Clinicopathological features and treatment of C1q nephropathy in children / 中华肾脏病杂志

ABSTRACT

Objective To investigate the clinicopathological characteristics and treatment of C1q nephropathy in children.Methods Data of 23 C1q nephropathy cases in Nanjing Children's Hospital during recent eight years were retrospectively reviewed. Results The incidence of C1q nephropathy was 4.78％ in primary glomerulonephritis proven by biopsy.Among 23 patients,15 were boys and 8 were girls.The mean age at onset was (5.0±3.4) years old with a range of 0.9-12.4 years.The clinical manifestations included nephrotic syndrome(NS) in 18 cases (78.3％),nephrotic-range proteinuria in 4 cases(17.4％) and microhematuria in 1 case.Two patients with NS and one patient with nephrotic-range proteinuria also presented microhematuria.One patient with NS who received oral herbal medicine for two weeks developed acute renal insufficiency at the same time of diagnosis.Three cases had a family history of kidney disease,among them two patients(presented nephrotic range proteinuria) were siblings,their father had proteinuria as well,and routine genetic examination confirmed familial Denys-Drash syndrome in association with C1q nephropathy.One NS patient's sister had nephrotic-range proteinuria too,but renal biopsy was not performed.No patient had hypertension.None of the patients had low C3 or C4 levels,and serological markers of systemic lupus erythematosus were absent.Light microscopy showedminimalchangedisease (MCD)in13cases (56.5％), mesangialproliferative glomerulonephritis(MsPGN) in 6(26.1％) and focal segmental glomerulosclerosis(FSGS) in 4(17.4％).Immunofluorescence displayed C1q co-deposits of IgG(78.3％),IgM(78.3％),IgA (34.8％) and C3 (47.8％),and a full-house pattern was found in 6 patients (26.1％).Electron microscopy revealed 4 out of 19 had mesangial deposits,except for 4 patients whose glomerulus could not be found.Children with either NS(18 cases) or nephrotic-range proteinuria(2 cases)received prednisone,among them,15 were steroid-resistant,4 were steroid-dependent,only 1 was steroid-sensitive.Those with steroid-resistant(15 cases) or steroid-dependent(3 cases) received further immunosuppression with cyclophosphamide(CTX) or cyclosporine A (CsA).One NS case of steroid-dependent received prednisone re-induction therapy.The siblings associated with DenysDrash syndrome and one case presented microhematuria were commenced on angiotensin-converting enzyme inhibitor(ACEI).Of the 19 patients with sufficient follow-up date,15 cases (78.9％)achieved complete remission,2 cases(10.5％) achieved partial remission,and 2 cases (10.5％) were ineffective.Median follow-up was 15 months.Remission of the NS occurred in 94.4％ (17/18)while nephrotic-range proteinuria was 50.0％(2/4).Remission of MCD was 100.0％,MsPGN was 83.4％(5/6),but FSGS was only 50.0％(2/4).Conclusions C1q nephropathy is rare,and often manifests as steroid-resistant or steroid-dependent NS and nephrotic-range proteinuria.The most common histological feature is MCD,and some as MsPGN or FSGS.A combination of prednisone and immunosuppressive agent is always effective for MCD and MsPGN,but FSGS always has a poor response.