Contribution of SARS-CoV-2 infection preceding COVID-19 mRNA vaccination to generation of cellular and humoral immune responses in children.

Primary COVID-19 vaccination for children, 5-17 years of age, was offered in the Netherlands at a time when a substantial part of this population had already experienced a SARS-CoV-2 infection. While vaccination has been shown effective, underlying immune responses have not been extensively studied. We studied immune responsiveness to one and/or two doses of primary BNT162b2 mRNA vaccination and compared the humoral and cellular immune response in children with and without a preceding infection. Antibodies targeting the original SARS-CoV-2 Spike or Omicron Spike were measured by multiplex immunoassay. B-cell and T-cell responses were investigated using enzyme-linked immunosorbent spot (ELISpot) assays. The activation of CD4+ and CD8+ T cells was studied by flowcytometry. Primary vaccination induced both a humoral and cellular adaptive response in naive children. These responses were stronger in those with a history of infection prior to vaccination. A second vaccine dose did not further boost antibody levels in those who previously experienced an infection. Infection-induced responsiveness prior to vaccination was mainly detected in CD8+ T cells, while vaccine-induced T-cell responses were mostly by CD4+ T cells. Thus, SARS-CoV-2 infection prior to vaccination enhances adaptive cellular and humoral immune responses to primary COVID-19 vaccination in children. As most children are now expected to contract infection before the age of five, the impact of infection-induced immunity in children is of high relevance. Therefore, considering natural infection as a priming immunogen that enhances subsequent vaccine-responsiveness may help decision-making on the number and timing of vaccine doses.

Is CT-based body composition associated with long-term chemotherapy-induced peripheral neuropathy in colorectal cancer survivors?

BACKGROUND: Chemotherapy-induced peripheral neuropathy (CIPN) is a common side effect among colorectal cancer (CRC) survivors, and the severity is mainly dependent on the chemotherapy dose. Nowadays, chemotherapy dose is based on body surface area, while determination based on more accurate measures of body composition may be better. This study aimed to investigate the association between body composition and long-term CIPN among CRC survivors 2-11 years after diagnosis. METHODS: Data from CRC survivors from the population-based PROFILES registry were used. Survivors were included when they received chemotherapy, filled in the EORTC QLQ-CIPN20, and had a computed tomography (CT) scan at diagnosis (n = 202). Total, sensory, motor, and autonomic CIPN were based upon the EORTC QLQ-CIPN20. The abdominal CT scans were used to determine skeletal muscle index (SMI), skeletal muscle density (SMD), visceral adipose tissue (VAT), subcutaneous adipose tissue (SAT), and total adipose tissue (TAT). Logistic regression was used to analyze the association between CIPN outcomes and body composition variables. RESULTS: CIPN was experienced by 64% of the CRC survivors several years after chemotherapy. More SAT was associated with a higher odds of reporting total CIPN (OR = 1.01 95% CI 1.00-1.01, p = 0.01), motor CIPN (OR = 1.01 95% CI 1.00-1.01, p = 0.01), and sensory CIPN (OR = 1.01 95% CI 1.00-1.01, p = 0.04). No associations of other body composition parameters with CIPN were observed. CONCLUSION: Only SAT was associated with total, motor, and sensory CIPN. Based on these results, we cannot conclude that determining the chemotherapy dose based on body composition is preferred over determining the chemotherapy dose based on body surface to prevent CIPN. More research is needed to assess associations of body composition with CIPN, a common side effect of chemotherapy.

Individual dietary intervention in adult patients with mitochondrial disease due to the m.3243 A>G mutation.

OBJECTIVE: The aim of this study was to evaluate the effect of an individually tailored dietary intervention on personalized goals, body composition (BC), functioning, and quality of life (QoL) in adult patients with mitochondrial disease (MD) due to the m.3243 A>G mutation. METHODS: This explorative randomized controlled trial included 39 patients with MD. The intervention group (n = 20) received an individually tailored dietary intervention over a 6-mo period. The control group (n = 19) received standard care over a 6-mo timeframe (control period), followed by an individually tailored dietary intervention for the next 6 mo (intervention period). Nutritional assessment and QoL measurements were performed at 3-mo intervals. Personalized treatment goals of the patients with MD were evaluated at 3 and 6 mo during the dietary intervention. Achievement of the personalized goals was assessed using descriptive statistics and mixed models. Linear mixed models were used to test the effect of the dietary intervention on continuous outcomes. RESULTS: The personal goals of patients were significantly more frequently achieved in the intervention group than in the control group. After 3 mo of intervention, 57% of the goals were achieved. Most goals were achieved for BC, handgrip strength (HGS), and gastrointestinal complaints. Intervention increased HGS (P = 0.037), the vitality component of QoL (P = 0.026), and decreased the fatigue score (P = 0.024) after 3 mo of treatment. Effects did not seem to last after 3 mo, however. CONCLUSION: An individually tailored dietary intervention is promising to achieve personalized goals of patients with MD, especially with regard to BC, HGS, and gastrointestinal complaints. The intervention also improves QoL, and decreases fatigue.