High-affinity CD4 T cells produce IL-21 to help CD8 T cells differentiate into tissue-resident memory cells in the brain.

Cancer-related fatigue is a common, burdensome symptom of cancer and a side-effect of chemotherapy. While a Mediterranean Diet (MedDiet) promotes energy metabolism and overall health, its effects on cancer-related fatigue remain unknown. In a randomized controlled trial, we evaluated a rigorous MedDiet intervention for feasibility and safety as well as preliminary effects on cancer-related fatigue and metabolism compared to usual care. Participants had stage I–III cancer and at least six weeks of chemotherapy scheduled. After baseline assessments, randomization occurred 2:1, MedDiet:usual care. Measures were collected at baseline, week 4, and week 8 including MedDiet adherence (score 0–14), dietary intake, and blood-based metabolic measures. Mitochondrial respiration from freshly isolated T cells was measured at baseline and four weeks. Participants (n = 33) were 51.0 ± 14.6 years old, 94% were female, and 91% were being treated for breast cancer. The study was feasible, with 100% completing the study and >70% increasing their MedDiet adherence at four and eight weeks compared to baseline. Overall, the MedDiet intervention vs. usual care had a small-moderate effect on change in fatigue at weeks 4 and 8 (ES = 0.31, 0.25, respectively). For those with a baseline MedDiet score <5 (n = 21), the MedDiet intervention had a moderate-large effect of 0.67 and 0.48 at weeks 4 and 8, respectively. The MedDiet did not affect blood-based lipids, though it had a beneficial effect on fructosamine (ES = −0.55). Fatigue was associated with mitochondrial dysfunction including lower basal respiration, maximal respiration, and spare capacity (p < 0.05 for FACIT-F fatigue subscale and BFI, usual fatigue). In conclusion, the MedDiet was feasible and attenuated cancer-related fatigue among patients undergoing chemotherapy, especially those with lower MedDiet scores at baseline.

Tissue-resident memory CD8 T (T_RM) cells defend against microbial reinfections at mucosal barriers; determinants driving durable T_RM cell responses in non-mucosal tissues, which often harbor opportunistic persistent pathogens, are unknown. JC polyomavirus (JCPyV) is a ubiquitous constituent of the human virome. With altered immunological status, JCPyV can cause the oft-fatal brain demyelinating disease progressive multifocal leukoencephalopathy (PML). JCPyV is a human-only pathogen. Using the mouse polyomavirus (MuPyV) encephalitis model, we demonstrate that CD4 T cells regulate development of functional antiviral brain-resident CD8 T cells (bT_RM) and renders their maintenance refractory to systemic CD8 T cell depletion. Acquired CD4 T cell deficiency, modeled by delaying systemic CD4 T cell depletion until MuPyV-specific CD8 T cells have infiltrated the brain, impacted the stability of CD8 bT_RM, impaired their effector response to reinfection, and rendered their maintenance dependent on circulating CD8 T cells. This dependence of CD8 bT_RM differentiation on CD4 T cells was found to extend to encephalitis caused by vesicular stomatitis virus. Together, these findings reveal an intimate association between CD4 T cells and homeostasis of functional bT_RM to CNS viral infection. Tissue resident memory cells (T_RM) persist in nonlymphoid organs serving as frontline defense against microbial reinfection. The requirements for generating pathogen-specific T_RM to acutely resolved infections is well documented; however, little is known about the development of T_RM to persistent infections. In this study, we investigated the importance of CD4 T cell availability to CD8 T_RM development during persistent viral encephalitis. Using mouse polyomavirus (MuPyV) brain infection and systemic CD4 T cell insufficiency, we found that loss of CD4 T cells abrogated brain T_RM (bT_RM) development, disrupted the metabolic homeostasis of CD8 T cells, and reduced CD8 T cell responses upon viral reinfection. Additionally, CD8 T cells in CD4 T cell-deficient mice required resupply from circulating CD8 T cells, directly contrasting the independence from circulation in canonical T_RM. Upon delayed CD4 T cell depletion and brain infection with an acutely resolving viral infection, CD8 T cells also had aberrant bT_RM development and required resupply from the vasculature. Our findings demonstrate that CD4 T cells are essential for establishing long-lasting, virus-specific CD8 bT_RM for antiviral CNS immunosurveillance. Our data also raise important clinical implications for developing therapies to augment CD4 T cell help to bolster protective CD8 bT_RM responses.

Cancer-related fatigue is a common, burdensome symptom of cancer and side-effect of chemotherapy. While a Mediterranean Diet (MedDiet) promotes energy metabolism and overall health, its effects on cancer-related fatigue remain unknown. In a randomized controlled trial, we evaluated a rigorous MedDiet intervention for feasibility and safety as well as preliminary effects on cancer-related fatigue and metabolism compared to usual care. Participants had stage I-III cancer and at least 6 weeks of chemotherapy scheduled. After baseline assessments, randomization occurred 2:1, MedDiet:usual care. Measures were collected at baseline, week 4, and week 8 including MedDiet adherence, dietary intake, and blood-based metabolic measures. Mitochondrial respiration from freshly isolated T cells was measured at baseline and 4 weeks. Participants (n=33) were 51.0±14.6 years old, 94% were female, and 91% were being treated for breast cancer. The study was feasible, with 100% completing the study and >70% increasing their MedDiet adherence at 4 and 8 weeks compared to baseline. Overall, the MedDiet intervention vs. usual care had a small-moderate effect on change in fatigue at weeks 4 and 8. For those with a baseline MedDiet score<5 (n=21), the MedDiet intervention had a moderate-large effect of 0.67 and 0.48 at weeks 4 and 8, respectively. The MedDiet did not affect blood-based lipids, though it had a beneficial effect on fructosamine (ES= -0.55). Fatigue was associated with mitochondrial dysfunction including lower basal respiration, maximal respiration, and spare capacity (p<0.05 for FACIT-F fatigue subscale and BFI, usual fatigue). In conclusion, the MedDiet was feasible and attenuated cancer-related fatigue among patients undergoing chemotherapy, especially those with lower MedDiet scores at baseline.

Tumor necrosis factor (TNF)α is a major regulator of inflammation. However, the epigenetic regulation of TNFα in the context of an exercise intervention among older adults with cancer is understudied. In this exploratory analysis, we used data from a single-arm mobile health (mHealth) exercise intervention among older adults with myeloid malignancies to 1) assess changes in TNFα promoter methylation, TNFα mRNA expression, serum TNFα and other related-cytokine levels after intervention; and 2) assess correlations between blood markers and exercise levels. Twenty patients were included. From baseline to post-intervention, there was no statistical changes in TNFα promoter methylation status at seven CpG sites, TNFα mRNA expression, and serum TNFα levels. Effect sizes, however, were moderate to large for several CpG sites (-120, -147, -162, and -164; Cohen's d = 0.44-0.75). Median serum TNFα sR1 levels increased (83.63, IQR 130.58, p = 0.06; Cohen's d = 0.18) but not the other cytokines. Increases in average daily steps were correlated with increases in TNFα promoter methylation at CpG sites -147 (r = 0.48; p = 0.06) and -164 (r = 0.51; p = 0.04). Resistance training minutes were negatively correlated with TNFα promoter methylation at CpG site -120 (r = -0.62; p = 0.02). All effect sizes were moderate to large. In conclusion, after a mHealth exercise intervention, we demonstrated changes with moderate to large effect sizes in several CpG sites in the TNFα promoter region. Exercise levels were correlated with increases in TNFα promoter methylation. Larger exercise trials are needed to better evaluate TNFα regulation to inform interventions to augment TNFα regulation in order to improve outcomes in older adults with cancer.

SUMMARY: JCPyV polyomavirus, a member of the human virome, causes Progressive Multifocal Leukoencephalopathy (PML), an oft-fatal demyelinating brain disease in individuals receiving immunomodulatory therapies. Mutations in the major viral capsid protein, VP1, are common in JCPyV from PML patients (JCPyV-PML) but whether they confer neurovirulence or escape from virus-neutralizing antibody (nAb) in vivo is unknown. A mouse polyomavirus (MuPyV) with a sequence-equivalent JCPyV-PML VP1 mutation replicated poorly in the kidney, a major reservoir for JCPyV persistence, but retained the CNS infectivity, cell tropism, and neuropathology of the parental virus. This mutation rendered MuPyV resistant to a monoclonal Ab (mAb), whose specificity overlapped the endogenous anti-VP1 response. Using cryo EM and a custom subvolume refinement approach, we resolved an MuPyV:Fab complex map to 3.1 Å resolution. The structure revealed the mechanism of mAb evasion. Our findings demonstrate convergence between nAb evasion and CNS neurovirulence in vivo by a frequent JCPyV-PML VP1 mutation.