Kjersti Thorvaldsen Hagen

• Rapp, Emma; Berset, Ingrid Prytz; Umu, Sinan Ugur; Bækkevold, Espen Sønderaal; Utheim, Karen Sivertsen & Dietrich, Alexander [Show all 13 contributors for this article] (2026). Longitudinal transcriptomic analysis of mucosa in ulcerative colitis after anti-tumor necrosis factor withdrawal compared to continued treatment. Journal of Crohn's and Colitis. ISSN 1873-9946. 20(8). doi: 10.1093/ecco-jcc/jjag121. Full text in Research Archive Show summary

  Background and Aims Monoclonal antibodies against tumor necrosis factor (anti-TNF) are effective agents in the treatment of moderate-to-severe ulcerative colitis (UC). It is unclear whether such treatment can safely be discontinued without relapse. This study aimed to identify biomarkers to predict which patients can successfully stop anti-TNF treatment, and to increase our understanding of the pathogenesis of relapse after withdrawal and flare on continued therapy. Methods We analyzed longitudinal bulk RNA-sequencing data derived from rectal mucosal biopsies from 163 patients in the BIOSTOP study collected at baseline, after 2 years (end of study), and at flares or relapse points. Results In this cohort, pre-withdrawal transcriptomic profiles did not distinguish patients who later relapsed from those who remained in long-term remission. Longitudinal analysis of patients who relapsed or flared were both characterized by inflammatory gene expression profiles (eg, CXCL9, CXCL10, OSMR, SELE) and changes in cell-type composition typical for active UC (eg, monocytes/macrophages and THY1+ FAP+ PDPN+ activated fibroblasts). Both groups showed enrichment of T-cell-associated transcriptional signatures, including CD8 T-cell-related genes and IL-17-associated pathways. Additionally, both patient groups showed increased expression of targets of alternative therapeutic agents, suggesting potential treatment options for specific patient subgroups. Conclusions Our findings provide insights into the inflammatory mechanisms driving relapse after anti-TNF withdrawal and flare on continued treatment. The dataset offers a valuable resource for future research to improve personalized treatment strategies in UC.

• Islam, Rakibul; Islam, Mohammad Mirazul; Nilsson, Per H.; Mohlin, Camilla; Hagen, Kjersti Thorvaldsen & Paschalis, Eleftherios I. [Show all 13 contributors for this article] (2021). Combined blockade of complement C5 and TLR co-receptor CD14 synergistically inhibits pig-to-human corneal xenograft induced innate inflammatory responses. Acta Biomaterialia. ISSN 1742-7061. 127, p. 169–179. doi: 10.1016/j.actbio.2021.03.047. Full text in Research Archive Show summary

  Inadequate supplies of donor corneas have evoked an escalating interest in corneal xenotransplantation. However, innate immune responses contribute significantly to the mechanism of xenograft rejection. We hypothesized that complement component C5 and TLR co-receptor CD14 inhibition would inhibit porcine cornea induced innate immune responses. Therefore, we measured cytokine release in human blood, induced by three forms of corneal xenografts with or without inhibitors. Native porcine cornea (NPC) induced interleukins (IL-1β, IL-2, IL-6, IL-8, IL-1ra), chemokines (MCP-1, MIP-1α, MIP-1β) and other cytokines (TNF, G-CSF, INF-γ, FGF-basic). Decellularized (DPC) and gamma-irradiated cornea (g-DPC) elevated the release of those cytokines. C5-blockade by eculizumab inhibited all the cytokines except G-CSF when induced by NPC. However, C5-blockade failed to reduce DPC and g-DPC induced cytokines. Blockade of CD14 inhibited DPC-induced cytokines except for IL-8, MCP-1, MIP-1α, and G-CSF, while it inhibited all of them when induced by g-DPC. Combined blockade of C5 and CD14 inhibited the maximum number of cytokines regardless of the xenograft type. Finally, by using the TLR4 specific inhibitor Eritoran, we showed that TLR4 activation was the basis for the CD14 effect. Thus, blockade of C5, when combined with TLR4 inhibition, may have therapeutic potential in pig-to-human corneal xenotransplantation. Statement of significance Bio-engineered corneal xenografts are on the verge of becoming a viable alternative to allogenic human-donor-cornea, but the host's innate immune response is still a critical barrier for graft acceptance. By overruling this barrier, limited graft availability would no longer be an issue for treating corneal diseases. We showed that the xenograft induced inflammation is initiated by the complement system and toll-like receptor activation. Intriguingly, the inflammatory response was efficiently blocked by simultaneously targeting bottleneck molecules in the complement system (C5) and the TLR co-receptor CD14 with pharmaceutical inhibitors. We postulate that a combination of C5 and CD14 inhibition could have a great therapeutic potential to overcome the immunologic barrier in pig-to-human corneal xenotransplantation.

• Casado, Raquel Bartolomé; Landsverk, Ole J. B.; Chauhan, Sudhir Kumar; Sætre, Frank Ove; Hagen, Kjersti Thorvaldsen & Yaqub, Sheraz [Show all 12 contributors for this article] (2020). CD4+ T cells persist for years in the human small intestine and display a TH1 cytokine profile. Mucosal Immunology. ISSN 1933-0219. 14(2), p. 402–410. doi: 10.1038/s41385-020-0315-5. Full text in Research Archive Show summary

  Studies in mice and humans have shown that CD8+ T cell immunosurveillance in non-lymphoid tissues is dominated by resident populations. Whether CD4+ T cells use the same strategies to survey peripheral tissues is less clear. Here, examining the turnover of CD4+ T cells in transplanted duodenum in humans, we demonstrate that the majority of CD4+ T cells were still donor-derived one year after transplantation. In contrast to memory CD4+ T cells in peripheral blood, intestinal CD4+ TRM cells expressed CD69 and CD161, but only a minor fraction expressed CD103. Functionally, intestinal CD4+ TRM cells were very potent cytokine producers; the vast majority being polyfunctional TH1 cells, whereas a minor fraction produced IL-17. Interestingly, a fraction of intestinal CD4+ T cells produced granzyme-B and perforin after activation. Together, we show that the intestinal CD4+ T-cell compartment is dominated by resident populations that survive for more than 1 year. This finding is of high relevance for the development of oral vaccines and therapies for diseases in the gut.

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