Tumor necrosis factor receptor-associated factor 3 (TRAF3) is an anti-inflammatory molecule that negatively regulates the non-canonical nuclear factor-κB pathway. Although TRAF3 haploinsufficiency (TRAF3 HI) can influence innate and adaptive immune cells, its effect on inflammatory bowel disease (IBD) development remains unclear. Here, we report the first case of severe early-onset IBD with a novel TRAF3 variant leading to HI, successfully treated with ustekinumab. A 6-year-old girl with a recurrent parotitis, otitis media, tonsilitis, and atopic dermatitis developed IBD involving the stomach, small intestine, and colon. At diagnosis, the immunoglobulin (Ig)G and IgA levels were relatively high, and lymphocyte subsets showed increased counts of plasmablasts, class-switch recombination B cells, and circulating T-follicular helper cells. Treatment with azathioprine and infliximab failed to maintain remission marked by several relapses accompanied by erythema nodosum and arthritis; however, ustekinumab, an anti-interleukin (IL)-12/23p40 antibody, led to long-term clinical remission, normalizing the Ig level and reducing abnormal lymphocyte counts. Whole-exome sequencing revealed a novel heterozygous mutation in TRAF3 [p.(Pro487Leufs*8)], resulting in TRAF3 under-expression. Our case may highlight the contribution of TRAF3 HI to the development of IBD and provide insights into IBD pathophysiology, suggesting the involvement of the IL-12/23-T-follicular helper cell pathway affected by genetic mutations.

Sweat contains electrolytes (minerals), therefore, it is necessary to consider its loss through sweat in the fluid replacement strategy in sports. The purpose of this study was to compare the concentration of components in sweat, such as electrolytes (minerals), when endurance exercise is performed in hot and neutral thermal environments. Eight men cycled for 60 min at 55% VO2peak under two envitonment conditions: a hot environment (WetBulb Globe Temperature (WBGT): 29.0±0.2℃; Heat) and a neutral thermal environment (WBGT: 20.5±0.2℃; Con). During exercise, sweat loss, core temperature, and heart rate (HR) were measured, and sweat from the chest, back, and thigh was collected. The core temperature, sweat loss, and HR increased significantly in Heat. The sweat electrolyte concentration was significantly higher in Heat than in Con only for Na. Regarding the amount of electrolyte loss from sweat, Na and K showed a significantly higher value than Con in Heat in comparison of each region, and the total loss amount of three regions in Cu also had a significantly higher value than Con in Heat. In addition, there was no difference in the concentration of Ca and Cu between the regions, but there was a significant difference in the amount of loss. It was concluded that even if there was no difference in the electrolyte concentration in sweat, the amount of electrolyte loss increased in K and Cu in a hot environment, and that there was a site difference in the amount of loss in Ca and Cu.