Intestinal Thrombotic Microangiopathy Research Articles

Intestinal Transplant-Associated Thrombotic Microangiopathy: Histopathological Review. a Single Center Experience

INTRODUCTIONTransplant-associated thrombotic microangiopathy (TMA) is a severe complication after allogeneic stem cell transplantation (ASCT) due to endothelial injury caused by many factors such Calcineurin-inhibitors. In most severe cases, TMA could affect different organs. Intestinal TMA could be fatal and missdiagnosed in many patients. Clinical and pathological criteria to differentiate from intestinal GVHD are needed in order to distinguish both entities with different therapeutical approach. The aim of this study was to review pathological TMA features in patients diagnosed of systemic TMA .PATIENTS AND METHODSWe analyzed the incidence of TMA in 527 pts who underwent ASCT in our institution between jan-2010 and apr-2018. Patients were identified if they had TMA according to probable TMA criteria by Ho. We do a pathological review in 96 samples from 18 of 42 patients in whom an endoscopy have been performed after the diagnosis of the TMA; endoscopy have been performed between 30 days before and 60 days after diagnosis of TMA for initial clinical diagnosis of GVHD. Review was performed by a pathologist expert. He examined the biopsies in search of features of GVHD, TMA or viral infection. Diagnosis of GVHD was stablished according to Mcdonald and Sales criteria, intestinal TMA diagnosis was perfomed by the 8 criteria summarized by Warren et al (perivascular mucosal hemorrhage, endothelial cell swelling, endothelial cell separation, intraluminal schistocytes, fibrin or microthrombi, loss of glands and mucosal denudation).RESULTSBaseline/transplant characteristics of patients with TMA are shown in table 1, TMA data in 2 and review hystological features of biopsies in 3.45 (8.5%) were diagnosed of TMA with a median time from transplant of 75 days. Median age was 49 (19-69). Prophylaxis of GVHD was: Calcineurin inhibitor-MTX in 16 (35.5%), Tacrolimus-Sirolimus in 21 (46.6%), Tacrólimus-MMF and Cyclophosphamide in 8 (17.6%). 42 (93%) had prior or simultaneous acute GVHD, half of them grade III-IV, and 80% with gastrointestinal GVHD. 42% had elevated levels of tacrolimus and 13.6% elevated levels of sirolimus, one week before the diagnosis of TMA.Gastrointestinal MAT have been reported only in 5 patients (28%) at diagnosis whereas when review based on Warren criteria was performed, in 16 patients (89%) the pathologist found at least 1 of the criteria of endothelial damage and 50 % of the patients met 3 or more Warren criteria. The most frequent features were endothelial cell swelling (13 patients, 73 %) and perivascular mucosal hemorrhage (12 patients, 66.7%). In 3 biopsies which we perfomed the inmunochemistry of C4d, an activation of classic way of complement biomarker, it was positive. 4 of the 18 patients (22.2%) presented refractory-hypertension and 3 of them (26.6%) more than 30 mg/d Lof proteinuria, both suggested of poor prognosis.Regarding GVHD, it was founded in 72% at diagnosis and in all patients (18) at pathological review. 13 had grade I, 1 grade II, 1 grade III and 3 histological grade IV).With a median follow-up of 5 months (2-25) 25 of the 45 (56%) are dead. 6 of the deaths (24%) were related to TMA (1 due to TMA, 3 due to TMA+GVHD, 2 due to TMA+infection). Other causes of death were progression (4), GVHD+Infection (7), GVHD (3), infection (2), sinusoidal obstruction síndrome (1) and other causes (2).CONCLUSIONTMA is a frequent complication, related with GVHD and underdiagnosed frequently. Only 5 of 18 patients were diagnosed of gastrointestinal TMA.In our study, we found that most of our patients had endotelial damage in the gastrointestinal biopsy pathological reviews. Although histological criteria of GVHD were present at review, in most of them it was only grade I; it contrasts with the severe clinical features. That lack of correlation would suggest that TMA and not GVHD is the main feature.Management of TMA and GVHD are different. To stress an appropiate diagnosis in gastrointestinal TMA is needed in order to offer the patients the best approach.REFERENCESWarren et al. A Complete Histologic Approach to Gastrointestinal Biopsy From Hematopoietic Stem Cell Transplant Patients With Evidence of Transplant-Associated Gastrointestinal Thrombotic Microangiopathy. Arch Pathol Lab Med.2017 Nov;141(11):1558-1566.Jodele S et al. A new paradigm: Diagnosis and management of HSCT-associated thrombotic microangiopathy as multi-system endothelial injury. Blood Rev. 2015;29(3):191-204. [Display omitted] DisclosuresNo relevant conflicts of interest to declare.

Type Three Secretion System-Dependent Microvascular Thrombosis and Ischemic Enteritis in Human Gut Xenografts Infected with Enteropathogenic Escherichia coli.

Enteropathogenic Escherichia coli (EPEC) is a leading cause of severe intestinal disease and infant mortality in developing countries. Virulence is mediated by a type three secretion system (T3SS), causing the hallmark attaching and effacing (AE) lesions and actin-rich pedestal formation beneath the infecting bacteria on the apical surface of enterocytes. EPEC is a human-specific pathogen whose pathogenesis cannot be studied in animal models. We therefore established an EPEC infection model in human gut xenografts in SCID mice and used it to study the role of T3SS in the pathogenesis of the disease. Following EPEC O127:H6 strain E2348/69 infection, T3SS-dependent AE lesions and pedestals were demonstrated in all infected xenografts. We report here the development of T3SS-dependent intestinal thrombotic microangiopathy (iTMA) and ischemic enteritis in ∼50% of infected human gut xenografts. Using species-specific CD31 immunostaining, we showed that iTMA was limited to the larger human-mouse chimeric blood vessels, which are located between the muscularis mucosa and circular muscular layer of the human gut. These blood vessels were massively invaded by bacteria, which adhered to and formed pedestals on endothelial cells and aggregated with mouse neutrophils in the lumen. We conclude that endothelial infection, iTMA, and ischemic enteritis might be central mechanisms underlying severe EPEC-mediated disease.

Histologic Features of Intestinal Thrombotic Microangiopathy in Pediatric and Young Adult Patients after Hematopoietic Stem Cell Transplantation

High-risk transplantation-associated thrombotic microangiopathy (TMA) can present with multisystem involvement and is associated with a poor outcome after hematopoietic stem cell transplantation (HSCT), with < 20% 1-year survival. TMA may involve the intestinal vasculature and can present with bleeding and ischemic colitis. There are no established pathologic criteria for the diagnosis of intestinal TMA (iTMA). The goal of our study was to identify histologic features of iTMA and describe associated clinical features. We evaluated endoscopic samples from 50 consecutive HSCT patients for 8 histopathologic signs of iTMA and compared findings in 3 clinical groups based on the presence or absence of systemic high-risk TMA (hrTMA) and the presence or absence of clinically staged intestinal graft-versus-host disease (iGVHD): TMA/iGVHD, no TMA/iGVHD, and no TMA/no iGVHD. Thirty percent of the study subjects had a clinical diagnosis of systemic hrTMA. On histology, loss of glands, intraluminal schistocytes, intraluminal fibrin, intraluminal microthrombi, endothelial cell separation, and total denudation of mucosa were significantly more common in the hrTMA group (P < .05). Intravascular thrombi were seen exclusively in patients with hrTMA. Mucosal hemorrhages and endothelial cell swelling were more common in hrTMA patients but this difference did not reach statistical significance. Patients with hrTMA were more likely to experience significant abdominal pain and gastrointestinal bleeding requiring multiple blood transfusions (P < .05). Our study shows that HSCT patients with systemic hrTMA can have significant bowel vascular injury that can be identified using defined histologic criteria. Recognition of these histologic signs in post-transplantation patients with significant gastrointestinal symptoms may guide clinical decisions.

Histologic Features of Intestinal Thrombotic Microangiopathy in Patients with High Risk TMA after HSCT

Histologic Features of Intestinal Thrombotic Microangiopathy in Patients with High Risk TMA after HSCT

Diagnosis of Intestinal Graft-versus-Host Disease and Thrombotic Microangiopathy after Allogeneic Stem Cell Transplantation

Severe diarrhea is a serious complication after allogeneic hematopoietic stem cell transplantation (HSCT). Acute graft-versus-host disease (GVHD) has been one of the major causes of diarrhea after HSCT, which is triggered by donor-derived cytotoxic T-lymphocytes. On the other hand, intestinal thrombotic microangiopathy (TMA) sometimes coexists with acute GVHD, and intensified immunosuppression to treat acute GVHD could exacerbate intestinal TMA, presumably through the vascular endothelial cell damage. The differential diagnosis between intestinal TMA and acute GVHD of the gut has mainly relied on the pathological findings, as clinical diagnosis of intestinal TMA has not been established. Therefore, we aimed to assess the feasibility of our clinical diagnosis for the patients with diarrhea after HSCT. We made tentative clinical criteria for intestinal TMA and acute GVHD of the gut, based on the clinical manifestations, laboratory data and colonoscopic findings, and started treatment before pathological diagnosis were made. Subsequently, a pathologist retrospectively assessed the accuracy of clinical diagnosis in a blind manner. In this study, we enrolled 19 patients complicating watery diarrhea after HSCT, and diagnosed as having acute GVHD (n = 10), intestinal TMA (n = 3), or both (n = 6) according to our criteria. We demonstrated that our clinical diagnosis for intestinal TMA and acute GVHD of the gut was overall correct, in terms of the response to the therapy and the pathological diagnosis. The present study may provide a clue on making clinical diagnosis of patients with watery diarrhea after HSCT, which enables us to start a prompt therapy.

Specific Colonoscopic Findings of Intestinal Graft-Versus-Host Disease, Intestinal TMA, and CMV Colitis After Allogenic Hematopoietic Stem Cell Transplantaion

Background: After allogenic hematopoietic stem cell transplantation (HSCT), significant complications involving the gastrointestinal tract occur, such as graft-versus -host disease (GVHD), thrombotic microangiopathy (TMA), and cytomegalovirus (CMV) colitis. Although the therapeutic strategies for these disorders are completely different, it is difficult to establish the differential diagnosis based on the clinical grounds alone. Little is known about the specific colonoscopic findings of these three disorders. Aim: To clarify the specific colonoscopic findings of intestinal GVHD, intestinal TMA, and CMV colitis. Patients and Methods: Between April 2001 and March 2008, 31 patients suffering from GI symptoms within the first 100 days after allogenic HSCT underwent 38 colonoscopies. The final diagnoses of these patients were made by a retrospective review of the medical records, and all 38 colonoscopic findings were analyzed. We picked up the relatively specific findings such as “spotty redness”, “sloughing of the mucosa”, “tortoiseshell pattern”, “diffuse redness”, and “punched-out ulcer” which are not usually observed in infectious colitis or inflammatory bowel diseases. To examine the diagnostic values of these colonoscopic findings, the sensitivity and, if possible, specificity of these findings for diagnosis were examined, retrospectively. Results: All 38 cases were finally diagnosed as intestinal GVHD. Eight cases were diagnosed as intestinal GVHD overlapping intestinal TMA. One case was diagnosed as intestinal GVHD overlapping CMV colitis. Spotty redness, sloughing of the mucosa, tortoiseshell pattern, diffuse redness, and punched-out ulcer were observed in 19/38 (50.0%), 29/38 (76.3%), 38/38 (100%), 7/38 (18.4%), and 1/38 (2.6%) respectively. Spotty redness, sloughing of the mucosa, and tortoiseshell pattern tended to be frequently observed in intestinal GVHD. Diffuse redness tended to be frequently observed in the cases which were diagnosed as GVHD overlapping intestinal TMA. The calculated sensitivity and specificity of this finding for the diagnosis of intestinal TMA were 75.0% and 96.8%, respectively. In only one case diagnosed as CMV colitis overlapping intestinal GVHD, multiple punched-out ulcers were detected in the descending and sigmoid colon. Conclusions: Specific colonoscopic findings may be valuable for making a differential diagnosis of intestinal GVHD, intestinal TMA, and CMV colitis after HSCT. The proposed specific findings are as follows. 1) Spotty redness, sloughing of the mucosa, and tortoiseshell pattern for intestinal GVHD. 2) Diffuse redness for intestinal TMA. 3) Punched-out ulcer for CMV colitis.

Gastrointestinal Complications Following Hematopoietic Stem Cell Transplantation in Children

Gastrointestinal system involvement is one of the principal complications seen in the recipients of hematopoietic stem cell transplantation (HSCT), and it is also a major cause of morbidity and death in these patients. The major gastrointestinal complications include typhlitis (neutropenic enterocolitis), pseudomembranous enterocolitis, viral enteritis, graft-versus-host disease, benign pneumatosis intestinalis, intestinal thrombotic microangiopathy, and post-transplantation lymphoproliferative disease. As these patients present with nonspecific abdominal symptoms, evaluation with using such imaging modalities as ultrasonography and CT is essential in order to assess the extent of gastrointestinal involvement and to diagnose these complications. We present here a pictorial review of the imaging features and other factors involved in the diagnosis of these gastrointestinal complications in pediatric HSCT recipients.

Incidence and Clinical Outcome of Intestinal Thrombotic MicroAngiopathy (TMA) in Patients Suspected to Clinical Graft Versus Host Disease (GVHD).

Intestinal TMA, a upcoming and serious problem after HSCT, usually manifests diarrhea, vomiting, GI bleeding and abdominal pain as initial clinical presentations similar to those of intestinal GVHD. But intestinal TMA should be distinguished from GVHD, because they needed to be treated in absolutely different way. Here we investigated the incidence of intestinal TMA and evaluated their clinical progressions in HSCT patients. We retrospectively reviewed 243 gastrointestinal mucosal biopsy slides obtained from HSCT patients having suffered from GI problems in the Catholic University Hospital, from 2000 to 2004. The collected cases were reviewed by two pathologists blindly and classified into TMA; showing microthrombi formation in the lumina of microvasculatures, GVHD; showing epithelial apoptosis and/or loss of glands, TMA+GVHD and non-specific inflammation. And next, their incidence and clinical outcomes were analyzed. On histopathological examination, 15 out of 243 cases (6.2%) showed luminal thrombi of microvasculature compatible with TMA, 58 cases (23.9%) showed findings compatible with GVHD, 3 cases (1.2%) showed both TMA and GVHD, and 173 cases (71.2%) showed nonspecific gastroenteritis. On peripheral blood smear examination, all 15 TMA cases showed less than 1% of fragmented RBC at the time of biopsy. But 2 out of 15 cases (13.3%) showed increase to 8% and 10% of fragmented RBC in follow-up, and they had been aggravated clinically and improved only after treatments including discontinuing immunosuppressant and plasma exchange. Among 58 GVHDs, 34 patients (75.9%) were improved with steroid pulse therapy, but 14 patients (24.1%) failed. These results show that intestinal TMA is not infrequent in HSCT patients and can be combined with intestinal GVHD. In conclusion, intestinal TMA should be recognized in pathological diagnosis of HSCT patients. It is important to differentiate intestinal TMA from GVHD in patients suffering from severe and refractory diarrhea after HSCT.

Intestinal thrombotic microangiopathy induced by FK506 in rats

Thrombotic microangiopathy (TMA) is one of the severe complications after stem cell transplantation (SCT) and is associated with graft-versus-host disease (GVHD) prophylaxis including FK506. In this study, we experimented on rats using FK506 to demonstrate the occurrence of intestinal TMA. FK506 was administrated into Wistar/ST rats intraperitoneally for 7 days. Rats were examined histopathologically after FK506 injection using light and electron microscopy and immunohistochemistry. FK506 concentrations in whole blood were measured by enzyme immunoassay. In the acute phase, hemorrhagic lesions with multifocal erosions and crypt loss were found in the small intestines of all treated rats. Capillary vessels were dilated, and a few platelet thrombi were found. Electron microscopy demonstrated degenerative swelling of endothelial cells and platelet aggregates adhering to the vessel walls. In the later phase, epithelial regenerative failure, characterized by crypt ghosts, was found in the affected mucosa. Apoptotic epithelial cells were increased in number. The extent of intestinal injury was proportional to the whole blood levels of FK506. The intestinal lesions in rats were consistent with TMA and induced by the injection of FK506 alone. Apoptotic enteropathy was also observed and similar to intestinal GVHD. In this study, we established an intestinal TMA model induced by immunosuppressant (Tacrolimus) only without irradiation.

Epstein–Barr virus‐associated enteritis with multiple ulcers after stem cell transplantation: First histologically confirmed case

The present case involves unique enteritis forming multiple ulcers associated with Epstein-Barr virus (EBV). A 57-year-old man had undergone a reduced intensity allogeneic stem cell transplantation for a relapse of multiple myeloma following sequential autologous peripheral blood stem cell transplantation. The ileum, resected for massive melena, showed multiple irregular ulcers with occasional cobblestone-like appearance. There was inflammation including numerous plasma cells in the ulcer bases and surrounding areas, where many EBV-infected plasma cells were detected by double staining with EBV-encoded small RNA-1 (EBER-1) in situ hybridization and CD79a, while EBV-infected epithelial cells were not noted. The number of EBER-1-positive cells in the ileum (mucosa, 1451 cells/mm(2); submucosa, 465 cells/mm(2)) was much larger than in control samples (malignant lymphoma or leukemia after allogeneic stem cell transplantation, n = 4, range 0-113 cells/mm(2); malignant lymphoma after chemotherapy, n = 14, range 0-0.89 cells/mm(2); colon cancer, n = 12, range 0-3.5 cells/mm(2)). In the mucosa near the ulcers, EBER-1-positive cells often surrounded and involved the glandular epithelium, forming lymphoepithelial-like lesions. The histological findings differ from post-transplant lymphoproliferative disorders or intestinal thrombotic microangiopathy, and this is the first case of EBV-associated enteritis with ulcers characterized by numerous plasma cells and lymphoepithelial-like lesions after stem cell transplantation.

Fulminant hepatitis after allogenic bone marrow transplantation caused by reactivation of hepatitis B virus with gene mutations in the core promotor region

Under immunosuppressive conditions after hematopoietic stem cell transplantation (HSCT), even if hepatitis B virus (HBV) antigen is negative but hepatitis B surface antibody (HBsAb) or hepatitis B core antibody (HBcAb) is presented, HBV reactivates and sometimes causes fulminant hepatitis. However, it remains unclear which patients will develop fulminant hepatitis, or whether fulminant hepatitis is caused by host-related factors or by virus-related factors. A 30-yr-old man with a history of aplastic anemia since 3 yr of age underwent allogenic BMT, when HBsAb and HBcAb were positive but HBs antigen (HBsAg) was negative. The donor was negative for HBsAg, HBsAb and HBcAb. After transplantation, the patient was complicated by acute graft-vs.-host disease (GVHD), cytomegalovirus infection, intestinal thrombotic microangiopathy and aspergillus colitis. Chronic GVHD was well controlled by FK506 and prednisolone. Twenty months after transplantation, the patient was admitted with general fatigue and liver dysfunction and was found to be positive for HBsAg and HBeAg. His serum HBV-DNA level was >8.8 log of the genome equivalent (LGE)/mL. Therefore, he was diagnosed as having hepatitis B caused by HBV reactivation and 100 mg/d lamivudine treatment was started. However, jaundice and hepatic failure deteriorated and became fatal. On analysis of the HBV-DNA, two adjacent gene mutations in the core promoter region (T1762/A1764) were detected. Increased replication of the mutated HBV might have caused HBV reactivation which progressed to fulminant hepatitis.

Intestinal thrombotic microangiopathy following reduced-intensity umbilical cord blood transplantation

Thrombotic microangiopathy (TMA) is a significant complication after hematopoietic stem-cell transplantation (HSCT); however, there is little information on it following reduced-intensity cord blood transplantation (RI-CBT). We reviewed the medical records of 123 adult patients who received RI-CBT at Toranomon Hospital between January 2002 and August 2004. TMA was diagnosed in seven patients based on intestinal biopsy (n = 6) or autopsy results (n = 1). While these patients showed some clinical symptoms such as diarrhea and/or abdominal pain, mental status alterations or neurological disorders were not observed in any of them. Laboratory results were mostly normal at the onset of TMA; >2% fragmented erythrocytes (n = 1), <10 mg/dl haptoglobin (n = 1), and >200 IU/dl lactic dehydrogenase (LD) (n = 4). On endoscopic examination, TMA lesions, consisting of ulcers, erosions, and diffuse exfoliation, were distributed spottily from terminal ileum to rectum. Intestinal graft-versus-host disease (GVHD) and cytomegalovirus (CMV) colitis were confirmed in five and four patients, respectively. With therapeutic measures including supportive care (n = 4), fresh frozen plasma (n = 1), and a reduction of immunosuppressive agents (n = 1), TMA improved in four patients. The present study demonstrates that intestinal TMA is a significant complication after RI-CBT. Since conventional diagnostic criteria can overlook TMA, its diagnosis requires careful examination of the gastrointestinal tract using endoscopy with biopsy.

ABO Incompatibility Is a Risk Factor for Intestinal Thrombotic Microangiopathy (TMA) after Allogeneic Stem Cell Transplantation.

Intestinal thrombotic microangiopathy (TMA) after allogeneic stem cell transplantation is emerging as a major clinical issue, which is different from aGVHD in pathogenesis and clinical management. We performed a retrospective analysis of 140 pediatric patients with acute leukemia (82 ALL and 58 AML) who underwent allogeneic stem cell transplantation in Japanese Red Cross Nagoya First Hospital from 1991 to 2003 (69 from HLA matched sibling, 13 from HLA mismatched family donors and 58 from unrelated volunteer donors). Blood type was matched in 78 patients and mismatched in 62 patients (25 in minor , 26 in major and 11 in bidirectional). Seventeen patients developed intestinal TMA with a cumulative incidence of 13%. The median time to onset was 28 days (range, 10–104 days). Intestinal TMA was defined histopathologically by colonoscopic biopsies in 7 patients and bloody diarrhea and laboratory findings. Intestinal TMA occured in 28% of ABO minor mismatched transplantation, 32.5% of bidirectional, 14.4% of major mismatched and 5.8% in matched transplantation (p<0.01)(Fig1)p. In multivariate analysis, ABO minor mismatched transplants (HR=5.3, 95%CI 1.4–19.7, p=0.01), HLA mismatched related donors (HR=16.6, 95%CI 1.6–173.3, p=0.02 ) and unrelated donors (HR=16.4, 95%CI 2.0–130.6, p<0.01 ) were significantly associsted with the risk of intestinal TMA. The estimated 5-year overall survival (OS) was 47.1% in intestinal TMA patients compared with 56.7% in patients with no intestinal TMA (p=0.18). Intensified immunosuppressants for the treatment of intestinal TMA (n=5) lead to poor OS (20%). Seven out of 12patients (58%) who had reduced immunosuppressant were still alive with a median follow-up of 24 months (p=0.29). Our findings suggest that ABO mismatched transplantation, especially ABO minor mismatch, is a risk factor for developing intestinal TMA. Successful treatment for intestinal TMA by diminishing immunosuppressive drugs is warranted. [Display omitted] [Display omitted]