Citations

Abstract Introduction The ability of the adaptive immune system to have memory of previous pathogen encounters is the basis for vaccination as one of the most successful medical interventions. With increasing age, the ability to develop protective immunity after vaccination declines. Differentiation into T memory cells is at least in part determined during the early cell divisions after activation when cells undergo assymmetric cell division (ACD). Fate decisions depend on the uneven distribution of signaling molecules and transcription factors with accumulation of mTORC1 activity biasing for an effector and TCF1 for a memory state. We explored whether ACD of naïve CD4 T cells is impaired in older adults. Methods We used human primary cells from young and older adults. Human naive CD4 T cells were isolated and cultured in RPMI, 10% FBS and antibiotics on plates coated with anti-CD3 Ab, anti-CD28 Ab and huICAM1 for 3 days. We used transfection by electroporation to modify gene expression. Read out systems included confocal microscopy, flow cytometry and lysosome function assays. Results were compared by t-test with values of p < 0.05 considered significant. Results Naive CD4 T cell responses from older adults is characterized by increased activation of the AKT-mTORC1 pathway and reduced ACD of mTORC1 activity. Increased RICTOR expression resulting in increased mTORC2 activity in naive CD4 T cells from older individuals accounted for the activation of the AKT-mTORC1 pathway. AKT inhibition or silencing of RICTOR restores ACD of mTORC1 activity as well as of TCF1. Conversely, ACD was also improved through inducing WNT signaling by GSK3β inhibition irrespective of RICTOR expression. Conclusion Our data show that increased RICTOR expression in naïve T cells from older adults at least in part accounts for defective memory cell generation. Silencing of RICTOR or downstream AKT inhibition can enforce both mTORC1 ACD and TCF1 ACD suggesting that mTORC2 is a promising target to improve vaccine responses. Funding Source n/a Topic Categories Lymphocyte Differentiation and Peripheral Maintenance (LYM)

Objective Medium‐vessel vasculitis involving the visceral vasculature in adults is rare. Pancreatic ductal adenocarcinoma (PDAC) has been implicated in medium artery vascular thickening secondary to extravascular migratory metastasis with involvement of the celiac and superior mesenteric vessels. Methods Patients presenting to the rheumatology vasculitis subspecialty clinic were retrospectively identified using an electronic health record data exploration tool evaluating for diagnosis of pancreatic cancer, periaortitis, and vasculitis between January 2015 and December 2024. Results We retrospectively identified four patients with PDAC initially presenting with periarterial thickening of the celiac and superior celiac and superior mesenteric vessels (100% White, 50% male, median age 70.5 years). All four patients had abdominal pain with significant unintentional weight loss, with a median weight loss of 25 pounds (range 25–50 pounds). The median time to correct diagnosis was 221 days (range 162–340 days). All four patients had an elevated carbohydrate antigen 19‐9 level (range from 114 to 10,702, with a median of 341.5 U/mL). All four patients were diagnosed with endoscopic ultrasound–guided fine‐needle aspirations. The median number of biopsies required to make the diagnosis was three. Conclusion Isolated celiac and superior mesenteric periarterial thickening or “cuffing” is a vasculitis mimic that should prompt a comprehensive malignancy workup. Expedited referral to a tertiary center is essential given difficulty in tissue sampling with conventional methods and to avoid further delays in diagnosis.

Older adults are susceptible to infections in part due to waning of immune memory. To uncover mechanisms of a long-lasting immune memory, we contrasted varicella zoster virus antigen–specific memory T cell responses in adults vaccinated at young (<20 years) or older age (>50 years) with a live-attenuated vaccine conferring durable protection only when given at young age or with an adjuvanted component vaccine eliciting long-lasting immunity in older adults. Unlike VZV-specific CD4 + T cells, CD8 + T cells exhibited profound age-sensitive changes including memory subset shifts, reduced T cell receptor diversity, and loss of stem-like features. Vaccination of older adults with the adjuvanted vaccine did not restore CD8 + defects but selectively enhanced T helper 17 (T H 17) CD4 + T cells and prevented their conversion into regulatory T cells, likely through lipid metabolic regulation. Thus, durable vaccine efficacy with aging relies on antigen-specific T H 17 cells that compensate for CD8 + T cell defects.

ABSTRACT Older adults are susceptible to infections, in part due to waning of immune memory. To determine mechanisms that determine long-lasting versus short-term immunity, we examined varicella zoster virus (VZV) vaccination as a model system. We contrasted VZV antigen-specific T cells several years after vaccination in adults who had been vaccinated at young (<20 years) or older age (>50 years) with a live-attenuated vaccine that confers durable protection only when given at young age, or with an adjuvanted VZV component vaccine that elicits effective, long-lasting immunity in older adults. CD8 + T cells were highly sensitive to age-related changes showing T cell subset shifts, loss in TCR diversity and reduced stem-like features while gaining NK-like signatures without evidence for cellular senescence or exhaustion. VZV-specific CD4 + T cells were largely resilient to age and maintained phenotypic and TCR diversity. Immunization of older adults with the adjuvanted VZV vaccine did not reverse age-associated defects in CD8 + T cells. Instead, it selectively improved the functionality of VZV-specific Th17 CD4 + T cells and prevented their acquisition of Treg features, likely as consequence of lipid metabolic pathways. Collectively, our data indicate that effective vaccination in older adults is supported by the generation of a durable, antigen-specific CD4 + Th17 population that resists mis-differentiation into Tregs and that compensates for age-related defects in CD8 + T cells. One sentence summary Aging primarily impairs the CD8 + T cell VZV vaccine response, while effective VZV vaccination in older adults induces antigen-specific Th17 CD4 + T cells to compensate for aging defects.

IgG4-related disease (IgG4-RD) is a systemic immune-mediated fibroinflammatory disease whose pathomechanisms remain poorly understood. Here, we identified gene variants in familial IgG4-RD and determined their functional consequences. All 3 affected members of the family shared variants of the transcription factor IKAROS, encoded by IKZF1 , and the E3 ubiquitin ligase UBR4. The IKAROS variant increased binding to the FYN promoter, resulting in higher transcription of FYN in T cells. The UBR4 variant prevented the lysosomal degradation of the phosphatase CD45. In the presence of elevated FYN, CD45 functioned as a positive regulatory loop, lowering the threshold for T cell activation. Consequently, T cells from the affected family members were hyperresponsive to stimulation. When transduced with a low-avidity, autoreactive T cell receptor, their T cells responded to the autoantigenic peptide. In parallel, high expression of FYN in T cells biased their differentiation toward Th2 polarization by stabilizing the transcription factor JunB. This bias was consistent with the frequent atopic manifestations in patients with IgG4-RD, including the affected family members in the present study. Building on the functional consequences of these 2 variants, we propose a disease model that is not only instructive for IgG4-RD but also for atopic diseases and autoimmune diseases associated with an IKZF1 risk haplotype.

ABSTRACT Crohn's disease is a chronic inflammatory disorder of the gastrointestinal tract, frequently presenting with extraintestinal manifestations. Granulomatosis with polyangiitis is a systemic vasculitis primarily affecting the respiratory tract and kidneys. Extraintestinal Crohn's disease and granulomatosis with polyangiitis may have similar clinical presentations and, in rare occurrences, can coexist. This case report highlights the diagnostic and therapeutic complexities of this uncommon overlap syndrome.