In the combined group of RA, severe asthma, ILD and RA-ILD patients, the level of cultured fibrocytes and CD45+ CD34+CD11b+ cells was significantly higher in the patients with normal C-reactive protein (CRP) (<10 mg/L) than in patients with elevated CRP (both p = 0.001). The gene discussed is PTPRC; the disease is interstitial lung disease.