CD226 and systemic sclerosis: A search performed in the PubMed database for studies published in the last 10 years related to the SSc-ILD association genes revealed interferon regulatory factor 5 (IRF-5), signal transducer and activator of transcription 4 (STAT4), DNAX accessory molecule 1 (CD226), and interleukin-1 receptor-associated kinase 1 (IRAK-1) (Table 3).