Mucosal cytokine production during remission after resection for Crohn's disease and its relationship to future relapse

Results of the Eighth Scientific Workshop of ECCO: Pathophysiology and Risk Factors of Postoperative Crohn's Disease Recurrence after an Ileocolonic Resection

Postoperative recurrence [POR] after an ileocolonic resection with ileocolonic anastomosis is frequently encountered in patients with Crohn's disease. The 8th Scientific Workshop of ECCO reviewed the available evidence on the pathophysiology and risk factors for POR. In this paper, we discuss published data on the role of the microbiome, the mesentery, the immune system and the genetic background. In addition to investigating the causative mechanisms of POR, identification of risk factors is essential to tailor preventive strategies. Potential clinical, surgical and histological risk factors are presented along with their limitations. Emphasis is placed on unanswered research questions, guiding prevention of POR based on individual patient profiles.

Intra-abdominal septic complications after ileocolic resection increases risk for endoscopic and surgical postoperative Crohn's disease recurrence

BACKGROUND

Postoperative recurrence [POR] of Crohn's disease following ileocolonic resection is common. The impact of immediate postoperative intra-abdominal septic complications [IASC] on endoscopic and surgical recurrence has not been elucidated.

AIMS

To evaluate if IASC is associated with an increased risk for endoscopic and surgical POR.

METHODS

This was a retrospective study of adult Crohn's disease patients undergoing ileocolonic resection with primary anastomosis between 2009 and 2020. IASC was defined as anastomotic leak or intra-abdominal abscess within 90 days of the date of surgery. Multivariable logistic and Cox proportional hazard modelling were performed to assess the impact of IASC on endoscopic POR [modified Rutgeerts' score ≥ i2b] at index postoperative ileocolonoscopy and long-term surgical recurrence.

RESULTS

In 535 Crohn's disease patients [median age 35 years, 22.1% active smokers, 35.7% one or more prior resection] had an ileocolonic resection with primary anastomosis. A minority of patients [N = 47; 8.8%] developed postoperative IASC. In total, 422 [78.9%] patients had one or more postoperative ileocolonoscopies, of whom 163 [38.6%] developed endoscopic POR. After adjusting for other risk factors for postoperative recurrence, postoperative IASC was associated with significantly greater odds (adjusted odds ratio [aOR]: 2.45 [1.23-4.97]; p = 0.01) and decreased time (adjusted hazards ratio [aHR]: 1.60 [1.04-2.45]; p = 0.03] to endoscopic POR. Furthermore, IASC was associated with increased risk (aOR: 2.3 [1.04-4.87] p = 0.03) and decreased survival-free time [aHR: 2.53 [1.31-4.87]; p = 0.006] for surgical recurrence.

CONCLUSION

IASC is associated with an increased risk for endoscopic and surgical POR of Crohn's disease. Preoperative optimization to prevent IASC, in addition to postoperative biological prophylaxis, may help reduce the risk for endoscopic and surgical POR.

The Role of Inflammation in Crohn's Disease Recurrence after Surgical Treatment

Introduction

Postoperative recurrence after surgery for Crohn's disease (CD) is virtually inevitable, and its mechanism is poorly known.

Aim

To review the numerous factors involved in CD postoperative recurrence (POR) pathogenesis, focusing on single immune system components as well as the immune system as a whole and highlighting the clinical significance in terms of preventive strategies and future perspectives.

Methods

A systematic literature search on CD POR, followed by a review of the main findings.

Results

The immune system plays a pivotal role in CD POR, with many different factors involved. Memory T-lymphocytes retained in mesenteric lymph nodes seem to represent the main driving force. New pathophysiology-based preventive strategies in the medical and surgical fields may help reduce POR rates. In particular, surgical strategies have already been developed and are currently under investigation.

Conclusions

POR is a complex phenomenon, whose driving mechanisms are gradually being unraveled. New preventive strategies addressing these mechanisms seem promising.

Exploring inflammatory and apoptotic signatures in distinct Crohn's disease phenotypes: Way towards molecular stratification of patients and targeted therapy

BACKGROUND

Crohn's disease (CD) is chronic inflammatory bowel disease with different phenotypic characteristics influencing disease prognosis and therapeutic strategies. The aim of this pilot study was to analyze selected inflammatory and apoptotic markers in non-inflamed and inflamed samples of ileal mucosa of non-stricturing/non-penetrating (NS/NP) and stricturing (S) CD mucosal phenotypes in order to characterize their distinct profiles.

METHODS

From twenty CD patients (9 NS/NP, 11 S) paired non-inflamed and inflamed ileal biopsies were collected and used for analysis of cytokine (TNF and IL6) and apoptotic (Bcl2, Bax, Fas and FasL) genes' expression levels by real-time PCR, while NFκB transcriptional potency was assessed by electromobility gel shift assay.

RESULTS

Our results demonstrated significant upregulation of TNF and IL6 in inflamed area of both NS/NP (p = 0.03, p = 0.01) and S phenotypes (p = 0.04, p = 0.04), respectively. However, TNF increase was more prominent in NS/NP compared to S inflamed mucosa (p = 0.02). Also, level of proapoptotic Bax was significantly higher in NS/NP compared to S inflamed mucosa (p = 0.01). Opposing transcription potency of NFκB has been detected between two phenotypes: being decreased in NS/NP (p = 0.07) and increased in S (p = 0.1) inflamed compared to non-inflamed mucosa, demonstrating trend towards statistical significance.

CONCLUSIONS

We found that two distinct CD phenotypes have specific molecular signatures. Obtained results could direct improvement of current and development of new therapeutic strategies based on more specific molecular stratification of CD patients.

Microbiome-skin-brain axis: A novel paradigm for cutaneous wounds

Chronic wounds cause a significant burden on society financially, medically, and psychologically. Unfortunately, patients with nonhealing wounds often suffer from comorbidities that further compound their disability. Given the high rate of depressive symptoms experienced by patients with chronic wounds, further studies are needed to investigate the potentially linked pathophysiological changes in wounds and depression in order to improve patient care. The English literature on wound healing, inflammatory and microbial changes in chronic wounds and depression, and antiinflammatory and probiotic therapy was reviewed on PubMed. Chronic wound conditions and depression were demonstrated to share common pathologic features of dysregulated inflammation and altered microbiome, indicating a possible relationship. Furthermore, alternative treatment strategies such as immune-targeted and probiotic therapy showed promising potential by addressing both pathophysiological pathways. However, many existing studies are limited to a small study population, a cross-sectional design that does not establish temporality, or a wide range of confounding variables in the context of a highly complex and multifactorial disease process. Therefore, additional preclinical studies in suitable wound models, as well as larger clinical cohort studies and trials are necessary to elucidate the relationship between wound microbiome, healing, and depression, and ultimately guide the most effective therapeutic and management plan for chronic wound patients.

A Nomogram Combining Fecal Calprotectin Levels and Plasma Cytokine Profiles for Individual Prediction of Postoperative Crohn's Disease Recurrence

BACKGROUND

The aims of this study were to characterize the immune response profile in patients with Crohn's disease (CD) and early postoperative recurrence (POR), to identify predictive biomarkers, and to develop a noninvasive predictive tool for individual estimation of POR risk.

METHODS

Sixty-one patients who had undergone ileocolonic resection for CD were prospectively included and followed up for 24 months. Fecal calprotectin (FC), analytical parameters, and plasma cytokines were obtained before surgery and at various time points during postoperative follow-up. Morphological recurrence was assessed by ileocolonoscopy or magnetic resonance enterography within 6-12 months after surgery. Clinical activity was scored using the Harvey-Bradshaw Index.

RESULTS

Twenty-seven patients (44.3%) had morphological recurrence during follow-up. Fecal calprotectin values were significantly associated with POR risk over time. The receiver operating characteristic curve for FC provided an area under the curve (AUC) of 0.88 (95% confidence interval, 0.75-0.96), and morphological recurrence was best predicted by FC ≥160 μg/g at 6 months after surgery (85% sensitivity, 70% specificity, 26% predictive positive value, 98% negative predictive value [NPV]). The plasma cytokine profile showed higher presurgery interleukin (IL)-13 plasma levels and higher IL-6 and interferon (IFN)-γ levels at 6 months after surgery in patients with POR compared with patients without recurrence. The combination of FC, IL-6, and IFN-γ values at 6 months gave an AUC of 0.90 for predicting an early recurrence.

CONCLUSIONS

FC values <160 μg/g at 6 months have a high NPV to rule out early lesions. Combined values of FC, IL-6, and IFN-γ levels at 6 months postsurgery constitute a prognostic index with a high predictive capacity to assess the risk of early POR.

The utility of faecal calprotectin to predict post-operative recurrence in Crohńs disease

OBJECTIVE

Endoscopic recurrence in Crohńs disease occurs in up to 80% of patients during the first year after surgery. Due to this, these patients need close monitoring. Faecal calprotectin has been proposed to be used as a non-invasive marker to monitor inflammatory activity. Up to now the use of faecal markers in endoscopic recurrence has been scarcely studied and with contradictory results.

MATERIAL AND METHODS

This was a cross-sectional observational study of diagnostic validity. It included all patients with Crohńs disease (CD) and ileocolic resection retrospectively who had had an ileocolonoscopy and a determination of faecal calprotectin before this colonoscopy, from 2007 to 2015.

RESULTS

Ninety-seven patients were included. We observed that the mean value of faecal calprotectin increased as the Rutgeerts score increased. The variable of that most statistical significance obtained in bivariate analysis was faecal calprotectin (p < 0.0001). Area under curve (AUC) of faecal calprotectin in endoscopic recurrence was 0.74 (95% CI: 0.644-0.842), and an optimal cut-off of 60 mcrgr/gr, obtained a score of 0.45 using Youden test. This indicated that calprotectin would have 88% Sensitivity and 58% Specificity in detecting any recurrence, the NPV was approximately 83,9%. None of the other variables studied had a significant correlation.

CONCLUSION

Faecal calprotectin predicts endoscopic recurrence in CD patients who have gone through surgery, however the cut-off point is still a problem so we cannot recommend calprotectin as a substitute of colonoscopy for CD monitoring and treatment adjustment.

LPS-Stimulated Whole Blood Cytokine Production Is Not Related to Disease Behavior in Patients with Quiescent Crohn's Disease

Introduction

Crohn’s disease (CD) is a chronic inflammatory disease in which cytokines play a pivotal role in the induction and maintenance of inflammation. Innate cytokine production is genetically determined and varies largely between individuals; this might impact the severity of inflammation. We aimed to assess whether ex-vivo endotoxin-stimulated levels of cytokines could be associated with disease phenotype.

Methods

Patients with quiescent CD (Harvey-Bradshaw Index ≤ 4 and negative inflammation markers) who were not using immunomodulating drugs or biologicals were eligible. Historical disease characteristics (localization, behavior, number of bowel resections, drug history, extra-intestinal symptoms) were extracted from medical records. We measured cytokine levels (tumor necrosis factor (TNF)-α, interleukin (IL)-1β, IL-6 and IL-10) in supernatants of lipopolysaccharide (LPS) -stimulated whole blood cultures and correlated these with disease characteristics and age- and sex-matched healthy controls. In addition, we analyzed whether single nucleotide polymorphisms (SNPs) in the promoter region of the TNF-α gene were related to TNF-α levels.

Results

We included 75 patients with CD and 24 healthy controls. Six patients were excluded because of increased inflammation markers resulting in a total of 69 patients. The mean age (SD) of patients with CD was 51.2 (12.3) years with a mean (SD) disease duration of 24.1 (11.5) years. Disease localization, peri-anal involvement and behavior were not related to LPS-stimulated TNF-α, IL-1β, IL-6 or IL-10 levels. In addition, combination of localization with behavior to differentiate mild from severe disease type showed no significant differences. TNF-α levels were higher in patients with CD (428 pg/ml IQR [267-468]) compared to healthy controls (459 pg/ml IQR [364-570], p=0.02). We found no associations between SNPs in the promoter region and TNF-α levels.

Conclusion

In this study, innate cytokine production of TNF-α, IL-1β, IL-6 and IL-10 was not related to historical disease characteristics or disease severity in patients with quiescent CD. These findings suggest that genetically determined levels of these cytokines obtained from LPS-stimulated whole blood cultures are not linked with disease behavior or severity.

NOD2-mediated dysbiosis predisposes mice to transmissible colitis and colorectal cancer

Instability in the composition of gut bacterial communities (dysbiosis) has been linked to common human intestinal disorders, such as Crohn's disease and colorectal cancer. Here, we show that dysbiosis caused by Nod2 deficiency gives rise to a reversible, communicable risk of colitis and colitis-associated carcinogenesis in mice. Loss of either Nod2 or RIP2 resulted in a proinflammatory microenvironment that enhanced epithelial dysplasia following chemically induced injury. The condition could be improved by treatment with antibiotics or an anti-interleukin-6 receptor-neutralizing antibody. Genotype-dependent disease risk was communicable via maternally transmitted microbiota in both Nod2-deficient and WT hosts. Furthermore, reciprocal microbiota transplantation reduced disease risk in Nod2-deficient mice and led to long-term changes in intestinal microbial communities. Conversely, disease risk was enhanced in WT hosts that were recolonized with dysbiotic fecal microbiota from Nod2-deficient mice. Thus, we demonstrated that licensing of dysbiotic microbiota is a critical component of disease risk. Our results demonstrate that NOD2 has an unexpected role in shaping a protective assembly of gut bacterial communities and suggest that manipulation of dysbiosis is a potential therapeutic approach in the treatment of human intestinal disorders.

Predicting, treating and preventing postoperative recurrence of Crohn's disease: the state of the field

The majority of patients diagnosed with Crohn's disease eventually require surgical intervention. Unfortunately, postsurgical remission tends to be short lived; a significant number of patients experience clinical relapse and many require additional operations. The pathogenesis of this postoperative recurrence is poorly understood and, currently, there are no reliable tools to predict when and in whom the disease will recur. Furthermore, the postoperative prophylaxis profiles of available Crohn's disease therapeutic agents such as 5-aminosalicylates, immunomodulators, steroids and probiotics have been disappointing. Recently, the combination of antibiotics and azathioprine in selected high-risk patients has demonstrated some potential for benefit. The goal of the present article is to provide a coherent summary of previous and new research to guide clinicians in managing the challenging and complex problem of postoperative Crohn's disease recurrence.

Psychoneuroimmunologic factors in inflammatory bowel disease

BACKGROUND

Bidirectional relationships between the immune system, nervous system, and psychological processes likely exist in inflammatory bowel disease (IBD) because stress can affect IBD, and IBD is associated with an increased risk of psychological difficulty. The field of psychoneuroimmunology (PNI) sheds light on specific mechanisms that are involved in these relationships, and this research can be applied specifically to IBD. The purpose of this article is to review research on PNI processes in IBD and provide recommendations for future research.

METHODS

A literature search was conducted using the PubMed and PsychInfo computerized databases and bibliographies of relevant articles.

RESULTS

The hypothalamic-pituitary-adrenal axis, sympathetic-adrenomedullary system, proinflammatory cytokines, substance P, and mast cells play roles in inflammatory processes in IBD. These processes also respond to stress, and they have been implicated in psychological problems in otherwise healthy individuals. These overlapping processes in inflammation and psychological function have received limited attention in IBD, but preliminary evidence suggests that these mechanisms may play a role in the psychological difficulty experienced by those with IBD.

CONCLUSIONS

Several bidirectional PNI mechanisms overlap in IBD, suggesting ways that stress and psychological function can affect disease activity and, conversely, avenues by which the inflammation in IBD may contribute to psychological difficulty. More research on specific PNI processes is needed to fully understand these factors in IBD.

Cytokine network in rectal mucosa in perianal Crohn's disease: relations with inflammatory parameters and need for surgery

BACKGROUND

Nowadays anti-TNF-alpha antibodies are used for the treatment of perianal Crohn's disease (CD). Nevertheless, this treatment is effective in only a part of these patients and recent studies suggested a role for other cytokines in chronic bowel inflammation. The aim of this study was to assess the cytokine profile in the rectal mucosa of patients affected by perianal CD and to understand its relations with the systemic cytokine profile and inflammatory parameters and the need for surgery.

METHODS

Seventeen patients affected by perianal CD, 7 affected by CD without perianal involvement, and 17 healthy controls were enrolled and underwent blood sampling and endoscopy. During endoscopy rectal mucosal samples were taken and the expression of TNF-alpha, IL-6, IL-1 beta, IL-12, and TGF-beta1 was quantified with enzyme-linked immunosorbent assay (ELISA). Local cytokine levels were compared and correlated with diagnosis, therapy, phenotype (fistulizing and stenosing), and disease activity parameters.

RESULTS

In the group with perianal CD, rectal mucosal IL-1 beta, IL-6, and serum IL-6 and TNF-alpha were higher than in patients with small bowel CD and healthy controls. IL-12 and TGF-beta1 mucosal levels did not show any differences among the 3 groups. Mucosal IL-6 significantly correlated with the Perianal Crohn's Disease Activity Index and mucosal TNF-alpha and IL-1 beta. Mucosal TNF-alpha and IL-1 beta showed a direct correlation with the histological grade of disease activity.

CONCLUSIONS

The cytokines network analysis in perianal CD shows the important involvement of IL-1 beta, IL-6, and TNF-alpha. Furthermore, mucosal levels of IL-6 and IL-12 are predictors of recurrence and of need for surgery in perianal CD patients.

Mucosal inflammation in the terminal ileum of ulcerative colitis patients: endoscopic findings and cytokine profiles

BACKGROUND

Currently, published reports of mucosal inflammation in the terminal ileum of ulcerative colitis (UC) before colectomy are scarce.

AIM

To investigate inflammation in the terminal ileum of UC patients by endoscopic examinations and measurement of mucosal cytokine profiles.

METHODS

Fifty consecutive patients with active UC were studied. At ileocolonoscopy, mucosal biopsies were taken from the terminal ileum. As control, mucosal biopsies from 20 patients without inflammation were examined.

RESULTS

Thirty-eight patients showed endoscopically normal terminal ileum, four showed backwash ileitis, and eight showed non-backwash ileitis (ileitis with normal caecum). Pancolitis was observed in all of four patients with backwash ileitis, in 4 of 8 (50%) with non-backwash ileitis, and in 4 of 38 (11%) without ileal inflammation (P=0.0002). Extraintestinal manifestations were observed in none of 4 patients with backwash ileitis, in 6 of 8 (75%) with non-backwash ileitis, and in 3 of 38 (8%) without ileal inflammation (P<0.0001). In patients with backwash ileitis and non-backwash ileitis, ileal interleukin [IL]-1beta, IL-6, IL-8 and tumour necrosis factor-alpha levels were significantly elevated compared with the control group. Only extraintestinal manifestation was associated with higher ileal cytokine levels, whereas age, sex, and duration, extent and severity of UC did not show any apparent association.

CONCLUSIONS

In patients with backwash ileitis, elevated ileal cytokines might reflect a reaction to regurgitation of colonic content into the ileum, but in patients without backwash ileitis, alternative factors are expected to contribute to the aetiology of ileal inflammation. Patients with extraintestinal manifestations had elevated ileal cytokine levels.

Impacts of long-term enteral nutrition on clinical and endoscopic disease activities and mucosal cytokines during remission in patients with Crohn's disease: a prospective study

BACKGROUND

Long-term enteral nutrition may maintain clinical and endoscopic remission in patients with Crohn's disease (CD). The aim of this prospective study was to investigate the impacts of long-term enteral nutrition on clinical and endoscopic disease activities and mucosal tissue cytokines in patients with quiescent CD.

METHODS

Forty patients with CD who achieved clinical remission were included. Of these, 20 received continuous elemental diet (Elental) infusion during the nighttime and a low-fat diet during the daytime (EN group) and 20 received neither nutritional therapy nor food restriction (non-EN group). With these regimens, all 40 patients were monitored for 1 year. Further, ileocolonoscopy was performed at entry, at 6 and 12 months, and mucosal biopsies were taken for cytokine assays.

RESULTS

On an intention-to-treat basis, 5 patients (25%) in the EN group and 13 (65%) in the non-EN group had a clinical relapse during the 1-year observation (P = 0.03). The mean endoscopic inflammation (EI) scores were not significantly different between the groups at both entry and 6 months, but at 12 months EI scores were significantly higher in the non-EN group than in the EN group (P = 0.04). Additionally, the mucosal tissue interleukin (IL)-1beta, IL-6, and tumor necrosis factor (TNF)-alpha levels significantly increased with time in the non-EN group (entry versus 12 months, IL-1beta, P = 0.02; IL-6, P = 0.002; TNF-alpha, P = 0.001). In the EN group these cytokines did not show a significant increase.

CONCLUSIONS

Long-term enteral nutrition in patients with quiescent CD has a clear suppressive effect on clinical and endoscopic disease activities and the mucosal inflammatory cytokine levels.

Impact of selective leukocytapheresis on mucosal inflammation and ulcerative colitis: cytokine profiles and endoscopic findings

BACKGROUND

This prospective study assessed the impact of selective leukocytapheresis (SLA) on mucosal inflammation in patients with active ulcerative colitis (UC) by endoscopic investigations and measurement of mucosal cytokine profiles.

MATERIALS AND METHODS

Twenty-eight patients with moderately active UC received 5 SLA sessions with the Adacolumn over 5 consecutive weeks. The Adacolumn leukocytapheresis carriers selectively adsorb granulocytes, monocytes/macrophages, and smaller subsets of lymphocytes (FcgammaR and complement receptors bearing leukocytes). Before and after treatment, mucosal biopsies were obtained from multiple sites in the large bowel. As control, colonic biopsies from 20 patients without bowel inflammation were examined. Mucosal cytokines were measured by enzyme-linked immunosorbent assay.

RESULTS

At entry, the mucosal concentrations of interleukin-1beta (IL-1beta), IL-1 receptor antagonist (IL-1ra), IL-6, IL-8, and tumor necrosis factor-alpha (TNF-alpha) were significantly higher compared with the control group, whereas IL-1ra/IL-1beta ratio was significantly lower. Clinical remission was achieved in 19 (68%) patients. In patients with clinical remission but not in those without remission, the mucosal tissue concentrations of IL-1beta, IL-1ra, IL-6, IL-8, and TNF-alpha significantly decreased, whereas the IL-1ra/IL-1beta ratio significantly increased. Furthermore, endoscopic remission of mucosal inflammation was observed in 14 (50%) patients, which was associated with a decline in mucosal IL-1beta, IL-1ra, IL-6, IL-8, and TNF-alpha and an increase in IL-1ra/IL-1beta ratio.

CONCLUSIONS

Depleting granulocytes and monocytes/macrophages by SLA should mitigate cytokine profiles in the intestinal mucosa and correct an imbalance between pro- and anti-inflammatory cytokines in active UC.

The impact of the fecal stream and stasis on immunologic reactions in ileal pouch after restorative proctocolectomy for ulcerative colitis: a prospective, pilot study

OBJECTIVE

The etiology of pouch inflammation after restorative proctocolectomy is unknown. The fecal stream and immunological reactions are potential pathological factors. This study was performed to examine the impact of the fecal stream and stasis on immunological reactions in the pouch.

METHODS

Patients who underwent a restorative proctocolectomy with a covering ileostomy for ulcerative colitis were studied. Mucosal biopsy specimens were obtained from both the pouch and the proximal ileum at the time of ileostomy closure, and 3, 6, and 12 months after ileostomy closure. As a control group, normal ileal biopsies were obtained from patients with colonic polyps.

RESULTS

At the time of ileostomy closure, mucosal interleukin-1beta, interleukin-6, interleukin-8, and tumor necrosis factor-alpha levels in the pouch and the proximal ileum were not significantly different from those in the normal control group. At 3 months after ileostomy closure, the mucosal cytokine levels in the pouch increased significantly compared with those at ileostomy closure, and their levels were significantly higher than those in the proximal ileum. At 6 and 12 months after ileostomy closure, the mucosal cytokine levels in the pouch did not change significantly compared with those at 3 months after ileostomy closure. The mucosal cytokine levels in the proximal ileum did not change significantly during the entire study.

CONCLUSIONS

The immunological reactions in the pouch occurred soon after ileostomy closure, and continued for at least 1 yr. The fecal stream and stasis play an important part in the pathogenesis of immunological reactions in the ileal pouch.

Postoperative Crohn's disease

More than three quarters of patients with Crohn's disease (CD) will require surgery. After resection, disease recurs postoperatively with a median time to second resection of about 10 years. Despite its importance, the postoperative period remains one of the most poorly understood clinical settings in the field. Postoperatively, CD may exhibit unique pathophysiologic features, but the current state of knowledge does not allow for identification of patients at risk for relapse, and leaves clinicians without guidance on optimal maintenance treatment. Therapies used as maintenance for CD in other settings may have different efficacies when used after surgery, and clinical research in patients requiring surgery is limited by the subset of patients available for study. Despite the many limitations in current knowledge of postoperative CD, it is an exciting field because new developments have improved patient care, and ongoing research has the potential for further gains.

Systemic and local cytokine production in quiescent ulcerative colitis and its relationship to future relapse: a prospective pilot study

BACKGROUND

The main aim of this prospective study was to examine whether systemic (plasma) and local (mucosal) cytokine production is a predictor of future relapse in patients with quiescent ulcerative colitis (UC). The impact of other clinical and laboratory parameters on relapse was also studied.

METHODS

Fifty consecutive patients with quiescent UC were included. At enrollment, blood and mucosal (rectal biopsies) samples were collected. All patients were followed up regularly for 1 year after enrollment. Plasma and mucosal cytokine levels were measured by enzyme-linked immunosorbent assay. To identify independent significant predictive factors for relapse, time-dependent analyses using the Kaplan-Meier method and the Cox proportional hazard model were performed.

RESULTS

Thirty-four patients remained in remission, and 16 patients relapsed during the 1-year follow-up. Higher interleukin (IL)-8 levels in the rectal mucosa were significantly associated with relapse. In contrast, IL-1beta, IL-6, and tumor necrosis factor-alpha levels in the rectal mucosa were not associated with relapse. Conventional blood markers and plasma cytokines (IL-1beta, IL-6, IL-8, and tumor necrosis factor-alpha) did not correlate with relapse. Among clinical factors, age and number of prior relapses were significantly associated with relapse. In multivariate analysis, a higher rectal mucosal IL-8 level (> or = 160 pg/mg of tissue; hazard ratio, 4.7), younger age (<30 yr; hazard ratio, 7.3), and a greater number of prior relapses (> or = 5; hazard ratio, 4.3) were independent significant risk factors for future relapse.

CONCLUSIONS

Rectal mucosal IL-8 measurement might be an additional objective diagnostic tool that can predict relapse in patients with quiescent UC.