Decreased serum erythropoietin and its relation to anti-erythropoietin antibodies in anaemia of systemic lupus erythematosus

Objective. This study was performed to assess erythropoietin levels and anti-erythropoietin antibodies in patients with systemic lupus erythematosus (SLE). Methods. The sera of 100 patients with SLE were investigated for serum erythropoietin levels and the presence of anti-erythropoietin antibodies by ELISA. Routine laboratory parameters such as peripheral blood count, relevant parameters of blood chemistry, and immunological parameters of SLE were recorded. Results. Erythropoietin levels were significantly decreased in SLE patients when related to individual haemoglobin and haematocrit values (P <0.001), suggesting an inadequate erythropoietin response in SLE. Anti-erythropoietin antibodies were found in 46% of SLE patients. and erythropoietin levels (but not haemoglobin or haematocrit values were significantly decreased in these patients compared with patients without anti-erythropoietin antibodies. Serum erythropoietin concentration as determined by ELISA was reduced in the presence of anti-erythropoietin antibodies. Furthermore. anti-erythropoietin antibodies also correlated with younger age, decreased serum levels of complement factors C3 and C4 and elevated anti-double-stranded DNA antibodies. Conclusions. We conclude that the anaemia of SLE is characterized by an inadequate erythropoietin response. Anti-erythropoietin antibodies are frequently present in SLE and interfere with the measurement of serum erythropoietin level. However, these antibodies are not associated with increased severity of SLE-associated anaemia.