Daratumumab in Treatment of PGNMID and C3 GN

Inclusion Criteria: * Age ≥ 18 years of age * Renal biopsy read at Mayo Clinic confirming the diagnosis of PGNMID or C3 GN * In cases of C3GN serum electrophoresis with immunofixation should confirm presence of monoclonal gammopathy * Proteinuria ≥ 1000 mg over 24 hours * eGFR ≥ 20 mL/min/SA * Subjects able and willing to give informed consent Exclusion Criteria: * Pregnancy * Hepatitis B or C, HIV * Multiple myeloma * Anemia with Hgb \< 8.5 g/dL * Thrombocytopenia with platelet count \< 100,000 * Leukopenia with WBC \< 3.5 * Any other disease, metabolic dysfunction, physical examination finding, or clinical laboratory finding giving reasonable suspicion of a disease or condition that contraindicates the use of an investigational drug or that may affect the interpretation of the results or render the patient at high risk from treatment complication * Unable to provide consent * Patients receiving therapy with oral prednisone or glucocorticoid equivalent in the last 6 weeks * Patients who had received immunosuppressive therapy including cyclophosphamide, MMF, cyclosporine, tacrolimus or azathioprine in the last 3 months * Patients who received rituximab previously with CD20 count of zero at the time of enrollment