Potential Antibody Blood Test Shows Accuracy in Detecting Sarcoidosis

Diagnosing sarcoidosis may involve invasive biopsies and multiple tests.

Sarcoidosis is an inflammatory disorder characterised by abnormal clusters of immune cells called granulomas. They can affect different organs but usually occur in the lungs. Diagnosing the disorder requires identifying these granulomas and carrying out additional tests to rule out other diseases.

“Diagnosing sarcoidosis is currently not a straightforward process. It requires removing tissue and testing it, together with additional examinations to rule out diseases such as tuberculosis or lung cancer,” said James Kiley, MD, director of the Division of Lung Diseases at the NIH National Heart, Lung, and Blood Institute. Kiley was not directly involved in this study.

Although the causes of sarcoidosis are not fully understood, immune proteins called antibodies are believed to be important in initiating granuloma formation.

Each antibody can bind to a specific molecular target called an antigen. Some antibodies that attach to their particular antigens may be the first step in granuloma formation. However, identifying what these antigens might be has been difficult.

Specific Antigens for Sarcoidosis Diagnosis: Cofilin micro and Chain A

Scientists at Wayne State analysed antibodies from people with sarcoidosis and other respiratory diseases. They found that antibodies targeting two specific antigens—Cofilin micro and Chain A—were much more common in people with sarcoidosis.

Based on this finding, the scientists developed a diagnostic test. In simple terms, the test exposes a person’s blood sample to Cofilin micro and Chain A to determine whether the person has antibodies against these antigens.

The researchers then assessed the test’s accuracy in identifying sarcoidosis in 386 people: 186 patients with sarcoidosis, 100 people without known health problems and 100 people with other lung diseases—specifically tuberculosis or lung cancer.

The results showed that, based on Cofilin micro alone, the test correctly identified 97% of people with sarcoidosis and 90% of those without the disease. Based on Chain A alone, it correctly identified 90% and 83% of people with and without sarcoidosis, respectively. Accuracy was even higher when the two antigens were combined.

“These results provide a new antibody-based test for sarcoidosis,” the researchers concluded, suggesting that the findings could be used to develop a simple blood test to help diagnose the disorder.

“Using a blood test could help diagnose sarcoidosis more quickly, especially in organs that are more difficult to biopsy, while causing less harm to the patient,” Kiley said.

Source: https://sarcoidosisnews.com/news/antibody-blood-test-may-help-diagnose-sarcoidosis-quickly/