Recent findings may help provide a new diagnostic indicator for the clinical detection of systemic lupus erythematosus (SLE) in previously undiagnosed patients. The study, “Evaluation of PBMC Distribution and TLR9 Expression in Patients with Systemic Lupus Erythematosus,” published in the Iranian Journal of Allergy, Asthma, and Immunology, revealed that specific receptor TLR9, is increased in certain immune cells in the blood of SLE patients.

What are Toll-like receptors?

TLRs are proteins that play a significant role in the innate immune system’s ability to detect foreign matter by the body’s white blood cells, known as macrophages and dendritic cells.

Evidence has shown there is a correlation between certain TLRs, such as TLR7, and SLE disease progression, but the exact role that TLR9 plays in driving disease has yet to be fully explained.

About this study

To understand the distinct role TLR9 plays in SLE, researchers looked at the immune cell make-up in 35 patients with SLE and 38 healthy control volunteers.

The team measured T, B, NK and mononulear cells, also known as peripheral blood mononuclear cells (PBMCs), in all of the enrolled patients using flow cytometry, an experimental technique that uses wavelengths of light particles to make accurate cell counts.

After analysis of the distinct immune cell counts, the results showed that in SLE patients the immune expression of TLR9 and overall percentage of T-cells and monocytes were significantly higher than that of healthy controls. But, the percentage of NK cells were significantly lower than in healthy controls.

Based on the results, TLR9 expression is involved in SLE pathogenesis. Because SLE patients and healthy controls have a significant difference in TLR9 expression, the receptor could account for a future diagnostic indicator in clinical tests.

The authors wrote in the report: “to put in a nut shell, we showed that PBMCs balance is disturbed in SLE patients, and difference in TLR9 expression can be attributed as an indication of functional deviation.”