Histopathologie der Graft-versus-Host-Erkrankung

Effect of GVHD on the gut and intestinal microflora

Graft-versus-host disease (GVHD) is one of the most important cause of death in patients undergoing allogeneic hematopoietic stem cell transplantation (allo-HSCT). The gastrointestinal tract is one of the most common sites affected by GVHD. However, there is no gold standard clinical practice for diagnosing gastrointestinal GVHD (GI-GVHD), and it is mainly diagnosed by the patient's clinical symptoms and related histological changes. Additionally, GI-GVHD causes intestinal immune system disorders, damages intestinal epithelial tissue such as intestinal epithelial cells((IEC), goblet, Paneth, and intestinal stem cells, and disrupts the intestinal epithelium's physical and chemical mucosal barriers. The use of antibiotics and diet alterations significantly reduces intestinal microbial diversity, further reducing bacterial metabolites such as short-chain fatty acids and indole, aggravating infection, and GI-GVHD. gut microbe diversity can be restored by fecal microbiota transplantation (FMT) to treat refractory GI-GVHD. This review article focuses on the clinical diagnosis of GI-GVHD and the effect of GVHD on intestinal flora and its metabolites.

Gastrointestinal Biopsies for Evaluation of Acute Graft-Versus-Host Disease in Allogeneic Hematopoietic Stem Cell Transplant Patients

Graft-versus-host disease (GVHD) is the major complication post hematopoeitic stem cell transplantation (HSCT) causing significant morbidity and mortality. Colonic biopsies were performed in 25 post HSCT patients presenting the diarrhea for diagnosis of acute graft versus host disease (A-GVHD). The present study was undertaken to evaluate and illustrate histomorphological features of A-GVHD in GI biopsies and to grade them. Histopathological features of gastrointestinal biopsies from 25 allogeneic HSCT patients having clinical suspicion of A-GVHD were evaluated and compared with colonic biopsies from negative controls. A-GVHD was observed in 17 cases, CMV colitis was present in 3 cases and one case had herpes simplex infection diagnosed in conjunction with serological findings. A-GVHD was graded as grade 1 and 2 in 10 cases and grade 3 and 4 in 7 cases. Apoptosis of crypt epithelial cells was the cardinal feature for diagnosis. Grade 1 and grade 2 A-GVHD cases showed crypt apoptosis in all cases as well as pericryptal apoptosis in lamina propria in many cases. Occasional crypt loss was seen in grade 2 GVHD. Inflammatory infiltrate was composed of lymphocytes and plasma cells. Neutrophils were inconspicuous. Grade 3 and grade 4 A-GVHD cases showed contiguous areas of multiple crypt loss and ulceration with inflammatory infiltrate predominantly composed of lymphocytes and plasma cells, but neutrophils were more prominent than in grade 1 and 2 A-GVHD. Apoptosis of crypt epithelial cells was present in all grade 3 &4 cases except one case. CMV cases were diagnosed by CMV inclusions and IHC stain. Several factors including drug-induced side effects and infections can cause difficulty in histologic interpretation of gastrointestinal biopsies for GVHD. Proper histomorphological interpretation of intestinal A-GVHD is critical for clinical management. A-GVHD is treated with immunosuppression which may worsen infective condition, if present.

Hematopoietic stem cell transplantation: graft versus host disease and pathology of gastrointestinal tract, liver, and lung

Hematopoietic stem cell transplantation (HCT), formerly known as bone marrow transplantation, is an integral part of treatment for many hematological malignancies. HCT is associated with several complications and comorbidities with differential effects on a wide spectrum of organs and tissues. We present an update on HCT-associated complications such as graft versus host disease (GVHD) and infection, with focus on the surgical pathology of the gastrointestinal (GI) tract, liver, and lung. Although the grading system for GI tract acute GVHD was proposed 40 years ago, recent studies have shed light on minimal histologic criteria for diagnosis of GVHD, as well as its differential diagnosis, including histologic effects of various medications. GI dysfunction in autologous transplant recipients is increasingly appreciated and patients are often biopsied. Acute liver injury in HCT is often due to sinusoidal obstruction syndrome (previously known as venoocclusive disease), or acute GVHD. Liver dysfunction at later time posttransplantation may be associated with acute or chronic GVHD, iron overload, or other causes of hepatitis. Lung injury in HCT is multifactorial, and it remains crucially important to diagnose and treat pulmonary infections. The pulmonary biopsy yields clinically unsuspected diagnoses in the majority of cases and its utilization is likely to increase. The pathology of the skin and kidney in HCT patients are detailed in accompanying articles.