Abstract: Objective To study the clinicopathologic features of Churg-Strauss syndrome (CSS) with renal involvement. Methods The clinicopathologic data of patients with CSS in Peking Union Medical College Hospital in last 10 years were retrospectively collected and analyzed. The outcome of CSS cases with renal involvement after one month intervention was evaluated. Results Forty cases were enrolled with a mean age of （43.6±18.1）years. Antineutrophil cytoplasmic antibody (ANCA) was positive in nine of forty patients (22.5%), with specificity for myeloperoxidase(MPO) in six patients（15%）. Renal involvements were found in thirteen patients (32.5%), six cases (46.2%) manifested as isolated urinary abnormalities, seven cases（53.8%）manifested as renal insufficiency with estimated glomerular filtration rate(eGFR) <60 ml/min/1.73m2. The positive rates of ANCA were significant higher in patients with nephropathy than those without nephropathy (46.2% versus 14.8%, P < 0.05). The values of eGFR in patients with renal involvement were significantly increased after treatment with full dose prednisone and CTX for one month (73.5±36.5 ml/min/1.73m2 versus 102.0±35.3 ml/min/1.73m2, P<0.05). Proteinuria and hematuria in CSS patients were decreased considerably after treatment. Conclusion Renal involvements in CSS patients are not rare, the renal abnormalities are relatively mild and response well to the corticosteroid and CTX therapy. The renal impairment in CSS patients may be related to the ANCA, particularly antibodies against MPO.

Key words: Churg-Strauss syndrome, Renal involvement