AIDS and the gut

There are increasing challenges for the practising gastroenterologist in treating AIDS-related gastrointestinal diseases. The differential diagnoses of dysphagia and odynophagia include cytomegalovirus (CMV) and herpes simplex virus (HSV) infection, non-specific aphthous ulceration and non-AIDS oesophageal diseases, especially reflux oesophagitis. Chronic subacute abdominal pain with nausea, vomiting, early satiety and weight loss is suggestive of an obstructive lesion caused by lymphoma or Kaposi's sarcoma. Severe acute abdominal pain can indicate pancreatitis or intestinal perforation due to cytomegalovirus. Right upper quadrant pain (with or without fever, vomiting or abnormal liver function tests with a cholestatic profile) is suggestive of hepatobiliary pathology including cholecystitis, cholangitis, acalculous cholecystitis and AIDS cholangiopathy. Diarrhoea is the most common gastrointestinal symptom of AIDS, affecting 50–90% of patients. Causes of AIDS diarrhoea include protozoa (Cryptosporidium parvum, Isospora belli, Enterocytozoon bieneusi, Septata intestinalis, Cyclospora spp, Entamoeba histolytica and Giardia lamblia), bacteria (Mycobacterium avium-intracellulare, Clostridium difficile, Salmonella, Shigella and Campylobacter jejuni), and viruses (CMV, HSV and possibly HIV). Chronic diarrhoea, malnutrition and weight loss can shorten the life-span of patients with AIDS. Elemental diets, isotonic formulas, medium chain triglycerides and total parenteral nutrition have been tried with little success in AIDS patients with severe diarrhoea and wasting.     

HIV／AIDS合并溶组织内阿米巴感染患者5例临床分析

溶组织内阿米巴是HIV／AIDS患者常见的机会感染病原体之一,是HIV感染者腹泻的主要原因,可引起肝脓肿、脑脓肿及浆膜腔脓肿等危及患者生命的并发症。     

Increased frequency of HLA-DR3 and complotype SCO1 in Mexican mestizo children with amoebic abscess of the liver

The increase of HLA-DR3 and complotype SCO1 previously found in Mexican mestizo adults with E. histolytica amoebic abscess of the liver, was also found in Mexican mestizo children of either sex with the same disease, when compared to the healthy control population (adults and/or children) of the same ethnic and socioeconomic background. This HLA and complotype pattern was not found in Mexican Mestizo patients with amoebic rectocolitis. No linkage disequilibrium was found between these and the other MHC determinants tested in this survey. Thus, HLA-DR3 and SCO1 may constitute primary, independent risk factors, not for any kind of amoebic tissue invasion (i.e. amoebic rectocolitis), but specifically for amoebic liver abscess, irrespective of age or sex. The possibility of linkage disequilibrium with other factors (i.e. the TNF family) within or close to the MHC that were not tested in this study, is discussed. Children with amoebic liver abscess revealed a significant increase in HLA-DR5, and the absence of HLA-DR6 when compared to adults with amoebic liver abscess, suggesting that at least in this ethnic group these class II HLA traits may contribute to some of the peculiarities of pediatric amoebic liver abscess as opposed to the adult version of this disease. HLA-DR3, SCO1, but also HLA-DR5 and HLA-DR6 have all been associated with certain forms of immune-dysfunction, and may thus contribute to some of the clinical and immunological features of this parasitic disease.     

溶组织内阿米巴重组人单克隆抗体Fab段的筛选与表达

目的　制备抗溶组织内阿米巴滋养体表面抗原的重组人单克隆抗体Fab段。　方法　提取无症状溶组织内阿米巴包囊携带者外周血淋巴细胞 ,分离总RNA ,行逆转录聚合酶链反应扩增IgG轻链和重链Fd片段 ,并与原核表达质粒连接 ,转化大肠埃希菌构建抗体库。通过抗原夹心膜法、间接荧光抗体试验等方法 ,筛选特异性表达抗溶组织内阿米巴滋养体表面抗原的重组人单克隆抗体Fab段的克隆 ,并纯化其表达产物。　结果　共筛选 3× 10⁴个克隆 ,其中一个克隆表达的Fab段识别的抗原表位位于滋养体表面。　结论　运用原核表达系统可制备抗溶组织内阿米巴重组人单克隆抗体Fab段 ,在临床诊断和治疗上均有应用前景。     

溃疡性结肠炎合并阿米巴肠病临床特点探讨

目的 探讨溃疡性结肠炎合并阿米巴肠病的临床特点.方法 回顾性分析2003～2010年共104例溃疡性结肠炎患者诊治资料,其中15例确诊合并阿米巴肠病(A组),单纯性溃疡性结肠炎患者89例(B组),统计各患者的腹泻次数、贫血程度、低白蛋白血症程度及结肠病变范围.结果 A、B组患者中腹泻＞6次/d者分别为13例、40例,血红蛋白＜90 g/L患者分别为8例、16例,血清蛋白＜30 g/L患者分别为10例、23例,结肠病变范围超过1/2的患者分别为12例、31例,两组存在统计学差异;15例溃疡性结肠炎合并阿米巴肠病患者中7例为先确诊溃疡性结肠炎,后获得阿米巴感染并致病,其余8例患者无法判断两种疾病的发病先后顺序.所统计病例中溃疡性结肠炎并发阿米巴肠病发病率为14.4％(15/104),高于阿米巴肠病在普通人群中发病率(同地区平均为0.44％,最高2.43％).结论 溃疡性结肠炎合并阿米巴肠病病情较单纯性溃疡性结肠炎患者严重;溃疡性结肠炎患者较普通人群更容易获得溶组织内阿米巴感染并致病.     

Secretory immune response in patients with intestinal amoebiasis

The secretory immune response in saliva from intestinal amoebiasis patients against antigens obtained from Entamoeba histolytica membranes was studied. Western blot analysis indicated that patient saliva contains secretory IgA antibodies against antigens with molecular masses ranging from 170 to 24 kDa, some of which were also recognized by saliva from healthy subjects. However, antigens of 170, 125, 46 and 37 kDa are recognized more frequently (> 90%) by the secretory IgA from patients with intestinal amoebiasis than by that from healthy subjects (< 10%).     

内阿米巴属原虫分子检测及基因分型方法研究进展

内阿米巴属原虫是可寄生于人和动物肠道及其他内脏器官的人兽共患原虫,属内种类较多,但致病性种类主要是溶组织内阿米巴,可引起人和动物出现痢疾和肝脓肿,严重者可危及生命。致病性和非致病性的内阿米巴属原虫的包囊和滋养体在形态上很难区别,且同种的致病性、感染力等也存在一定的差异,因此,临床上传统的诊断方法很难确定病原的种类,相应也直接影响了临床用药,为了解内阿米巴属原虫的种类分布及其分型情况,本文就内阿米巴属原虫分子检测及基因分型方法的研究进展情况进行综述。