Bone Marrow Erythroid Maturation and Cytokine Production in Refractory Anemia Patients with Positive Mitogen-Stimulated-Direct Antiglobulin Test.

Autoimmune phenomena, particularly directed against RBC, are described in MDS. We already reported that the amount of anti-erythroblast antibodies was significantly greater in BM cultures of MDS patients versus controls, as detected by a new method named mitogen-stimulated-direct antiglobulin test (MS-DAT). We compared BM erythroid maturation and cytokine production in patients with refractory anemia (RA) and RA with ringed sideroblasts (RARS), with or without MS-DAT positive BM cultures. MS-DAT was performed by stimulating marrow cultures with PMA and PHA and anti-erythroblast antibodies were detected by competitive solid phase ELISA. Cytokine production (IL-2, IL-4, IL-10, TNF-alpha, TGF-beta and IFN-gamma) was investigated in BM cultures by ELISA assay. Eleven out of 23 patients showed positive MS-DAT in BM (cut off value 200 ng/ml+3SD), whereas none of them was positive in PB. By comparing patients with MS-DAT positive in BM versus negative patients, we found increased erythroblast counts and peripheral signs of hemolysis (i.e higher reticulocytes, indirect bilirubin, and LDH, and lower haptoglobin) in the former, in spite of a negative MS-DAT in BP. In BM MS-DAT positive patients TNF-alpha, IL-4, and IL-10 production was lower compared with MS-DAT negative patients. BM MS-DAT positivity suggests the existence of an anti-erythroblast autoimmunity and could support steroid therapy in some early MDS patients.