Background Cytopenias are a common manifestation in systemic lupus erythematosus (SLE), and it is fundamental to determine their etiology in order to establish an adequate therapeutic strategy. The aim of this study was to determine the relevance of bone marrow aspirations (BMA) and biopsies while studying the cause of cytopenias in SLE patients, as well as describing associated clinical and laboratory features.

Methods We performed a retrospective study in a third-level hospital in Mexico City. We included patients who fulfilled ACR criteria for SLE, presented with cytopenias and had a BMA and biopsy performed between 2000 and 2016. We described the main aspirate and biopsy findings, and also analyzed the final diagnosis and its association with clinical, laboratory and serological features.

Results We included 101 patients; 81.2% were women. Median age was 32 years. Leukopenia (<3000 cells/µl) was found in 47.5% of patients; with lymphopenia (<1000 cells/L) being a common finding (71.3% of patients). Moderate-to-severe thrombocytopenia (<50 K/µl) was present in 28.7% of patients. Finally, 25.8% of patients presented with pancytopenia.

In 72.3% of patients, bone marrow interpretation, along with clinical and laboratory findings, lead to a conclusive diagnosis. The most common final diagnoses were disease activity (24.8%) and drug-associated toxicity (28.7%). The agreement between the initial diagnostic impression and the conclusion after BMA was performed was 45.5%.

We analyzed factors associated with the most common etiologies (table 1). Regarding BMA findings, when cytopenias were secondary to disease activity, it was more frequent for the bone marrow to be hypercellular (56 vs 23%, p=0.006) and to have increased megakaryocytes (40 vs 17.4%, p=0.048). Conversely, granulocytic dysplasia was less common in this group of patients (17.4% vs 54.3%, p=0.036).

After multivariate analysis, a neutrophil count <1000 cells/µl was a protective factor for disease activity (OR 0.021; 95% CI 0.001–0.428, p 0.012). On the other hand, a history of renal activity (OR 4.3; 95% CI 1.3–14.2, p=0.024) and neutrophils<1000 cells/µl (OR 4.05; 95% CI 1.15–14.19, p=0.029) were found to be independent risk factors for myelotoxicity.

Conclusions The most frequent diagnoses of SLE patients presenting with cytopenias were disease activity and drug-associated bone marrow toxicity. There are clinical characteristics and laboratory findings that may guide the diagnostic approach and thus, choose the most appropriate therapeutic intervention. BMA and biopsy play a key role in complementing the study of cytopenias in SLE patients, allowing for a complete evaluation of the particular context of each patient.

Funding Source(s): None