Abstract
Thrombocytopenia in Systemic Lupus Erythematosus (SLE) is a common clinical manifestation affecting up to one third of patients in published cohorts. Anti-platelet antibodies have been implicated in its pathogenesis, as sensitized platelets interact with macrophages through the Fc receptor eliminating them from circulation. Non-specific, immunecomplex mediated platelet destruction is also implicated as are antiphospholipid syndrome, thrombotic microangiopathies and hemophagocytic syndrome. A few cases of thrombocytopenia with amegakaryocytic hypoplasia due to antibodies against c-mpl receptor have recently been identified. Pathophysiology has recently been intrigued by frequent findings of anti-thrombopoietin antibodies and faulty hemopoiesis in SLE patients with cytopenias. More specifically, histologic data has shown dysplastic changes and stromal alteration suggesting that bone marrow is a target organ in SLE. Although thrombocytopenia, per se, is a benign complication, with hemorrhagic manifestations being infrequent, it is associated with a more active disease and worse outcome: it marks a subgroup of SLE patients, having a higher risk of irreversible end-organ events throughout their disease course. These patients exhibit a predilection to a distinct pattern of damage, rendering thrombocytopenia a quantitive and qualitative marker of impending damage. Immunosuppressive therapy is required to restore normal platelet counts and treat concomitant organ involvement of other systems. Common therapeutic modalities include corticosteroids, intravenous immunoglobulin (IVIG), cytotoxic agents (mainly cyclophosphamide), immunomodulators (azathioprine) and androgens (Danazol). More recently, B-lymphocyte depletion (anti- CD20 immunotherapy) and mycofenolate mofetil have been successfully used in refractory cases with splenectomy as a last resort should other options fail.
Keywords: Systemic lupus erythematosus, thrombocytopenia, pathogenesis, prognosis
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