Booster Dose of SARS-CoV-2 mRNA Vaccine in Kidney Transplanted Patients Induces Wuhan-Hu-1 Specific Neutralizing Antibodies and T Cell Activation but Lower Response against Omicron Variant.

Kidney transplanted recipients (KTR) are at high risk of severe SARS-CoV-2 infection due to immunosuppressive therapy. Although several studies reported antibody production in KTR after vaccination, data related to immunity to the Omicron (B.1.1.529) variant are sparse. Herein, we analyzed anti-SARS-CoV-2 immune response in seven KTR and eight healthy controls after the second and third dose of the mRNA vaccine (BNT162b2). A significant increase in neutralizing antibody (nAb) titers were detected against pseudoviruses expressing the Wuhan-Hu-1 spike (S) protein after the third dose in both groups, although nAbs in KTR were lower than controls. nAbs against pseudoviruses expressing the Omicron S protein were low in both groups, with no increase after the 3rd dose in KTR. Reactivity of CD4+ T cells after boosting was observed when cells were challenged with Wuhan-Hu-1 S peptides, while Omicron S peptides were less effective in both groups. IFN-γ production was detected in KTR in response to ancestral S peptides, confirming antigen-specific T cell activation. Our study demonstrates that the 3rd mRNA dose induces T cell response against Wuhan-Hu-1 spike peptides in KTR, and an increment in the humoral immunity. Instead, humoral and cellular immunity to Omicron variant immunogenic peptides were low in both KTR and healthy vaccinated subjects.

Comparison of two diets of varying glycemic index on carotid subclinical atherosclerosis in obese children.

Childhood obesity is associated with an increased carotid intima-media thickness (IMT) and stiffness. Increased carotid wall thickening and rigidity are considered markers of subclinical atherosclerosis. The aim of the present study was to test the effect of two hypocaloric diets of varying glycemic index on weight loss and markers of subclinical atherosclerosis in obese children. Seventy consecutive obese children attending the Outpatient Weight Clinic of the Department of Pediatrics were invited to participate in an intensive dietary protocol. Twenty-six accepted and were randomly assigned to two different groups: the first group followed a hypocaloric low-glycemic index diet and the second a hypocaloric high-glycemic index diet. Anthropometric measures and biochemical tests were performed in all children. Quantitative B-mode ultrasound scans were used to measure intima-media thickness (IMT) and diameters of the common carotid artery. Considering both groups together, at 6 months, body mass index decreased from 28.3 +/- 3.1 to 25.8 +/- 3.3 kg/m(2), systolic blood pressure from 119 +/- 12 to 110 +/- 11 mmHg (P< 0.001), diastolic blood pressure from 78 +/- 8 to 74 +/- 7 mmHg (P< 0.001), IMT from 0.48 +/- 0.05 to 0.43 +/- 0.07 mm (P< 0.001), stiffness from 3.57 +/- 1.04 to 2.98 +/- 0.94 mm (P = 0.002), and high-sensitivity C-reactive protein from 1.5 +/- 0.9 (values log transformed) to 0.4 +/- 1.1 (P < 0.001). No differences were detectable in fasting serum triglycerides, total cholesterol, and high-density lipoprotein cholesterol. Insulin resistance (calculated by the HOmeostatic Model Assessment index [HOMA] score) significantly reduced only in the low-glycemic-index diet group (P < 0.04). In conclusion, this study confirms a benefit of hypocaloric diets on carotid IMT and stiffness in obese children and demonstrates, for the first time, an amelioration of insulin sensitivity in obese children after a low-glycemic index diet. These results justify the advice to obese children to follow a low-glycemic index diet in order to improve their cardiometabolic profile.