IL-1 is not required for Bhlhe40 expression or GM-CSF production in colon-derived CD4⁺ T cells during GVHD. (A-D) Lethally irradiated Balb/c mice were transplanted with B6 Rag-1^−/− BM (5 × 10⁶) supplemented with 1 × 10⁶ purified CD4⁺ T cells from WT or IL-1R^−/− mice. (A) Bhlhe40 expression in flow-sorted H-2K^b+ TCR-β⁺ CD4⁺ cells from the colons of mice 14 days posttransplantation by quantitative reverse transcription polymerase chain reaction is shown. Fold change expression was normalized to the median expression of Bhlhe40 over 18S. Results are from 2 experiments with 5 to 6 mice per group. (B) Representative flow plots gated on H-2K^b+ TCR-β⁺ CD4⁺ cells depicting production of GM-CSF and IFN-γ in the colons of mice 14 days posttransplantation. (C-D) The frequency and total number of donor-derived CD4⁺ T cells in the colon producing IFN-γ (C) or GM-CSF (D). Results are from 2 experiments with 9 to 10 mice/group. (E-H) Lethally irradiated Balb/c mice were transplanted with B6 BM (5 × 10⁶) supplemented with 1 × 10⁶ purified CD4⁺ T cells from WT mice. Recipient mice received intraperitoneal injections of either Anakinra or PBS, as described in the supplemental Methods. (E) Bhlhe40 expression in flow-sorted H-2K^b+ TCR-β⁺ CD4⁺ cells from the colons of mice 14 days posttransplantation by quantitative polymerase chain reaction is shown. Fold change expression was normalized to the median expression of Bhlhe40 over 18S. Results are from 2 experiments with 8 to 10 mice/group. (F) Representative dot plots gated on H-2K^b+ TCR-β⁺ CD4⁺ depicting expression of GM-CSF and IFN-γ in the colons of mice 14 days posttransplantation. (G-H) The frequency and total number of donor-derived CD4⁺ T cells producing IFN-γ (G) or GM-CSF (H). Results are from 2 experiments with 9 to 10 mice/group. **P < .01.