Autoimmune haemolytic anaemia and autoimmune thrombocytopenia in childhood-onset systemic lupus erythematosus: updates on pathogenesis and treatment.

Abstract

Autoimmune haemolytic anaemia (AIHA) and autoimmune thrombocytopenia are common complications of childhood-onset lupus, which may be life-threatening. A greater understanding of the pathogenesis of these haematologic manifestations will enhance our understanding of the biology of systemic lupus erythematosus (SLE) and inform the identification of novel treatments. The mechanisms underlying AIHA and autoimmune thrombocytopenia are incompletely understood and likely multifactorial. Although the development of auto-antibodies is central to the disease process, recent studies have demonstrated the importance of cytokines in the underlying pathologic process. In-vitro and in-vivo evidence points to a role for IL17 in the pathogenesis of AIHA, which involves loss of tolerance to red cell auto-antigens and the development of autoantibodies. Sirolimus, an mTor inhibitor, has benefited patients with primary autoimmune cytopenias, possibly by stimulating T regulatory cells, and may also have efficacy for SLE-associated cytopenias. Similarly, low-dose recombinant human IL-2 therapy has shown promising results for improving platelet counts in patients with autoimmune thrombocytopenia, possibly by restoring the balance between T regulatory, T helper and Th17 cells. The emergence of new agents directed at restoring immune dysregulation hold promise for the treatment of AIHA and autoimmune thrombocytopenia and should provide better tolerated alternatives to high-dose corticosteroids.