What's new with sarcoidosis? And what is it?

     One of the 100+ autoimmune diseases is sarcoidosis, a chronic multi-system disease which may affect many body systems. Characterized by small round spots (tubercles) of granulated (dead) tissue, it may be misdiagnosed as tuberculosis. Sarcoidosis can occur in the lymph nodes, liver, eyes, skin, or other tissues but almost always also in the lungs. Persistent enlargement of the lymph glands that are asymptomatic, not tender or hot, is a common finding. Both enlarged and normal-sized lymph nodes may contain the characteristic sarcoid tubercles.

     Some patients have few if any symptoms while others experience many. Although sarcoidosis may go away spontaneously without treatment, the majority of patients will have it for their lifetime.

     While two thirds of the people who get sarcoidosis get better with minimal therapy, one third go on to develop complicated sarcoidosis, neurologic sarcoidosis, cardiac sarcoidosis, and progressive lung disease. Complicated sarcoidosis, an inflammatory lung disease, can cause lung damage which, in a small percentage of cases, can be fatal. The challenge, says Dr. Joe G.N. Garcia, Vice President for Health Affairs, University of Illinois, Dr. Garcia, is that there is no difference in the clinical presentation between patients with simple sarcoidosis and those who develop more serious disease.

     Researchers at the University of Illinois Hospital & Health Sciences System, with Dr. Garcia as principal investigator, have identified a genetic signature that distinguishes patients with complicated sarcoidosis from patients with a more benign form of the disease. This gene signature could become the basis for a simple blood test.

     In the study, blood was taken from patients with both simple and complicated sarcoidosis as well as patients without the disease in order to look for a pattern of gene expression unique to complicated sarcoidosis. The researchers were able to identify a distinct 20-gene pattern of gene expression that reliably could identify the cases that were most likely to progress to complicated sarcoidosis. Dr. Garcia points out that while a 31-gene expression signature had been identified previously, a smaller panel of genes makes the new test less expensive and more clinically useful.

--Sources: "Sarcoidosis," American Autoimmune Related Diseases Association; "Gene Test Flags Risk of Complications in Sarcoidosis," University of Illinois Hospital & Health Sciences System, via Newswise, October 12, 2012