Researchers have developed a way of discriminating between patients who have sarcoidosis complicated by pulmonary hypertension (PH) and those without blood-pressure issues.
The approach may improve the diagnosis of those who have sarcoidosis with PH.
Their research, “Expression profiling elucidates a molecular gene signature for pulmonary hypertension in sarcoidosis,” was published in the journal Pulmonary Circulation.
Sarcoidosis patients with PH have more health problems and a higher risk of death than those without PH. Because symptoms are similar between the two types of patients, it often takes time to diagnosis those with high blood pressure.
Both PH and advanced lung sarcoidosis give rise to shortness of breath, less capacity to exercise, and fatigue. Only when lung hypertension has reached advanced stages, and is causing heart failure, can it be easily differentiated from sarcoidosis, however.
To try to address this issue, researchers at the University of Illinois at Chicago analyzed the genetic activity of all genes in a blood sample. This genome-wide approach allowed them to create a fingerprint of sarcoidosis.
The team recruited eight patients with sarcoidosis and PH, 17 with sarcoidosis without PH, and 45 healthy controls. The participants’ blood samples were used for gene expression analysis.
In the first stage of the research, the team identified 275 genes that were either more active or less active in sarcoidosis patients with PH than in those without PH. From this large set of genes, they developed a gene signature, composed of only 18 genes, which could distinguish between the two patient groups with 100 percent accuracy.
The signature could also differentiate between patients with both sarcoidosis and PH and both groups without lung hypertension — the other sarcoidosis patients and the healthy controls. The accuracy was 97.8 percent.
Researchers compared their findings with an analysis of lung tissue samples. Surprisingly, they did not find many similarities. That suggested that the gene expression changes they saw are not just specific to sarcoidosis with lung hypertension, but are also specific to blood cells.
Researchers admit their study had limitations, such as the small number of patients analyzed.
“If validated in a large replicate cohort, this signature could potentially be used as a diagnostic molecular biomarker for sarcoidosis-associated PH,” they concluded.