New study shows Lyme disease alters immune system

A new study has shown that the bacteria that causes Lyme disease alters the immune system, causing it to attack the healthy cells in the human body.

The bacteria that causes Lyme disease – Borrelia burgdorferi – has been shown to stop communication between dendritic cells and T-cells, which normally signals for a response against foreign invaders.

The study, carried out by researchers at the Johns Hopkins Lyme Disease Clinical Research Center, has demonstrated that the bacteria alters dendritic cells, which normally present proteins from pathogens such as bacteria and viruses, known as antigens, to immune system T-cells, which then signals an immune response against any viruses or infections.

The study has been published in Frontiers in Medicine.

Lyme disease and autoimmune conditions

A Lyme disease infection is known to cause a weak immune system. To understand how this happens, the researchers isolated dendritic cells from healthy study participants and exposed them to Borrelia burgdorferi, finding that the bacterial infection causes receptor sites on the surface of dendritic cells, known as HLA-DRs, to mature and become active. Normally, these HLA-DRs cells would present antigens to killer T-cells, the immune system agents that remove invaders from the body.

The researchers believe that when the HLA-DRs interact with Borrelia burgdorferi, they are structurally changed and keep the dendritic cells from “marking” the bacterial proteins as foreign, which leads to the dendritic cells attracting T-cells, but instead of attacking the Lyme disease bacteria, instead attacks the healthy cells.

Senior author Mark Soloski, PhD, co-director for basic research at the centre, and professor of medicine at the Johns Hopkins University School of Medicine, said: “We believe these observations are relevant not only to how Borrelia burgdorferi disrupts the immune system but other infections as well. Antibodies that react with a person’s own tissues or organs have been reported in patients with infections, including COVID-19.”

The researchers say that if a person has a genetic predisposition to autoimmune diseases such as lupus or rheumatoid arthritis, infection by Borrelia burgdorferi may trigger their development. They highlight that further research on HLA-DR and dendritic cell response to Borrelia burgdorferi could help to develop new treatments for Lyme disease and contribute to a better understanding of how autoimmune diseases may be caused.