Preliminary Study of the Autoantigens on the Membrane of Erythropoietic Cells of the Patients with BMMNC- Coomb's Test(+) Hemocytopenia

Abstract

AbstractAbstract 4435 ObjectiveTo observe the relationship between EPO receptor(EPOR) and autoantibodies-IgG/IgM (auto-Ab) on the membrane of erythropoietic cells of the patients with bone marrow mononuclear cell Coomb's (BMMNC-Coomb's) test(+) immuno-related pancytopenia(IRP), and then explore the probable autoantigens of auto-Ab in IRP. Methods46 newly diagnosed IRP patients (15 with auto-Ab on erythropoietic cells and 31 without auto-Ab on erythropoietic cells) and 18 healthy donors as controls were enrolled in this study. EPOR expression on their nuclear erythrocytes were tested with flow cytometry to observe the relationship between EPOR and auto-Ab; After sorting erythropoietic cells in bone marrow, EPOR mRNA and protein Stat5,P-Stat5 were investigated by RT-PCR and Western blot to observe the production of EPOR and EPO/EPOR signal transduction; Finally, EPOR expression on the membrane were tested again after stripping auto-Ab with glycine buffer. Results(1) EPOR of auto-Ab(+) arm(1.59±0.87)% was significantly lower than that of auto-Ab (-) arm(4.58±4.09)%(P<0.01), and the latter was significantly higher than that of normal controls (2.27±1.76)%(P<0.05); EPOR of IRP patients was negatively correlated with their auto-Ab (r=-0.543,P=0.000) and its regression equation was Y(EPOR)=0.040-0.335X(auto-Ab);(2)EPOR mRNA of auto-Ab(+) arm(0.685±0.136)was significantly higher than that of auto-Ab (-) arm(0.554±0.116)(P<0.01)and normal controls (0.580±0.119)(P<0.05);(3)Protein Stat5 of auto-Ab(+) arm(1.45±0.94) was significantly higher than that of normal controls (0.54±0.36)(P<0.05); While P-Stat5 of auto-Ab(+) arm(0.42±0.18) was significantly lower than that of normal controls (0.85±0.38)(P<0.05); (4) EPOR expression became higher while auto-Ab became lower after stripping with glycine buffer. ConclusionThe auto-Ab of some IRP patients might block or competitively inhibit the EPOR on the membrane of erythropoietic cells. EPOR was one of autoantigens in IRP. Disclosures:No relevant conflicts of interest to declare.