The human oropharyngeal microbiota and common variable immunodeficiency

The respiratory tract microbiota is essential for human health and well-being and is driven by genetic, lifestyle and environmental factors. By the other side, mucosal immune system is crucial in shaping the host-microbial symbiosis, allowing the colonization of defined mucosal niches by commensal species through exclusion of exogenous competitors. This relationship can be enlightened by studies of microbiota in subjects with inborn errors of immunity. Due to primary antibody defect, CVID subjects suffer from recurrent respiratory tract infections, leading to chronic lung disease and increasing mortality. The upper airways have been shown to reflect colonization of the lower airways, the actual site of inflammation in CVID, which is hardly accessible.Objective: We sought to characterize the bacterial communities in the upper respiratory tract obtained from adults followed up in a single Italian Center for PID from Italy and to relate these to CVID clinical and immunological features.