Polymicrobial cholangitis and Kaposi's sarcoma in blood product transfusion-related acquired immune deficiency syndrome

Host cell actin remodeling in response to Cryptosporidium

Cryptosporidium exhibits a complex strategy to invade and establish productive infection sites, involving complimentary parasite and host cell processes. While the work regarding host cell actin remodeling has greatly enhanced our understanding of the molecular pathways involved in the parasite induced actin reorganization, the specific function of host cell actin remodeling is still equivocal. We contend that host cell actin polymerization contributes to the development of productive C. parvum infection sites by generating membrane protrusion events, which may assist in the retention of the parasite at the apical surface within the unique extracytoplasmic niche. With our current understanding of the molecular pathways initiating actin remodeling upon C. parvum interactions with host cells, the next logical step is to determine the upstream events resulting in PI3K activation and the specific role of actin remodeling in parasite development, a process that may have implications beyond host-pathogen interactions.

Transmission of human herpesvirus 8 by blood transfusion

BACKGROUND

Whether human herpesvirus 8 (HHV-8) is transmissible by blood transfusion remains undetermined. We evaluated the risk of HHV-8 transmission by blood transfusion in Uganda, where HHV-8 is endemic.

METHODS

We enrolled patients in Kampala, Uganda, who had received blood transfusions between December 2000 and October 2001. Pretransfusion and multiple post-transfusion blood specimens from up to nine visits over a 6-month period were tested for HHV-8 antibody. We calculated the excess risk of seroconversion over time among recipients of HHV-8-seropositive blood as compared with recipients of seronegative blood.

RESULTS

Of the 1811 transfusion recipients enrolled, 991 were HHV-8-seronegative before transfusion and completed the requisite follow-up, 43% of whom received HHV-8-seropositive blood and 57% of whom received seronegative blood. HHV-8 seroconversion occurred in 41 of the 991 recipients. The risk of seroconversion was significantly higher among recipients of HHV-8-seropositive blood than among recipients of seronegative blood (excess risk, 2.8%; P<0.05), and the increase in risk was seen mainly among patients in whom seroconversion occurred 3 to 10 weeks after transfusion (excess risk, 2.7%; P=0.005), a result consistent with the transmission of the virus by transfusion. Blood units stored for up to 4 days were more often associated with seroconversion than those stored for more than 4 days (excess risk, 4.2%; P<0.05).

CONCLUSIONS

This study provides strong evidence that HHV-8 is transmitted by blood transfusion. The risk may be diminished as the period of blood storage increases.

Cryptosporidium parvum activates nuclear factor kappaB in biliary epithelia preventing epithelial cell apoptosis

BACKGROUND & AIMS

Our previous studies have shown that Cryptosporidium parvum induces biliary epithelial cell apoptosis in vivo and causes apoptosis in bystander uninfected biliary epithelia in vitro. We analyzed C. parvum-induced nuclear factor kappa B (NF-kappaB) activation in human biliary epithelial cells and assessed its relevance to epithelial cell apoptosis.

METHODS

In vitro models of cryptosporidial infection using a human biliary epithelial cell line were used to assay C. parvum- induced NF-kappaB activation and associated apoptosis.

RESULTS

Degradation of I(kappa)B and nuclear translocation of the NF-kappaB family of proteins (p65 and p50) were observed in the biliary epithelial cell cultures directly exposed to the parasite. Activation of NF-kappaB was found only in directly infected cells (but not in bystander uninfected cells). A time-dependent secretion of a known NF-kappaB gene product, interleukin 8, from infected cell cultures was detected. C. parvum-induced biliary epithelial cell apoptosis was limited to bystander uninfected cells. In contrast, inhibition of NF-kappaB activation resulted in apoptosis in directly infected cells and significantly enhanced C. parvum-induced apoptosis in bystander uninfected cells.

CONCLUSIONS

These observations support the concept that, while C. parvum triggers host cell apoptosis in bystander uninfected biliary epithelial cells, which may limit spread of the infection, it directly activates the NF-kappaB/I(kappa)B system in infected biliary epithelia thus protecting infected cells from death and facilitating parasite survival and propagation.

Mechanisms of attachment and internalization of Cryptosporidium parvum to biliary and intestinal epithelial cells

BACKGROUND & AIMS

Although infection of the intestinal and biliary tracts by Cryptosporidium parvum is a major problem in patients with the acquired immunodeficiency syndrome, the specific microbial and host molecules involved in C. parvum infection are unknown. We tested the hypothesis that lectin-carbohydrate interactions and cytoskeleton reorganization are involved in the infection of biliary and intestinal epithelia by C. parvum.

METHODS

In vitro models of cryptosporidial infection using human biliary and intestinal epithelial cell lines were used to assay C. parvum attachment and invasion.

RESULTS

Exposure of C. parvum sporozoites to the sugar, galactose-N-acetylgalactosamine (Gal/GalNAc), and to bovine mucin reduced C. parvum attachment to biliary and intestinal epithelia up to 70%. Preincubation of cell monolayers with either lectins specific to Gal/GalNAc, or glycosidases that specifically release Gal/GalNAc oligosaccharides from glycoproteins, decreased attachment up to 80%. Cytochalasin B and cytochalasin D, but not nocodazole, decreased invasion of cells by C. parvum up to 70% without affecting attachment. During cell invasion (but not attachment), confocal microscopy showed recruitment of actin (but not tubulin) in biliary and intestinal epithelia directly adjacent to C. parvum.

CONCLUSIONS

Gal/GalNAc epitopes of glycoproteins on the epithelial apical membrane and Gal/GalNAc-specific sporozoite surface lectins are involved in the mechanism(s) of C. parvum attachment to intestinal and biliary epithelial cells, and actin remodeling in host cells is required for C. parvum invasion.

Cryptosporidium parvum is cytopathic for cultured human biliary epithelia via an apoptotic mechanism

While the clinical features of sclerosing cholangitis secondary to opportunistic infections of the biliary tree in patients with acquired immunodeficiency syndrome (AIDS) are well known, the mechanisms by which microbial pathogens such as Cryptosporidium parvum associated with this syndrome actually cause disease are obscure. We established an in vitro model of biliary cryptosporidiosis employing a human biliary epithelial cell line. Using morphological and biochemical techniques, we examined the interaction of C. parvum with cultured human cholangiocytes. When the apical plasma membrane of polarized, confluent monolayers of human biliary epithelial cells was exposed to C. parvum oocysts that had been excysted in vitro, sporozoites attached to and invaded the cells in a time-, dose-, temperature-, and pH-dependent manner. The infectious process was both plasma membrane domain- and cell-specific, because no attachment or invasion occurred when the basolateral membrane of cholangiocytes was exposed to the parasite, or when a human hepatocyte cell line (HepG2) was used. Time-lapse video microscopy and scanning electron microscopy (SEM) showed that sporozoite attachment was rapid, involved extensive cholangiocyte membrane ruffling, and culminated in parasite penetration into a tight-fitting vacuole formed by invagination of the plasma membrane similar to those found in naturally occurring infection in vivo. Transmission electron microscopy (TEM) showed that C. parvum organisms formed parasitophorus vacuoles and were able to undergo a complete reproductive cycle, forming both asexual and sexual reproductive stages. Unexpectedly, direct cytopathic effects were noted in infected monolayers, with widespread programmed cell death (i.e., apoptosis) of biliary epithelial cells as assessed both morphologically and biochemically beginning within hours after exposure to the organism. The novel finding of specific cytopathic invasion of biliary epithelia by C. parvum may be relevant to the pathogenesis and possible therapy of the secondary sclerosing cholangitis seen in AIDS patients with biliary cryptosporidiosis.

Surgical therapy for 101 patients with acquired immunodeficiency syndrome and symptomatic cholecystitis

BACKGROUND

Hepatobiliary disease in patients with acquired immunodeficiency syndrome (AIDS) has been well documented. Cytomegalovirus and Cryptosporidium are the pathogens most frequently associated. Previous reports of cholecystectomies and AIDS have had conflicting results on morbidity and mortality.

METHOD

Retrospective review of 101 patients with AIDS and symptomatic cholecystitis who underwent cholecystectomy from December 1989 to May 1995.

RESULTS

All patients had symptoms characteristic of gallbladder disease, the most common being abdominal pain and fever. Thickening of the gallbladder was the most common diagnostic finding. Fifty-six patients underwent open cholecystectomy and 45 laparoscopic cholecystectomy. Pathologic examination revealed an abnormal gallbladder in all cases and gallstones in 29%. A specific pathogen or malignancy was identified as the etiologic agent in 44% of patients. Perioperative morbidity was similar (<5%) in both surgical groups. Perioperative mortality was 4% among all the patients treated.

CONCLUSIONS

Both open and laparoscopic cholecystectomy improved the quality of life of these patients and should be considered as the treatment for persistent hepatobiliary symptoms in patients with AIDS.

The pancreas in AIDS

Although autopsy studies reveal significant pancreatic lesions in about 10% of AIDS patients, pancreatic lesions infrequently produce symptoms and are rarely recognized premortem. Patients with AIDS can develop pancreatic disease from causes not related to AIDS or AIDS-specific lesions. AIDS-specific causes include opportunistic infection, AIDS-associated neoplasia, and medications used to treat complications of AIDS. Pancreatic involvement is usually part of a widely disseminated tumor and rarely produces clinical symptoms.

AIDS-related cholangitis: diagnostic features and course in 15 patients

About 60 cases of cholangitis in patients with the acquired immune deficiency syndrome (AIDS) have been described. We report our experience concerning 15 patients infected with the human immunodeficiency virus (HIV) and who had cholangitis as defined by radiological findings. Cholangitis was the revealing event of AIDS or HIV infection in 4 patients (27%). Twelve (80%) of the patients were homosexual men. The main diagnostic features were abdominal pain (73%), cholestasis without jaundice (100%), intestinal cryptosporidiosis (80%) and abnormal findings on abdominal ultrasonography (87%). Endoscopic retrograde cholangiopancreatography appears to be essential for diagnostic and therapeutic purposes, particularly for patients with papillary stenosis who represented 64% of our population. Biological and morphological pancreatic abnormalities were associated in 2 of the 8 patients who underwent retrograde opacification of the Wirsung duct. The microbiological yield was highest in patients who underwent multiple biopsies (duodenal and papillary) and bile sampling. The organisms found included Cryptosporidium (57%) of cases), CMV (28%) and Microsporidia (7%). Twelve-month survival after the diagnosis of cholangitis was only 14% and all deaths were related to AIDS progression. Endoscopic sphincterotomy relieved abdominal pain in 86% of the patients who underwent the procedure. Evaluation of medical treatment, particularly ursodeoxycholic acid, is necessary.

Cryptosporidiosis in the acquired immunodeficiency syndrome: a study of 15 autopsy cases

The pathologic changes associated with human cryptosporidiosis have not been well characterized. In this report, 15 cases of cryptosporidiosis in acquired immunodeficiency syndrome patients are described. Organisms were found in autopsy tissue specimens in 13 cases, and only in antemortem stool samples in two. Gastrointestinal/hepatobiliary distribution of organisms was as follows: small intestine (13 cases), extrahepatic bile ducts (eight), intrahepatic bile ducts (seven), large intestine (six), pancreas (five), stomach (three), and esophagus (one). At all sites, infection was usually associated with nonspecific reactive epithelial changes, architectural abnormalities such as villous flattening in the small intestine, and interstitial edema with mixed inflammatory cell infiltrates. Presence of organisms and associated mucosal injury were patchy and of variable severity in the intestine. In the biliary tract, injury was commonly diffuse and severe. Pancreatic duct injury was generally mild and often limited to hyperplastic squamous metaplasia. In late-stage acquired immunodeficiency syndrome patients with cryptosporidiosis, widespread infection in the gastrointestinal and biliary systems by this coccidian was more common and severe than previously suggested. Although the mechanisms have yet to be determined, infection usually is accompanied by pathologic changes that may be causally related to pathophysiologic abnormalities, such as diarrhea and malabsorption, and may account for other clinical manifestations of pancreatitis, cholangitis, and obstructive cholestasis.

Aggressive Kaposi's sarcoma and campylobacter bacteremia in a female with transfusion associated AIDS

The vast majority of patients with Kaposi's sarcoma (KS) of the epidemic, endemic or sporadic variety are men. Although 35 percent of men with AIDS will develop KS, only three percent of women will develop this malignancy. To date, a single case report of transfusion associated KS in an HIV-infected female has been described in the medical literature. We report a second case. A 54-year-old HIV-infected female without other identifiable risk factors for AIDS developed disseminated KS six years after a blood transfusion. Her illness was marked by rapidly proliferating tumors not responsive to a single course of chemotherapy. Another unusual aspect of this case is that, in conjunction with weight loss and diarrhea, Campylobactercinaedi was recovered from her blood. This enteric pathogen has previously been described exclusively in homosexual men. Autopsy studies showed KS tumors involving all major visceral organs. This case report demonstrates that in HIV-infected females KS may follow an aggressive course similar to that seen occasionally in male KS patients with profound immunosuppression.

Empyema of the gallbladder in a patient with AIDS-related complex

A case of staphylococcus aureus empyema of the gallbladder in a patient with AIDS-related complex is presented. The case is remarkable for the indolence of the clinical presentation and the magnitude of gallbladder dilatation noted at computed tomographic (CT) examination. Empyema of the gallbladder may constitute an unusual manifestation of bacterial disease in patients with AIDS or AIDS-related complex and cholelithiasis.

Sonographic diagnosis of cholangitis in AIDS patients

Eleven acquired immunodeficiency syndrome (AIDS) patients were initially evaluated by ultrasound of the liver because of biochemical evidence of cholestasis. Sonography was very useful for demonstrating dilatation and/or wall thickening of the common bile duct associated with dilated intrahepatic bile ducts. Periportal hypo- or hyperchoic areas were also visualized. In seven patients, gallbladder walls were thickened. In six patients, the diagnosis of cholangitis was confirmed by endoscopic retrograde cholangiography and/or histology. Cytomegalovirus infection or digestive tract cryptosporidiosis were often present and accounted for diarrhea in most patients. We believe the association of upper right quadrant pain and anicteric cholestasis in the course of AIDS is suggestive of cholangitis, but a disparity may exist between mild symptoms and sonographically demonstrated extensive biliary involvement.

Sclerosing cholangitis in acquired immunodeficiency syndrome. Case reports and review of the literature

Four patients with acquired immunodeficiency syndrome (AIDS) (CDC group IV) were investigated for biliary disease because of the presence of both severe upper abdominal pain and raised levels of serum alkaline phosphatase. None was clinically jaundiced. Upper abdominal ultrasound was abnormal in three. All had endoscopic retrograde cholangiographic evidence of both an intrahepatic sclerosing cholangitis suggestive of primary sclerosing cholangitis and an irregular suprapapillary common bile duct dilation suggestive of papillary stenosis. Three had evidence of gastrointestinal cryptosporidiosis and two of disseminated cytomegalovirus infection. Endoscopic sphincterotomy, performed in two patients, gave good pain relief. We propose the name 'AIDS sclerosing cholangitis' for this form of secondary cholangitis. The cause of this disorder remains unclear. Recent evidence is discussed which suggests that it is not due to HIV itself but to an opportunistic infection. Cryptosporidium appears to be the most likely candidate.

Cholangitis in the acquired immunodeficiency syndrome: report of two cases and review of the literature

We report the cases of one patient with the acquired immunodeficiency syndrome as a result of human immunodeficiency virus type 1/lymphadenopathy associated virus type 1/human T-cell lymphotrophic virus type III (HIV-1/LAV-1/HTLV-III) infection and of another patient with AIDS related complex caused by human immunodeficiency virus type 2/lymphadenopathy associated virus type 2 (HIV-2/LAV-2) infection, who were suffering from cholangitis. The manifestations and possible mechanisms for cholangitis in these patients and in 10 previously reported similar cases are reviewed.