Treatment of glomerulonephritis in microscopic polyangiitis and Churg-Strauss syndrome. Indications of plasma exchanges, Meta-analysis of 2 randomized studies on 140 patients, 32 with glomerulonephritis.

UNLABELLED: Although plasma exchanges (PE) have no added benefit in the treatment of vasculitides of the polyarteritis nodosa (PAN) group with steroids (CS) +/- cyclophosphamide (CY), this has not been demonstrated in patients presenting with glomerulonephritis (GN). We therefore reanalyzed the records of microscopic polyangiitis (MPA) or Churg-Strauss syndrome (CSS) patients presenting with GN.

PATIENTS AND METHODS: Patients were included consecutively in 2 randomized trials: a) comparing CS vs CS + PE (n = 78) and b) comparing CS + pulse CY +/- PE in PAN and CSS with factors of poor prognosis (n = 62); 9-12 PE/patient were performed.

RESULTS: 32 patients, 18 men and 14 women, presented with GN, 28 MPA and 4 CSS, mean age 53.2 +/- 17 years. Clinical/biological manifestations before treatment were comparable in both groups: weight loss 84.4%, fever 62.5%, mononeuritis multiplex 62.5%, purpura 28.1%, GI tract involvement 43.8%, arthritis 37.5%, asthma 12.5%, CNS manifestations 9.4%; cardiac involvement 9.4%; mean creatininemia was 303 +/- 286 mumol/l, proteinuria > 0.5 g/l or 1g/d was found in every case, microscopic hematuria in 20/32 patients, leukocyturia in 12/32. Eight out of/16 were ANCA-positive, ELISA detected anti-MPO antibodies in 5 and anti-PR3 in 3. HBV infection was never observed. After 1 year of treatment, creatininemia decreased from 374.4 +/- 352 to 290 +/- 352 mumol/l in the PE group and from 287 +/- 292 to 170 +/- 67 in the non PE group (NS). Six patients of the PE group and 2 of the non-PE group were dialyzed at onset of treatment. Four of the 6 PE patients and 1 of the 2 not treated with PE were off dialysis 1 year later. In addition 1 patient from the PE group developed a flare with renal failure and required chronic dialysis. The 5-year survival was higher in the PE group (4 deaths/19) than in the non PE group (7/13). The survival curve was 74% in the PE group vs 54% in the non-PE group (NS).

CONCLUSION: This study confirms that PE have no added benefit in the treatment of GN in MPA and CSS.