Enzyme’s Activity Could Help Diagnose, Track Progression of Lupus, Study Reports

Determining the activity of an enzyme in the blood could help doctors diagnose and track the progression of lupus, a Chinese study suggests.

The research, “Serum adenosine deaminase activity is increased in systemic lupus erythematosus patients and correlated with disease activity,” was published in the journal Immunologic Research.

A molecule called adenosine is a key element in controlling the immune system and preventing an excessive inflammatory response — a condition known as immune tolerance.

Loss of immune tolerance is one of the mechanisms underlying autoimmunity diseases — disorders in which the immune system attacks healthy tissue instead of invaders.

The adenosine deaminase enzyme breaks down adenosine. Scientists have linked the enzyme’s over-activity to several autoimmune diseases, including lupus, however.

Wondering whether the enzyme’s activity could play a key role in diagnosing and tracking the progression of lupus, researchers at China’s Fourth Military Medical University studied 120 patients and 120 age- and sex-matched healthy subjects. The patients included 13 men and 110 women.

The team took blood samples to determine participants’ adenosine deaminase enzyme activity.

Their analysis showed that the enzyme’s activity was significantly higher in lupus patients than in controls.

The finding prompted them to write that the enzyme’s activity “could be a potential diagnostic marker for SLE [lupus] patients.”

Scientists have been looking for a better marker for diagnosing lupus. The adenosine deaminase enzyme-activity marker is more accurate than several conventional markers, such as levels of high-sensitivity C-reactive protein, anti-double-stranded DNA antibodies, and anti-Sm antibodies, the researchers said.

The team also decided to evaluate whether various enzyme-activity levels would equate with different levels of lupus activity.

They divided patients into three categories of disease activity, based on their scores on the Systemic Lupus Erythematosus Disease Activity Index. They deemed patients with a score of 0-4 to have an inactive disease, those with a score of 5-9 a mildly active disease, and those with a score of 10 or more the most active disease.

Patients with the highest enzyme activity had the most active disease, suggesting that enzyme activity “detection could be helpful in estimating and monitoring the disease activity of SLE [lupus] patients,” the team wrote.

Overall, “our data reveal the potential applied value” adenosine deaminase enzyme “activity detection for diagnosing and monitoring SLE,” the study concluded.