IgG Subclasses Abnormal in Immune-Related Pancytopenia

In recent years, we found some patients with idiopathic cytopenia of undetermined significance (ICUS)responded well to corticosteroid and/or high-dose intravenous immunoglobulin treatment. We had detected both IgG and IgM antibodies by bone marrow mononuclear-cell-Coombs test, flow cytometric and immunofluorescence analysis on the various bone marrow cell membrane. We also detected IgG in the BM supernatant of these ICUS patients, which can target several antigens on hematopoietic cells membranes by western blot. Then We termed this group of ICUS cases with autoantibodies as immuno-related hemocytopenia(IRP). IgG include IgGl, IgG2, IgG3, IgG4. IgG subclass defects, increased or imbalance in autoimmune diseases, infectious diseases, cancer and other diseases is an indication of the immune response, and IgG subclass in the development of the disease process also plays a different effect. Analysis of IgG subclass is beneficial for the disease etiology, pathogenesis and prognosis. 46 IRP patients and 20 normal controls were enrolled in this study. 58.69% patients’ hematopoietic cell antibody IgG were positive tested by flow cytometric. Hematopoietic cell antibody IgG-positive patients’ bone marrow supernatant were detected and analyzed, IgG1 and IgG3 were increased in the bone marrow supernatant of the patients with IRP, positively related to CD5+ B lymphocytes, and negative correlated with hematopoietic function. Further studies are needed to confirm which IgG subclass plays an important role in the pathogenesis of IRP.