Aging is a significant risk factor for various diseases, including asthma, and it often leads to poorer clinical outcomes, particularly in elderly individuals. It is recognized that age-related diseases are due to a time-dependent accumulation of cellular damage, resulting in a progressive decline in cellular and physiological functions and an increased susceptibility to chronic diseases. The effects of aging affect not only the elderly but also those of younger ages, posing significant challenges to global healthcare. Thus, understanding the molecular mechanisms associated with aging in different diseases is essential. One intriguing factor is the aryl hydrocarbon receptor (AhR), which serves as a cytoplasmic receptor and ligand-activated transcription factor and has been linked to the aging process. Here, we review the literature on several major hallmarks of aging, including mitochondrial dysfunction, cellular senescence, autophagy, mitophagy, epigenetic alterations, and microbiome disturbances. Moreover, we provide an overview of the impact of AhR on these hallmarks by mediating responses to environmental exposures, particularly in relation to the immune system. Furthermore, we explore how aging hallmarks affect clinical characteristics, inflammatory features, exacerbations, and the treatment of asthma. It is suggested that AhR signaling may potentially play a role in regulating asthma phenotypes in elderly populations as part of the aging process.

Objective: To evaluate the efficacy of allogeneic hematopoietic stem cell transplantation (allo-HSCT) from different donors as first-line treatment for children and adolescents with severe aplastic anemia (SAA) . Methods: The clinical data of 79 children and adolescents with SAA diagnosed from January 2013 to December 2016 in Henan Province were retrospectively analyzed. There were 50 males and 29 females, with a median age of 14(4-18) years. 40 cases received matched sibling transplantation (MSD-HSCT), 17 with unrelated donor transplantation (UD-HSCT), and 22 with haploidentical transplantation (haplo-HSCT). Results: The comparison of MSD-HSCT, UD-HSCT, haplo-HSCT groups was conducted and the median times of neutrophils engraftment were statistically significant [12(9-25) d, 14(10-22) d, 16(11-26) d, respectively (χ²=13.302, P=0.001)], but no difference in+30 d engraftment rate [97.3%(36/37), 100%(15/15), 100%(20/20), χ²=0.959, P=0.619]. The median times of PLT engraftment were not statistically significant [14(6-34)d, 16(7-32)d, 19(10-34)d, respectively, χ²=5.892, P=0.053], and the +30 d engraftment rate had no difference [97.3%(36/37), 100%(15/15), 100%(20/20), χ²=0.959, P=0.619]. The post-transplant infection rate showed no statistically significance [35.0% (14/40), 29.4% (5/17), 45.5% (10/22), χ²=1.158, P=0.560], as well as the incidences of aGVHD, grade III/IV aGVHD and cGVHD(χ²=0.230, P=0.891; χ²=2.628, P=0.269; χ²=3.187, P=0.203). The two-years OS rate was not statistically significant respectively [(77.1±6.7)%, (70.6±11.1)%, (77.3±8.9)%, χ²=0.330, P=0.845]. Severe post-transplant infection (RR=4.617, P=0.009), grade Ⅲ/Ⅳ aGVHD (RR=2.707, P=0.048) were independent risk factors for OS. Conclusion The overall efficacy of MSD-HSCT, UD-HSCT and haplo-HSCT as first-line therapy for children and adolescents with SAA/VSAA is comparable.