January 11, 2021

Microbial RNA and rheumatoid arthritis

Small RNAs — short stretches of genetic material — from microbes may be playing a role in rheumatoid arthritis and other autoimmune diseases.

Microbial small RNAs (sRNAs), short stretches of RNA derived from microbes, are found in human plasma and can alter host immune function. 

Michelle Ormseth, MD, MSCI, and colleagues examined plasma microbial sRNAs in patients with rheumatoid arthritis (RA) compared to controls, and before and after treatment with DMARDs (disease-modifying antirheumatic drugs). They evaluated whether microbial sRNAs were altered in patients with RA, associated with measures of RA disease activity and altered by DMARDs. 

They reported in the Annals of the Rheumatic Diseases that composition of microbial sRNAs is altered in patients with RA and that higher levels were associated with lower disease activity. 

They also found that greater abundance of microbial sRNAs and specific sRNAs at baseline were associated with better response to DMARD treatment. Treatment did not alter microbial sRNAs in patients with RA. 

The findings support further studies to clarify the role of microbial sRNAs in RA and other autoimmune diseases.

This research was supported by the Veterans Health Administration, Arthritis Foundation, Alpha Omicron Pi and the National Institutes of Health (grants AR056116, TR000445).