Gut microbiome profiles and associated metabolic pathways in patients of adult-onset immunodeficiency with anti-interferon-gamma autoantibodies.

Autoantibodies against interferon-gamma (AutoAbs-IFN-γ) can cause the immunodeficiency condition following various opportunistic infections. Gut microbiota can affect the human immune system in many ways. Many studies have shown that gut dysbiosis was associated with some immune diseases, such as autoimmune diseases and human immunodeficiency virus (HIV) infection, while its relationship at anti-IFN-γ AAbs remains unknown. We aimed to identify the anti-IFN-γ AAbs specific microbiome and the possible association with immunodeficiency. We profiled fecal microbiome for two cohorts of forty subjects, including seven patients with anti-IFN-γ AAbs and 33 individuals with competent immune. The study shows that patients with anti-IFN-γ AAbs have characterized the gut microbiome and have lower alpha diversity indexes than healthy controls (HC). There are significant differences in the microbiome structure at both the family and genera level between the two cohorts. The anti-IFN-γ AAbs cohort featured some microbiome such as Clostridium, including the possible opportunistic pathogen and fewer genera including Bacteroides, Ruminococcus, and Faecalibacterium, some of them with possible immune-related genera. The PICRUSt2 pathway demonstrated the decreased abundance of some immune-related pathways and one potential pathway related to the immune alternations in the anti- IFN-γ AAbs cohort. This was the first study to examine the gut microbiome characteristics in patients with anti-IFN-γ AAbs. It could be involved in the pathogenesis of anti-IFN-γ AAbs and contribute to the derived immune condition in this disease. This could lead to new strategies for treating and preventing patients suffering from this disease.