IL4 and pulmonary fibrosis: In addition, despite recent reports that KL-6 can be used as a lung fibrosis severity marker, and that the presence of elevated CXCL11 in BALF could serve as a prognostic factor for the decline of pulmonary function in SS-ILD (Sfriso et al. 2012; Kumánovics et al. 2014), we did not confirm those data nor determine serum pro-fibrotic cytokines such as IL-4 and IL-13.