CD154 als früher Aktivierungsmarker zur Detektion von antigenspezifischen CD4+ T-Zellen in PBMC von Pemphigus vulgaris-Patienten und Birkenpollenallergikern

The analysis of T lymphocyte proliferation and activation following antigenic or mitogenic stimulation is an important parameter in the diagnosis of various immunodeficiencies and in monitoring the success of therapy. In this study, new insights were gained into the role of antigen-specific activated T cells in the cellular and humoral mechanisms of the adaptive autoimmune response in pemphigus vulgaris (PV) and birch pollen allergy (BPA). Both after stimulation with human desmoglein (Dsg) 3, the major autoantigen in PV, and after stimulation with birch pollen extract (BPE), the expression of CD154 was significantly increased in PV patients and BPA compared to healthy controls (K). The appearance of reactive CD4+CD154+ T cells was not limited to specific TH subtypes. Furthermore, stimulation with immunodominant Dsg3 epitopes, especially P2, induced a strong CD4+ T cell response via a CD40-CD154 interaction similar to the human Dsg3 protein. Patients with active disease (partial remission) had higher numbers of Dsg3 and peptide-specific reactive CD4+ T cells than patients in complete remission or K. By isolating these cells using surface and intracellular staining and subsequent flow cytometry, rapid ex vivo manipulation and detailed analysis of CD4+ CD154+ T cells could be performed. This method enabled the detection of CD154+CD4+ T cells independent of their cytokine production and MHC haplotype. The results show that CD154 expression is highly sensitive and specific for human antigen-specific activated CD4+ T cells in PV and BPA. The work suggests that antigen-specifically activated CD154+ CD4+ T cells play a central role in pathogenesis. Further studies are needed to better understand the various factors influencing CD154 expression and the long-term effects. This work lays a foundation for future predictive tools to monitor disease activity and test immunotherapies.