LAUSR

To the Editor: Varied dosing regimens of rituximab (RTX) have been successfully used in the management of primary membranous nephropathy (PMN). An ideal RTX dose and the long-term adverse effect of a larger cumulative dose are not clear. CD19 levels are used to gauge the drug effect. Economic viability is a major part of any new therapeutic regimen. Low-dose RTX (100 mg) has been successfully used in ABO incompatible renal transplant. In the present study, we report a similar approach of CD19 depletion using 100 mg of RTX in the management of M-type phospholipase A2 receptor antibody (aPLA2R)associated PMN refractory, dependent on or intolerant to conventional immunosuppressive regimens recommended by Kidney Disease: Improving Global Outcomes. All the study subjects had aPLA2R-related PMN. The mean duration of nephrotic syndrome before RTX therapy was 33.67 19.76 (median 13, range 10–62) months. Before receiving RTX, all the patients had an immunosuppression-free washout period of minimum 3 months. The mean proteinuria, serum albumin, and creatinine were 12.06 10.78 (median 7.59, range 2.30–31.00) g/d, 2.09 0.95 (median 1.64, range 1.30–3.50) g/dl, and 0.81 0.21 (median 0.80, range 0.60–1.10) mg/dl, respectively. Five (83.3%) study subjects had nephrotic range proteinuria (>4 g/d) and 1 (16.7%) patient had subnephrotic proteinuria (2.3 g/d) and was treated as he had anasarca with severe hypoalbuminemia (1.3 g/dl) and hypercholesteremia. All the study subjects (4 resistant to cyclophosphamide and steroids, 1 intolerant to tacrolimus treatment, and 1 with relapsing disease) were treated with 100 mg of rituximab (CD19 monitored on day 2 and at every 4to 6-week interval). In subjects with no response at 6 months, further infusion and monitoring was stopped (extended follow-up continued). All the subjects achieved CD19 depletion (<1%) with a single dose of