SERUM INHIBITORS OF HEMATOPOIESIS IN A PATIENT WITH APLASTIC-ANEMIA AND SYSTEMIC LUPUS-ERYTHEMATOSUS - RECOVERY AFTER EXCHANGE PLASMAPHERESIS

A 36 year old black woman with serologic evidence of systemic lupus erythematosus had aplastic anemia that failed to respond to corticosteroid or androgen therapy. Bone marrow culture studies were performed to determine if the marrow aplasia was immunologically mediated. A potent serum inhibitor of in vitro myeloid and erythroid colony formation was demonstrated. Incubation of normal bone marrow cells with the patient's serum and a source of complement caused a 95 per cent reduction in myeloid colony formation. Under these conditions, bone marrow from 35 normal volunteer subjects formed a mean of 5 ± 1 colonies per 2 × 105 marrow cells plated (control = 95 ± 8 colonies). The addition of the patient's serum plus complement to normal marrow cultured in methylcellulose also caused a 98 per cent reduction in erythroid colony numbers. Assay of serum immunoglobulin fractions obtained by gel filtration demonstrated that the inhibitory activity was contained in the immunoglobulin G (IgG) fraction. In association with a series of plasma exchanges, the titer of inhibitor fell, and marrow cellularity and peripheral blood counts returned to normal. Additional studies indicated that the inhibitor of allogeneic marrow was not directed against HLA or B-cell" antigens. Incubation of the patient's recovery marrow with stored preplasmapheresis serum and complement did not produce a reduction in myeloid colony formation. It seems most likely that the inhibitor represents alloantibody directed against heretofore unrecognized antigens widely distributed on normal human hematopoietic progenitor cells. © 1979."