Biomarkers for Pulmonary Sarcoidosis Seen in Gene Analysis of Lung Samples from Patients

Genome-wide analysis of lung samples from pulmonary sarcoidosis patients and a healthy control group identified a set of genes whose expression is altered only in disease samples. These results may lead to new biomarkers for pulmonary sarcoidosis.

The study, “Bioinformatics analysis of gene expression profile data to screen key genes involved in pulmonary sarcoidosis,” was published in the online journal Gene.  

Sarcoidosis is an inflammatory disease affecting multiple organs, but its most common manifestation is pulmonary sarcoidosis (90% of sarcoidosis patients experience lung involvement). Because the clinical symptoms of sarcoidosis are usually variable and common to other lung diseases, such as tuberculosis and cancer, its diagnosis can be difficult.

Effective biomarkers for pulmonary sarcoidosis would benefit and significantly improve both diagnosing and treating the disease.

Researchers performed a bioinformatics analysis of the gene expression profile in pulmonary sarcoidosis. This genome-wide study (an approach that involves rapidly scanning markers across the complete sets of DNA, or genomes, of many people to find genetic variations associated with a particular disease) included six pulmonary sarcoidosis samples and six normal lung samples. Genes that showed differences in expression between pulmonary sarcoidosis patients and controls (called differentially expressed genes, DEGs) were identified and further analyzed.

In total, authors identified 208 DEGs in pulmonary sarcoidosis samples — with 179 genes showing increased expression in pulmonary sarcoidosis (up-regulated genes), and 29 others  showing decreased expression (down-regulated genes).

The team discovered that the class of identified DEGs could clearly distinguish pulmonary sarcoidosis samples from normal lung samples, highlighting their potential use as biomarkers for pulmonary sarcoidosis.

Specifically, the genes CXCL9, STAT1, CCL5, CXCL11 and GBP1 showed a potential to be of particular importance to pulmonary sarcoidosis development. In fact, the analysis suggested that these genes can interact with each other, and may contribute to disease by regulating immune responses in the lungs.

Future experimental studies are now needed to understand the contribution of each of these genes to the disease and its progression.