Many advances have been made in the understanding of Crohn’s disease (CD) pathogenesis during the last decade. CD is currently seen as a predominantly T-lym-phocyte-driven disease characterized by the presence of a c...Many advances have been made in the understanding of Crohn’s disease (CD) pathogenesis during the last decade. CD is currently seen as a predominantly T-lym-phocyte-driven disease characterized by the presence of a complex cocktail of interacting cytokines, chemokines and other mediators produced by a variety of cell types. Prevailing theories of CD pathogenesis suggest that patients’ T-lymphocytes are inappropriately activated in the setting of an immune imbalance, which is itself caused by an unfortunate confluence of genetic and en- vironmental factors. The T-cell response then leads to the chronic inflammation characteristic for the disease. Various environmental factors may play a role in the development of CD, but microbes are most consistently implied. This theory is based on epidemiological, clinico- pathological, genetic and experimental evidence. Despite the abundance of arguments for the implication of bac-teria in the aetiopathogenesis of CD, the precise role of bacteria in this disease still remains elusive. Three not necessarily mutually exclusive theories have been pro- posed: (1) an unidentified persistent pathogen; (2) an abnormally permeable mucosal barrier leading to exces-sive bacterial translocation; and (3) a breakdown in the balance between putative "protective" versus "harmful" intestinal bacteria ("dysbiosis"). At present, one cannot exclude with certainty any of these three proposed hy-potheses; they may all apply to CD to a certain extent.展开更多
AIM： To examine the fetal and neonatal esophagogastric junction region （EGJ） histologically for the presence of an equivalent to adult cardiac mucosa （CM）; to study the expression patterns of all cytokeratins （C...AIM： To examine the fetal and neonatal esophagogastric junction region （EGJ） histologically for the presence of an equivalent to adult cardiac mucosa （CM）; to study the expression patterns of all cytokeratins （CK） relevant to the EGJ during gestation; to compare the CK profile of the gestational and the adult EGJ; and to determine the degree of development in the adult EGJ histology and CK profile during gestation. METHODS： Forty-eight fetal autopsy specimens of the EGJ were step-sectioned and stained with hematoxylin and eosin （H＆E） to select sections showing the mucosal lining. Immunohistochemistry for CK5, 7, 8, 13, 18, 19, and 20 was performed. Antibody staining was then graded for location, intensity, and degree. RESULTS： The distal esophagus was lined by simple columnar epithelium from 12-wk gestational age （GA）. The proximal part of this segment consisted of mucusproducing epithelium, devoid of parietal cells. CK5 and 13 were present exclusively in multilayered epithelia and CK8, 18, and 19 predominantly in simple columnar epithelium. There were no differences in the frequencies of the coordinate CK7＋/20＋ and the CK7-/20- immunophenotypes between different locations. The prevalence of the CK7＋/ 20- immunophenotype decreased, and that of the CK7-/ 20＋ immunophenotype increased significantly from the distal esophagus to the distal stomach. CONCLUSION： Fetal columnar-lined lower esophagus （fetal CLE） may be the equivalent and precursor of the short segments of columnar epithelium found in the distal esophagus of some normal adult subjects. Esophageal simple columnar epithelium without parietal cells （ESN） may be the precursor of adult CM. The similarities between the fetal and adult EGJ and stomach CK expression pattems support the conclusion that adult CN has an identifiable precursor in the fetus. This would then indicate that at least a part of the adult CM has a congenital origin.展开更多
AIM: To investigate how t(11;18)(q21;q21)-positive gastrointestinal MALT lymphomas relate to other marginal zone lymphomas with respect to the somatic mutation pattern of the VH genes and the expression of the marker ...AIM: To investigate how t(11;18)(q21;q21)-positive gastrointestinal MALT lymphomas relate to other marginal zone lymphomas with respect to the somatic mutation pattern of the VH genes and the expression of the marker CD27. METHODS: The VH gene of 7 t(11;18)(q21;q21)-positive gastrointestinal MALT lymphomas was amplif iedby PCR using family specif ic VH primers and a consensus JH primer. PCR products were sequenced and mutation analysis of the CDR and the FR regions was performed. All cases were immunostained for CD27. RESULTS: One case showed unmutated VH genes while the others showed mutated VH genes with mutation frequencies ranging from 1.3 to 14.7% and with evidence of antigen selection in 2 cases. These data suggest that the translocation t(11;18)(q21;q21) can target either B-cells at different stages of differentiation or naive B-cells that retain the capacity to differentiate upon antigen stimulation. All cases but one displayed weak to strong CD27 expression which did not correlate with the VH gene mutation status. CONCLUSION: t(11;18)(q21;q21)-positive gastro- intestinal MALT lymphomas are heterogeneous with respect to the VH mutation status and CD27 is not a marker of somatically mutated B-cells.展开更多
BACKGROUND Predispositions for severe coronavirus disease 2019(COVID-19)are age,immunosuppression,and co-morbidity.High levels of maintenance immunosuppression render intestinal transplant(ITx)patients vulnerable for ...BACKGROUND Predispositions for severe coronavirus disease 2019(COVID-19)are age,immunosuppression,and co-morbidity.High levels of maintenance immunosuppression render intestinal transplant(ITx)patients vulnerable for severe COVID-19.COVID-19 also provokes several gastroenterological pathologies which have not been discussed in ITx,so far.CASE SUMMARY During the second European COVID-19 wave in November 2020,an ITx recipient was admitted to the hospital because of electrolyte disturbances due to dehydration.Immunosuppression consisted of tacrolimus,azathioprine,and low-dose corticosteroids.During hospitalization,she tested positive on screening COVID-19 nasopharyngeal polymerase chain reaction swab,while her initial test was negative.She was initially asymptomatic and had normal inflammatory markers.Tacrolimus levels were slightly raised,as Azathioprine was temporarily halted.Due to elevated Ddimers at that time,prophylactic low-molecular weight heparin was started.Seven days after the positive test,dyspnea,anosmia,and C-reactive protein increase(25 mg/L)were noted.Remdesivir was administered during 5 d in total.High stomal output was noted in two consecutive days and several days thereafter.To exclude infection or rejection,an ileoscopy and biopsy were performed and excluded these.Four weeks later,she was discharged from the hospital and remains in good health since then.CONCLUSION Early eradication of severe acute respiratory syndrome coronavirus 2 in ITx recipients may be warranted to prevent acute rejection provocation by it.展开更多
文摘Many advances have been made in the understanding of Crohn’s disease (CD) pathogenesis during the last decade. CD is currently seen as a predominantly T-lym-phocyte-driven disease characterized by the presence of a complex cocktail of interacting cytokines, chemokines and other mediators produced by a variety of cell types. Prevailing theories of CD pathogenesis suggest that patients’ T-lymphocytes are inappropriately activated in the setting of an immune imbalance, which is itself caused by an unfortunate confluence of genetic and en- vironmental factors. The T-cell response then leads to the chronic inflammation characteristic for the disease. Various environmental factors may play a role in the development of CD, but microbes are most consistently implied. This theory is based on epidemiological, clinico- pathological, genetic and experimental evidence. Despite the abundance of arguments for the implication of bac-teria in the aetiopathogenesis of CD, the precise role of bacteria in this disease still remains elusive. Three not necessarily mutually exclusive theories have been pro- posed: (1) an unidentified persistent pathogen; (2) an abnormally permeable mucosal barrier leading to exces-sive bacterial translocation; and (3) a breakdown in the balance between putative "protective" versus "harmful" intestinal bacteria ("dysbiosis"). At present, one cannot exclude with certainty any of these three proposed hy-potheses; they may all apply to CD to a certain extent.
文摘AIM： To examine the fetal and neonatal esophagogastric junction region （EGJ） histologically for the presence of an equivalent to adult cardiac mucosa （CM）; to study the expression patterns of all cytokeratins （CK） relevant to the EGJ during gestation; to compare the CK profile of the gestational and the adult EGJ; and to determine the degree of development in the adult EGJ histology and CK profile during gestation. METHODS： Forty-eight fetal autopsy specimens of the EGJ were step-sectioned and stained with hematoxylin and eosin （H＆E） to select sections showing the mucosal lining. Immunohistochemistry for CK5, 7, 8, 13, 18, 19, and 20 was performed. Antibody staining was then graded for location, intensity, and degree. RESULTS： The distal esophagus was lined by simple columnar epithelium from 12-wk gestational age （GA）. The proximal part of this segment consisted of mucusproducing epithelium, devoid of parietal cells. CK5 and 13 were present exclusively in multilayered epithelia and CK8, 18, and 19 predominantly in simple columnar epithelium. There were no differences in the frequencies of the coordinate CK7＋/20＋ and the CK7-/20- immunophenotypes between different locations. The prevalence of the CK7＋/ 20- immunophenotype decreased, and that of the CK7-/ 20＋ immunophenotype increased significantly from the distal esophagus to the distal stomach. CONCLUSION： Fetal columnar-lined lower esophagus （fetal CLE） may be the equivalent and precursor of the short segments of columnar epithelium found in the distal esophagus of some normal adult subjects. Esophageal simple columnar epithelium without parietal cells （ESN） may be the precursor of adult CM. The similarities between the fetal and adult EGJ and stomach CK expression pattems support the conclusion that adult CN has an identifiable precursor in the fetus. This would then indicate that at least a part of the adult CM has a congenital origin.
基金Supported by A Grant of the "Belgian Cancer Association"the "Fonds voor Wetenschappelijk Onderzoek Vlaanderen"
文摘AIM: To investigate how t(11;18)(q21;q21)-positive gastrointestinal MALT lymphomas relate to other marginal zone lymphomas with respect to the somatic mutation pattern of the VH genes and the expression of the marker CD27. METHODS: The VH gene of 7 t(11;18)(q21;q21)-positive gastrointestinal MALT lymphomas was amplif iedby PCR using family specif ic VH primers and a consensus JH primer. PCR products were sequenced and mutation analysis of the CDR and the FR regions was performed. All cases were immunostained for CD27. RESULTS: One case showed unmutated VH genes while the others showed mutated VH genes with mutation frequencies ranging from 1.3 to 14.7% and with evidence of antigen selection in 2 cases. These data suggest that the translocation t(11;18)(q21;q21) can target either B-cells at different stages of differentiation or naive B-cells that retain the capacity to differentiate upon antigen stimulation. All cases but one displayed weak to strong CD27 expression which did not correlate with the VH gene mutation status. CONCLUSION: t(11;18)(q21;q21)-positive gastro- intestinal MALT lymphomas are heterogeneous with respect to the VH mutation status and CD27 is not a marker of somatically mutated B-cells.
文摘BACKGROUND Predispositions for severe coronavirus disease 2019(COVID-19)are age,immunosuppression,and co-morbidity.High levels of maintenance immunosuppression render intestinal transplant(ITx)patients vulnerable for severe COVID-19.COVID-19 also provokes several gastroenterological pathologies which have not been discussed in ITx,so far.CASE SUMMARY During the second European COVID-19 wave in November 2020,an ITx recipient was admitted to the hospital because of electrolyte disturbances due to dehydration.Immunosuppression consisted of tacrolimus,azathioprine,and low-dose corticosteroids.During hospitalization,she tested positive on screening COVID-19 nasopharyngeal polymerase chain reaction swab,while her initial test was negative.She was initially asymptomatic and had normal inflammatory markers.Tacrolimus levels were slightly raised,as Azathioprine was temporarily halted.Due to elevated Ddimers at that time,prophylactic low-molecular weight heparin was started.Seven days after the positive test,dyspnea,anosmia,and C-reactive protein increase(25 mg/L)were noted.Remdesivir was administered during 5 d in total.High stomal output was noted in two consecutive days and several days thereafter.To exclude infection or rejection,an ileoscopy and biopsy were performed and excluded these.Four weeks later,she was discharged from the hospital and remains in good health since then.CONCLUSION Early eradication of severe acute respiratory syndrome coronavirus 2 in ITx recipients may be warranted to prevent acute rejection provocation by it.
