Transforming Growth Factor-β- and Interleukin-13-Producing Mast Cells Are Associated with Fibrosis in Bone Marrow

Publication date: Available online 31 January 2017
Source:Human Pathology
Author(s): Shoko Nakayama, Taiji Yokote, Nobuya Hiraoka, Toshikazu Akioka, Uta Nishiwaki, Takuji Miyoshi, Kazuki Iwaki, Ayami Fumimoto, Yuki Masuda, Jun Hatooka, Mayumi Fujimoto, Yasuichiro Nishimura, Motomu Tsuji
Although bone marrow fibrosis is a lethal condition, its underlying mechanism is not fully understood. This study aimed to investigate the pathogenesis of fibrosis in the bone marrow through histological examination of mast cell infiltration and the expression of fibrosis-associated cytokines. We analyzed 22 bone marrows with fibrosis [eight primary myelofibrosis (PMF), five post-essential thrombocythemia (ET) myelofibrosis (MF), and nine myelodysplastic syndrome (MDS) with bone marrow fibrosis (BMF)]. Immunohistochemical and immunofluorescence staining were performed using anti-mast cell tryptase, interleukin (IL)-13, transforming growth factor-beta (TGF-β), CD34, and CD42b antibodies. The number of mast cells in bone marrows with fibrosis was significantly higher than that in controls (P<.0001 for all cases with fibrosis vs control, P=.0470 for PMF vs control, P<.0001 post- ET MF vs control, and P=.0005 for MDS with BMF vs control). Moreover, bone marrows with higher fibrotic grades exhibited greater amounts of infiltrating mast cells. Mast cells were positive for TGF-β and IL-13 in bone marrows with fibrosis of all three groups. Megakaryocytes were negative for TGF-β in post-ET and MDS with BMF, but some megakaryocytes in PMF were weakly positive for TGF-β. Megakaryocytes were negative for IL-13 in all three groups. Blasts were negative for both TGF-β and IL-13 in all three groups. Thus, TGF-β- and IL-13-producing mast cells might be key players in the development of bone marrow fibrosis. Therefore, mast cells could be potential therapeutic targets for the treatment of bone marrow fibrosis.



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