Cytomegalovirus colitis in HIV-1-infected patients: a prospective research in 55 patients

Viral infections in inflammatory bowel disease: Tips and tricks for correct management

Over the past decades, the treatment of inflammatory bowel diseases (IBD) has become more targeted, anticipating the use of immune-modifying therapies at an earlier stage. This top-down approach has been correlated with favorable short and long-term outcomes, but it has also brought with it concerns regarding potential infectious complications. This large IBD population treated with immune-modifying therapies, especially if combined, has an increased risk of severe infections, including opportunistic infections that are sustained by viral, bacterial, parasitic, and fungal agents. Viral infections have emerged as a focal safety concern in patients with IBD, representing a challenge for the clinician: they are often difficult to diagnose and are associated with significant morbidity and mortality. The first step is to improve effective preventive strategies, such as applying vaccination protocols, adopt adequate prophylaxis and educate patients about potential risk factors. Since viral infections in immunosuppressed patients may present atypical signs and symptoms, the challenges for the gastroenterologist are to suspect, recognize and diagnose such complications. Appropriate treatment of common viral infections allows us to minimize their impact on disease outcomes and patients’ lives. This practical review supports this standard of care to improve knowledge in this subject area.

Estimating the Risk of Human Herpesvirus 6 and Cytomegalovirus Transmission to Ugandan Infants from Viral Shedding in Saliva by Household Contacts

Human herpesvirus 6 (HHV-6) and cytomegalovirus (CMV) infections are common in early childhood. In a prospective Ugandan birth cohort study, most infants acquired HHV-6 (24/31; 77%) and CMV (20/30; 67%) during follow-up. To assess the transmission risk, we modeled a dose-response relationship between infant HHV-6 and CMV infections and weekly oral viral shedding by mothers and all other ("secondary") children in the home. Oral viral loads that were shed by mothers and secondary children were significantly associated with HHV-6 but not CMV transmission. While secondary children had higher and more frequent HHV-6 shedding than their mothers, they had a lower per-exposure transmission risk, suggesting that transmission to maternal contacts may be more efficient. HHV-6 transmission was relatively inefficient, occurring after <25% of all weekly exposures. Although HHV-6 transmission often occurs following repeated, low dose exposures, we found a non-linear dose-response relationship in which infection risk markedly increases when exposures reached a threshold of > 5 log₁₀ DNA copies/mL. The lack of association between oral CMV shedding and transmission is consistent with breastfeeding being the dominant route of infant infection for that virus. These affirm saliva as the route of HHV-6 transmission and provide benchmarks for developing strategies to reduce the risk of infection and its related morbidity.

Stability of the gorilla microbiome despite simian immunodeficiency virus infection

Simian immunodeficiency viruses (SIVs) have been discovered in over 45 primate species; however, the pathogenic potential of most SIV strains remains unknown due to difficulties inherent in observing wild populations. Because those SIV infections that are pathogenic have been shown to induce changes in the host's gut microbiome, monitoring the microbiota present in faecal samples can provide a noninvasive means for studying the effects of SIV infection on the health of wild-living primates. Here, we examine the effects of SIVgor, a close relative of SIVcpz of chimpanzees and HIV-1 of humans, on the gut bacterial communities residing within wild gorillas, revealing that gorilla gut microbiomes are exceptionally robust to SIV infection. In contrast to the microbiomes of HIV-1-infected humans and SIVcpz-infected chimpanzees, SIVgor-infected gorilla microbiomes exhibit neither rises in the frequencies of opportunistic pathogens nor elevated rates of microbial turnover within individual hosts. Regardless of SIV infection status, gorilla microbiomes assort into enterotypes, one of which is compositionally analogous to those identified in humans and chimpanzees. The other gorilla enterotype appears specialized for a leaf-based diet and is enriched in environmentally derived bacterial genera. We hypothesize that the acquisition of this gorilla-specific enterotype was enabled by lowered immune system control over the composition of the microbiome. Our results indicate differences between the pathology of SIVgor and SIVcpz/HIV-1 infections, demonstrating the utility of investigating host microbial ecology as a means for studying disease in wild primates of high conservation priority.

Cytomegalovirus colitis in a human immunodeficiency virus-positive patient with a normal CD4 count

Cytomegalovirus (CMV) is the most common cause of life-threatening opportunistic viral infection in patients with the human immunodeficiency virus (HIV) disease. The colon is a well-known target organ for CMV in these patients. CMV colitis is commonly associated with the later stages of HIV disease but rarely occurs in early HIV infection. In this study, an unusual case of CMV colitis in a 22-year-old man who had a normal CD4 count but at the same time was found to be HIV positive with a moderately high viral load is reported.

Small bowel perforation due to CMV enteritis infection in an HIV-positive patient

BACKGROUND

Cytomegalovirus infection of the gastrointestinal tract is common and is more often seen in patients with acquired immunodeficiency syndrome (AIDS). Although small bowel infection is less common than infection of other parts of the gastrointestinal system, it may lead to perforation, an acute complication, with dreadful results.

CASE PRESENTATION

This article reports a case of Cytomegalovirus ileitis with multiple small bowel perforations in a young man with human immunodeficiency virus (HIV) infection. The patient developed abdominal pain with diarrhea and fever, and eventually acute abdomen with pneumoperitoneum. The patient had poor prognosis and deceased despite the prompt surgical intervention and the antiviral therapy he received. At pathology a remarkable finding was the presence of viral inclusions in smooth muscle fibers. The destruction of muscle cells was the main cause of perforation.

CONCLUSION

Morbidity and mortality associated with perforation from CMV enteritis in AIDS patients are high and the life expectancy is short. Cytomegalovirus disease is multifocal; therefore, excision of one portion of the gastrointestinal tract may be followed by a complication elsewhere. Our case elucidate that muscle cell destruction by the virus is a significant cause leading to perforation.

Idiopathic AIDS enteropathy and treatment of gastrointestinal opportunistic pathogens

Diarrhea in patients with acquired immune deficiency syndrome (AIDS) has proven to be both a diagnostic and treatment challenge since the discovery of the human immunodeficiency virus (HIV) virus more than 30 years ago. Among the main etiologies of diarrhea in this group of patients are infectious agents that span the array of viruses, bacteria, protozoa, parasites, and fungal organisms. In many instances, highly active antiretroviral therapy remains the cornerstone of therapy for both AIDS and AIDS-related diarrhea, but other targeted therapies have been developed as new pathogens are identified; however, some infections remain treatment challenges. Once identifiable infections as well as other causes of diarrhea are investigated and excluded, a unique entity known as AIDS enteropathy can be diagnosed. Known as an idiopathic, pathogen-negative diarrhea, this disease has been investigated extensively. Atypical viral pathogens, including HIV itself, as well as inflammatory and immunologic responses are potential leading causes of it. Although AIDS enteropathy can pose a diagnostic challenge so too does the treatment of it. Highly active antiretroviral therapy, nutritional supplementation, electrolyte replacements, targeted therapy for infection if indicated, and medications for symptom control all are key elements in the treatment regimen. Importantly, a multidisciplinary approach among the gastroenterologist, infectious disease physician, HIV specialists, oncology, and surgery is necessary for many patients.

Cytomegaloviral colitis in HIV positive patients: endoscopic findings

BACKGROUND

Diarrhea in seropositive human immunodeficiency virus patients is one of the most important and disabling symptoms, and often decreases their quality of life. Cytomegalovirus colitis is among the principal causes of this symptom and colonoscopy is the gold standard examination to diagnose it.

AIM

To define the main endoscopic findings in seropositive human immunodeficiency virus patients with cytomegalovirus colitis.

METHODS

Two hundred and forty-three colonoscopies were performed in 200 seropositive human immunodeficiency virus patients with diarrhea associated or not to abdominal pain or gastrointestinal bleeding, over 10-year period, whom 51 patients were diagnosed with cytomegalovirus colitis. Full length colonoscopy with ileum intubation was always tried and multiple biopsies of all segments examined, including endoscopically normal segments, were attempted. All diagnoses were confirmed by histologic and immunohistochemical studies.

RESULTS

Total colonoscopy was possible in 98.03% and ileum intubation in 88.23% of these cytomegalovirus colitis patients. At colonoscopy, a heterogeneous ulcerative pattern was presented in 72.54%, an inflammatory process of the mucosa in 21.56% and 5.88% of the patients mucosa was endoscopically normal.

CONCLUSION

Full length colonoscopy with ileum intubation and multiples biopsies of all segments, even when they are endoscopically normal, have always to be attempted in cases of seropositive human immunodeficiency virus patient with diarrhea.

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.

Acute cytomegalovirus infection associated with the onset of inflammatory bowel disease

A 29-year-old man was admitted with high-grade fever, crampy abdominal pain, and watery diarrhea that had persisted for 2 weeks before his admission. Symptomatic treatment (acetaminophen only) was of no benefit. On physical examination, there was diffuse abdominal tenderness. Laboratory tests showed a leukomoid reaction with atypical lymphocytosis, and serology tests revealed acute cytomegalovirus infection. Abdominal computed tomography and colonoscopy revealed an inflammatory process involving the large intestine. On histologic examinations of intestinal biopsy samples, there was an active inflammation with no inclusion bodies. The patient was treated with ganciclovir with only mild improvement. Adding 5-aminosalicylic acid caused little further improvement. Repeated colonoscopy performed 2 months later showed severe chronic ulcerative colitis. Only the addition of systemic steroids caused complete resolution of the symptoms. On review of the literature (Medline search for cytomegalovirus colitis in immunocompetent patients), 18 cases were found. On follow-up, 10 of these patients were found to have inflammatory bowel disease.

Virtual screening of HIV-1 protease inhibitors against human cytomegalovirus protease using docking and molecular dynamics

The clearance of cytomegalovirus viraemia in HIV-1-infected patients may partly result from the inhibition of cytomegalovirus protease by HIV-1 protease inhibitors contained in highly active antiretroviral therapy. We used a computational method to calculate the binding affinity of six HIV-1 protease inhibitors to cytomegalovirus protease based on its X-ray crystallography structure. The calculations showed that amprenavir and indinavir occupy the substrate-binding site of the cytomegalovirus protease with high affinity, and may be implicated in alleviating cytomegalovirus infection.

Self-limited colitis during the course of rubella and cytomegalovirus infection in an immunocompetent adult

We report a case of self-limited colitis in cytomegalovirus (CMV) infection in an immunocompetent adult. A 22-year-old man developed a high fever and diarrhea. Laboratory data revealed an increased number of lymphocytes and liver damage. Enzyme immunoassays for anti-virus antibodies revealed that the patient was recently infected with CMV and rubella. Colonoscopy revealed severe erosive and edematous mucosa that resembled ulcerative colitis (UC). The symptoms, laboratory data and colonoscopic findings improved without any medical treatment. This case indicates that UC-like self-limited colitis can occur in an immunocompetent individual during the course of CMV infection.

Low prevalence of Helicobacter pylori but high prevalence of cytomegalovirus-associated peptic ulcer disease in AIDS patients: Comparative study of symptomatic subjects evaluated by endoscopy and CD4 counts

BACKGROUND AND AIMS

The role of Helicobacter pylori infection in gastroduodenal lesions might be different between the general population and AIDS patients. The aim of the present study was to compare the prevalence of H. pylori and cytomegalovirus (CMV) infection in AIDS patients and HIV-negative controls. The impact of CD4 lymphocyte counts on H. pylori and CMV infection in the same subjects was also assessed.

METHODS

One hundred and fifty-six patients (52 HIV-positive, 104 HIV-negative) with gastrointestinal symptoms were evaluated with upper gastrointestinal endoscopy and biopsy. Comparison of the prevalence of H. pylori and CMV infection was made by dividing AIDS patients into two groups: those with CD4 counts >100/mm3 and those with CD4 counts <100/mm3, and ulcer and non-ulcer patients.

RESULTS

In comparison with HIV-negative controls, AIDS patients had a lower prevalence of H. pylori infection (P < 0.0001) but a higher prevalence of CMV infection (P < 0.0001). Cytomegalovirus infection was frequently found in AIDS patients with CD4 count <100/mm3, in comparison with those with a CD4 count >100/mm3. In AIDS patients, CMV was more frequently detected in subjects with peptic ulcers (P = 0.0125). Conversely, the prevalence of H. pylori infection in AIDS patients was not different between those with and without peptic ulcers.

CONCLUSIONS

The low prevalence of H. pylori infection and peptic ulcer in AIDS patients suggests a different role of H. pylori infection in peptic ulcer or even a different mechanism of peptic ulcerogenesis in HIV-positive subjects. Cytomegalovirus, rather than H. pylori, may be the main causative pathogen of peptic ulcers in AIDS patients.

A case of severe CMV-colitis in an HIV positive patient despite moderate immunodeficiency

CMV-colitis is rare in HIV positive patients with CD4 counts higher than 100 microl(-1). We report a patient who was suffering from extensive CMV-colitis despite modest immune defect. The diagnosis was confirmed by repeated biopsies. The patient experienced an unusually long recovery which was only achieved after initiation of HAART.

Other viruses causing gastroenteritis

Besides the viruses producing the majority of human viral gastroenteritis, other viruses infect more rarely but are sometimes able to cause epidemics. In particular, they cause chronic infection in the immunocompromised. Some of these viruses discussed in this chapter are toroviruses, picobirnaviruses, enteroviruses, human immunodeficiency virus (HIV), herpesviruses, and coronaviruses. Toroviruses make up a genus of the Coronaviridae family. They are a well-described cause of diarrhea in calves and horses but may also infect sheep, goats, and pigs. Picobirnaviruses are related to members of the Birnaviridae family. They are found in the feces of HIV-infected patients with diarrhea more frequently than in HIV-infected patients without diarrhea, but a virus-specific immune response was not measurable. The genus Enterovirus is of the Picornaviridae family. All enteroviruses infect man via the gastrointestinal tract where they have their first site of replication, probably in lymphoid tissues of the pharynx and gut. HIV, the causative agent of the acquired immunodeficiency syndrome (AIDS), is a member of the Lentivirus genus of the Retroviridae family. Cytomegalovirus (CMV) and herpes simplex viruses, members of the Herpesviridae family, are found as the cause of colitis and esophagitis, mainly in HIV-infected patients. Coronavirus is another genus of the Coronaviridae family. Coronaviruses infect the respiratory and gastrointestinal tracts. They are a recognized cause of the common cold in man.

Life-threatening cytomegalovirus colitis in the immunocompetent patient: report of a case and review of the literature

Cytomegalovirus colitis in the immunocompetent patient is an unusual clinical entity. We describe a patient with life-threatening cytomegalovirus colitis in the absence of immune deficiency and review the medical literature available on this topic.

Enteric viruses in HIV-related diarrhoea

HIV-related diarrhoea is an important cause of morbidity and mortality in HIV infection. Cytomegalovirus is a well-established cause of diarrhoea, but the role of other enteric viruses is less clear and will be discussed here. The clinical manifestations, disease mechanisms, diagnostic techniques and current treatments for the management of these infections are reviewed.

Outcome of AIDS-associated cytomegalovirus colitis in the era of potent antiretroviral therapy

The effect of protease inhibitors (PIs) on the outcome of AIDS-associated cytomegalovirus (CMV) colitis is unknown. The aim of this study was to determine the impact of PIs on the recurrence of CMV disease and long-term survival in a large cohort of acquired immunodeficiency syndrome (AIDS) patients with CMV colitis. We reviewed the medical records of 252 AIDS patients who were diagnosed with CMV colitis by colonoscopy between January 1992 and January 1997 at Bellevue Hospital (New York, NY, U.S.A.). Follow-up data were obtained from chart review and direct telephone contact. A complete response to ganciclovir and/or foscarnet therapy was seen in 87.0% of the patients. Recurrence of CMV colitis occurred in 53.1% of patients and was significantly less common in those who received maintenance therapy (36.1% vs. 56.7%; p = 0.03) and in those who were treated with PIs (22.8% vs. 71.9%; p < 0.001). During follow-up. 69.3% of patients died. Multivariate analysis using Cox regression showed that mortality was increased in patients with recurrent CMV colitis (relative risk [RR] of death, 1.7: 95% CI, 1.1-2.6; p = 0.02) and comorbid disease (RR, 1.5: 95% CI, 1.1-2.2; p = 0.02), and decreased in those who were treated with PIs (RR, 0.42; 95% CI, 0.3-0.7; p = 0.001). The median survival was 71 weeks and was significantly longer in patients who were treated with PIs than in those who did not receive these potent anti-retroviral medications (99 vs. 51 weeks; p < 0.001). PIs significantly improve the outcome of AIDS-associated CMV colitis.

Emergency Surgery for Generalized Peritonitis Caused by Cytomegalovirus Colitis in a Patient with AIDS

Cytomegalovirus infection of the colon is a late and severe complication in human immunodeficiency virus patients. Despite availability of medical treatment, occasional life-saving emergency surgery must be performed. The controversial surgical aspects of treatment are discussed based upon an unusual case of aseptic generalized peritonitis without perforation. The feasibility and value of limited resection are emphasized.

V3 recombinants indicate a central role for CCR5 as a coreceptor in tissue infection by human immunodeficiency virus type 1

Binding of the human immunodeficiency virus type 1 (HIV-1) envelope glycoprotein gp120 to both CD4 and one of several chemokine receptors (coreceptors) permits entry of virus into target cells. Infection of tissues may establish latent viral reservoirs as well as cause direct pathologic effects that manifest as clinical disease such as HIV-associated dementia. We sought to identify the critical coreceptors recognized by HIV-1 tissue-derived strains as well as to correlate these coreceptor preferences with site of infection and dementia diagnosis. To reconstitute coreceptor use, we cloned HIV-1 envelope V3 sequences encoding the primary determinants of coreceptor specificity from 13 brain-derived and 6 colon-derived viruses into an isogenic (NL4-3) viral background. All V3 recombinants utilized the chemokine receptor CCR5 uniformly and efficiently as a coreceptor but not CXCR4, BOB/GPR15, or Bonzo/STRL33. Other receptors such as CCR3, CCR8, and US28 were inefficiently and variably used as coreceptors by various envelopes. CCR5 without CD4 present did not allow for detectable infection by any of the tested recombinants. In contrast to the pathogenic switch in coreceptor specificity frequently observed in comparisons of blood-derived viruses early after HIV-1 seroconversion and after onset of AIDS, the characteristics of these V3 recombinants suggest that CCR5 is a primary coreceptor for brain- and colon-derived viruses regardless of tissue source or diagnosis of dementia. Therefore, tissue infection may not depend significantly on viral envelope quasispeciation to broaden coreceptor range but rather selects for CCR5 use throughout disease progression.

Risk of developing CMV retinitis following non-ocular CMV end organ disease in AIDS patients

AIM

To describe the risk of developing cytomegalovirus (CMV) retinitis after a first episode of extraocular CMV disease in AIDS patients.

METHODS

A review of the clinical records of 20 AIDS patients, without CMV retinitis, with histologically confirmed extraocular CMV disease, was performed. The main outcome measures were occurrence of CMV retinitis, time to development of CMV retinitis, relation to maintenance therapy, and survival.

RESULTS

A CMV retinitis was diagnosed in 17 of 20 (85%) patients with an immunohistologically confirmed diagnosis of extraocular CMV disease after a mean follow up of 6.4 months. Four patients received maintenance therapy. Three of them developed retinitis after a mean of 9.6 months (range 2-16 months). Sixteen did not receive maintenance and retinitis was diagnosed in 14 of them after a mean of 5.7 months (range 2-11 months). Mean survival was 9.9 months after the diagnosis of extraocular disease, and 4.5 months after the diagnosis of retinitis. In the four patients receiving maintenance therapy, mean survival was 11.5 months, and in the 16 other patients mean survival was 9.5 months. Patients did not receive protease inhibitors.

CONCLUSION

In the preprotease inhibitor era extraocular CMV disease strongly predisposes to the subsequent development of CMV retinitis. Although maintenance therapy did not prevent the occurrence of retinitis, the time period between both events seems to lengthen considerably. In patients receiving maintenance survival is also longer.

Cytomegalovirus colitis in acquired immunodeficiency syndrome: a clinical and endoscopic study

BACKGROUND

Cytomegalovirus colitis is an important complication of the acquired immunodeficiency syndrome (AIDS), although the clinical and colonoscopic manifestations of this disease have not been systematically characterized.

METHODS

Patients with AIDS and cytomegalovirus colitis were prospectively identified at two medical centers. The diagnosis of cytomegalovirus disease was based on established endoscopic and histologic criteria. At the time of sigmoidoscopic and/or colonoscopic examination, clinical features were recorded; the location, size, and appearance of all endoscopic abnormalities were documented; and multiple biopsies of any lesions were performed.

RESULTS

Fifty-six patients were studied. The majority of the patients were homosexual men with severe immunodeficiency (median CD4 lymphocyte count 15/mm3, range 1 to 294/mm3). Chronic diarrhea and abdominal pain were the most frequent clinical manifestations, seen in 45 (80%) and 28 (50%) patients, respectively. Five patients (9%) presented with lower gastrointestinal hemorrhage, three of whom had no antecedent history of diarrhea. The colonoscopic abnormalities could be categorized into three main groups: colitis associated with ulcer (39%), ulceration alone (38%), or colitis alone (20%). Subepithelial hemorrhage was a prominent endoscopic manifestation of disease. Of the 31 patients undergoing colonoscopy to the cecum, in four (13%) endoscopic evidence of disease was limited to the colon proximal to the splenic flexure.

CONCLUSIONS

Cytomegalovirus colitis in AIDS appears to have variable but stereotypical clinical and colonoscopic manifestations. Distal colitis associated with ulceration is the most common colonoscopic pattern.

Cytomegalovirus colitis in immunocompetent individual

A woman with peripheral vascular disease developed cytomegalovirus colitis following repair of abdominal aortic aneurysm. Cytomegalovirus colitis developing in an immunocompetent individual may be caused by a breach in the integrity of the mucosal lining of the colon from various causes and should alert the clinician to explore these causes in order to provide effective care.

Prevalence and etiology of gastroduodenal ulcer in HIV-positive patients: a comparative study of 497 symptomatic subjects evaluated by endoscopy

OBJECTIVE

In 497 HIV-positive (+) patients with upper digestive tract symptoms, 23 (5%) had gastroduodenal ulcers (GDU) at upper endoscopy.

METHODS

To establish the causes of GDU in this setting, 16 of these patients who had had comprehensive histological evaluation (group I) were compared with 20 HIV+ subjects with upper gastrointestinal symptoms but without ulcer (group II), and with 16 seronegative patients with GDU (group III). Eighty-one percent of group I subjects and 90% of group II patients had C3 AIDS. The presence of gastritis and Helicobacter pylori, fungi, mycobacteria, viruses (especially cytomegalovirus [CMV] and herpes simplex [HSV]), and parasites was determined in all three groups by histopathological and microbiological studies.

RESULTS

The prevalence of chronic active gastritis was 13/16 (81%) in group I, 12/20 (60%) in group II, and 15/16 (94%) in group III. It was associated with H. pylori in group III, and with opportunistic pathogens in groups I and II and with none in group III. H. pylori was detected in 5/16 patients (31%) in group I, in 12/20 (60%) in group II, and 11/16 (69%) in group III. Cytomegalovirus was histologically diagnosed in 8/16 patients (50%) in group I and in 1/20 (5%) in group II. This virus was the only factor shown to be significantly associated with GDU in these cases (p = 0.0046). Cryptosporidium was found in 2/16 (12.5%) patients in group I, in 1/20 (5%) in group II, and in none in group III. Differences between groups I and II were not statistically significant. No other organisms were observed in the three groups.

CONCLUSIONS

Gastroduodenal ulcers were infrequent in HIV+ subjects with upper digestive tract symptoms and CMV was the only organism significantly associated with GDU in HIV+ patients. Among HIV+ patients, H. pylori was an uncommon cause of ulcer. Among HIV+ subjects with ulcer, chronic active gastritis was more common than H. pylori and it was associated with other pathogens. Finally, HIV+ patients with GDU should have endoscopic biopsies to detect opportunistic infections, especially CMV, because H. pylori infection is uncommon.

Cytomegalovirus (CMV) infection in AIDS patients is associated with a CD3 receptor-mediated T cell hyporesponsiveness

HIV+ individuals with human CMV (HCMV) reactivation have a CD3 receptor-mediated T cell hyporesponsiveness when compared with CD4-matched HIV+ and HCMV- control groups. The impairment of proliferation was not reversed by exogenous IL-2. A typical increase in NFkappaB expression was observed following cross-linking of the CD3 receptor, but did not lead to increased CD25 cell surface expression or cell proliferation. The HCMV-induced non-responsiveness was not observed when cells were stimulated with phorbol esters. Lymphocytes cultured with media collected from cell cultures infected with HCMV showed a dose-dependent inhibition in the total T cell population even though cells staining dually for CD8/57 increased in number. The altered growth factor requirements of CD8/57+ cells may therefore account for their presence in AIDS and patients following bone marrow transplantation.

Etiology and outcome of lower gastrointestinal bleeding in patients with AIDS

OBJECTIVE

The objective of the study was to investigate bleeding (LGIB) in patients with acquired immunodeficiency syndrome (AIDS).

METHODS

All hospitalized AIDS patients with LGIB evaluated by the gastroenterology service at a large city-county hospital during a 6 yr period were identified by database review and by endoscopy and consultation records.

RESULTS

Of the 691 AIDS patients seen during the study period, 18 (2.6%) (median age 41+/-7 years) were evaluated for LGIB. In these patients, LGIB was caused by human immunodeficiency virus type 1 (HIV)-associated disorders in 72% including cytomegalovirus colitis in seven patients, idiopathic colonic ulcers in five patients, and intestinal Kaposi's sarcoma in one patient. HIV-associated thrombocytopenia contributed to substantial bleeding from hemorrhoidal disease in two patients. Rebleeding occurred in four patients (22%), including hemorrhoids in three and idiopathic colonic ulcers in one. Surgery was not performed in any patient. Following the institution of ganciclovir therapy, no patient with CMV colitis had recurrent bleeding. The in-hospital mortality was high (28%), although bleeding was the direct cause of death in only one patient.

CONCLUSIONS

LGIB is infrequent in patients with AIDS and is usually caused by opportunistic diseases specifically related to immunodeficiency. Although some of these conditions are potentially treatable medically, in-hospital mortality is high and long-term prognosis is poor because of AIDS-related comorbidity.

Definition and diagnosis of cytomegalovirus colitis in patients infected by human immunodeficiency virus

The definition and routine diagnosis of cytomegalovirus (CMV) colitis in patients infected by human immunodeficiency virus (HIV) are controversial. In 100 consecutive HIV-infected patients who underwent colonoscopy for the investigation of diarrhea, we compared the yields of routine diagnostic tools for CMV infection and assessed the risk of further CMV organ disease in subgroups of patients with the following features: full evidence of CMV colitis (group 1), colonic CMV infection but no endoscopic lesions (group 2), and no evidence of colonic CMV infection (group 3). All biopsies taken during colonoscopy were examined immediately by routine hematoxylin and eosin (H&E) staining and viral culture and then pooled for second-line H&E staining and immunohistology. Among the 15 diagnoses of CMV colitis (group 1), two were missed during initial H&E examination, and both patients developed further CMV organ disease during follow-up. Of the 12 group 2 patients 11 were not receiving anti-CMV drugs at the time of initial colonoscopy. CMV organ disease was not significantly more common in these patients than in group 3 during follow-up. We conclude that routine H&E staining of colonic biopsy specimens for CMV inclusions is not 100% sensitive for CMV colitis. The favorable outcome of colonic CMV infection without endoscopic lesions suggests that only patients with full evidence of CMV colitis warrant specific antiviral therapy.

Agents of diarrhea

Diarrhea is a common problem for AIDS patients, and is chronic and debilitating. A thorough evaluation will reveal a pathogen in the majority of patients, and the organisms most frequently identified in AIDS patients with chronic diarrhea are Cryptosporidium, microsporidia, and Mycobacterium avium complex. Bacterial pathogens are more common in AIDS patients than in the general population and may present in different ways from infections in immunocompetent hosts. Other pathogens, including Cryptosporidium and microsporidia, are difficult to diagnose and have no effective therapy. Moreover, enteric viruses and HIV itself may contribute to the diarrhea. In addition to microbes, other factors such as medication, immune dysregulation, automatic dysfunction, and nutritional supplementation play a substantial role in diarrhea of AIDS patients.

Intestinal cytomegalovirus disease in immunocompromised patients may be ruled out by search for cytomegalovirus DNA in stool samples

Cytomegalovirus (CMV) PCR from stool specimens was adopted as a diagnostic tool for patients with suspected CMV colitis. After being established, the method was evaluated in 17 AIDS patients and 19 other immunocompromised patients by comparison of PCR results with clinical, histological, and microbiological or virological data. CMV PCR was positive in 4 symptomatic patients with proven CMV colitis and negative in 15 of 16 patients without characteristic histopathology. Neither CMV immunoglobulin G seropositivity nor intestinal symptoms alone were significantly associated with positive PCR results, but severe active systemic CMV infection may lead to a positive PCR. Absence of CMV DNA in stool samples may prove useful in ruling out CMV related colitis.