Celiac.com 09/04/2019 - Class II human leukocyte antigen (HLA) allele combinations exert strong genetic control over susceptibility to numerous autoimmune diseases. Researchers know that these genes are the most significant risk factors for Type 1 diabetes and celiac disease, but they still know very little about how HLA influences the makeup of the human gut microbiome, which could be an environmental factor for disease susceptibility.
A team of researchers recently compared the gut microbiomes of kids with high genetic risk for Type 1 diabetes against those of kids with low genetic risk. Their results show that the two groups have very different gut microbiomes.
Using data from a study of All Babies in Southeast Sweden, the team found that genetic risk for the development of Type 1 diabetes autoimmunity is associated with clear changes in the gut microbiome, with both core microbiome and beta diversity differing according to HLA risk group and genotype. Interestingly, protective HLA haplotypes are connected with bacterial genera Intestinibacter and Romboutsia.
These results show that general population cohorts can help researchers spot potential environmental triggers or protective factors for autoimmune diseases that can otherwise remain obscured by strong genetic influence.
Certain bacterial species were totally absent in children with high genetic risk, but present in children with low or no risk.
"[T]his could mean that certain species [of gut bacteria] have protective effects and may be useful in future treatment to prevent autoimmune diseases. It may be that certain species cannot survive in individuals with high genetic risk”, says Johnny Ludvigsson, senior professor in the Department of Clinical and Experimental Medicine, Linköping University, and senior consultant at HRH Crown Princess Victoria Children’s Hospital, Linköping University Hospital.
The researchers in this study are variously affiliated with the Department of Microbiology and Cell Science, Institute of Food and Agricultural Sciences University of Florida, Gainesville, FL, USA; the Biological Sciences, Universidade Federal do Pampa, São Gabriel, Brazil; the Crown Princess Victoria Children’s Hospital, Region Östergötland, Division of Pediatrics, Linköping University, Linköping, Sweden; the Immunogenetics Laboratory, Institute of Biomedicine, University of Turku, and Clinical Microbiology, Turku University Hospital, Turku, Finland; the Department of Pathology, University of Florida Diabetes Institute, Gainesville, FL, USA; the Department of Pediatrics, College of Medicine, University of Florida, Gainesville, FL, USA; and the Department of Microbiology and Cell Science, Institute of Food and Agricultural Sciences University of Florida, Gainesville, FL, USA.