The following is a summary of “Frequency of HLA-DR+CD38hi T cells identifies and quantifies T-cell activation in hemophagocytic lymphohistiocytosis, hyperinflammation, and immune regulatory disorders,” published in the January 2024 issue of Allergy & Immunology by Nguyen, et al.
Quantifying T-cell activation is crucial for diagnosing and assessing treatment response in various hyperinflammatory and immune regulatory disorders, such as hemophagocytic lymphohistiocytosis. Plasma-soluble IL-2 receptor (sIL-2R) serves as a well-established biomarker for evaluating systemic T-cell activation. However, limited availability of sIL-2R testing may lead to delayed diagnosis, and elevated sIL-2R levels may not always accurately reflect T-cell activation. For a study, researchers sought to investigate whether cell surface markers of T-cell activation, namely HLA-DR and CD38, assessed through flow cytometry, could quantify systemic T-cell activation across different inflammatory disease states and correlate with sIL-2R levels.
Patient medical records provided results for sIL-2R, CXCL9, and ferritin assays. Flow cytometry was used to assess the frequency of HLA-DR+CD38high (hi) T-cells in various T-cell subsets.
In the study cohort, activation levels in total CD8+ T-cells (r = 0.65; P < .0001) and CD4+ T-cells (r = 0.42; P < .0001) significantly correlated with plasma sIL-2R levels. At disease onset, the frequency of HLA-DR+CD38hi T-cells in CD8+ and CD4+ effector memory (TEM) compartments showed strong correlations with sIL-2R levels. Evaluation of T-cell activation markers in follow-up samples also revealed positive correlations between CD4+ TEM and CD8+ TEM activation with sIL-2R levels, indicating utility in initial diagnosis and treatment response evaluation. Moreover, the frequency of HLA-DR+CD38hiT-cells in the CD8+ TEM compartment correlated with plasma CXCL9 (r = 0.42; P = .0120) and ferritin levels (r = 0.32; P = .0037).
Flow cytometry-based direct T-cell activation assessment through HLA-DR+CD38hi T-cells accurately quantifies T-cell activation and strongly correlates with sIL-2R levels across various hyperinflammatory and immune dysregulation disorders.
Reference: jacionline.org/article/S0091-6749(23)00928-4/abstract