Bone marrow as a target organ of systemic lupus erythematosus: analysis of cases with myelofibrosis.

Abstract

Cytopenia in the course of systemic lupus erythematosus (SLE) may be due to multiple factors. In this study, we aimed primarily to evaluate the detailed results of bone marrow (BM) biopsies of SLE patients, secondly to determine the myelofibrosis (MF) frequency and thirdly to compare BM morphologic findings as well as the clinical and laboratory parameters between groups (with MF and without MF) in cytopenic SLE patients. We retrospectively analyzed 224 SLE patients' files. Patients were divided into two groups according to whether they had MF or not. Concurrent SLE organ involvements, medical therapy and detailed BM findings were recorded. Forty-five (20%) of 224 SLE patients were found to have undergone BM biopsy due to cytopenia. Four patients were excluded (two drug-induced cytopenia, one lymphoma, one insufficient BM biopsy samples). While MF was detected in 29 (70.7%) of the 41 patients, 12 patients did not have MF. Between the two groups, no differences were identified in terms Systemic Lupus Erythematosus Disease Activity Index, BM cellularity, or BM dysplastic changes (P = 0.788, P = 0.672 and P = 0.494, respectively). In the SLE-associated MF group, 27 patients responded to immunosuppressive therapy and corticosteroids, but two patients were unresponsive. The response time was longer for the SLE-associated MF group compared to the without MF group (3.3 ± 3.1 months vs. 1.7 ± 1.2 months, P = 0.091). Correlation analysis revealed that increased degree of BM fibrosis delayed the response time (r = 0.471, P = 0.002). MF is common in SLE patients. SLE-associated MF as an additional factor for cytopenia in SLE patients may lead to delayed response to appropriate therapy, which may be dependent on the increased grade of BM fibrosis.