Elevated levels of FIZZ1 and YM1 mRNA or protein have since been detected in parasite infection models [20,22], allergic lung inflammation [21,23,24], allergic peritonitis [24], bleomycin-induced lung fibrosis [25] and hypoxia-induced pulmonary hypertension [26]. This evidence concerns the gene RETNLB and pulmonary arterial hypertension.