METHODS: Circulating CD8+ T cells were analysed for differentiation status (CD45RO, CCR7), markers of activation (CD69 and CD25) and proliferation (Ki-67) in 14 newly diagnosed GCA patients and 18 healthy controls by flow cytometry. Proliferative capacity of CD8+ T cells upon anti-CD3 and anti-CD3/28 in vitro stimulation was assessed. Single-cell RNA sequencing of peripheral blood mononuclear cells of patients and controls (n = 3 each) was performed for mechanistic insight. Immunohistochemistry was used to detect CD3, CD8, Ki-67, TNF-α and IFN-γ in GCA-affected tissues.
RESULTS: GCA patients had decreased numbers of circulating effector memory CD8+ T cells but the percentage of Ki-67-expressing effector memory CD8+ T cells was increased. Circulating CD8+ T cells from GCA patients demonstrated reduced T cell receptor activation thresholds and displayed a gene expression profile that is concurrent with increased proliferation. CD8+ T cells were detected in GCA temporal arteries and aorta. These vascular CD8+ T cells expressed IFN-γ but not Ki-67.
CONCLUSION: In GCA, circulating effector memory CD8+ T cells demonstrate a proliferation-prone phenotype. The presence of CD8+ T cells in inflamed arteries seems to reflect recruitment of circulating cells rather than local expansion. CD8+ T cells in inflamed tissues produce IFN-γ, which is an important mediator of local inflammatory responses in GCA.
RESULTS: Compared to the non-obese diabetic resistant (NOR) mice, the peritoneal macrophages of NOD mice expressed increased levels of PPARalpha but reduced levels of PPARgamma2, while PPARgamma1 expression was unchanged in all age groups. CD4-positive lymphocytes expressed low levels of PPARalpha in diabetic NOD mice and greatly reduced expression of PPARgamma2 in all age groups. Unlike peritoneal macrophages and CD4-positive cells, the CD8-positive cells expressed low levels of PPARgamma1 in diabetic NOD mice but no difference in PPARalpha and PPARgamma2 expression was observed compared to NOR mice.
CONCLUSION: The current findings may suggest an important regulatory role of PPARs in the pathogenesis of autoimmune diabetes.
METHODS: All PLWH enrolled in adult HIV cohorts of IeDEA Asia-Pacific who started with triple-ART with at least 1 CD4, CD8 (3-month window), and HIV-1 RNA measurement post-ART were included. CD4/CD8 ratio normalization was defined as a ratio ≥1. Longitudinal changes in CD4/CD8 ratio were analyzed by linear mixed model, the incidence of the normalization by Cox regression, and the differences in ratio recovery by group-based trajectory modeling.
RESULTS: A total of 5529 PLWH were included; 80% male, median age 35 years (interquartile range [IQR], 29-43). First-line regimens were comprised of 65% NNRTI, 19% PI, and 16% INSTI. The baseline CD4/CD8 ratio was 0.19 (IQR, 0.09-0.33). PLWH starting with NNRTI- (P = 0.005) or PI-based ART (P = 0.030) had lower CD4/CD8 recovery over 5 years compared with INSTI. During 24,304 person-years of follow-up, 32% had CD4/CD8 ratio normalization. After adjusting for age, sex, baseline CD4, HIV-1 RNA, HCV, and year of ART initiation, PLWH started with INSTI had higher odds of achieving CD4/CD8 ratio normalization than NNRTI- (P < 0.001) or PI-based ART (P = 0.015). In group-based trajectory modeling analysis, INSTI was associated with greater odds of being in the higher ratio trajectory.
CONCLUSIONS: INSTI use was associated with higher rates of CD4/CD8 ratio recovery and normalization in our cohort. These results emphasize the relative benefits of INSTI-based ART for immune restoration.