CD19 regulates skin and lung fibrosis via toll-like receptor signaling in a model of bleomycin-induced scleroderma

Ayumi Yoshizaki, Yohei Iwata, Kazuhiro Komura, Fumihide Ogawa, Toshihide Hara, Eiji Muroi, Motoi Takenaka, Kazuhiro Shimizu, Minoru Hasegawa, Manabu Fujimoto, Thomas F. Tedder, Shinichi Sato

Research output: Contribution to journalArticlepeer-review

173 Citations (Scopus)


Mice subcutaneously injected with bleomycin, in an experimental model of human systemic sclerosis, develop cutaneous and lung fibrosis with autoantibody production. CD19 is a general "rheostat" that defines signaling thresholds critical for humoral immune responses, autoimmunity, and cytokine production. To determine the role of CD19 in the bleomycin-induced systemic sclerosis model, we investigated the development of fibrosis and autoimmunity in CD19-deficient mice. Bleomycin-treated wild-type mice exhibited dermal and lung fibrosis, hyper-γ-globulinemia, autoantibody production, and enhanced serum and skin expression of various cytokines, including fibrogenic interleukin-4, interleukin-6, and transforming growth factor-β1, all of which were inhibited by CD19 deficiency. Bleomycin treatment enhanced hyaluronan production in the skin, lung, and sera. Addition of hyaluronan, an endogenous ligand for Toll-like receptor (TLR) 2 and TLR4, stimulated B cells to produce various cytokines, primarily through TLR4; CD19 deficiency suppressed this stimulation. These results suggest that bleomycin induces fibrosis by enhancing hyaluronan production, which activates B cells to produce fibrogenic cytokines mainly via TLR4 and induce autoantibody production, and that CD19 deficiency suppresses fibrosis and autoantibody production by inhibiting TLR4 signals.

Original languageEnglish
Pages (from-to)1650-1663
Number of pages14
JournalAmerican Journal of Pathology
Issue number6
Publication statusPublished - 06-2008
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • Pathology and Forensic Medicine


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