Abstract
Previously, we demonstrated concordance in differentially expressed genes in sarcoidosis blood and lung, implicating shared dysfunction of specific immune pathways. In the present study, we hypothesised that expression levels of candidate genes in sarcoidosis blood could predict and track with disease outcomes longitudinally.
We applied Ingenuity Pathway Analysis to a cross-sectional derivation microarray dataset (n=38) to identify canonical pathways and candidate genes associated with sarcoidosis. In a separate longitudinal sarcoidosis cohort (n=103), we serially measured 48 candidate gene transcripts, and assessed their relation to disease chronicity and severity.
In the cross-sectional derivation study, pathway analysis showed upregulation of genes related to interferon signalling and the role of pattern recognition receptors, and downregulation of T-cell receptor (TCR) signalling pathways in sarcoidosis. In the longitudinal cohort, factor analysis confirmed coregulation of genes marking these pathways and identified CXCL9 as an additional candidate pathway. CXCL9 and TCR factors discriminated between chronic versus nonprogressive disease, and CXCL9 predicted disease outcomes longitudinally. Interferon factor was similarly increased in both disease phenotypes. Factors associated with lung function decline included decreased TCR factor and increased CXCL9.
These findings demonstrate blood transcriptomic signatures reflecting TCR signalling and CXCL9 predict sarcoidosis chronicity and correlate with disease severity longitudinally.
Abstract
Blood gene transcript measurements predict sarcoidosis chronicity and severity longitudinally http://ow.ly/zFGnP
Footnotes
This article has supplementary material available from erj.ersjournals.com
Support statement: Funding for this project was supported by grants from the US National Institutes of Health (NIH)/National Heart, Lung and Blood Institute (U01HL112696), NIH/National Institute of Allergy and Infectious Diseases (1R56AI087652) and the Nina Ireland Lung Disease Program. R. Su received funding from the Rheumatology Research Foundation Scientist Development Award.
Conflict of interest: None declared.
- Received February 27, 2014.
- Accepted July 10, 2014.
- ©ERS 2014