Finally, three genes of the complement component are within the 18 candidate genes of reduced Blmpf1. There is experimental evidence that reducing complement activation can decrease lung fibrosis (Cipolla et al. 2017), although our studies in the related model of radiation-induced pulmonary fibrosis revealed a C4b deficiency not to affect the fibrosis trait (Fox et al. 2013). The gene discussed is C4B; the disease is pulmonary fibrosis.