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Bone marrow involvement in systemic lupus erythematosus

Background
Besides peripheral cytopenias, bone marrow abnormalities, such as fibrosis, pure red cell aplasia and aplastic anemia have been reported in patients with systemic lupus erythematosus (SLE), suggesting that bone marrow may be a 25 target organ in SLE.


Aim
Our objective was to describe this bone marrow involvement.


Methods
This registry is a nationwide retrospective study. Centers provided data concerning medical history, SLE manifestations, type of hematologic disorder, treatments and outcome. Bone marrow aspirations and/or biopsies were transferred for centralized review.


Results
Thirty patients from 19 centers were included. Central hematologic manifestations comprised bone marrow fibrosis (n = 17; 57%), pure red cell aplasia (n = 8; 27%), myelodysplastic syndrome (n = 3; 10%), aplastic anemia and agranulocytosis (n = 1; 3% each). Bone marrow involvement was diagnosed concomitantly with SLE in 12 patients. Bone marrow biopsies showed fibrosis in 19 cases, including one case of pure red cell aplasia and one case of agranulocytosis and variable global marrow cellularity. Treatments included corticosteroids (90%), hydroxychloroquine (87%), rituximab (33%), intravenous immunoglobulins (30%), mycophenolate mofetil (20%) and ciclosporine (20%). After a median follow-up of 27 months (range: 1-142), 24 patients manifested complete improvement. No patient died.


Conclusions
This registry comprises the largest series of SLE patients with bone marrow involvement. It demonstrates the strong link between SLE and bone marrow fibrosis. Patients with atypical or refractory cytopenia associated with SLE should undergo bone marrow examination to enable appropriate, and often effective, treatment. Long-term prognosis is good.