Mycophenolate mofetil-related gastrointestinal mucosal injury: variable injury patterns, including graft-versus-host disease-like changes. Am J Surg Pathol. 2008;32:1367-1372. [PMID: 18763324 DOI: 10.1097/pas.0b013e31816bf3fe]

Pointers and pitfalls of mycophenolate-associated colitis

AIMS

Mycophenolate-associated colitis has been previously reported to show patterns of colonic mucosal injury mimicking a host of conditions, including graft-versus-host disease, ischaemia and inflammatory bowel disease (IBD). The aim of this study is to characterise, semiquantitatively, pathological changes of mycophenolate mofetil (MMF) mucosal injury.

METHODS

Seven transplant patients receiving MMF who underwent colonoscopic examination and biopsy were identified retrospectively over a 2-year period. Multiple histologic parameters, including architectural distortion, cryptitis, stromal active inflammation, individual damaged crypts (IDC) and crypt apoptotic figures were evaluated in the biopsies semiquantitatively. Where biopsy site was identified, the parameters were assessed separately in biopsies from right and left colon.

RESULTS

All cases showed mixed patterns of mucosal injury. All seven cases showed focal architectural distortion (in 58% of fragments per case), focal cryptitis (mean 3.0 foci per case), increased crypt apoptosis (mean 26.5/100 crypts) and IDC (mean 3.0 foci). Focal changes resembling acute self-limited colitis were noted in three cases. Possible proximal accentuation of some changes was noted with right side biopsies tending to show greater crypt apoptotic activity and more foci of architectural distortion. Three cases showed dual pathology (two with cytomegalovirus (CMV) infection and one with IBD).

CONCLUSIONS

Although a wide spectrum of changes may be seen in MMF-associated colitis, important microscopic clues include a mixed pattern of injury (typically a combination of crypt apoptosis, isolated crypt damage and architectural distortion), and possible proximal accentuation of pathologic changes. The need for clinical correlation and follow-up is emphasised by the occurrence of dual pathology in patients treated with MMF.

The Differential Diagnosis of Colitis in Endoscopic Biopsy Specimens: A Review Article

Context.—A variety of inflammatory disorders may affect the colon, with widely differing clinical outcomes and management. These conditions encompass a spectrum of acute and chronic conditions.

Objective.—Review the pathology of the major colitides and highlight the most diagnostically useful features.

Data Sources.—Review of recent literature supplemented with personal experience in the field of gastrointestinal pathology.

Conclusions.—The etiologies associated with the various types of colitis are diverse and the range of histologic changes is somewhat limited. Nevertheless, the combination of clinical and endoscopic data coupled with histopathology allows for accurate classification in the majority of cases.

Increased incidence of endoscopic erosive esophagitis in solid organ transplant recipients

Background/Aims

Solid organ transplant recipients frequently report gastrointestinal symptoms, especially heartburn or dyspepsia. However, the prevalence of endoscopic erosive esophagitis (EE) and associated risk factors after transplantation are unknown. The aim of this study was to determine whether there was a high incidence of endoscopic findings of EE in solid organ transplant recipients.

Methods

This retrospective case-control study included 256 of 3,152 solid organ transplant recipients who underwent sequential screening upper endoscopic examinations and an equal number of controls.

Results

Forty-four (17.2%) and 16 (6.2%) cases of EE were detected in the solid organ transplant and control groups, respectively (p<0.001). In the multivariate analysis, transplantation was significantly associated with EE (odds ratio [OR], 6.48; 95% confidence interval, 2.74 to 15.35). Factors such as old age (OR, 1.17), the presence of a hiatal hernia (OR, 5.84), an increased duration of immunosuppression (OR, 1.07), and the maintenance administration of mycophenolate mofetil (OR, 4.13) were independently associated with the occurrence of EE in the solid organ transplant recipients.

Conclusions

A significant increase in the incidence of endoscopically detected EE was observed in solid organ transplant recipients. This increased incidence was associated with the type and duration of the immunosuppressive therapy.

Mycophenolate mofetil for the induction and maintenance treatment of lupus nephritis

Mycophenolate mofetil (MMF) inhibits purine synthesis by inhibiting inosine-5’-monophosphate dehydrogenase. Since 1995, it has been approved in the USA for the prevention of allograft rejection in solid organ transplant patients. In the last two decades, it has been frequently used as an immunosuppressive therapy for numerous autoimmune conditions including lupus nephritis. Management of lupus nephritis has been advanced by well-designed randomized clinical trials establishing MMF as a viable alternative to established therapies such as pulse intravenous cyclophosphamide in selected patients. This article outlines the pharmacologic properties of MMF and summarizes recent randomized clinical trials in lupus nephritis.

Serial intestinal endoscopic examinations of patients with persistent diarrhea after allo-SCT

Gastrointestinal (GI) GVHD after allo-SCT is diagnosed on the basis of symptoms and findings in endoscopic mucosal biopsy specimens. However, GI symptoms often persist despite treatment and whether a second endoscopy may be helpful in determining the most suitable therapy is not established. We identified 31 patients with persistent diarrhea who underwent more than one endoscopic study. All cases underwent serial microbiological stool analysis and CMV-detecting assays on serum and biopsies. Of the 31 initial GI biopsies, 20 (64.5%) were classified as GVHD, two (6.5%) as GVHD with CMV, four (13%) as non-CMV infection, and five (16%) as normal or unspecific. The second GI biopsies were diagnostic of GVHD in nine cases (29%), GVHD simultaneously with CMV infection in four (13%), regenerative changes post-GVHD in five (16%), CMV infection in four (13%), and normal or unspecific in nine (29%). In 22 of the 31 patients (71%), the histological findings of the second/third endoscopic biopsies differed from the findings of the first endoscopy and led to a therapy change in 77%. In conclusion, serial GI endoscopies are of reliable diagnostic value and can impact on therapeutic decision-making for patients with persistent diarrhea after allo-SCT.

The spectrum of drug-related colitides: important entities, though frequently overlooked

BACKGROUND

There is at present a relative lack of knowledge concerning drug-related colitides, although these may be not infrequent entities in clinical practice.

AIMS

To assess the frequency and the clinical-pathological subtypes of drug-related colitides in a gastrointestinal pathology referral centre.

METHODS

All charts of endoscopic biopsy samples referred for colitis in a eight-year period were reviewed. To be classified as drug related colitis, patients' charts should report the use of any drug in a two month period before colonoscopy and no other obvious cases of colitis be present. For analysis, we considered only patients taking one drug in this period.

RESULTS

We found 122 cases of drug-related colitis out of 3877 charts reviewed (3% of the overall colitis group). These cases were represented by microscopic colitis (50%), eosinophil rich infiltrate of the left colon (34%), ischemic colitis (11%), pseudomembranous colitis (3%), apoptotic colopathy (2%). The drugs most frequently associated with these colitides were represented by non-steroidal anti-inflammatory drugs.

CONCLUSION

It is important to raise awareness concerning drug-related colitides, to avoid diagnostic errors and provide a better therapeutic approach to patients with these conditions.

Mycophenolate monitoring in liver, thoracic, pancreas, and small bowel transplantation: a consensus report

Assessing the value of mycophenolic acid (MPA) monitoring outside renal transplantation is hindered by the absence of any trial comparing fixed-dose and concentration-controlled therapy. However, in liver and thoracic transplantation particularly, clinical trials, observational studies with comparison groups, and case series have described MPA efficacy, exposure/efficacy relationships, pharmacokinetic variability, and clinical outcomes relating to plasma MPA concentrations. On the basis of this evidence, this report identifies MPA as an immunosuppressant for which the combination of variable disposition, efficacy, and adverse effects contributes to interindividual differences seemingly in excess of those optimal for a fixed-dosage mycophenolate regimen. Combined with experiences of MPA monitoring in other transplant indications, the data have been rationalized to define circumstances in which measurement of MPA concentrations can contribute to improved management of mycophenolate therapy in nonrenal transplant recipients.

Patterns of injury in mycophenolate mofetil-related colitis

Mycophenolate mofetil (MMF) was introduced as a new immune-suppression drug in the mid-1990s. It is widely utilized in solid-organ transplantation immune-suppression regimens. Side effects include gastrointestinal (GI) toxicity in the form of nausea, vomiting, and diarrhea. Physicians tend to reduce the dose of MMF or switch their patients to an enterio-coated formula to overcome the side effects. Because GI side effects are well linked to MMF, colonoscopy is not utilized in most of the cases to investigate the diarrhea. However, Crohn's disease-like changes in the colon, erosive enterocolitis, and graft versus host disease-like colonic changes associated with the use of MMF have been reported. Colonic findings in five patients whose symptoms resolved after substituting another agent for MMF are described in the present report. Repeat colonoscopy 4 months following discontinuation of MMF showed reparative changes in one of our patients. MMF is an important drug in organ transplantation immune-suppression regimens; however, with its widespread usage, additional side effects continue to be recognized.

Gastrointestinal pathology of autologous graft-versus-host disease following hematopoietic stem cell transplantation: a clinicopathological study of 17 cases

Graft-versus-host disease is the major complication after allogeneic hematopoietic stem cell transplantation and is attributable to donor T-cell recognition of recipient alloantigens. In patients undergoing autologous hematopoietic stem cell transplantation in which there is no genetic disparity to induce an alloresponse, a syndrome similar to allogeneic graft-versus-host disease has been described. Designated as autologous graft-versus-host disease, it typically involves the skin and has reportedly caused little morbidity in this patient population. Recent data, however, suggest that autologous graft-versus-host disease can cause significant disease in the gastrointestinal tract, but its pathological spectrum of abnormalities and disease incidence are not well established. We report the development of autologous graft-versus-host disease following hematopoietic stem cell transplantation in 17 patients (15 with multiple myeloma) based on 388 autologous stem cell transplants carried out at our institution over a 6-year period. This represents a total incidence rate of 4% and among those transplanted for multiple myeloma, 6%. In all, 16 of the 17 patients had colonic biopsies performed for the diagnostic evaluation of persistent diarrhea. Biopsies in all 16 patients showed pathological evidence for graft-versus-host disease and were graded using standard grading criteria established for allogeneic graft-versus-host disease. Grades ranged from mild (grade 1/4) to severe (grade 4/4). Changes secondary to medication or infection were excluded. Responses to steroid and immunosuppressive therapy were variable but improved with continuing institutional experience. Outcomes ranged from a prompt, complete resolution of symptoms to death. Patients treated with autologous hematopoietic stem cell transplantation, particularly those with multiple myeloma, may develop a potentially life-threatening syndrome pathologically identical to allogeneic graft-versus-host disease. This diagnosis must be considered when interpreting biopsies from patients with gastrointestinal symptoms following autologous hematopoietic stem cell transplantation.

The impact of histopathologic examination of graft-versus-host disease in the era of reduced-intensity conditioning regimen: a study from the Gruppo Italiano Trapianto di Midollo Osseo

Reduced-intensity conditioning regimens have reshaped the clinical presentation of graft-versus-host disease after hematopoietic stem cell transplants. However, histopathologic features of graft-versus-host disease following reduced-intensity conditioning regimens have not been fully characterized. In a series of 112 biopsies (skin, n = 60; gastrointestinal [GI] tract, n = 44; liver, n = 8), we described the morphologic profile of graft-versus-host disease following reduced-intensity conditioning and investigated whether histopathologic changes of graft-versus-host disease following reduced-intensity conditioning have a diagnostic and/or prognostic value. Forty-four patients (49.5%) experienced acute graft-versus-host disease, 2 (2.2%) late-onset acute graft-versus-host disease (grade I, n = 13; grade II-IV, n = 33), 24 (27.0%) chronic graft-versus-host disease (de novo n = 12, progressive n = 12) and 19 (21.3%) overlap syndrome. In the skin, we observed: (i) phase-nonspecific changes, such as acute graft-versus-host disease features in chronic graft-versus-host disease patients (n = 4/24; 16.6%), (ii) subtle alterations such as superficial fibrosis in widened dermal papillae (n = 8), in acute graft-versus-host disease/late-onset graft-versus-host disease (n = 6/46; 13.0%) or chronic graft-versus-host disease (n = 2/24, 8.3%) patients, and (iii) features of chronic and acute graft-versus-host disease coexisting in the same specimen in overlap syndrome (n = 3/19; 15.7%). In the GI tract, we did not demonstrate peculiar features differing from those commonly observed in the myeloablative setting. By univariate analysis, a reduced overall survival was associated with graft-versus-host disease type (chronic graft-versus-host disease P = .006, acute graft-versus-host disease P = .03), older age (P = .04), and histopathologic diagnosis of "consistent with" + definite graft-versus-host disease (P = .02). Histopathologic diagnosis retained an independent prognostic value by multivariate analysis (P = .01). The present study indicates that pathologists should be aware of the peculiar morphologic changes of cutaneous graft-versus-host disease following reduced-intensity conditioning and further recommends histopathology in the diagnostic workup of graft-versus-host disease in patients undergoing reduced-intensity conditioning regimen.

Solid organ transplant-associated acute graft-versus-host disease

Solid organ transplant-associated graft-versus-host disease is an infrequent and potentially lethal complication. The incidence of this complication varies according to the type of organ transplant with higher rates associated with liver and small bowel transplants. The clinical presentation typically includes fever and skin rash, and most cases quickly advance to become a multisystem disease affecting the bone marrow and other nontransplanted solid organs. The diagnosis is based on the clinical symptoms, pathologic changes in biopsied tissues, and systemic lymphoid chimerism. The mortality of this disease can exceed 75% after liver transplant and most patients die from infections or hemorrhage due to bone marrow failure. There is no standard treatment strategy for this complication, and the management mainly consists of both prophylaxis and immediate treatment without delay. This short review summarizes the current pathogenesis, diagnosis, and treatment of this entity.

Mycophenolate mofetil-related gastrointestinal mucosal injury in multivisceral transplantation

Mycophenolate mofetil (MMF) has become an important and commonly used drug for maintenance immunosuppression therapy in recipients of all types of organ transplants. The drug is an antimetabolite that blocks the de novo pathway of purine synthesis. Although it selectively inhibits B- and T-lymphocyte proliferation, enterocytes are partially susceptible to MMF. One of the main limitations of this drug is gastrointestinal toxicity, with diarrhea the most frequently reported adverse effect. Most studies of MMF-associated gastrointestinal toxicity have been performed in patients with solid-organ transplants, although no data on changes related to MMF toxicity in bowel allografts have been published in the English literature. We evaluated mucosal intestinal biopsy tissue from patients with multivisceral transplants receiving MMF therapy. Our objective was to find morphologic changes that might be attributed to MMF toxicity, as well as changes that could differentiate MMF toxicity from acute rejection. Examination of the surface epithelium, lamina propria, and crypts in this small group of patients showed no specific changes that could be associated with MMF toxicity. Changes such as graft-vs-host disease or inflammatory bowel disease described in previous studies of solid-organ transplantation were not observed. Larger studies and the use of special stains and new markers might be necessary to characterize possible patterns of MMF toxicity and their differences from acute rejection.

Consensus Conference on Clinical Practice in Chronic GVHD: Second-Line Treatment of Chronic Graft-versus-Host Disease

Steroid refractory chronic graft-versus-host disease (cGVHD) is associated with a significant morbidity and mortality. Although first-line treatment of cGVHD is based on controlled trials, second-line treatment is almost solely based on phase II trials or retrospective analyses. The consensus conference on clinical practice in cGVHD held in Regensburg aimed to achieve a consensus on the current evidence of treatment options as well as to provide guidelines for daily clinical practice. Treatment modalities are the use of steroids and calcineurin inhibitors as well as immunomodulating modalities (photopheresis, mTOR-inhibitors, thalidomide, hydroxychloroquine, vitamin A analogs, clofazimine), and cytostatic agents (mycophenolate mofetil, methotrexate, cyclophosphamide, pentostatin). Recent reports showed some efficacy of rituximab, alemtuzumab, and etanercept in selected patients. Moreover, tyrosine kinase inihibitors such as imatinib came into the field because of their ability to interfere with the platelet-derived growth factor (PDGF-R) pathway involved in fibrosis. An other treatment option is low-dose thoracoabdominal irradiation. Although different treatment options are available, the "trial-and-error system" remains the only way to identify the drug effective in the individual patient, and valid biomarkers are eagerly needed to identify the likelihood of response to a drug in advance. Moreover, the sparse evidence for most treatment entities indicates the urgent need for systematic evaluation of second-line treatment options in cGVHD.

Intestine transplantation in children: update 2010

This article reviews the current status of pediatric intestinal transplantation, focusing on referral and listing criteria, surgical techniques, patient management, monitoring, complications after transplant, and short- and long-term patient outcome. Intestine transplantation has become the standard of care for children who develop life-threatening complications associated with intestinal failure. The results of intestinal failure treatment have significantly improved in the last decade following the establishment of gut rehabilitation programs and advances in transplant immunosuppressive protocols, surgical techniques, and posttransplant monitoring. The 1-year patient survival is now 80% and more than 80% of the children who survive the transplant are weaned off parenteral nutrition. Early referral for pretransplant assessment and careful follow-up after transplant with prompt recognition and treatment of transplant-related complications are key factors contributing to superior patient outcomes and survival. The best results are being obtained at high-volume centers with survival rates of up to 75% at 5 years.

Graft-versus-Host Disease-Like Pattern in Mycophenolate Mofetil Related Colon Mucosal Injury: Role of FISH in Establishing the Diagnosis

Mycophenolate mofetil (CellCept®), a commonly used immunosuppressive drug in solid organ transplantation, has recently been shown to cause graft-versus-host disease (GVHD)-like changes in the gastrointestinal tract. On rare occasions, true GVHD has also been documented in the gastrointestinal tract of solid organ transplant patients. Because the treatment for these two entities is different, i.e. removal of the offending agent versus the administration of steroids, proper identification of the cause is imperative. We present a case of mycophenolate mofetil colitis mimicking grade I GVHD of the gut. In our study, we used fluorescence in situ hybridization for the Y chromosome to document the lack of male donor lymphocytes in the female recipient colon biopsy. We suggest that molecular techniques including fluorescence in situ hybridization could be used to discriminate between MMF-related colitis and true GVHD in order to help guide therapy.

Mycophenolic acid (cellcept and myofortic) induced injury of the upper GI tract

BACKGROUND

Mycophenolic acid (MPA) is an immunosuppressant drug commonly used in patients undergoing solid organ transplant. Although its pattern of inducing injury in the colon is well-known and features prominent crypt apoptosis that mimics graft-versus-host-disease, the injury pattern in the upper gastrointestinal (GI) tract is less extensively documented. We studied the pattern of upper GI tract injury in symptomatic patients taking MPA.

DESIGN

Twenty solid organ transplant patients who were taking MPA and had concurrent upper GI tract biopsies were identified on a laboratory information system search. From these 20 patients, 17 duodenal, 18 gastric, and 7 esophageal biopsies were examined. All patients were symptomatic. Apoptosis and patterns of chronic and active injuries were assessed on standard hematoxylin and eosin, periodic acid-Schiff/Alcian blue, and Diff-Quik stained slides. To measure the significance of apoptosis, we standardized the apoptotic counts in normal biopsies using duodenal, gastric, and esophageal biopsies from 45 normal cases and performed statistical analysis. For the purposes of this study, we regarded apoptotic counts higher than the mean plus 2 SDs as significant. Thus the cut-off values for apoptosis were > or =2 apoptotic bodies/100 crypts for duodenum, > or =3/100 glands for stomach, and > or =2/10 high-power field for esophagus.

RESULTS

GI-related symptoms and abnormalities manifested between 1 month and 10 years posttransplant and included diarrhea (55%); nausea (45%); abdominal pain (35%); vomiting (25%); GI bleeding (15%); dysphagia (10%); dyspepsia, anemia, and hematemesis (5% for each). Most (14 out of 17, 82%) duodenal biopsies showed apoptotic counts of > or =2/100 crypts, 28% (5 out of 18) of gastric biopsies showed apoptotic counts of > or =3/100 glands, and 57% (4 out of 7) of esophageal biopsies showed apoptotic counts of > or =2/10 high-power field. Four gastric biopsies showed a previously undescribed injury pattern of parietal cells resembling the ballooning degeneration. Additional pathologic findings included: chronic peptic duodenitis (6 out of 17, 35%), active duodenitis (1 out of 17, 6%), and celiac-like features (2 out of 17, 12%) in the duodenum; chemical gastropathy (3 out of 18, 17%), active chronic gastritis without Helicobacter pylori (2 out of 18, 11%), and erosion (1/18,6%) in the stomach; reactive epithelial change (3 out of 7, 43%), active esophagitis (3 out of 7, 43%), ulceration (2 out of 7, 29%), and erosion (1 out of 7, 14%) in the esophagus. Serum MPA levels were available in 7 patients, 6 of whom had abnormal duodenal apoptotic counts. On follow-up, available for 16 patients, symptoms improved in all the patients whose dose was decreased or whose medication was withdrawn (10 out of 10) and symptoms persisted in all the patients whose dose was not altered (6 out of 6). Follow-up biopsies after reduction of the medication dose were available for 1 patient and showed substantial reduction in apoptosis. In contrast, follow-up biopsies from 1 patient whose dosage was not altered showed persistent abnormal apoptotic counts in the duodenum.

CONCLUSIONS

As noted by others (Parfitt JR, Jayakumar S, Driman DK. Am J Surg Pathol. 2008; 32:1367-1372), mycophenolate mofetil-associated injury of the upper GI tract, like that in the colon, is characterized by prominent apoptosis similar to that of mild or grade I graft-versus-host-disease injury. We offer apoptotic count guidelines, which we hope will facilitate recognition of mycophenolate mofetil-associated injury in the upper GI tract.

What is new in esophageal injury (infection, drug-induced, caustic, stricture, perforation)?

PURPOSE OF REVIEW: We will focus separately on infectious, drug-induced and caustic injury of the esophagus and their possible complications such as stricture and perforation. RECENT FINDINGS: There has been a decrease in opportunistic esophageal infection in HIV-positive patients, in particular candidiasis, which remains an important cause of inpatient charges, length of stay and total hospital costs, and new antifungal therapy are currently explored. As far as drug-induced esophageal injury is concerned, more than 1000 cases of all cases due to nearly 100 different medications have been described during the last 10 years. However, the estimated case frequency is probably much higher and the related literature is of low quality, as cases are reported selectively and stimulated by clustering of cases, newly implicated pills or unusual complications. Finally, in the field of caustic ingestion-related injury, there has been greater understanding of geographical differences in prevalence and more frequently involved substances, choice of optimal timing for endoscopy, relationship between symptoms and severity of lesions and appropriate role of steroids and other therapies, such as the topical application of mytomicin C. SUMMARY: This update covers the most relevant papers published on the three areas of interest during the last year.

Drug-induced esophagitis

Drug-induced esophagitis is being recognized increasingly in the past few years. Since 1970 more than 650 cases have been reported worldwide caused by 30 or more medications. We have reviewed these cases with a view to classifying this disease based on underlying pathological mechanism. Drug-induced esophageal injury tends to occur at the anatomical site of narrowing, with the middle third behind the left atrium predominating (75.6%). The disease is broadly classified into two groups. The first group being transient and self-limiting as exemplified by the tetracycline group induced injury (65.8%). The second is the persistent esophagitis group, often with stricture, with two distinct entities: (i) patients on nonsteroidal anti-inflammatory agents whose injury is aggravated by gastroesophageal reflux (21.8%) (reflux aggravated); and (ii) patients with potasium chloride and quinidine sulphate induced injury (12.4%) (persistent drug injury). Severe esophageal injury has been reported in some women taking biphosphonates as treatment for postmenopausal osteoporosis. Endoscopic findings in such patients with esophageal injury generally suggested a chemical esophagitis, with erosions or ulcerations and exudative inflammation accompanied by thickening of the esophageal wall. Most cases of medication-induced esophageal injury heal without intervention within a few days. Thus, the most important aspect of therapy is to make the correct diagnosis and then to avoid reinjury with the drug. When possible, potentially caustic oral medications should be discontinued.

Endoscopic and histological features of mycophenolate mofetil colitis in patients after solid organ transplantation

BACKGROUND

Mycophenolate mofetil (MMF) is an immunosuppressive agent commonly used after organ transplantation. Gastrointestinal side effects occur in approximately 45% of patients. The spectrum of histologic features associated with MMF colitis has been well described, but data on the endoscopic features is lacking. The aim of the study was to describe the endoscopic features of MMF colitis in solid organ transplant recipients (SOTRs) as well as the frequency of histologic features and identify associated risk factors.

METHODS

A retrospective review of all SOTRs taking MMF and who underwent colonoscopy between 2000 and 2010 was performed. 36 cases of MMF colitis were identified and 361 patients served as controls. Descriptive statistics and data analysis looking for associated risk factors were performed.

RESULTS

Among SOTRs taking MMF who underwent colonoscopy, MMF colitis was diagnosed in 9%. Endoscopic findings ranged from erythema (33%) to erosions/ulcers (19%). 47% of patients had a normal colonoscopy and everyone had rectal sparing. Histological findings included acute colitis-like findings (50%), inflammatory bowel disease-like characteristics (36%), ischemia-like findings (5.6%), and graft-versus-host disease-like features (8.3%). Diarrhea occurred in 83%. Kidney transplantation was associated with a higher risk of MMF colitis (OR 5.8 [2.86-11.86], P<0.0001) whereas liver transplantation was associated with a lower risk (OR 0.06 [0.03-0.16], P<0.0001).

CONCLUSION

MMF colitis is fairly prevalent in SOTRs taking MMF who undergo colonoscopy. Diarrhea is the most common reason for colonoscopy referral (83%) and up to 47% of patients have normal colonoscopy, suggesting the need for routine biopsies to help confirm the diagnosis.