Systemic lupus erythematosus (SLE) pathogenesis is mediated in part by autoantibodies. We describe a patient with central nervous system lupus who developed a loss of B cells with associated hypogammaglobulinemia and sinopulmonary infections requiring intravenous immunoglobulin. The SLE went into complete remission. Of 18 reported patients with SLE developing persistent hypogammaglobulinemia, only 5 patients including ours had a nearly complete loss of circulating B cells. Of those whose SLE and B cell status was reported, 5/5 with B cell loss and 1/10 without B cell loss experienced a durable response of SLE (p = 0.002). These cases illustrate that B cell ablative therapies may have efficacy for SLE.