CD8+ S100B+ T cells

CD8+ S100B+ T cells are a phenotypically distinct subset of CD8+ cytotoxic T lymphocytes identified by co-expression of the S100B protein marker alongside the canonical CD8 surface antigen and T cell receptor complex. These cells represent a specialized population within the broader CD8+ T cell compartment with demonstrable relevance to immune-mediated inflammatory diseases, particularly psoriasis. Recent Mendelian randomization studies have identified CEBPD (CCAAT/enhancer binding protein delta) transcription factor expression specifically in CD8+ S100B+ T cells as a protective genetic factor against psoriasis development, indicating that this subset possesses distinct transcriptional programming that modulates disease susceptibility and immune homeostasis.

Like other CD8+ T cells, CD8+ S100B+ T cells are presumed to function as cytotoxic effector lymphocytes capable of antigen recognition and killing of infected or abnormal target cells through perforin and granzyme-mediated mechanisms. The precise functional and developmental significance of S100B co-expression—whether associated with tissue residency, developmental maturation state, metabolic programming, or specialized immune functions—remains incompletely understood. The identification of this subset illustrates functional heterogeneity within the CD8+ T cell pool and exemplifies how high-resolution immunophenotyping integrated with genetic approaches can reveal cell-type-specific disease mechanisms and potential therapeutic targets in immune-mediated pathology.