HRH4 and pulmonary fibrosis: We report here that the treatment with JNJ7777120, an H4R antagonist/inverse agonist, ameliorates the functional and structural features of bleomycin-induced lung fibrosis in WT mice, while, in the absence of GILZ gene, the treatment with JNJ seems to be less effective in controlling inflammation and fibrosis, with small differences between the two animal strains, suggesting that other factors could be involved in the regulatory mechanism.