CD38, CD81 and BAFFR combined expression by transitional B cells distinguishes active from inactive systemic lupus erythematosus.

In view of its heterogeneous presentation and unpredictable course, clinical management of systemic lupus erythematosus (SLE) is difficult. There is a need for biomarkers and diagnostic aids to monitor SLE disease activity and severity prior to, during and after treatment. We undertook this study to search for unique phenotypic patterns in each peripheral blood (PB) B cell subset, capable of distinguishing SLE patients with inactive disease versus SLE patients with active disease versus controls by using an automated population separator (APS) visualization strategy. PB was collected from 41 SLE patients and 28 age- and gender-matched controls. We analyzed the cell surface markers (in a tube CD20/CD27/CD19/CD45/CD38/CD81/BAFFR combination) expression on PB B cell subsets using principal component analysis, implemented in the APS software tool. Overall, our analysis indicates that active SLE can be distinguished from inactive SLE on the basis of a single tube analysis, focused on the decreased expression of CD38, CD81 and BAFFR in transitional B cells. The cluster analysis of immunophenotypic profiles of B cell subsets highlighted disease-specific abnormalities on transitional B cells that emerge as promising surrogate markers for disease activity. Further validation is needed with larger samples and prospective follow-up of patients.