Transient panhypogammaglobulinaemia and B-lymphocyte deficiency in a patient with neuropsychiatric systemic lupus erythematosus after immunosuppressive therapy.

Panhypogammaglobulinaemia is a rare complication of systemic lupus erythematosus (SLE), but its cause and mechanism are unclear. We observed transient panhypogammaglobulinaemia in a patient with neuropsychiatric SLE after treatment with prednisolone and cyclophosphamide. After the patient developed recurrent infections, laboratory findings disclosed panhypogammaglobulinaemia with B-lymphocyte deficiency. The serum immunoglobulin level returned to the normal range after the prednisolone was tapered off. Because lupus patients are susceptible to infections associated with disease exacerbation or immunosuppressive treatment, recurrent infections might be expected during the disease course without need for further evaluation of the immunodeficiency. However, this reversible, probably drug-induced case of hypogammaglobulinaemia highlights the need for immunoglobulin measurements when immunodeficiency is suspected in lupus patients.