Blocking miR-31 alleviates cGVHD. (A-B) BALB/c mice were lethally irradiated and transferred with 5 × 10⁶ T cell–depleted (TCD) BM plus 5 × 10⁶ splenocytes from B10.D2 mice. Recipient mice were treated with anti–miR-31 starting on day 0 (A) or day 21 (B) after BMT. The clinical scores with macroscopic photos are shown on day 40 after BMT. (C-D) Cutaneous pathologic scores (C) and collagen deposition in skin evaluated with Masson’s trichrome stain (D) are shown on day 50. (E-G) In the experiments where anti–miR-31 treatment started at day 21, frequencies of CD4⁺, CD8⁺, and B220⁺ in gated donor Ly9.1⁻ cells (E), Foxp3⁺ in gated donor Ly9.1⁻ CD4 T cells (F), and HIF1α⁺ cells in gated donor Ly9.1⁻ CD4 or CD8 T cells (G) are shown in recipient spleens on day 50. In the experiments where anti–miR-31 treatment started at day 0, frequency of IL-17⁺ in gated donor Ly9.1⁻ CD4 T cells is shown in recipient skin-draining LNs on day 50 (F). *P < .05, **P < .01. PBS, phosphate-buffered saline; SSC, side scatter.