Understanding Key Immune System Monitor for RA and Infection Risk

Researchers from University of California San Diego School of Medicine warn that patients with rheumatoid arthritis (RA) who take interleukin-1beta (IL-1beta) inhibitors are at 300 times greater risk for development of invasive Group A Streptococcal, or flesh-eating, infections than are RA patients not taking these medications. The findings are based on an analysis of an FDA database on adverse events associated with RA patients who took the IL-1beta inhibitor anakinra. In autoimmune diseases such as RA, the body’s own immune system malfunctions and attacks “self” proteins instead of just bacterial invaders. Anakinra combats RA by suppressing the immune response stimulator IL-1beta but, the research hypothesizes, can also allow bacterial strains to progress to invasive infections. The findings are published in the journal Science Immunology.

The researchers say that their findings additionally emphasize the role of IL-1beta as the body’s “early warning system” that can be triggered not only by the host, as previously thought, but also by bacterial enzymes such as SpeB, whose secretion by invading strep bacteria can serve to activate the IL-1beta molecule. Senior author Victor Nizet, MD, professor of pediatrics and pharmacy at UC San Diego School of Medicine and Skaggs School of Pharmacy and Pharmaceutical Sciences, observed, “Inhibiting the body’s bacterial sensor can put a person at risk for invasive infection. But just the fact that we now know that this patient population is at higher risk, and why, means we can take simple steps—such as close monitoring and prophylactic antibiotics—to prevent it from happening.”

Read a news study about the findings and cautions here.

The journal abstract may be read here.

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