Background Some studies in animal models, support an association between occupational exposure to Organic Solvents (OS) and Systemic Lupus Erythematosus (SLE). The specific physiopathological changes that these chemicals could induce to accelerate an autoimmune response are not known. Dysregulation of B cells is central in SLE, but very little is known on how OS exposure could influence it. This study aimed to examine the distribution of B cell subsets on Healthy Controls and SLE patients occupationally exposed to OS.

Methods 40 SLE patients who met ACR criteria and 17 Healthy Controls were recruited and classified as occupationally exposed or not to OS. Cryopreserved peripheral lymphocytes were analyzed by multiparametric Flow Cytometry using CD3, CD19, CD27, and IgD markers.

Results SLE patients exposed to OS had increased frequencies of CD27+ Switched Memory (SWM) cells. This change was associated with a specific OS like degreasers and ketones. Additionally, the few HC exposed to OS showed a decrease in Unswitched (USM) cells, with similar frequencies as those seen in SLE patients.

Conclusions Exposure to OS increased SWM cells on SLE patients and decreased USM cells on Healthy Controls. The influence of OS on SWM differentiation may be mediated through T cells. Previous reports of exposure to Trichloroethylene (a common OS), showed increased CD4+ T cell activation and secretion of INF-γ, this causes excessive T follicular helper development and germinal center formation in mice that could induce abnormalities in B cell subsets, and a similar mechanism may operate in OS exposed patients. Further research is needed to verify this hypothesis.