G-CSF rescue of FOLFIRINOX-induced neutropenia leads to systemic immune suppression in mice and humans.

BACKGROUND: Recombinant granulocyte colony-stimulating factor (G-CSF) is routinely administered for prophylaxis or treatment of chemotherapy-induced neutropenia. Chronic myelopoiesis and granulopoiesis in patients with cancer has been shown to induce immature monocytes and neutrophils that contribute to both systemic and local immunosuppression in the tumor microenvironment. The effect of recombinant G-CSF (pegfilgrastim or filgrastim) on the production of myeloid-derived suppressive cells is unknown. Here we examined patients with pancreatic cancer, a disease known to induce myeloid-derived suppressor cells (MDSCs), and for which pegfilgrastim is routinely administered concurrently with FOLFIRINOX but not with gemcitabine-based chemotherapy regimens. METHODS: Serial blood was collected from patients with pancreatic ductal adenocarcinoma newly starting on FOLFIRINOX or gemcitabine/n(ab)paclitaxel combination chemotherapy regimens. Neutrophil and monocyte frequencies were determined by flow cytometry from whole blood and peripheral blood mononuclear cell fractions. Serum cytokines were evaluated pretreatment and on-treatment. Patient serum was used in vitro to differentiate healthy donor monocytes to MDSCs as measured by downregulation of major histocompatibility complex II (HLA-DR) and the ability to suppress T-cell proliferation in vitro. C57BL/6 female mice with pancreatic tumors were treated with FOLFIRINOX with or without recombinant G-CSF to directly assess the role of G-CSF on induction of immunosuppressive neutrophils. RESULTS: Patients receiving FOLFIRINOX with pegfilgrastim had increased serum G-CSF that correlated with an induction of granulocytic MDSCs. This increase was not observed in patients receiving gemcitabine/n(ab)paclitaxel without pegfilgrastim. Interleukin-18 also significantly increased in serum on FOLFIRINOX treatment. Patient serum could induce MDSCs as determined by in vitro functional assays, and this suppressive effect increased with on-treatment serum. Induction of MDSCs in vitro could be recapitulated by addition of recombinant G-CSF to healthy serum, indicating that G-CSF is sufficient for MDSC differentiation. In mice, neutrophils isolated from spleen of G-CSF-treated mice were significantly more capable of suppressing T-cell proliferation. CONCLUSIONS: Pegfilgrastim use contributes to immune suppression in both humans and mice with pancreatic cancer. These results suggest that use of recombinant G-CSF as supportive care, while critically important for mitigating neutropenia, may complicate efforts to induce antitumor immunity.

Performance of a Triage Protocol for Monoclonal Antibodies in a Mixed Vaccinated and Unvaccinated Cohort of COVID-19 Patients Treated With Intravenous Infusion or Subcutaneous Injection.

Background: Several monoclonal antibodies (mAbs) have been shown to reduce rates of hospitalization in patients with coronavirus disease 2019 (COVID-19) who have risk factors for severe disease. Due to capacity constraints, many health systems have been unable to provide mAbs to all eligible patients. There is little evidence regarding the performance of triage protocols for allocation or the relative effectiveness of subcutaneous administration vs intravenous infusion. Methods: This was a retrospective cohort study of 1063 patients with COVID-19 consecutively referred for monoclonal antibody therapy in a single large academic health care system, who were prioritized for mAb therapy using an allocation protocol grouping patients by risk. Results: A triage protocol prioritizing patients who were not fully vaccinated and were at high risk of severe COVID-19 and patients who were heavily immunosuppressed performed well in terms of differentiating between groups of patients by risk of severe disease. The number needed to treat (NNT) to prevent 1 hospitalization was 4.4 for the highest priority group, 8.5 for the next highest priority group, and 21.7 for the third highest priority group. There was no significant correlation between route of administration and hospitalization for symptoms related to COVID-19 (odds ratio, 1.26 in the intravenous group compared with the subcutaneous group; 95% CI, 0.56-2.8; P = .58). Conclusions: This study demonstrates that triaging mAbs for patients with COVID-19 by risk can optimize benefit in terms of reducing rates of hospitalization and that rates of hospitalization may be no different between patients treated with subcutaneous injection and patients treated with intravenous infusion.

Intra- and Inter-cellular Rewiring of the Human Colon during Ulcerative Colitis.

Genome-wide association studies (GWAS) have revealed risk alleles for ulcerative colitis (UC). To understand their cell type specificities and pathways of action, we generate an atlas of 366,650 cells from the colon mucosa of 18 UC patients and 12 healthy individuals, revealing 51 epithelial, stromal, and immune cell subsets, including BEST4+ enterocytes, microfold-like cells, and IL13RA2+IL11+ inflammatory fibroblasts, which we associate with resistance to anti-TNF treatment. Inflammatory fibroblasts, inflammatory monocytes, microfold-like cells, and T cells that co-express CD8 and IL-17 expand with disease, forming intercellular interaction hubs. Many UC risk genes are cell type specific and co-regulated within relatively few gene modules, suggesting convergence onto limited sets of cell types and pathways. Using this observation, we nominate and infer functions for specific risk genes across GWAS loci. Our work provides a framework for interrogating complex human diseases and mapping risk variants to cell types and pathways.