Circulating L-selectin expressing-T cell subsets correlate with the severity of Foxp3 deficiency autoimmune disease

L-selectin (CD62L) is normally highly expressed in naïve T cells. The expression levels of CD62L have been reported to be decreased on T cells during the inflammatory state. It is currently unknown whether the frequency of CD62L⁺ T cell subsets in the peripheral blood can be used as a marker to indicate is disease severity during inflammation. Our study evaluated whether circulating CD62L⁺ T cell subsets correlate with the severity of disease by testing an autoimmune condition of scurfy (sf) mouse associated with multi-organ inflammation due to regulatory T cell deficiency. We observed that scurfy mice spontaneously developed an inflammatory phenotype with a significant decrease in the percentage of CD62L-expressing CD4⁺ T and CD8⁺ T cells in the peripheral blood. The percentage of CD62L⁺CD4⁺ T and CD62L⁺CD8⁺ T cells negatively correlated with disease severity, as determined by the weight of spleen and liver, as well as the mean area of lymphocyte infiltrates in lung and liver. The percentage of CD8⁺ T cells also correlated directly with these markers of disease severity. To conclude, our results support the concept that circulating CD62L-expressing T cells may be used as markers of disease severity in sf mice which is equivalent to a syndrome characterized by immune dysregulation with polyendocrinopathy, enteropathy, and X-linked inheritance (IPEX syndrome) in humans, or in other autoimmune or inflammatory conditions.