confirm that in ANCAassociated CGN a substantial percentage of patients have evidence of Ig deposition in renal biopsies. In this subgroup, Ig deposition was associated with a significantly greater degree of proteinuria. Further investigations are necessary to define the full clinical impact of immune-complex deposition on the clinical course of renal disease in pauci-immune CGN.