Expanded CD8 + CD38 + T Cell Population in Patients With Systemic Lupus Erythematosus Is Linked to Increased Infection Rates: A Prospective Study.

Objective: One of the leading causes of morbidity and mortality among patients with systemic lupus erythematosus (SLE) is infections. The expression of the ectonucleotidase CD38 on the surface of CD8 ⁺ T cells has been linked to compromised cytotoxic function. The aim of this prospective study was to assess whether the presence of CD8 ⁺ CD38 ⁺ in the peripheral blood of patients with SLE can serve as a biomarker for infectious complications.
Methods: A cohort of 80 patients with SLE were recruited over 18 months. The rate of clinically significant infections and presence of CD8 ⁺ CD38 ⁺ T cells in the peripheral blood were monitored at each clinic visit. The patients were classified into high CD38 ⁺ and low CD38 ⁺ CD8 ⁺ T cells using flow cytometry and a previously established cutoff rate of 28.4%.
Results: A total of 20 infections were registered over the study period. We observed that the patients with an expanded CD8 ⁺ CD38 ⁺ T cell population in the peripheral blood had a higher rate of recurrent infections and a higher likelihood of infection compared with patients with a low CD8 ⁺ CD38 ⁺ T cell population. The levels of CD38 in CD8 ⁺ T cells remained stable over time in the studied subjects.
Conclusion: High levels of CD8 ⁺ CD38 ⁺ T cells in the peripheral blood of patients with SLE identify a subgroup prone to infections for whom proper clinical measures should be applied.
(© 2024 The Author(s). ACR Open Rheumatology published by Wiley Periodicals LLC on behalf of American College of Rheumatology.)