The enriched T-cell biology, including iCOS signaling in T-helper cells, CD28 signaling, and T-helper cell differentiation is supported by our prior work, with similar analyses of a smaller gene set demonstrating that decreased expression of CD28, ICOS, LCK, and ITK predicted mortality in patients with IPF [16]. The gene discussed is ICOS; the disease is idiopathic pulmonary fibrosis.