Clinicopathologic Characteristics of C1q nephropathy / 대한신장학회지

ABSTRACT

PURPOSE: C1q nephropathy (C1qN) is a rare glomerulonephritis characterized by mesangial deposits, predominantly C1q, without the evidence of systemic lupus erythematosus (SLE). It showed various clinical courses, however, the clinicopathologic features of C1qN have not been well defined as yet. METHODS: We retrospectively reviewed the clinicopathologic features of 11 patients (0.8%) diagnosed as C1qN among 1,403 patients aged > or = 18 years who had undergone renal biopsy due to primary glomerular disease from Jan. 2000 to Jan. 2009. Diagnostic criteria of C1qN were as follows; 1) the presence of dominant or co-dominant immunofluorescence staining for C1q in the mesangium, 2) corresponding mesangial dense deposit by electron microscopy, and 3) lack of clinical evidence of SLE. RESULTS: The male-to-female ratio was 65 and their mean age was 41.1+/-22.6 yrs (range, 19-69 yrs). Eight patients presented with urinary abnormalities and three with nephrotic syndrome. At the time of biopsy, three patients had hypertension. The mean value of 24-hour urine protein was 4.4+/-5.5 g/day (range, 0.5-18.5 g/day). On light microscopy, normal glomerular architecture (4/11) and segmental sclerosis (7/11) were observed. Complete or partial remission was achieved in six of the seven patients treated with immunosuppressive agents (steroid and/or immunosuppressants). Among these patients, two using steroid monotherapy had relapsed. The mean follow-up duration was 14+/-11 months (range, 2-31 months) and renal function deterioration was observed in three patients. CONCLUSION: C1qN showed various clinical manifestations and prognosis. Therefore, additional studies are needed to fully define the clinicopathologic features.