Elizabeth M. Staley MD, PhD, Huy P. Pham MD, MPH

Transfusion Medicine and Hemostasis (Fourth Edition), Elsevier, 2025, chapter 87, Pages 399-401, ISBN 9780323960144, https://doi.org/10.1016/B978-0-323-96014-4.00049-5.

Leukocytaphersis (or leukapheresis) is a therapeutic procedure in which white blood cells (WBCs) are selectively removed from the patient’s circulation. The procedure is performed for the treatment of hyperleukocytosis most commonly in the setting of leukemia. Adsorptive cytapheresis utilizes apheresis in association with a medical device to selectively extract leukocyte subsets (activated monocytes and granulocytes) from the patient’s circulation. Adsorptive cytapheresis has been utilized for the treatment of multiple inflammatory conditions including inflammatory bowel disease, systemic lupus erythematosus, psoriasis, Behçet’s disease, and rheumatoid arthritis.

D Kioroglou, J L Cabriada, U Martinez Marigorta, I Rodriguez-Lago. Journal of Crohn’s and Colitis, Volume 18, Issue Supplement_1, January 2024, Page i389,doi.org=10.1093/ecco-jcc/jjad212.0236

Background
Granulocyte-monocyte apheresis (GMA) is a non-pharmacological treatment approved for the management of ulcerative colitis (UC), particularly steroid-dependent cases. The exact mechanism of action and immunological changes associated with GMA remain undescribed. Gene expression analysis at the single-cell level (through scRNA-Seq) has emerged as a key tool of choice to characterize drug response at the molecular level. We used scRNA-Seq to characterize the transcriptomic effects and immune cell population alterations in GMA.

Methods
We generated scRNA-Seq from peripheral blood mononuclear cells (PBMC) of two ulcerative colitis (UC) patients undergoing GMA treatment. We compared the gene expression profile before and after 5 sessions of GMA treatment. The analytical pipeline included quality control and classical filtering steps, cell-type annotation, differential gene expression analysis and pathway enrichment profiling.

Results
We report three main results. First, we observed significant reductions of cell types directly affected by GMA treatment in UC patients. This includes classical CD14+ monocytes and Natural killers, which are central components of the innate system. Of note, we observed a remarkable increase in Double-negative T cells (dnT) after 5 sessions of GMA treatment, suggesting potential expansion of protective populations involved in decreased inflammation. Second, we observe a variety of genes and regulatory pathways altered by GMA treatment. In total, we detect 86 differentially expressed genes (DEGs), which overall are biased towards downregulation (63%). Of note, we detected dnT-s exhibiting upregulation of NEFL that is associated with the MAPK cascade and downregulation of genes related to immune response and signaling pathways. Finally, the effects of GMA treatment extend beyond the above mentioned populations, with particular alterations in CD4+ T cell populations such as CD4+ central memory and CD4+ Naive (7 and 13 DEGs, respectively).

Conclusion
For the first time, we generated single-cell transcriptomic profiles to characterize the effects of GMA treatment in peripheral blood of UC patients. Our preliminary analysis detects important alterations in the gene regulation and cell type composition in samples obtained after 5 sessions of GMA. Through expansion of this dataset to include more time points and profiles for more individuals, we will discuss the longitudinal changes and molecular mechanisms involved in response to GMA treatment.

D. Kioroglu1 , J.L. Cabriada2, U. M. Marigorta1,3, I. Rodríguez-Lago Ueg journal

Volume11, Issue S8 Supplement: 31st United European Gastroenterology Week 2023 October 2023 Pages 799

Introduction: Granulocyte–monocyte apheresis (GMA) is a non-pharmacological therapy approved for the treatment of ulcerative colitis (UC), mainly in steroid-dependent cases. Its mechanism of action is based onthe removal of activated leukocytes, but its exact immunological changes have not been fully described yet. Aims & Methods: Our aim was to characterize the response in the transcriptome at the single-cell resolution level and cell population effects of GMA device. We analysed scRNASeq data from peripheral blood mono-nuclear cells (PBMC) of two UC patients undergoing their first GMA session. Their gene expression profile was compared before (PRE) and one month after (POST) the GMA treatment, from the inflow and outflow lines, respectively. The analytical pipeline included quality control and filtering, cell-type annotation, differential gene expression and pathway enrichment analysis. Results: Two patients with UC (mean age 59 years; both E2) were included.Overall, the cell populations that appear to have been affected by the GMA treatment were natural killer cells and monocytes with both populations being reduced after the treatment. The distribution of the annotated cell-types was 2,369 B cells (PRE:50%, POST:49%), 11,462 CD4+ (PRE:49%,POST:50%) and 8,845 CD8+ T-cells (PRE:51%, POST:48%), 47 dendritic cells (PRE:40%, POST:59%), 3,773 natural killer cells (PRE:54%, POST:45%) and 2,352 monocytes (PRE:59%, POST:40%). Annotation at higher resolution identified 27 cell-types with monocytes being subannotated as 1,972 CD14 (PRE:62%, POST:37%) and 380 CD16 (PRE:48%, POST:51%) monocytes. Differential gene expression analysis identified in total 86 significant genes across six cell-types (CD4+ naive and central memory T-cells, natural killer cells, B intermediate cells, double-negative T-cells and CD14monocytes) with 63% of these genes being downregulated after the GMA treatment. Pathway enrichment analysis identified higher contribution of the double-negative T-cells to the enriching genes. More specifically, after the treatment the double-negative T-cells exhibited upregulation of the NEFL that is associated with the MAPK cascade and downregulation of genes related to immune response and signalling pathways. Regarding the CD14 monocytes, after the GMA treatment we observed significant downregulation of the genes LINC02315, IGHEP1 and IGHE, with the latter being linked to innate immune response pathways. Conclusion: GMA induces a range of modifications in the gene expression profile across different cell types that change the immunological environment of UC patients.