Selective IgA deficiency in a case of systemic lupus erythematosus

A 41-year-old female with high grade fever and polyarthralgia was diagnosed as SLE from polyarthralgia, leukopenia, LE cell and high titer anti-nuclear antibody. The serum IgA level was as long as 9mg/dl and unchanged by the treatment with prednisolone, while the serum IgG and IgM were increased and responded to the treatment. The persentage of E rosette-forming lymphocytes in the peripheral blood was 79% and the persentage of surface-IgA bearing cells in non E rosette-forming cells was 20%. When PWM-induced IgA synthesis by lymphocytes from normal control and the patient were measured, the level of IgA was about a quarter of normal synthesis. Co-culture of T cells from normal control and B cells from the patient resulted in reduced synthesis of IgA. Co-culture of the patient T cells and normal B cells also resulted in reduced synthesis of IgA. Thus the pathogenesis of IgA deficiency in the patients may be due to both B cells and T cells dysfunction.