Objective To investigate the presentationand significance of circulating autoantibodies to erythropoietin receptor (EPOR) in sera from patients with systemic lupus erythematosus (SLE). Methods One hundred and twenty-four consecutive patients with SLE, seven with autoimmune hemolytic anemia (AIHA), 19 patients with iron deficiency anemia (IDA) and 45 normal individuals were involved in this study. In all patients with SLE, the disease activity was evaluated using the European consensus Lupus Activity Measurement scale. Antibodies to EPOR were detected by enzyme-linked immunosorbent assay (ELISA). All data were tested with Chi-squared or Student's t tests by SPSS software. Results A higher frequency of antibodies to EPOR were detected in SLE patients than healthy controls (20.2% vs 2.2%, P=0.004), however, they could not be detected in AIHA and IDA patients. Moreover, anti-EPOR antibodies were detected in 17 (33.3%) of 51 SLE patients with anemia, compared with that in 8 (11.0%, P=0.002) of 73 patients without anemia. Furthermore, patients with antibodies to EPOR had more severe anemia and often presented as microcytic anemia (P =0.005) than those without anti-EPOR antibodies. Finally, anti-EPOR antibodies seemed to be more likely to occur in patients with skin rash (P=0.014), low levels of C3 component of complement (P=0.01), positive anti-dsDNA antibodies (P=0.000) and higher disease activity scores (P= 0.024). Conclusion The higher incidence of antibodies to EPOR in SLE patients with anemia suggest that anti-EPOR antibodies might play a vital role in the development of anemia in SLE patients. Thus, detecting anti-EPOR antibodies in SLE patients with anemia may be helpful.

This study was purposed to investigate the mechanism of thrombocytopenia in patients with systemic lupus erythematosus (SLE) through detecting anti-megakaryocyte antibodies in SLE patients. The serum anti-megakaryocyte antibodies in 36 SLE cases with thrombocytopenia were detected by using indirect immunofluorescence, the detected results were compared with detected results of 30 SLE cases without thrombocytopenia and 30 healthy persons. The results showed that the positive incidences of anti-megakaryocyte antibody in serum of 36 SLE cases with thrombocytopenia, 30 SLE cases without thrombocytopenia and 30 healthy persons were 19.4% (7/36), 6.7% (2/30) and 3.3% (1/30) respectively. As compared with SLE patients without thrombocytopenia and healthy persons, SLE patients with thrombocytopenia had higher incidence of anti-megakaryocyte antibodies, moreover there was significant difference between SLE patients with thrombocytopenia and healthy persons (p < 0.05), while there was no significant difference between SLE patients with or without thrombocytopenia (p > 0.05). It is concluded that autoantibodies against megakaryocytes exist in SLE patients and may partially contribute to the incidence of thrombocytopenia in SLE patients. The detection of anti-megakaryocyte antibodies with a enough case number is needed to make a final conclusion on thrombocytopenia pathogenesis in SLE.
Adult ; Autoantibodies ; blood ; Female ; Fluorescent Antibody Technique, Indirect ; Humans ; Lupus Erythematosus, Systemic ; blood ; immunology ; Male ; Megakaryocytes ; immunology ; Middle Aged