Yashwant R. Mahida

Background: Intravenous immunoglobulin (IVIg) for Clostridioides difficile infection (CDI) no longer features in treatment guidelines. However, IVIg is still used by some clinicians for severe or recurrent CDI (rCDI) cases. The main objective of this study was to investigate the efficacy of IVIg and to identify possible predictors of disease resolution post IVIg administration for patients with CDI. Methods: This retrospective observational cohort study of patients ≥2 years old hospitalised with severe, relapsing, or rCDI treated with IVIg therapy was performed in a large UK tertiary hospital between April 2018 and March 2023. Scanned electronic notes from patient admissions and clinical reporting systems were used to collect relevant data. Results: In total, 20/978 patients diagnosed with CDI over the 5-year study were treated with IVIg. Twelve (60%) had hospital-onset CDI. Eleven of the twenty patients (55%) responded to treatment, with a mean of 8.6 (SD 10.7) days to disease resolution. Sixteen (80%) patients were treated for severe CDI and four (20%) for rCDI (n = 3) and relapsing CDI (n = 1). There were no statistically significant differences in possible independent predictors of disease resolution post IVIg administration between groups. There was an average of 6.2 (4.9) days to IVIg administration after diagnosis with no difference between responders and non-responders (p = 0.88) and no further significant difference in additional indicators. Four (36%) of the responders were immunosuppressed compared to just one (11%) of the non-responders (p = 0.15). Six of the responders (two with recurrent and four with severe CDI) improved rapidly within 2 days, and three of these were immunosuppressed. Conclusion: We observed disease resolution post IVIg therapy in over 50% of patients with refractory CDI. Our data also support a potential enhanced effect of IVIg in immunosuppressed individuals. Thus, the role of IVIg for CDI treatment, particularly in the immunosuppressed, warrants future case–control studies coupled to mechanistic investigations to improve care for this ongoing significant healthcare-associated infection.

Some text in this abstract has been reproduced from Lindsay J, Din S, Hawkey C, Hind D, Irving P, Lobo A, et al. OFR-9 An RCT of autologous stem-cell transplantation in treatment refractory Crohn’s disease (low-intensity therapy evaluation): ASTIClite. Gut 2021;70(Suppl. 4):A4. Background: Treatment-refractory Crohn’s disease is characterised by chronic symptoms, poor quality of life and high costs to the NHS, and through days of work lost by patients. A previous trial of autologous haematopoietic stem cell transplant (HSCT) failed its end point of medication-free clinical remission for 3 months with no evidence of disease activity, and reported high toxicity. Subsequent studies suggest that HSCT achieves complete mucosal healing in 50% of patients, and that toxicity likely relates to the cyclophosphamide dose. Objectives: The primary objective was to assess the efficacy of HSCTlite (HSCT with low-dose cyclophosphamide) compared with standard care for inducing regression of intestinal ulceration in patients with refractory Crohn’s disease at week 48. Secondary objectives included the assessment of disease activity, quality of life and regimen safety. Mechanistic objectives included immune reconstitution after HSCTlite. Design: Two-arm, parallel-group randomised controlled trial with a 2 : 1 (intervention : control) allocation ratio. Setting: Nine NHS trusts (eight trusts were recruitment sites; one trust was a treatment-only site). Participants: Adults with treatment-refractory Crohn’s disease, for whom surgery was inappropriate or who had declined surgery. Interventions: The intervention treatment was HSCTlite using cyclophosphamide, and the control was any current available treatment for Crohn’s disease, apart from stem cell transplantation. Main outcomes: The primary outcome was treatment success at week 48 [mucosal healing (Simple Endoscopic Score for Crohn’s Disease ulcer subscore of 0) without surgery or death], assessed by central readers blinded to allocation and timing of assessment. Key secondary outcomes were clinical remission, Simple Endoscopic Score for Crohn’s Disease scores at week 48, change in Crohn’s Disease Activity Index scores and safety. Results: The trial was halted owing to Suspected unexpected serious adverse events that took place after randomising 23 patients (HSCTlite arm, n = 13; usual-care arm, n = 10). Ten out of the 13 patients randomised to the HSCTlite arm received the intervention and nine (one death) reached the 48-week follow-up. In the usual-care arm 9 out of the 10 patients randomised reached the 48-week follow-up (one ineligible). The primary outcome was available for 7 out of 10 HSCTlite patients (including the patient who died) and six out of nine usual-care patients. Absence of endoscopic ulceration without surgery or death was reported in three out of seven (43%) HSCTlite patients, compared with zero out of six (0%) usual-care patients. Centrally read Simple Endoscopic Score for Crohn’s Disease scores [mean (standard deviation)] were 10.8 (6.3) and 10.0 (6.1) at baseline, compared with 2.8 (2.9) and 18.7 (9.1) at week 48, in the HSCT and usual-care arms, respectively. Clinical remission (Crohn’s Disease Activity Index scores of < 150) occurred in 57% and 17% of patients in the HSCTlite and usual-care arms, respectively, at week 48. Serious adverse events were more frequent in the HSCTlite arm [38 in 13 (100%) patients] than in the usual-care arm [16 in 4 (40%) patients]. Nine suspected unexpected serious adverse reactions were reported in six HSCTlite patients, including three cases of delayed renal failure due to proven thrombotic microangiopathy. Two HSCTlite patients died. Conclusions: Within the limitations of reduced patient recruitment and numbers of patients assessed, HSCTlite meaningfully reduced endoscopic disease activity, with three patients experiencing resolution of ulceration. Suspected unexpected serious adverse reactions, particularly relating to thrombotic microangiopathy, make this regimen unsuitable for future clinical use. Limitations: The early trial closure prevented complete recruitment, and the impact of the coronavirus pandemic prevented completion of some study investigations. Small participant numbers meant analysis could only be descriptive. Future work: Owing to undetermined aetiology of thrombotic microangiopathy, further trials of HSCTlite in this population are not considered appropriate. Priorities should be to determine optimal treatment strategies for patients with refractory Crohn’s disease, including those with a stoma or multiple previous resections. Trial registration: This trial is registered as ISRCTN17160440 and EudraCT 2017-002545-30. Funding: This award was funded by the Efficacy and Mechanism Evaluation (EME) programme, a Medical Research Council (MRC) and National Institute for Health and Care Research (NIHR) partnership. This is published in full in Efficacy and Mechanism Evaluation; Vol. 11, No. 3. See the NIHR Funding and Awards website for further award information.

Background: Clostridium difficile infection is transmitted via spores, and the disease is mediated via secreted toxins. It represents a significant healthcare problem, and clinical presentation can range from asymptomatic carriage to life-threatening pseudomembranous colitis. Sources of data: publications in the field, with a focus on recent developments and concepts. Areas of agreement: infection control measures, antibiotic stewardship and current management of the initial episode of C. difficile infection. Areas of controversy: selection and sequence of interventions for the management of recurrent C. difficile infection; management of persistent carriers of toxigenic C. difficile in patients at high risk of subsequent C. difficile infection. Growing points: use of faecal microbiota transplantation for recurrent C. difficile infection. Areas timely for developing research: role of specific microbiota-mediated interventions and vaccination in the treatment and prevention of C. difficile infection.

The epithelium of the gastrointestinal tract represents the interface between the luminal contents of the gut and that of the host tissues and plays a central role not only in regulating absorption of dietary nutrients but also in providing a barrier to prevent the entry of bacteria and other pathogens. Repair and replacement of damaged aging cells within the epithelium is modulated by stem cells, which are located in the intestinal crypts of the small intestine. Two distinct populations of intestinal stem cells have been described in the literature, one population at the very base of the crypt and a second population of long-lived stem cells located just above the Paneth cell zone. Herein, we describe a method to label this population of long-lived GFP label retaining cells. This method is free from confounding factors of previous methodologies based on radioactive tracers and also enables functional studies not previously possible using the radioactive tracer techniques described in the literature.

Summary: The aim of our studies was to investigate the expression of Toll-like receptor (TLR)-2 and TLR-4 (and in some studies TLR-5) in myofibroblasts and small and large intestinal crypt epithelial cells from control patients and those affected by Crohn's disease and ulcerative colitis. Isolated and disaggregated crypt epithelial cells and monolayers of myofibroblasts were used for studies by reverse transcription–polymerase chain reaction (RT–PCR), real-time RT–PCR, flow cytometry, immunocytochemistry and Western blot analysis. Compared to control cells, crypt epithelial cells isolated from active ulcerative colitis and Crohn's disease colonic mucosal samples showed significantly higher expression of TLR-2 and TLR-4 transcripts and protein (on the cell surface). There was also enhanced expression of TLR-4 in crypt cells from ileal Crohn's disease. Expression of TLR-2 and TLR-4 transcripts in crypt epithelial cells isolated from inflamed mucosa of distal ulcerative colitis did not differ significantly from such cells obtained from the normal proximal colon. Crypt epithelial cells with side population characteristics (putative stem cells) also expressed transcripts and protein for TLR-2, TLR-4 and TLR-5. Colonic myofibroblast expression of these TLRs was much weaker than in crypt epithelial cells. In conclusion, enhanced TLR-2 and TLR-4 expression by crypt epithelial cells in active inflammatory bowel disease likely reflects greater ability to respond to microbial products. Results from our studies using mucosal samples from patients with distal ulcerative colitis suggest that the enhanced expression of these TLRs could be constitutive. TLR-2, TLR-4 and TLR-5 expression by stem cells imply ability to respond to distinct bacterial products.

C. difficile infection (CDI) is rarely reported in cystic fibrosis (CF) patients despite frequent hospitalisations and antibiotic usage. Conversely, the prevalence of CDI in inflammatory bowel disease (IBD) has received increased attention. We investigated components of the IgG-specific humoral immune response to C. difficile toxins A and B in patients with C. difficile-associated diarrhoea (CDAD), IBD patients with CDI, CF patients and healthy controls. Serum anti-toxin IgG was determined by ELISA. Circulating antigen-activated B-cells were investigated using Alexa Fluor 488-labelled toxin A and assessed by flow cytometry. Following induction of differentiation of memory B-cells, toxin A- and B-specific antibody secreting cells (ASCs) were quantified using ELISpot. We present the first data showing levels of serum anti-toxin A and B antibodies were significantly higher in patients with CF (without a history of CDI) than in CDAD patients and were stably maintained over time. Notably, the CDAD patients were significantly older than the CF patients. We also show that circulating toxin A-specific memory B-cells (IgD-negative) can be detected in CDAD patients [0.92 (0.09–1.78)%], and were prominent (5.64%, 1.14%) in two CF patients who were asymptomatic carriers of C. difficile. There was correlation between toxin A- and B-specific ASCs, with significantly higher proportions of the latter seen. In some with CDAD, high serum antibody levels were seen to only one of the two toxins. Mucosal secretion of toxin-specific IgG was detected in an additional group of IBD patients with no history of CDI. We conclude that enhanced and stable humoral immune responses to toxins A and B may protect CF and some IBD patients against CDI. The impaired ability to generate strong and/or sustained toxin-specific antibody and memory B-cell responses may increase susceptibility of older patients to CDI and highlight the need to investigate the role of immune senescence in future studies.