Gastrointestinal manifestations of HIV infection

Abdominal Pain in the Immunocompromised Patient

Abdominal pain in an immunocompromised patient represents a common clinical scenario that may have uncommon causes. Evaluation relies first on identifying the immunocompromise, whether due to congenital immunodeficiencies, malignancy, hematopoietic stem cell transplant, solid organ transplant, or human immunodeficiency virus/acquired immunodeficiency syndrome. Based on this determination, the emergency physician may then build a focused differential of pathophysiologic possibilities. Careful evaluation is necessary given the absence of classic physical examination findings, and liberal use of laboratory and cross-sectional imaging is prudent. Conservative evaluation and disposition of these high-risk patients is important to consider.

Exocrine pancreatic insufficiency is common in people living with HIV on effective antiretroviral therapy

OBJECTIVES

The primary aim of this prospective study was to determine the prevalence of exocrine pancreatic insufficiency (EPI) in people living with HIV (PLHIV) on suppressive antiretroviral therapy (ART).

METHODS

PLHIV ≥18 years of age and on ART for >6 months and with HIV RNA <50 copies/mL plasma were included. Faecal elastase-1 measurement was performed on a single stool sample, serum markers of malnutrition were collected, and participants answered a short questionnaire about gastrointestinal symptoms. Participants with EPI and symptoms were offered pancreatic enzyme replacement therapy (PERT), and the result of this therapy was also evaluated.

RESULTS

Of 100 participants, 32% had EPI (faecal elastase-1 < 200 μg/g) and 20% severe EPI (faecal elastase-1 < 100 μg/g). We did not find any correlation between self-reported symptoms and degree of EPI. Twelve out of the 32 participants with EPI accepted to start PERT. Nine out of 12 (75%) reported improvement or became asymptomatic within 14 days.

CONCLUSION

EPI is common in PLHIV on effective ART. We could, however, not find a correlation between gastrointestinal symptoms and the presence of EPI. Assessment of pancreatic exocrine function could be considered in PLHIV particularly in those with gastrointestinal discomfort, since there is a possible gain in treating them with relief of symptoms and improved quality of life. The effects of PERT in PLHIV on effective ART need further study.

Changes of the Intestinal Microbiome-Host Homeostasis in HIV-Infected Individuals - A Focus on the Bacterial Gut Microbiome

Human immunodeficiency virus (HIV) infections cause severe CD4+ T cell depletion leading to chronic inflammation and immune activation, impaired barrier function, and microbial translocation. Even under effective antiretroviral therapy, these processes persist, leading to gut microbiome dysbiosis and disturbance of microbiome–host homeostasis. This systematic review aims at analyzing how gut microbiome and host immune system influence each other during HIV pathogenesis. An online search applying the PubMed database was conducted. The number of total results (n = 35) was narrowed down to 5 relevant studies focusing on the interaction between the host and gut microbiome, whereas strict exclusion criteria were applied, thereby assuring that no other comorbidities impacted study results. Our analyses revealed that gut microbiome diversity correlated positively with CD4+ T cell counts and negatively with microbial translocation markers. However, quantitative changes in bacterial richness did not consistently correlate with the numbers of metabolically active bacterial populations. Despite the reported increase in potentially pathogenic bacteria and, conversely, decrease in protective populations, the gut microbiota exhibited immune-modulating qualities given that mucosal inflammatory sequelae were dampened by decreasing pro-inflammatory and accelerating anti-inflammatory cytokine responses. Future research is needed to further elucidate these findings, to gain a deeper insight into host–microbiota interactions and to develop novel therapeutic strategies.

The investigation of patients with HIV infection: 10 years of progress

The past decade has seen great advances in the management of patients with HIV infection. The introduction of highly active antiretroviral therapy (HAART) has resulted in a decrease in opportunistic infections but the development of new clinical entities such as lipodystrophy and immune reconstitution illnesses. The use of investigations such as lipid profiles and dual energy X-ray absorptiometry (DEXA) scanning to assess lipodystrophy have been necessitated by these changes in the epidemic. Technological advances have resulted in new techniques such as viral resistance assays and single photon emission computed tomography (SPECT) scanning. The appropriate use of these investigations is subject to ongoing assessment.

The gut microbiome in human immunodeficiency virus infection

HIV/AIDS causes severe dysfunction of the immune system through CD4+ T cell depletion, leading to dysregulation of both the adaptive and innate immune arms. A primary target for viral infection is the gastrointestinal tract, which is a reservoir of CD4+ T cells. In addition to being a major immune hub, the human gastrointestinal tract harbors trillions of commensal microorganisms, the microbiota, which have recently been shown to play critical roles in health. Alterations in the composition and function of microbiota have been implicated in a variety of 'multi-factorial' disorders, including infectious, autoimmune, metabolic, and neoplastic disorders. It is widely accepted that, in addition to its direct role in altering the gastrointestinal CD4+ T cell compartment, HIV infection is characterized by gut microbiota compositional and functional changes. Herein, we review such alterations and discuss their potential local and systemic effects on the HIV-positive host, as well as potential roles of novel microbiota-targeting treatments in modulating HIV progression and associated adverse systemic manifestations.

Enteric pathogens in HIV infected and HIV uninfected individuals with diarrhea in Pune

BACKGROUND

Diarrhea in HIV infected individuals is a common complication seen in about 90% of patients in developing countries. The objective of this study was to identify enteric pathogens in HIV infected and HIV uninfected individuals in Pune.

METHOD

This study was conducted from January 2009 to May 2010 on 331 consecutive patients presenting with diarrhea admitted at Naidu Municipal Corporation Hospital, Pune and processed using conventional methods.

RESULTS

Intestinal parasitic pathogens were detected in 60% (39/65) of HIV infected and 14.3 (38/266) of HIV uninfected individuals. Bacterial pathogens were detected in 34% (22/65) of HIV infected individuals and 28.2% (75/266) of the HIV uninfected individuals. The common enteric pathogens detected in HIV infected individuals were Cystoisospora belli (28%, 18/65) followed by Cryprotosporidium parvum (12%, 8/65). In HIV uninfected individuals Entamoeba histolytica (7.1%, 19/266) followed by Shigella flexnari (4.9%, 13/266) were the most common pathogens. The difference in detection of enteric parasites in HIV infected individuals and HIV uninfected individuals was found to be significant (p < 0.01).

CONCLUSIONS

Intestinal parasitic pathogens are more common in HIV infected antiretroviral therapy naïve patients. Early detection of enteric pathogens by routine examination of stool samples will help in the management and to improve the quality of life for HIV infected individuals.

Micronutrient supplemented probiotic yogurt for HIV-infected adults taking HAART in London, Canada

The Human Immunodeficiency Virus has devastating effects worldwide. The burden is less pronounced, but still present in Canada where approximately 64,000 men and women are HIV positive. The virus and the life-saving antiretroviral therapies often contribute to diarrhea and other gastrointestinal disturbances. Certain probiotic organisms, such as Lactobacillus rhamnosus GR-1, have been shown to alleviate diarrhea as well as delay the decline of CD4 lymphocytes in some subjects. In addition, micronutrient formulae have been used extensively among HIV positive persons as a cost-effective method for improving quality of life and immune function. The objective of the present study was to combine probiotics and micronutrients into an affordable and highly palatable nutritional supplement and assess outcomes in 21 HIV-positive participants receiving highly active antiretroviral therapy in London, Ontario, Canada. The design was a randomized, double blind, three-period, cross-over controlled trial with three different formulations of supplemented yogurt; micronutrient and probiotic (A), micronutrient alone (B) and probiotic alone (C). The period of intake for each of the types was 30 days with a 14 day wash-out period between the intervention types. The mean increase in CD4 was greatest with B (41 cells/µL, SD 221). Supplement A showed a mean change of +19 cells/µL (SD 142) and supplement C a mean change of - 7 cells/µL (SD 154). All yogurt types caused an increase in subjective energy and ability to perform daily activity scores. According to the safety measures taken to assess the tolerance of the yogurt, there were no adverse events and the yogurt was well-tolerated. These preliminary findings suggest that micronutrient supplemented probiotic yogurt may support immune function among people living with HIV.

Faecal calprotectin in HIV-infected, HAART-naïve Ugandan children

OBJECTIVES

Calprotectin is a calcium- and zinc-binding protein and a marker in faeces of gastrointestinal inflammation. Reference values have been established in children older than 4 years. The aim of the present study was to determine the concentration of faecal calprotectin (FC) in human immunodeficiency virus (HIV)-infected, highly active antiretroviral therapy-naïve Ugandan children and compare it with the reference value.

METHODS

We tested 193 HIV-infected children ages 0 to 12 years in a hospital-based survey for FC. A standardised interview with sociodemographic information and medical history was used to assess risk factors. A cluster of differentiation 4 (CD4) cell percentage was prevalent in all of the children.

RESULTS

The median FC concentrations decreased with increasing age, as in healthy children. The median concentration was 208 mg/kg in infants 0 to 1 year, 171 mg/kg among toddlers 1 to 4 years, and 62 mg/kg for children 4 to 12 years. Children with advanced disease and a low CD4 cell percentage had significantly higher FC concentrations than those with a high CD4 cell percentage. Children older than 4 years with diarrhoea had significantly higher FC concentrations compared with those without diarrhoea.

CONCLUSIONS

HIV-infected children older than 4 years had a median FC concentration above the reference value, and gut inflammation in the children with elevated values is likely. Children with more advanced disease had increased FC concentrations regardless of age.

Hypothalamic inflammation: a double-edged sword to nutritional diseases

The hypothalamus is one of the master regulators of various physiological processes, including energy balance and nutrient metabolism. These regulatory functions are mediated by discrete hypothalamic regions that integrate metabolic sensing with neuroendocrine and neural controls of systemic physiology. Neurons and nonneuronal cells in these hypothalamic regions act supportively to execute metabolic regulations. Under conditions of brain and hypothalamic inflammation, which may result from overnutrition-induced intracellular stresses or disease-associated systemic inflammatory factors, extracellular and intracellular environments of hypothalamic cells are disrupted, leading to central metabolic dysregulations and various diseases. Recent research has begun to elucidate the effects of hypothalamic inflammation in causing diverse components of metabolic syndrome leading to diabetes and cardiovascular disease. These new understandings have provocatively expanded previous knowledge on the cachectic roles of brain inflammatory response in diseases, such as infections and cancers. This review describes the molecular and cellular characteristics of hypothalamic inflammation in metabolic syndrome and related diseases as opposed to cachectic diseases, and also discusses concepts and potential applications of inhibiting central/hypothalamic inflammation to treat nutritional diseases.

Opportunistic and other intestinal parasites among HIV/AIDS patients attending Gambi higher clinic in Bahir Dar city, North West Ethiopia

OBJECTIVE

To determine the magnitude of opportunistic and non-opportunistic intestinal parasitic infections among HIV/AIDS patients in Bahir Dar.

METHODS

Cross-sectional study was conducted among HIV/AIDS patients attending Gambi higher clinic from April1-May 30, 2009. Convenient sampling technique was employed to identify the study subjects and hence a total of 248 subjects were included. A pre-tested structured questionnaire was used to collect socio-demographic data of patients. Stool samples were examined by direct saline, iodine wet mount, formol-ether sedimentation concentration and modified Ziehl-Neelsen staining technique.

RESULTS

Out of 248 enrolled in the study, 171(69.0%) (90 males and 81 females) were infected with one or more intestinal parasites. The highest rate of intestinal parasites were observed among HIV/AIDS patients (80.3%, 151/188), and the infection rate of HIV negative individuals was 33.3% (20/60). Cryptosporidum parvum (43.6%), Isospora belli (15.5%) and Blastocystis hominis (10.5%) were opportunistic parasites that were found only in HIV/AIDS patients.

CONCLUSIONS

Opportunistic parasite infections are common health problem among HIV/AIDS patients in the study area. Therefore, early detection and treatment of these parasites are important to improve the quality of life of HIV/AIDS patients.

Prevalence of gastrointestinal symptoms among ambulatory HIV patients and a control population

BACKGROUND

The gastrointestinal tract is a common site of involvement in HIV-infected patients. Gastrointestinal symptoms are common in the general population and are associated with decreased quality of life.

METHODS

Ambulatory consecutive HIV-infected patients and consecutive healthy blood donors seen in Jamaica were studied. A 19-item questionnaire of GI symptoms was administered.

RESULTS

There were 196 respondents. Among 99 HIV patients, the mean number of symptoms was 2.9 and in 97 controls 3.3 (p=0.091). Dysphagia and odynophagia were present in 8.1% of HIV patients and 3.1% of the controls (p=0.129). Belching was present in 59.6% of HIV patients and in 96.8% of controls (p≤0.001). In the control group, 44.3% had heartburn compared to 29.3% of HIV patients. Within the preceding year, 26.3% of HIV participants and 12.4% of controls sought medical attention for their GI symptoms (p=0.001). GI symptomatology was directly related to immune status in the HIV group as patients with a CD4 count of less than 200 cells/μL reported up to 6 GI symptoms, those with CD4 of 201-350 cells/μL had 3 symptoms, and patients with CD4 greater than 351 cells/μL had 1 symptom. Pain on swallowing, and vomiting were significantly more common in patients with CD4 <350 cells/μL than in controls.

CONCLUSIONS

GI symptoms were common in HIV patients and controls. In HIV patients symptoms were directly related to CD4 count. Pain on swallowing and vomiting were significantly more common in patients with CD4 <350 cells/μL than in controls.

Exogenous HIV-1 Nef upsets the IFN-γ-induced impairment of human intestinal epithelial integrity

Background

The mucosal tissues play a central role in the transmission of HIV-1 infection as well as in the pathogenesis of AIDS. Despite several clinical studies reported intestinal dysfunction during HIV infection, the mechanisms underlying HIV-induced impairments of mucosal epithelial barrier are still unclear. It has been postulated that HIV-1 alters enterocytic function and HIV-1 proteins have been detected in several cell types of the intestinal mucosa. In the present study, we analyzed the effect of the accessory HIV-1 Nef protein on human epithelial cell line.

Methodology/Principal Findings

We used unstimulated or IFN-γ-stimulated Caco-2 cells, as a model for homeostatic and inflamed gastrointestinal tracts, respectively. We investigated the effect of exogenous recombinant Nef on monolayer integrity analyzing its uptake, transepithelial electrical resistance, permeability to FITC-dextran and the expression of tight junction proteins. Moreover, we measured the induction of proinflammatory mediators. Exogenous Nef was taken up by Caco-2 cells, increased intestinal epithelial permeability and upset the IFN-γ-induced reduction of transepitelial resistance, interfering with tight junction protein expression. Moreover, Nef inhibited IFN-γ-induced apoptosis and up-regulated TNF-α, IL-6 and MIP-3α production by Caco-2 cells while down-regulated IL-10 production. The simultaneous exposure of Caco-2 cells to Nef and IFN-γ did not affect cytokine secretion respect to untreated cells. Finally, we found that Nef counteracted the IFN-γ induced arachidonic acid cascade.

Conclusion/Significance

Our findings suggest that exogenous Nef, perturbing the IFN-γ-induced impairment of intestinal epithelial cells, could prolong cell survival, thus allowing for accumulation of viral particles. Our results may improve the understanding of AIDS pathogenesis, supporting the discovery of new therapeutic interventions.

Prevalence of Helicobacter pylori in HIV-infected, HAART-naïve Ugandan children: a hospital-based survey

BACKGROUND

The aim of this survey was to determine the prevalence of and factors associated with Helicobacter pylori (H. pylori) colonization in HIV-infected, highly active antiretroviral therapy-naïve Ugandan children aged 0-12 years.

METHODS

In a hospital-based survey, 236 HIV-infected children were tested for H. pylori colonization using a faecal antigen test. A standardized interview with socio-demographic information and medical history was used to assess risk factors. A cluster of differentiation 4 (CD4) cell percentage was prevalent in most children.

RESULTS

The overall prevalence of H. pylori in the HIV-infected children was 22.5%. Age-specific prevalence was as follows: up to one year, 14.7%; 1-3 years, 30.9%; and 3-12 years, 20.7%. HIV-infected children who were more seriously affected by their disease (low CD4 cell percentage or WHO clinical stage II-IV) were less likely to be colonized with H. pylori. There was a trend for a lower prevalence of H. pylori in children who had taken antibiotics for the preceding two weeks (21.6%) than in those who had not taken antibiotics (35.7%). There was no statistically significant difference in prevalence by gender, housing, congested living, education of the female caretaker, drinking water or toilet facilities.

CONCLUSIONS

HIV-infected, HAART-naïve Ugandan children had a lower prevalence of H. pylori colonization compared with apparently healthy Ugandan children (44.3%). Children with a low CD4 cell percentage and an advanced clinical stage of HIV had an even lower risk of H. pylori colonization. Treatment with antibiotics due to co-morbidity with infectious diseases is a possible explanation for the relatively low prevalence.

Emerging microsporidian infections in Russian HIV-infected patients

Microsporidia were identified in stool specimens by histochemistry and PCR of 30 (18.9%) of 159 HIV-infected patients presenting to the S. P. Botkin Memorial Clinical Hospital of Infectious Diseases, St. Petersburg, Russia. The higher prevalence of Encephalitozoon intestinalis, in 21 (12.8%) patients, than of Enterocytozoon bieneusi, in 2 patients (1.2%), was unexpected. Encephalitozoon cuniculi was detected in three patients: one with strain I and two with strain II. Encephalitozoon hellem was detected in one patient, and two patients were identified as being infected by Microsporidium species. One patient was infected with both E. intestinalis and E. cuniculi. In two patients, the microsporidian species were not identifiable. No statistically significant differences in gender, age, and stage of AIDS were observed between the microsporidian-positive and -negative HIV-infected patients. HIV-infected patients diagnosed with microsporidian infection, however, were significantly more likely to exhibit ≤ 100 CD4(+) T cells/μl blood (20/30 patients [67%]; odds ratio [OR], 3.150; 95% confidence interval [CI(95)], 1.280 to 7.750; P = 0.0116) and weight loss of >10% of the baseline (19/30 patients [63%]; odds ratio, 2.995; CI(95), 1.100 to 8.158; P = 0.0352) than HIV-infected patients not diagnosed with microsporidian infection. In summary, this is the first report describing the diagnosis of microsporidian infection of HIV-infected patients in Russia and the first detection of E. cuniculi strain II in a human.

Mutation of a diacidic motif in SIV-PBj Nef impairs T-cell activation and enteropathic disease

Background

The non-pathogenic course of SIV infection in its natural host is characterized by robust viral replication in the absence of chronic immune activation and T cell proliferation. In contrast, acutely lethal enteropathic SIVsmm strain PBj induces a strong immune activation and causes a severe acute and lethal disease in pig-tailed macaques after cross-species transmission. One important pathogenicity factor of the PBj virus is the PBj-Nef protein, which contains a conserved diacidic motif and, unusually, an immunoreceptor tyrosine-based activation motif (ITAM).

Results

Mutation of the diacidic motif in the Nef protein of the SIVsmmPBj abolishes the acute phenotype of this virus. In vitro, wild-type and mutant PBj (PBj-Nef202/203GG) viruses replicated to similar levels in macaque PBMCs, but PBj-Nef202/203GG no longer triggers ERK mitogen-activated protein (MAP) kinase pathway including an alteration of a Nef-associated Raf-1/ERK-2 multiprotein signaling complex. Moreover, stimulation of IL-2 and down-modulation of CD4 and CD28 were impaired in the mutant virus. Pig-tailed macaques infected with PBj-Nef202/203GG did not show enteropathic complications and lethality as observed with wild-type PBj virus, despite efficient replication of both viruses in vivo. Furthermore, PBj-Nef202/203GG infected animals revealed reduced T-cell activation in periphery lymphoid organs and no detectable induction of IL-2 and IL-6.

Conclusions

In sum, we report here that mutation of the diacidic motif in the PBj-Nef protein abolishes disease progression in pig-tailed macaques despite efficient replication. These data suggest that alterations in the ability of a lentivirus to promote T cell activation and proliferation can have a dramatic impact on its pathogenic potential.

Small intestine CD4+ cell reduction and enteropathy in simian/human immunodeficiency virus KS661-infected rhesus macaques in the presence of low viral load

Human immunodeficiency virus type 1, simian immunodeficiency virus and simian/human immunodeficiency virus (SHIV) infection generally lead to death of the host accompanied by high viraemia and profound CD4(+) T-cell depletion. SHIV clone KS661-infected rhesus macaques with a high viral load set point (HVL) ultimately experience diarrhoea and wasting at 6-12 months after infection. In contrast, infected macaques with a low viral load set point (LVL) usually live asymptomatically throughout the observation period, and are therefore referred to as asymptomatic LVL (Asym LVL) macaques. Interestingly, some LVL macaques exhibit diarrhoea and wasting similar to the symptoms of HVL macaques and are termed symptomatic LVL (Sym LVL) macaques. This study tested the hypothesis that Sym LVL macaques have the same degree of intestinal abnormalities as HVL macaques. The proviral DNA loads in lymphoid tissue and the intestines of Sym LVL and Asym LVL macaques were comparable and all infected monkeys showed villous atrophy. Notably, the CD4(+) cell frequencies of lymphoid tissues and intestines in Sym LVL macaques were remarkably lower than those in Asym LVL and uninfected macaques. Furthermore, Sym LVL and HVL macaques exhibited an increased number of activated macrophages. In conclusion, intestinal disorders including CD4(+) cell reduction and abnormal immune activation can be observed in SHIV-KS661-infected macaques independent of virus replication levels.

Advances in sexually transmitted infections of the gastrointestinal tract

The gastrointestinal mucosa is a target of many sexually transmitted infections, and major advances have increased our understanding of the consequences of such infections within the gastrointestinal system. HIV-1 is associated with a marked loss of mucosal CD4(+) T cells that express CC-chemokine receptor 5. This process seems to be more rapid and more severe in mucosa-associated lymphoid tissue than in the peripheral blood. Mechanistic insights into the underlying cause of acute and chronic gastrointestinal damage with HIV infection-microbial translocation, defects in intestinal epithelial barrier function and activation of a systemic immune response-have also been achieved. Increased understanding of the pathogenesis of mucosal HIV-1 infection may identify therapeutic targets to restore immunological function and the integrity of the intestinal mucosal epithelial barrier. The increasing prevalence of lymphogranuloma venereum in Europe, mostly in HIV-positive men who have sex with men, suggests a change in the epidemiology of what was previously considered to be a 'tropical' disease. The increasing incidence of acute HCV infection transmitted via sexual contact has also been fueled by high-risk sexual behaviors among men who have sex with men, many of whom are also HIV-positive. The first part of this Review discusses the pathogenesis and gastrointestinal complications of HIV infection, and the second part summarizes advances in our understanding of other sexually transmitted infections of the gastrointestinal system.

Cytomegalovirus colitis mimics amebic colitis in a man with AIDS

Opportunistic gastrointestinal infections are common in patients with HIV infection; both amebic colitis and cytomegalovirus (CMV) colitis are common causes of chronic diarrhea. It is difficult to distinguish these 2 diseases by nonspecific clinical symptoms such as diarrhea, abdominal pain, and weight loss. Here we report a case of CMV colitis mimicking amebic colitis with elevated indirect hemagglutination assay antibody titer against Entamoeba histolytica and negative IgM antibody titer against CMV. The diagnosis of CMV colitis was confirmed by eosinophilic nucleoli and inclusion bodies in colon biopsies. The patient recovered after ganciclovir and highly active antiretroviral therapy. Exact diagnoses are important for treating opportunistic infections. Other pathogens should be considered in patients with chronic diarrhea who are refractory to initial treatments. Our case highlights the importance of histopathological diagnosis for chronic diarrhea in patients with HIV infection and the possibility of false-positive results for indirect hemagglutination assay antibody against Entamoeba histolytica despite high titers.

HIV-associated Isospora belli infection: incidence and risk factors in the French Hospital Database on HIV

OBJECTIVE

To determine the incidence of Isospora belli infection in HIV-infected patients in France, and to study risk factors.

METHODS

The French Hospital Database on HIV (FHDH) is a prospective cohort study that collects demographic, clinical and therapeutic data on patients managed in 62 hospitals. We reviewed all cases of I. belli infection recorded between 1992 and 2003. We compared the incidence in 1992-1994 [before the use of dual therapy and combination antiretroviral therapy (cART)] and in 1997-2003 (when use of cART was widespread), after stratification for CD4 cell count (< 50, 50-99, 100-199 and > 200 cells/microL).

RESULTS

A total of 164 patients had I. belli infection either at enrollment (n=71) or during follow up (n=93). During the study period, I. belli infection tended to occur less frequently during follow up, and to be diagnosed mainly at database enrollment. The incidence of I. belli infection during follow up fell by 79% [relative hazard (RH) 0.21; 95% confidence interval (CI) 0.13-0.33] in the cART period compared with the pre-cART period; no such change was noted among patients with CD4 cell counts below 50 cells/microL. In multivariable analysis, the risk of I. belli infection was significantly higher among patients from sub-Saharan Africa (RH 4.3; 95% CI 2.6-7.3). After adjustment for CD4 cell count, patients receiving cotrimoxazole prophylaxis were found to be at a lower risk of I. belli infection (RH 0.3; 95% CI 0.2-0.6).

CONCLUSIONS

In France, I. belli infection among HIV-infected patients is now mainly seen in patients from sub-Saharan Africa, who present at an advanced stage.

Inhibitory effect of HIV-1 Tat protein on the sodium-D-glucose symporter of human intestinal epithelial cells

OBJECTIVE

The pathophysiology of HIV-1-related intestinal dysfunction is largely unknown. We previously found that the transactivator factor peptide (Tat) produced by HIV-1 induces ion secretion and inhibits cell proliferation in human enterocytes. Because sugar malabsorption is a frequent feature in AIDS patients, we evaluated whether Tat inhibits intestinal glucose absorption.

DESIGN AND METHODS

We measured Na-D-glucose symporter (SGLT-1) activity and determined its phenotypic expression in Caco-2 cells, in the presence and absence of Tat, in uptake experiments using a non-metabolized radiolabelled glucose analogue, and by western blot analysis, respectively. alpha-Tubulin staining was used to study the effects exerted by Tat on cell structure.

RESULTS

Tat dose dependently inhibited glucose uptake by human enterocytes. This effect was prevented by anti-Tat polyclonal antibodies and by L-type Ca channels agonist Bay K8644. Western blot analysis of cellular lysates and brush-border membrane preparations showed that Tat induced SGLT-1 missorting. Tat also caused a dramatic decrease in alpha-tubulin staining, which indicates dysruption of the cytoskeleton organization.

CONCLUSIONS

Tat acutely impairs intestinal glucose absorption through SGLT-1 missorting. This result indicates that Tat is directly involved in AIDS-associated intestinal dysfunction.

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Pancreatic exocrine insufficiency in HIV-positive patients

OBJECTIVES

We describe the management of a cohort of eight HIV-positive patients on antiretroviral medication with evidence of pancreatic insufficiency consisting of chronic diarrhoea and a low faecal elastase measurement.

PATIENTS AND METHODS

Twenty-two patients with chronic diarrhoea for whom a faecal elastase measurement was available were identified retrospectively. We compared baseline demographic characteristics, antiretroviral treatment and symptoms of steatorrhea between patients with evidence of pancreatic insufficiency, i.e. a low faecal elastase measurement of <200 microg/g (cases), and patients with evidence of normal pancreatic function, i.e. a normal faecal elastase measurement of >200 microg/g (controls). We describe the management of the patients with evidence of pancreatic insufficiency.

RESULTS

Of the 22 patients, eight had evidence of pancreatic insufficiency, i.e. a low faecal elastase measurement. Comparing cases with controls, cases were more likely to have symptoms of steatorrhea (P=0.03) or to have lost weight (P=0.02). Cases were also significantly more likely to have taken didanosine (ddI) as part of their antiretroviral treatment when their symptoms started. Seven cases were treated with oral pancreatic supplements and all had symptomatic improvement of their diarrhoea. One patient stopped treatment with oral pancreatic supplements because of side effects without a relapse of symptoms; he had also stopped zalcitabine (ddC).

CONCLUSIONS

We believe that measurement of faecal elastase to detect pancreatic insufficiency should be part of the standard investigation of HIV-positive patients with chronic diarrhoea alongside assessment for other causes of diarrhoea. Faecal elastase measurements should be requested, in particular, in all patients with diarrhoea and weight loss, or symptoms of steatorrhea, and in those on treatment with an antiretroviral regime containing ddI. If the faecal elastase level is low, a switch of antiretroviral medication to a nonddI/ddC-containing regime should be considered and treatment with oral pancreatic enzyme therapy should be instituted.

Acquired rectal fistula in human immunodeficiency virus-positive children: a causal or casual relationship?

Acquired rectal fistula in human immunodeficiency virus (HIV)-positive children is a new and worrisome entity. The aim of this paper is to highlight the relationship between HIV infection and acquired rectal fistula (RF) in children in order to create awareness among clinicians who attend to children. Over a 1-year period, 11 girls aged 4 weeks-11 months (median 5 months) with acquired RF were managed at our institution. Ten were HIV-positive by enzyme-linked immunosorbent assay and confirmed by Western blot test. One child defaulted before the test. All the mothers and three fathers of the 10 children were seropositive for HIV. Bronchopneumonia, otitis media, oral thrush, diarrhoea, and lymphadenopathy were common associations. Treatment was essentially conservative because the result of surgical intervention was disappointing. Two of the infants and one of the fathers are now dead from full-blown acquired immunodeficiency syndrome. Acquired RF seems to be a sign of HIV infection in children. It will be necessary to screen any child presenting with acquired RF for HIV infection.

Occurrence of Cryptosporidium oocysts in sewage effluents and correlation with microbial, chemical and physical water variables

Contaminated water are recognized as a potential source of Cryptosporidium oocysts. In Italy studies on the environmental spread of the parasite are still scarce even if a high frequency of serological responses could suggest high rates of endemic Cryptosporidium infections. In this investigation the occurrence of the parasite in water samples from a municipal wastewater treatment plant was monitored with the aim to evaluate possible correlation between oocysts and bacterial indicators, pathogens and physico-chemical parameters using a multivariate analysis. Data collected showed high numbers of oocysts, with a high percentage of positive samples and a significant correlation with pH, redox potential and total organic carbon. No correlation was found between Cryptosporidium concentration and that of the other microrganisms. The results, through a probing statistical analysis, show that none of the selected microrganisms was a reliable predictor of the presence of the parasite.

Effect of octreotide on small intestinal motility in HIV-infected patients with chronic refractory diarrhea

Octreotide has been used to treat HIV-associated diarrhea. We aimed to assess the effect of octreotide on small intestinal motility in a group of HIV infected individuals with chronic diarrhea. Small intestinal motility was measured continuously for 48 hr by ambulatory strain gauge manometry in 12 HIV seropositive subjects with chronic diarrhea. During the second 24-hr period, intravenous octreotide was administered (100 microg every 8 hr). Postprandial and nocturnal fasting motility data were compared before and during administration of octreotide. Octreotide was associated with increased numbers of migrating motor complexes (MMCs) (7.25 vs 4.92, P = 0.03), and a relative decrease in the duration of phase II (22% vs 49.8, P = 0.03) during nocturnal fasting activity. Postprandial activity was absent in half of the subjects and the duration significantly reduced in the remainder. In conclusion, octreotide has a significant effect on small intestinal motility in HIV-infected individuals with diarrhea, which may influence intestinal transit.

Efficacy of oral pancreatic enzyme therapy for the treatment of fat malabsorption in HIV-infected patients

BACKGROUND

Nutrient malabsorption is a negative prognostic factor in acquired immunodeficiency syndrome and recent studies have shown that pancreatic insufficiency is a codetermining factor of malabsorption.

AIMS

To evaluate the effectiveness of open-label oral pancreatic enzyme supplementation therapy in acquired immunodeficiency syndrome patients with fat malabsorption.

PATIENTS AND METHODS

Twenty-four consecutive patients with human immunodeficiency virus infection and fat malabsorption were recruited (11 males, 13 females; median age, 9.1 years). Faecal fat loss was evaluated by steatocrit assay at entry to the study (T-0), after 2 weeks (T-1) without pancreatic enzyme treatment and after a further 2 weeks (T-2) of treatment with pancreatic extracts (Creon 10 000 at a dose of 1000 units of lipase per gram of ingested dietary fat). Faecal elastase-1 and chymotrypsin were assayed at entry.

RESULTS

Six patients (25%) had abnormally low elastase-1 and/or chymotrypsin faecal concentration. In all patients, steatocrit values were elevated at both T-0 and T-1. Five patients proved intolerant to pancreatic enzyme treatment because of the onset of abdominal pain, and therapy was discontinued. In the 19 patients who concluded the study, steatocrit values during pancreatic enzyme treatment (T-2) were significantly lower than at entry (P < 0.0001). At T-2, in eight of 19 patients, steatocrit values were within the normal limit and the frequency of cases cured or improved on pancreatic enzyme therapy (at T-2) was significantly higher than that observed during the previous study period without enzyme treatment (T-1) (P < 0.01). A positive significant correlation was found between steatocrit values at entry and the Centers for Disease Control class (P < 0.0005); also, the decrease in steatocrit values during pancreatic enzyme therapy (difference between steatocrit value at T-2 and steatocrit value at T-0) positively correlated with the Centers for Disease Control class (P < 0.05).

CONCLUSIONS

This pilot, open-label study showed that pancreatic enzyme supplementation therapy is highly effective in reducing faecal fat loss in human immunodeficiency virus-infected patients with nutrient malabsorption. Further double-blind studies must be undertaken to verify these results and, if they are confirmed, pancreatic enzymes can be added to our weapons in the fight against human immunodeficiency virus-associated nutrient malabsorption.

Eradication of cryptosporidia and microsporidia following successful antiretroviral therapy

OBJECTIVES

Incidence of opportunistic protozoal infections causing diarrheal illnesses in patients with HIV has decreased since the introduction of highly active antiretroviral therapy (HAART). The objective of this study was to determine whether the parasites, cryptosporidia, and microsporidia were effectively eradicated or only suppressed following treatment.

DESIGN

Six HIV-positive patients with diarrheal symptoms caused by cryptosporidia or microsporidia were prospectively followed up with stool samples and duodenal biopsies. Samples were taken before HAART, between 1 to 3 months, and 6 months post-HAART.

METHODS

Duodenal samples were analyzed using routine histology and transmission electron microscopy. Stool samples were analyzed by both light microscopy and polymerase chain reaction (PCR) techniques.

RESULTS

Patients who responded successfully to HAART eradicated both cryptosporidial and microsporidial organisms. Symptoms improved within 1 month of therapy but complete eradication of the organisms was only observed after 6 months of treatment.

CONCLUSIONS

AIDs-related cryptosporidiosis and microsporidiosis can be cured following successful antiretroviral therapy.

Eradication of cryptosporidia and microsporidia following successful antiretroviral therapy

OBJECTIVES

Incidence of opportunistic protozoal infections causing diarrheal illnesses in patients with HIV has decreased since the introduction of highly active antiretroviral therapy (HAART). The objective of this study was to determine whether the parasites, cryptosporidia, and microsporidia were effectively eradicated or only suppressed following treatment.

DESIGN

Six HIV-positive patients with diarrheal symptoms caused by cryptosporidia or microsporidia were prospectively followed up with stool samples and duodenal biopsies. Samples were taken before HAART, between 1 to 3 months, and 6 months post-HAART.

METHODS

Duodenal samples were analyzed using routine histology and transmission electron microscopy. Stool samples were analyzed by both light microscopy and polymerase chain reaction (PCR) techniques.

RESULTS

Patients who responded successfully to HAART eradicated both cryptosporidial and microsporidial organisms. Symptoms improved within 1 month of therapy but complete eradication of the organisms was only observed after 6 months of treatment.

CONCLUSIONS

AIDs-related cryptosporidiosis and microsporidiosis can be cured following successful antiretroviral therapy.

Management of protozoal diarrhoea in HIV disease

Since the first reported case of HIV infection in 1981, many HIV-seropositive patients have died as a result of diarrhoea induced by opportunistic protozoal infections: pathogens that would normally cause only a transient illness in immunocompetent individuals. The introduction of highly active antiretroviral therapy (HAART) in 1996 has been associated with a significant decline in incidence and mortality arising from infections such as cryptosporidia and microsporidia. Previously, there were no chemotherapeutic agents known to be effective in eradicating these parasites, but since the availability of HAART, the memory of the emaciated terminally ill patient with advanced AIDS suffering from refractory diarrhoea will hopefully be a thing of the past. Significant advances in the knowledge of the pathogenesis of HIV disease, earlier detection and thus treatment of the virus, and availability of improved diagnostic techniques and HAART have transformed the way HIV-associated diarrhoea is managed. In this review, we look specifically at the management of protozoa-induced diarrhoea.

Enteric virus infections and diarrhea in healthy and human immunodeficiency virus-infected children

Forty-three stool samples from 27 human immunodeficiency virus (HIV)-seropositive children and 38 samples from 38 HIV-negative children, collected during a 15-month period, were examined for enteric viruses. Diagnostic assays included enzyme immunoassays for rotavirus, adenovirus, and Norwalk virus; polyacrylamide gel electrophoresis for picobirnavirus and atypical rotavirus; and PCR for astrovirus and enterovirus. Specimens from HIV-positive children were more likely than those of HIV-negative children to have enterovirus (56 versus 21%; P < 0.0002) and astrovirus (12 versus 0%; P < 0.02), but not rotavirus (5 versus 8%; P > 0.5). No adenoviruses, picobirnaviruses, or Norwalk viruses were found. The rates of virus-associated diarrhea were similar among HIV-positive and HIV-negative children. Enteroviruses were excreted for up to 6 months in HIV-positive children; however, no evidence for prolonged excretion of poliovirus vaccine was observed. These results suggest that although infection with enterovirus and astrovirus may be frequent in HIV-infected children, enteric viruses are not associated with the diarrhea frequently suffered by these children.

Viability and infectivity of two Cryptosporidium parvum bovine isolates from different geographical location

The viability of two Cryptosporidium parvum bovine isolates from Spain and Colombia was evaluated by in vitro excystation, inclusion/exclusion of two fluorogenic vital dyes (DAPI and PI) and infectivity assay in a suckling murine model. Excystation percentages were similar for both Spain and Colombia isolates (83% and 87%, respectively). The total viability of the Spain isolate, measured by inclusion/exclusion of two fluorogenic vital dyes, was 71% in comparison with that detected for oocysts of the Colombia isolate, 32.3%. The bovine C. parvum oocysts of both isolates were viable and infectious for suckling Swiss CD-1 mice. However, infectivity percentage and the mean intensity of infection were consistently higher in the Spain isolate than those from Colombia isolate. It was not possible to obtain a good correlation between in vitro excystation, inclusion/exclusion of vital dyes and in vivo infectivity for the Colombia isolate, while data obtained with the Spain isolate indicated that there was an apparent strong correlation between excystation efficiency, total viability and the infectivity. Although a comparative analysis of genetic variation among these isolates from different geographical location is necessary, variations observed between the both isolates seemed to be a result of parasite adaptation to environmental stresses such as temperature which appears to have a direct effect on the permeability of the oocysts.

Enteropathogens in adult patients with diarrhea and healthy control subjects: a 1-year prospective study in a Swedish clinic for infectious diseases

A 1-year prospective study was conducted to identify enteropathogens in adults with diarrhea (n=851) and in healthy control subjects (n=203) by use of conventional laboratory methods. Virulence factor genes for diarrheagenic Escherichia coli were detected by polymerase chain reaction. Enteropathogens were identified in 56% of patients and 16% of control subjects. The isolation rate was 65% for patients with symptoms for <1 week and for travelers; >1 pathogen was found in 11% of patients. The most frequent enteropathogens were Campylobacter (13% of patients), Clostridium difficile (13%), enterotoxigenic Escherichia coli (8%), Salmonella (7%), Shigella (4%), Blastocystis hominis (4%), calicivirus (3%), rotavirus (3%), enteroaggregative E. coli (2%), Aeromonas (2%), Giardia intestinalis (2%), Cryptosporidium (2%), and astrovirus (2%). Less frequently isolated (< or =1% of patients) were verotoxigenic E. coli, enteropathogenic E. coli, enteroinvasive E. coli, Entamoeba histolytica/Entamoeba dispar, microsporidia, and adenovirus. Fifty percent of the patients were hospitalized, and 43% needed intravenous fluids. The median duration of diarrhea was 14 days. Clinical features were not helpful for predicting the etiology of diarrhea.

A double blind, randomized, placebo-controlled phase II study to assess the safety and efficacy of orally administered SP-303 for the symptomatic treatment of diarrhea in patients with AIDS

OBJECTIVE

The aim of this study was to investigate the safety and effectiveness of orally administered SP-303 in patients with AIDS and diarrhea.

METHODS

This is a multicenter, phase II, randomized, double blind, placebo-controlled study. HIV-positive subjects with a history of a CD4 count <200 or an AIDS-defining illness were admitted to an inpatient study unit and screened for diarrhea defined as at least three abnormal (i.e., soft or watery) stools and >200 g of abnormal stool weight over a 24-h period. Subjects discontinued all antidiarrheal agents >24 h before enrollment. Stool samples were studied for routine pathogens. Subjects received 500 mg p.o. of SP-303 or placebo every 6 h for 96 h (4 days). Stool frequency and weights were recorded. Subjects were monitored for symptoms and side effects and were seen 1 wk later in follow-up.

RESULTS

A total of 26 subjects received SP-303, and 25 received placebo. There were no significant demographic differences between treatment arms. A total of 41 subjects (80%) were receiving antiretroviral therapy and 39 subjects (77%) were receiving at least one protease inhibitor. Stool studies revealed no pathogens in 48 of 51 patients (94%). There were no serious adverse events or laboratory abnormalities. The SP-303 treatment group demonstrated a mean reduction from baseline stool weight of 451 g/24 h versus 150 g/24 h with placebo on day 4 of treatment (p = 0.14), and a mean reduction in abnormal stool frequency of three abnormal stools in 24 h versus two in 24 h in the placebo group (p = 0.30). Daily measures analysis over 4 days of treatment demonstrated that SP-303 subjects had a significant reduction in stool weight (p = 0.008) and abnormal stool frequency (p = 0.04) when compared to placebo-treated subjects.

CONCLUSIONS

SP-303 is safe and well tolerated. These results suggest that SP-303 may be effective in reducing stool weight and frequency in patients with AIDS and diarrhea.

Evaluation of upper gastrointestinal tract symptoms in patients infected with HIV

OBJECTIVE

Upper gastrointestinal tract (UGI) symptoms are frequent in patients infected with the human immunodeficiency virus (HIV), but little published information exists about their characteristics or methods of evaluation. We evaluated the prevalence of nonesophageal UGI symptoms in a referral population, the utility of esophagogastroduodenoscopy (EGD) for diagnosis, and clinical predictors of abnormal endoscopic findings in patients infected with HIV.

METHODS

All HIV-infected patients referred to.the outpatient gastroenterology clinics were prospectively evaluated using recognized symptom questionnaires. EGD indications, results, and the patients' self-reported symptom scores were compared. HIV-infected patients undergoing EGD were compared with HIV-infected patients not receiving an EGD and with symptomatic non-HIV-infected patients undergoing EGD.

RESULTS

A total of 201 patients completed 280 questionnaires. Among 93 patients who underwent endoscopy, severe symptoms occurring at least several times per week included: anorexia (70%), upper abdominal pain (34%), vomiting (32%), or a recent weight loss of approximately 15 lb (31%). Patients undergoing EGD had more frequent/severe symptoms, but did not have differences in overall well-being or mean GI symptom score. The frequency of substantial and treatable endoscopic findings among patients infected with HIV was comparable to that found in the non-HIV-infected control group. There were no independent symptoms predicting substantial or treatable disease on EGD.

CONCLUSIONS

We conclude that: 1) upper gastrointestinal symptoms are common in HIV-infected patients referred for GI consultation; 2) symptomatic HIV patients have a high prevalence of both treatable and untreatable upper GI pathologies; 3) and physicians use symptom frequency and severity to select patients for EGD, but these factors correlate poorly with abnormalities on EGD. Given this discrepancy, longitudinal study is needed to determine whether treating endoscopic abnormalities improves UGI symptoms.

Micronutrients and the pathogenesis of human immunodeficiency virus infection

Micronutrient deficiencies may be common during human immunodeficiency virus (HIV) infection. Insufficient dietary intake, malabsorption, diarrhoea, and impaired storage and altered metabolism of micronutrients can contribute to the development of micronutrient deficiencies. Low plasma or serum levels of vitamins A, E, B6, B12 and C, carotenoids, Se, and Zn are common in many HIV-infected populations. Micronutrient deficiencies may contribute to the pathogenesis of HIV infection through increased oxidative stress and compromised immunity. Low levels or intakes of micronutrients such as vitamins A, E, B6 and B12, Zn and Se have been associated with adverse clinical outcomes during HIV infection, and new studies are emerging which suggest that micronutrient supplementation may help reduce morbidity and mortality during HIV infection.

Prevalence of intestinal pathogens in HIV patients with diarrhea: implications for treatment

Patients infected with the human immunodeficiency virus (HIV) commonly experience diarrhea at some time during their illness. A variety of enteric pathogens are identified in 50-80% of these patients, depending on the intensity of the diagnostic work-up that is done. In addition to the common enteric pathogens, several unusual enteric pathogens are recognized to cause diarrhea especially in HIV patients. These include protozoan parasites such as Cryptosporidia, Isospora belli, Cyclospora cayatenensis and Microsporidium species bacteria such as enteropathogenic Escherichia coli and Mycobacterium avium-intracellulare, fungi including Candida albicans and Histoplasma capsulatum, and viruses such as astroviruses and caliciviruses. Diagnosis of these infections sometimes involves special procedures not readily available every where, and empiric therapy based on knowledge of the likely pathogens has been advocated for developing countries. This article reviews the currently available data on geographic variation of enteric pathogens in HIV patients with diarrhea and outlines a rational strategy for empiric therapy of these patients.

Isolation and characterization of a neuropathogenic simian immunodeficiency virus derived from a sooty mangabey

Transfusion of blood from a simian immunodeficiency virus (SIV)- and simian T-cell lymphotropic virus-infected sooty mangabey (designated FGb) to rhesus and pig-tailed macaques resulted in the development of neurologic disease in addition to AIDS. To investigate the role of SIV in neurologic disease, virus was isolated from a lymph node of a pig-tailed macaque (designated PGm) and the cerebrospinal fluid of a rhesus macaque (designated ROn2) and passaged to additional macaques. SIV-related neuropathogenic effects were observed in 100% of the pig-tailed macaques inoculated with either virus. Lesions in these animals included extensive formation of SIV RNA-positive giant cells in the brain parenchyma and meninges. Based upon morphology, the majority of infected cells in both lymphoid and brain tissue appeared to be of macrophage lineage. The virus isolates replicated very well in pig-tailed and rhesus macaque peripheral blood mononuclear cells (PBMC) with rapid kinetics. Differential replicative abilities were observed in both PBMC and macrophage populations, with viruses growing to higher titers in pig-tailed macaque cells than in rhesus macaque cells. An infectious molecular clone of virus derived from the isolate from macaque PGm (PGm5.3) was generated and was shown to have in vitro replication characteristics similar to those of the uncloned virus stock. While molecular analyses of this virus revealed its similarity to SIV isolates from sooty mangabeys, significant amino acid differences in Env and Nef were observed. This virus should provide an excellent system for investigating the mechanism of lentivirus-induced neurologic disease.

Role of cytokines in AIDS wasting

There is now a large literature implicating cytokines in the development of wasting and cachexia commonly observed in a variety of pathophysiologic conditions. In the acquired immunodeficiency syndrome (AIDS), cytokines elicited by primary and secondary infections seem to exert subtle and sustained effects on behavioral, hormonal, and metabolic axes, and their combined effects on appetite and metabolism have been postulated to drive wasting. However, correlations of increased blood levels of a particular cytokine with wasting in AIDS have not been consistent observations, perhaps because cytokines act principally as paracrine and autocrine hormones, as well as indirectly by activating other systems. A better understanding of the mechanisms underlying the catabolic effects of cytokines in clearly needed if more efficacious strategies are to be developed for the prevention and treatment of wasting in AIDS. In this review we first examine the interacting factors contributing to the AIDS wasting syndrome. We then analyze the complex and overlapping role of cytokines in the pathophysiology of this condition, and put forward a number of hypotheses to explain some of the most important features of this syndrome.

Intestinal microsporidiosis in a HIV-seronegative patient

Microsporidial infections have been increasingly reported in immunocompromised patients, particularly those infected with the human immunodeficiency virus (HIV), but only rarely in immunocompetent individuals. We report a case of intestinal microsporidiosis in a HIV-seronegative patient with acute self-limited diarrhoea. Examination of stool specimens revealed plenty of spores that correspond with Enterocytozoon bieneusi in size and shape as well as ultrastructural details.

Diagnostic yield and cost-effectiveness of endoscopy in chronic human immunodeficiency virus-related diarrhea

BACKGROUND

Endoscopy is commonly performed in patients with chronic human immunodeficiency virus (HIV)-related diarrhea after negative stool studies. The aim of this study was to determine the diagnostic yield and cost-effectiveness of endoscopy in this setting.

METHODS

Consecutive HIV-infected patients with chronic unexplained diarrhea who were referred for diagnostic endoscopy were identified. Patient charts, pathology reports, and endoscopy records were reviewed.

RESULTS

A total of 479 endoscopic procedures were performed in 307 patients. A pathogen was identified in 147 patients (47.9%); cytomegalovirus was the most frequent organism found (21.5%). The average cost of identifying a pathogen by endoscopy was $3822.94. Colonoscopy had a greater diagnostic yield than flexible sigmoidoscopy (38.7% vs. 22.4%, p = 0.009) and was more cost-effective. The yield of upper endoscopy was 29.6%. In patients with a CD4 count of less than 100/mm3, endoscopy had a higher diagnostic yield (62.8% vs. 8.3%, p < 0.0001) and a lower cost of identifying a pathogen ($2943.92 vs. $21,583.51) than in those with higher CD4 counts.

CONCLUSIONS

Endoscopy frequently identifies a pathogen in HIV-related chronic diarrhea. Colonoscopy is the most cost-effective procedure. Endoscopic evaluation has a significantly higher diagnostic yield and is considerably more cost-effective in patients with a CD4 count of less than 100/mm3 than in those with higher CD4 counts.

Pancreatic dysfunction and its association with fat malabsorption in HIV infected children

BACKGROUND

Nutrient malabsorption frequently occurs in HIV infected children, but very few studies have investigated exocrine pancreatic digestive capacity in these cases.

AIMS

To investigate pancreatic function in HIV infected children and to determine whether faecal fat loss, a prominent feature of intestinal dysfunction, is associated with pancreatic dysfunction.

PATIENTS

Forty seven children with HIV infection without apparent pancreatic disease and 45 sex and age matched healthy controls.

METHODS

Pancreatic function was evaluated by measuring elastase 1 concentration and chymotrypsin activity in stools by ELISA and colorimetric methods, respectively. Intestinal function was evaluated by measuring fat and protein loss by the steatocrit method and by faecal alpha1 antitrypsin concentration.

RESULTS

14 (30%) had abnormal pancreatic function tests: seven had isolated elastase activity deficiency, three isolated chymotrypsin deficiency, and four pancreatic deficiencies in both enzymes. Patient enzyme values were significantly lower than those of controls. Low faecal pancreatic enzymes were not associated with symptoms. Twelve children had steatorrhoea and four had increased alpha1 antitrypsin. Steatorrhoea was significantly associated with reduced faecal pancreatic enzymes. There was a significant negative correlation between elastase 1 concentration and steatocrit. Children with pathological faecal elastase 1 or chymotrypsin values did not differ from the other HIV infected children with respect to nutritional and immunological status, stage of HIV disease, presence of opportunistic infections, or drug administration.

CONCLUSIONS

Abnormal pancreatic function tests are a frequent feature of paediatric HIV infection; this condition is associated with steatorrhoea, which probably contributes to the disease.

HIV enteropathy: comparative morphometry of the jejunal mucosa of HIV infected patients resident in the United Kingdom and Uganda

AIMS

To compare jejunal mucosal morphometry in HIV infected patients resident in London and Uganda.

PATIENTS

Twenty HIV positive patients from London and 16 from Uganda were studied, and compared with HIV negative control subjects from both sites.

METHODS

Stools and biopsy specimens were examined for enteropathogens. Surface area to volume (S:V) ratio was estimated morphometrically, mean crypt length of jejunal biopsy specimens was measured, and HIV infected cells detected immunohistochemically were quantified.

RESULTS

Enteric pathogens were detected in none of the London patients, and in three Ugandan patients. S:V ratio was lower, and mean crypt length higher, in the specimens of London patients than in normal subjects, but there was no difference in S:V ratio or mean crypt length between Ugandan patients and controls. A negative correlation was present between S:V ratio and mean crypt length in all biopsy specimens analysed. HIV infected cells were detected only in lamina propria.

CONCLUSION

Infection of cells in the lamina propria of the jejunum with HIV stimulates crypt cell proliferation, and a fall in villous surface area. The mucosal response to HIV is masked by other pathogens in the African environment.