Autoimmune hematologic diseases associated with infraclinical systemic lupus erythematosus in four patients. A human equivalent of the NZB mice.

In four patients with a diagnosis of autoimmune hemolytic anemia or idiopathic thrombocytopenic purpura antinuclear antibodies and circulating immune complexes (Clq-BA test) have developed at some time in their history. Renal biopsy material was assayed with different methods. Immunofluorescence studies revealed granular deposits of immunoglobulin G (IgG), immunoglobulin M (IgM) and third component of complement (C3). Upon optic microscopy, three patients had mild mesangial proliferation, one a focal glomerulonephritis. Upon electron microscopy, all patients exhibited mesangial and/or subendothelial deposits. The patients have been followed for 18 to 37 years since the beginning of their disease. There has been no clinical evidence of systemic lupus erythematosus (SLE), although they present in their glomeruli immunologic and anatomic features compatible with this disease. These patients seem to be a human equivalent of the black NZB mouse which presents immunohematologic disorders and some biologic markers of SLE without having a full clinical picture of SLE.