Svenja Maschke

IL-2/α-IL-2 Complex Treatment Cannot Be Substituted for the Adoptive Transfer of Regulatory T cells to Promote Bone Marrow Engraftment.

Cell therapy with recipient Tregs achieves engraftment of allogeneic bone marrow (BM) without the need for cytoreductive conditioning (i.e., without irradiation or cytotoxic drugs). Thereby mixed chimerism and transplantation tolerance are established in recipients conditioned solely with costimulation blockade and rapamycin. However, clinical translation would be substantially facilitated if Treg-stimulating pharmaceutical agents could be used instead of individualized cell therapy. Recently, it was shown that interleukin-2 (IL-2) complexed with a monoclonal antibody (mAb) (clone JES6-1A12) against IL-2 (IL-2 complexes) potently expands and activates Tregs in vivo. Therefore, we investigated whether IL-2 complexes can replace Treg therapy in a costimulation blockade-based and irradiation-free BM transplantation (BMT) model. Unexpectedly, the administration of IL-2 complexes at the time of BMT (instead of Tregs) failed to induce BM engraftment in non-irradiated recipients (0/6 with IL-2 complexes vs. 3/4 with Tregs, p<0.05). Adding IL-2 complexes to an otherwise effective regimen involving recipient irradiation (1Gy) but no Treg transfer indeed actively triggered donor BM rejection at higher doses (0/8 with IL-2 complexes vs. 9/11 without, p<0.01) and had no detectable effect at two lower doses (3/5 vs. 9/11, p>0.05). CD8 T cells and NK cells of IL-2 complex-treated naïve mice showed an enhanced proliferative response towards donor antigens in vitro despite the marked expansion of Tregs. However, IL-2 complexes also expanded conventional CD4 T cells, CD8 T cells, NK cells, NKT cells and notably even B cells, albeit to a lesser extent. Notably, IL-2 complex expanded Tregs featured less potent suppressive functions than in vitro activated Tregs in terms of T cell suppression in vitro and BM engraftment in vivo. In conclusion, these data suggest that IL-2 complexes are less effective than recipient Tregs in promoting BM engraftment and in contrast actually trigger BM rejection, as their effect is not sufficiently restricted to Tregs but rather extends to several other lymphocyte populations.

Regulatory T Cells Promote Natural Killer Cell Education in Mixed Chimeras

Therapeutic administration of regulatory T cells (Tregs) leads to engraftment of conventional doses of allogeneic bone marrow (BM) in nonirradiated recipient mice conditioned with costimulation blockade and mammalian target of rapamycin inhibition. The mode of action responsible for this Treg effect is poorly understood but may encompass the control of costimulation blockade–resistant natural killer (NK) cells. We show that transient NK cell depletion at the time of BM transplantation led to BM engraftment and persistent chimerism without Treg transfer but failed to induce skin graft tolerance. In contrast, the permanent absence of anti–donor NK reactivity in mice grafted with F1 BM was associated with both chimerism and tolerance comparable to Treg therapy, implying that NK cell tolerization is a critical mechanism of Treg therapy. Indeed, NK cells of Treg‐treated BM recipients reshaped their receptor repertoire in the presence of donor MHC in a manner suggesting attenuated donor reactivity. These results indicate that adoptively transferred Tregs prevent BM rejection, at least in part, by suppressing NK cells and promote tolerance by regulating the appearance of NK cells expressing activating receptors to donor class I MHC.

Incidental adenocarcinoma in patients undergoing surgery for stricturing Crohn's disease

AIM To evaluate frequency and clinical course of incidental adenocarcinoma in patients with stricturing Crohns disease (CD). METHODS In this study, consecutive patients, who were operated on for stricturing CD between 1997-2012, were included at an academic tertiary referral center. Demographic data and clinical course were obtained by an institutional database and individual chart review. Besides baseline characteristics, intraoperative findings and CD related history were also recorded. Colorectal cancer was classified and staged according to the Union for International Cancer Control (UICC). RESULTS During the study period 484 patients underwent resections due to stricturing CD. Incidental adenocarcinoma was histologically confirmed in 6 (1.2%) patients (4 males, 2 females). Patients diagnosed with colorectal cancer had a median age of 43 (27-66) years and a median history of CD of 16 (7-36) years. Malignant lesions were found in the rectum (n = 4, 66.7%), descending colon (n = 1, 16.7%) and ileocolon (n = 1, 16.7%). According to the UICC classification two patients were stages as I (33.3%), whereas the other patients were classified as stage IIA (16.7%), stage IIIB (16.7%), stage IIIC (16.7%) and stage IV (16.7%), respectively. After a median follow-up of 2 (0.03-8) years only 1 patient is still alive. CONCLUSION The frequency of incidental colorectal cancer in patients, who undergo surgery for stenotic CD, is low but associated with poor prognosis. However, surgeons need to be aware about the possibility of malignancy in stricturing CD, especially if localized in the rectum.

Anti-Interleukin-6 Promotes Allogeneic Bone Marrow Engraftment and Prolonged Graft Survival in an Irradiation-Free Murine Transplant Model

Transfer of recipient regulatory T cells (Tregs) induces mixed chimerism and tolerance in an irradiation-free bone marrow (BM) transplantation (BMT) model involving short-course co-stimulation blockade and mTOR inhibition. Boosting endogenous Tregs pharmacologically in vivo would be an attractive alternative avoiding the current limitations of performing adoptive cell therapy in the routine clinical setting. Interleukin-6 (IL-6) potently inhibits Treg differentiation and its blockade was shown to increase Treg numbers in vivo. Therefore, we investigated whether IL-6 blockade can replace adoptive Treg transfer in irradiation-free allogeneic BMT. Treatment with anti-IL-6 instead of Treg transfer led to multi-lineage chimerism (persisting for ~12 weeks) in recipients of fully mismatched BM and significantly prolonged donor skin (MST 58 days) and heart (MST > 100 days) graft survival. Endogenous Foxp3+ Tregs expanded in anti-IL-6-treated BMT recipients, while dendritic cell (DC) activation and memory CD8+ T cell development were inhibited. Adding anti-IL-17 to anti-IL-6 treatment increased Treg frequencies, but did not further prolong donor skin graft survival significantly. These results demonstrate that IL-6 blockade promotes BM engraftment and donor graft survival in non-irradiated recipients and might provide an alternative to Treg cell therapy in the clinical setting.

Phenotypes of Jackhammer esophagus in patients with typical symptoms of gastroesophageal reflux disease responsive to proton pump inhibitors

This trial was designed to assess the prevalence and characteristics of Jackhammer esophagus (JE), a novel hypercontractile disorder associated with progression to achalasia and limited outcomes following anti-reflux surgery in patients with typical symptoms of GERD and responsiveness to proton pump inhibitor (PPI) therapy. Consecutive patients, who were referred for surgical therapy because of PPI responsive typical symptoms of GERD, were prospectively assessed between January 2014 and May 2017. Patients diagnosed with JE subsequently underwent rigorous clinical screening including esophagogastroduodenoscopy (EGD), ambulatory pH impedance monitoring off PPI and a PPI trial. Out of 2443 evaluated patients, 37 (1.5%) subjects with a median age of 56.3 (51.6; 65) years were diagnosed with JE and left for final analysis. Extensive testing resulted in 16 (43.2%) GERD positive patients and 5 (13.9%) participants were observed to have an acid hypersensitive esophagus. There were no clinical parameters that differentiated phenotypes of JE. The prevalence of JE in patients with typical symptoms of GERD and response to PPI therapy is low. True GERD was diagnosed in less than half of this selected cohort, indicating the need for objective testing to stratify phenotypes of JE. (NCT03347903)

Outcome after liver transplantation in elderly recipients (>65 years) — A single-center retrospective analysis

BACKGROUND Liver transplantation (LT) in elderly recipients is controversially discussed in the literature with only little data on long-term outcome available. We aimed to evaluate the safety and efficiency of LT in elderly recipients (>65 years). METHODS Between 1989-2016, 139 patients >65 years-old were listed for liver transplantation, and 76 (55%) were transplanted. Patient outcome and characteristics were evaluated separately for the time period before (1989-2004) and after (2005-2016) MELD-implementation. Post-transplant outcome was compared between the elderly cohort and LT-recipients aged 18-65 years (n = 1395). RESULTS Overall survival of patients >65 years was better in the MELD-era compared to the earlier period (1- and 5-year-survival: 73%, 60% vs. 69%, 37%, respectively; p = 0.055). The main differences between the two groups included higher recipient age (p = 0.001) and BMI (p = 0.001), higher donor age (p < 0.001), less need of intraoperative red blood cells (p = 0.008) and a lower number of postoperative rejections (p = 0.03) after 2004. Comparing the overall survival of patients transplanted in the MELD-era aged 18-65 years vs. >65 years displayed comparable 1- and 5 year-survival rates (81%, 68% vs. 73% and 60%, respectively, p = 0.558). CONCLUSION In the modern era, outcome of patients receiving LT with >65 years is comparable to <65 year-old patients. After careful evaluation, patients >65 years old should be considered for LT.