Effect of aging on T cells in patients with Crohn’s disease

Aging is described as a gradual loss of function which impacts the organism at a cellular level. Aging was often linked to immune system disorders, which can induce systemic inflammation. For example, there is a prevalence of inflammatory bowel diseases (IBD) with increasing age. Until now, the effect of aging on T cells in patients with Crohn’s disease (CD) has not been studied.

To evaluate the impact of age-related changes on T cells in IBD, peripheral blood mononuclear cells (PMBCs) were isolated from blood samplesof patients diagnosed with CD and evaluated via flow cytometry for aged-related markers, such as CD45RA/CCR7 and CD27/CD28. The disease status was assessed via Harvey-Bradshaw Index (HBI). Patients with HBI< 5 were considered in remission, while patients with an HBI≥5 had active disease.

Our results revealed different patterns for naive/memory populations, when comparing young (< 50 years old) and old (≥50 years old) patients. The relative number of CD4+ and CD8+ T cells remained unchanged, but aging affected effector/memory subpopulations in CD8+ T cells. For example, CD8+ T cells showed a dramatic increase in terminally differentiated effector memory cells re-expressing CD45RA (TEMRA) that correlated with older patients (≥50 years old). CD4+ T cell subset showed a similar pattern in aged patients (≥50 years old), but less pronounced. Moreover, the loss of CD27/CD28 co-stimulatory molecules was predominant in both CD4+ and CD8+ T cells in aging patients, but was significantly more pronounced in CD8+ T cells. Interestingly, a correlation between disease status and age-related changes in T cell populations was also observed. Increased effector/memory and CD27-CD28- T cell accumulation was specific to older patients (≥50 years old) where CD was in remission, proposing an increased T cell exhaustion in this group of patients.

In conclusion, our data showed that age-related differences impact T cell populations in patients with Crohn’s disease. These findings suggest that highly differentiated T cells in older patients could potentially influence the course of the disease. Further studies could provide insights into mechanisms of T cell aging and exhaustion that could enable new therapeutic strategies in IBD.

Publication History

Article published online:
07 September 2021