Disseminated adenovirus infection in an immunocompromised host. Pitfalls in diagnosis

Adenoviral cytopathic changes in pleural fluid: A unique cytological presentation mimicking malignancy

Adenoviruses are emerging as important viral pathogens in immunocompromised patients due to immunodeficiency diseases and recently hematopoietic stem cell and solid organ transplant recipients, impacting morbidity and even mortality. Immunocompromised children are prone to respiratory infection, due to alterations in their immune system. When confronted with diseases involving the pleural effusions, such as viral infections, the diagnostic problem becomes more complex and special effort is needed to recognize and characterize them accurately and to differentiate them from other pathologies such as malignancies. However, cytology of adenoviral infection in pleural effusions has not been reported before. We report a case of an adenovirus infection of the pleural effusion which included lymphocytosis associated with background atypical cells showing a cytopathic effect (cytoplasmic viral particles). The differential diagnosis included lymphoma and infections. Immunohistochemical stain for adenovirus was positive and confirmed by molecular studies. Usually in viral infections there are cytopathic changes due to viral particles affecting epithelial cells but this case is unique as the viral particles were identified in macrophages. We discuss the significance of such infection in comparison with other viral changes indigenous to the pleural effusions, which could also occur in such specimens.

Disseminated adenovirus infection in a patient with a hematologic malignancy: a case report and literature review

Human adenoviruses cause a wide spectrum of illnesses, including invasive infections, in immunocompromised hosts. We report a case of disseminated adenovirus infection following unrelated cord–blood transplantation in a 46-year-old male with a lymphoma. A review of the literature on disseminated adenovirus infections in adult patients with hematopoietic stem cell transplantation has also been included. Despite antiviral therapy, the mortality rate in hematopoietic stem cell transplantation recipients with a disseminated adenovirus infection is as high as 72%, and estimating the risk of human adenovirus infection in a timely manner is crucial to improving outcomes.

Human adenoviruses are common viruses that cause a range of illness such as bronchitis, gastroenteritis and conjunctivitis. We recently experienced a case of disseminated adenovirus infection following hematopoietic stem cell transplantation in a patient with a lymphoma who received chemotherapy. Although disseminated adenovirus infection is not a rare disease in immunocompromised patients, it is noteworthy that its mortality remains high and it may not frequently occur. Therefore, this work provides a case presentation and a review of disseminated adenovirus infection in patients with hematopoietic stem cell transplantation in order to aid our understanding of the nature of illness of human adenovirus infections in immunocompromised patients.

Adenovirus

Adenoviruses are a highly prevalent infection that can cause a range of clinical syndromes in immunocompromised patients, ranging from localized disease of the respiratory tract, gastrointestinal tract, or urinary tract to disseminated disease. Adenovirus infections may develop in this unique population as the result of primary infection or reactivation of latent virus. Disease can be potentially progressive with high rates of mortality in patients with pneumonia and disseminated disease. Fortunately, cidofovir and its lipid ester, brincidofovir, appear to be effective for the treatment of adenovirus, although neither is specifically approved for this indication. Adenovirus should always be considered when immunocompromised patients present with any clinical syndrome that could be compatible with adenoviral infection. Once disease is suspected, cultures or molecular testing of appropriate specimens should be obtained and blood should be sent for adenovirus polymerase chain reaction (PCR) whenever adenovirus is suspected. Monitoring of quantitative viral loads in blood is helpful in predicting response to therapy with a significant drop (>1 log) associated with a higher probability of clinical response.

Clinical Features and Radiological Findings of Adenovirus Pneumonia Associated with Progression to Acute Respiratory Distress Syndrome: A Single Center Study in 19 Adult Patients

Objective

To describe radiologic findings of adenovirus pneumonia and to understand clinico-radiological features associated with progression to acute respiratory distress syndrome (ARDS) in patients with adenovirus pneumonia.

Materials and Methods

This study included 19 patients diagnosed with adenovirus pneumonia at a tertiary referral center, in the period between March 2003 and April 2015. Clinical findings were reviewed, and two radiologists assessed imaging findings by consensus. Chi-square, Fisher's exact, and Student's t tests were used for comparing patients with and without subsequent development of ARDS.

Results

Of 19 patients, nine were immunocompromised, and 10 were immunocompetent. Twelve patients (63%) progressed to ARDS, six of whom (32%) eventually died from the disease. The average time for progression to ARDS from symptom onset was 9.6 days. Initial chest radiographic findings were normal (n = 2), focal opacity (n = 9), or multifocal or diffuse opacity (n = 8). Computed tomography (CT) findings included bilateral (n = 17) or unilateral (n = 2) ground-glass opacity with consolidation (n = 14) or pleural effusion (n = 11). Patients having subsequent ARDS had a higher probability of pleural effusion and a higher total CT extent compared with the non-ARDS group (p = 0.010 and 0.007, respectively). However, there were no significant differences in clinical variables such as patient age and premorbid condition.

Conclusion

Adenovirus pneumonia demonstrates high rates of ARDS and mortality, regardless of patient age and premorbid conditions, in the tertiary care setting. Large disease extent and presence of pleural effusion on CT are factors suggestive of progression to ARDS.

Adenoviruses in immunocompromised hosts

SUMMARY

The number of patients with acquired immunodeficiency has grown steadily as a result of both a larger number of patients receiving solid organ and hematopoietic stem cell transplants and their longer survival times. The use of newer, more potent immunosuppressive regimens has increased the frequency of severe adenovirus infections. Human adenoviruses are a large group of viruses, represented by at least 52 serotypes with various genotypes divided into genomic clusters, and these may cause a broad variety of clinical manifestations. The development of molecular methods has increased the sensitivity and rapidity of adenovirus infection diagnosis. The implementation of PCR assays has significantly contributed to the identification of patients with disseminated adenovirus disease. More recently, the development of real-time PCR assays has permitted virus quantification and patient follow-up. There is no treatment for adenovirus with demonstrated efficacy, although cidofovir is widely used. Sensitive diagnostic tests for adenovirus can contribute to the early diagnosis and successful treatment of life-threatening adenovirus infections, especially in complex immunocompromised patients. The development of improved adenovirus therapy still remains a challenge. Adenovirus genetic diversity should be considered for diagnosis, typing, and therapeutic interventions.

Fatal disseminated adenoviral infection in an adult heart transplant patient

In heart transplant recipients, infection is one of the leading causes of morbidity and mortality. In adult heart transplant patients, cytomegalovirus is the most frequently encountered viral pathogen. Conversely, disseminated adenoviral infection is observed mainly in children, where it is predictive of allograft rejection and coronary vasculopathy. The literature contains only a few reports of adenoviral infections in adult heart transplant recipients. Limited information is available concerning the diagnosis and epidemiology of such infections and their relationship to organ rejection, heart failure and overall outcomes in these patients. To promote an awareness of this potentially lethal complication, we present a case of fatal disseminated adenoviral infection in an adult heart transplant recipient.

ADENOVIRUS NEPHRITIS IN HEMATOPOIETIC STEM-CELL TRANSPLANTATION

BACKGROUND

Although adenovirus (ADV) infections may involve many different organs, kidney infection is seldom reported in association with hematopoietic stem-cell transplantation (HSCT).

METHODS

In the present study, the diagnosis of ADV nephritis was established by the culture isolation of adenovirus or the immunocytochemical (ICC) demonstration of the adenoviral hexon protein. The clinical description of ADV nephritis was derived from retrospective review of clinical records to identify signs, symptoms, outcomes, and associated complications. ADV nephritis was characterized as a pathologic entity by the histologic and ICC analysis of tissue from the kidney and all other major organs to establish the distribution of the virus and the associated gross and microscopic alterations.

RESULTS

ADV nephritis was diagnosed in 21 HSCT patients, in 2 by biopsy and in 19 at autopsy. Focal signs of BK nephropathy were present in only one patient. Twenty had received allogeneic marrow and one had undergone autologous transplantation. Graft-versus-host disease was a risk factor. ADV nephritis was associated with acute renal failure in 90% of the infected patients. Prodromal symptoms included fever, hematuria, and flank pain. Adenoviruria was present in 78% of the patients. Kidney infection as determined by viral antigen ICC predominantly involved the tubular epithelial cells. ADV organ tropism was striking, with sero-types from subgenus B, cluster 2, primarily responsible for cases involving predominantly the urinary system. ADV infection was a major cause of death in 17 patients.

CONCLUSIONS

ADV nephritis is a specific renal complication in HSCT patients that can be diagnosed by renal biopsy in patients with hematuria and adenoviruria.

MxA expression in patients with viral infection after allogeneic stem cell transplantation

Many patients suffer febrile diseases soon after allogeneic stem cell transplantation (SCT). Some of the symptoms of viral infections and acute GVHD are often difficult to distinguish. However, an accurate diagnosis is important since the treatments for these conditions are different. It is known that MxA protein is specifically induced in patients with several viral infections. We investigated the cytoplasmic expression of MxA in the peripheral blood mononuclear cells (PBMCs) of patients with fever after allogeneic SCT using a newly generated monoclonal antibody (KM1135) and flow cytometry. The level of MxA expression was significantly higher in patients diagnosed with viral infections (n=6, cytomegalovirus in three, Epstein-Barr virus in one, human herpesvirus-6 in one, adenovirus in one) than control individuals (n=9) (P<0.05, Mann-Whitney test). The level of MxA in patients with aGVHD (n=7) was identical to that in controls. The level of MxA correlated well with the amount of the cytomegalovirus antigen-positive cells in the presence of acute GVHD in two patients. The measurement of MxA is simple and useful in distinguishing viral disease from acute GVHD after allogeneic SCT.

Adenovirus infections in adult recipients of blood and marrow transplants

Adenoviruses are increasingly recognized pathogens that affect blood and marrow transplant (BMT) recipients. Experiences with 2889 adult BMT recipients were reviewed to study the incidence, clinical spectrum, risk factors for dissemination, response to therapy, and outcome of adenovirus infections. Eight-five patients (3%) were diagnosed by means of culture (n=85) or culture and histopathological examination (n=6). Nine patients had asymptomatic viruria, and 76 had symptomatic infections, which included upper respiratory tract infection (n=20), enteritis (n=18), hemorrhagic cystitis (n=10), pneumonia (n=15), and disseminated disease (n=13). The overall mortality rate was 26%. A higher mortality rate was observed among patients with pneumonia (73%) and disseminated disease (61%). Risk factors for dissemination included receipt of an allogeneic transplant, presence of graft-versus-host disease (GVHD), and receipt of concurrent immunosuppressive therapy. Intravenous ribavirin was not associated with an appreciable benefit among 12 patients who received this treatment. In conclusion, adenovirus infections are an important cause of morbidity and mortality in adult BMT recipients, particularly allogeneic transplant recipients with GVHD who are receiving immunosuppressive therapy. The need for an effective, nontoxic antiviral therapy is apparent.

PCR detection of adenovirus in a bone marrow transplant recipient: hemorrhagic cystitis as a presenting manifestation of disseminated disease

Adenoviruses (AdV), causing fatal disseminated infections in bone marrow transplant (BMT) recipients, are associated not only with hemorrhagic cystitis (HC) but also with hepatitis, conjunctivitis, and viral interstitial pneumonia. The importance of this virus as a cause of disseminated disease, however, has remained underappreciated. AdV infection has been diagnosed primarily through the use of cell culture. The fact that cell culture is insensitive for detecting this virus has hindered recognition of the role that AdV may play in morbidity and mortality in BMT recipients. To emphasize these points, we describe a patient who presented with HC due to AdV serotype 11, genotype c, and died with disseminated infection. In addition to cell culture, this study used a newly developed PCR-based method, capable of detecting all AdV serotypes tested, including different genotypes of serotype 11. The PCR result was positive in all culture-positive samples, including samples of urine, conjunctiva, and bronchoalveolar lavage (BAL). Importantly, the PCR method provided evidence of urinary shedding of AdV in a pretransplant, culture-negative specimen and showed dissemination in a subset of culture-negative specimens, including BAL, blood, and bone marrow samples. The lack of widespread awareness of the fact that localized infections may presage dissemination, and the previous associated lack of rapid, sensitive diagnostic assays, has impaired recognition of AdV infections in patients undergoing BMT. Early detection may contribute to therapy modification and avoidance of unwarranted diagnostic procedures. It may also assist in epidemiologic control of this highly infectious pathogen and lead to a renewed interest in preventive and therapeutic approaches.

Adenovirus colitis in human immunodeficiency virus infection: an underdiagnosed entity

Adenovirus infection of the gastrointestinal tract in human immunodeficiency virus (HIV)-infected patients is rarely reported, probably because of a lack of familiarity of most pathologists with diagnostic criteria during routine light microscopy and possible misidentification as cytomegalovirus infection. We studied colonoscopic biopsy specimens from 135 HIV-infected patients with clinically suspected cytomegalovirus colitis during a 4.5-year period to morphologically identify the presence of adenovirus infection. Immunohistochemical staining for adenovirus was performed for confirmation on all suspected cases. Adenovirus infected cells showed characteristic amphophilic or eosinophilic nuclear inclusions, predominantly affecting the surface epithelium and characteristically involving goblet cells. Sixteen cases showed morphologic features of adenovirus infection, all confirmed by immunohistochemistry. Twelve cases also showed cytomegalovirus infection, whereas 4 showed adenovirus alone. In 10 cases, adenovirus colitis was not recognized during initial routine histopathologic diagnostic evaluation. Adenovirus inclusions also were discovered in the stomach, the duodenum, and the liver in single cases. Conclusions are as follows: (1) Adenovirus colitis has been underdiagnosed at our institution and, we suspect, in general. (2) The morphologic features and nuclear inclusions of adenovirus colitis are characteristic and can be identified reliably by routine light microscopy. (3) Adenovirus infection also may be diagnosed morphologically in extracolonic sites, such as the stomach, the small intestine, and the liver. (4) Coinfection of adenovirus with cytomegalovirus and other agents is seen frequently, but, less frequently, adenovirus may be identified as a sole pathogen.

Acute and chronic human adenovirus pneumonia: cellular and extracellular matrix components

We present a comparative histopathological study of both acute and chronic human adenovirus pneumonia, with reference to the cellular and extracellular matrix components. Seventeen lungs from autopsied patients whose ages ranged from 2 to 60 months were studied. Adenovirus types 1, 2, 3, 5, and 7 were isolated from 15 patients with acute lung disease, and types 2 and 7 were isolated from the other two patients with chronic pulmonary illness. The results indicated the occurrence of two basic patterns of adenovirus interstitial pneumonia (1) classic pattern (acute), characterized by necrosis and degeneration and many type II pneumocytes with intranuclear inclusion bodies, which were positive for adenovirus DNA by in situ hybridization, and (2) proliferative or proliferative-productive pattern (chronic), which presented with diffuse pulmonary fibrosis and the interstitial proliferation of fibroblast-like cells, compatible with myofibroblasts (positive for vimentin and alpha smooth muscle actin), and increase in collagen types I and III, elastic fibers, and proteoglycans. Alveolar collapse appears to be an important pathogenetic mechanism in the development of this pattern.

Fatal adenovirus 32 infection in a bone marrow transplant recipient

A case of disseminated adenovirus type 32 infection causing severe hepatitis, gastrointestinal ulceration and also with respiratory involvement is reported in a bone marrow transplant recipient. Typical viral inclusions were seen in the postmortem histological sections and adenovirus infection was confirmed using in situ hybridisation and isolation of adenovirus type 32 from separate organs at necropsy. This is the first case in which adenovirus 32 was the cause of fatal disseminated disease in a bone marrow transplant recipient.

Adenovirus pulmonary infections identified by PCR and in situ hybridisation in bone marrow transplant recipients

AIMS

To investigate adenovirus pulmonary infections in bone marrow transplant (BMT) recipients.

METHODS

Formalin fixed, paraffin wax embedded lung tissue was examined from 13 necropsy cases after BMT using PCR and in situ hybridisation to detect adenovirus DNA. The E1A region of the adenoviral genome was targeted for PCR. In situ hybridisation was performed only in the PCR positive cases.

RESULTS

Of the 13 lung specimens analysed, nine cases were negative for adenoviral nucleic acid. Four (30%) PCR and two (15%) in situ hybridisation positive cases were found. In some of the patients there were clinical and pathological indications that some diseases might be associated with adenovirus infection--haemorrhagic cystitis (three cases); necrotising pneumonia (one case). In necrotising pneumonia in which no pathogenic agents had been shown by conventional histological study, the in situ hybridisation technique showed positive staining for adenovirus. In a patient who died of renal failure caused by adenovirus nephritis, both PCR and in situ hybridisation were positive in the lung as well as in the kidney, although no histological change was found. Two PCR positive cases lacked positive sites for adenovirus by in situ hybridisation.

CONCLUSIONS

The combination of PCR and in situ hybridisation could be useful for diagnosing adenovirus infection of the lung in BMT recipients. These results provide a basis for exploring further the clinical use of PCR and in situ hybridisation to diagnose adenovirus infection.

Multiple viral infections in the immunocompromised host: recognition and interpretation

BACKGROUND

During the past decade, diagnostic virology has become an integral part of patient management. Concurrent infection with multiple viruses occurs in both the healthy and immunocompromised host. Many common viruses result in latent infection with the potential for reactivation throughout the life of the host. Superimposed on this are transient infections with yet other viruses.

OBJECTIVES

To review multiple viral infections in immunocompromised hosts, focusing on laboratory recognition and interpretation of results.

STUDY DESIGN

A review of the literature, with case examples from the author's laboratory.

RESULTS

Viral infections are more likely to cause morbidity and mortality in immunodeficient hosts, and early recognition and treatment may be lifesaving. To detect two or more viruses shed concurrently from the same body site requires the use of multiple test modalities, which are now available in many clinical laboratories. Establishing the significance of a virus isolate is a complex process. Knowledge of the specimen source, virus quantitation and characteristics of the patient are helpful. Careful evaluation of the patient's clinical findings together with other laboratory test results, including histopathology, X-rays and the detection of other microorganisms, is also essential.

CONCLUSIONS

The recognition and interpretation of multiple virus infections requires heightened awareness as well as close cooperation and communication between the professionals in the laboratory and physicians at the bedside.

Cytokines in adenoviral disease in children: association of interleukin-6, interleukin-8, and tumor necrosis factor alpha levels with clinical outcome

To explore the pathogenic mechanisms involved in adenovirus infection, we evaluated total levels of immunoglobulins, antiadenovirus antibodies, adenovirus-specific circulating immune complexes, and cytokines in serum samples obtained from 38 hospitalized children with adenovirus infection. According to their clinical findings and outcome, the infections were classified as follows: (1) moderate (group I, n = 10), (2) severe (group II, n = 12), and (3) fatal (group III, n = 16). About 60% of the children had elevated IgM levels. IgG-containing adenovirus-specific circulating immune complexes were initially detected in 7 of 16 group III patients, 4 of whom had low serum levels of the third component of complement. A decrease in initial antiadenovirus IgG antibodies was observed in 3 of 10 patients in group III. Serum interleukin-6 was not detected in group I (none of 10), but was present in group II (7 of 12, p = 0.016) and group III (13 of 16, p < 0.001). Interleukin-8 was detected in all groups; values in fatal cases were significantly higher than in surviving children. Tumor necrosis factor alpha was not observed in group I (none of 10) and was uncommon in group II (2 of 12) but was frequently detected in group III (9 of 15, p = 0.01). Interleukin-1 and interleukin-4 were rarely detected in serum samples. Increased concentrations of interleukin-6, interleukin-8, and tumor necrosis factor alpha were associated with hypoperfusion, febrile peaks, tonic-clonic seizures, and septic shock. In 5 of 10 patients in groups II and III, autoantibodies specific for smooth muscle were found. Our findings indicate that high serum values for interleukin-6, interleukin-8, and tumor necrosis factor alpha are associated with severity of adenovirus infection.

Disseminated adenoviral infection presenting as acute pancreatitis

Adenoviruses are gradually being recognized as a significant source of morbidity and mortality in the immunocompromised patient population. We report a bone marrow transplant patient who developed severe abdominal pain accompanied by marked elevations in serum pancreatic and hepatic enzyme levels. She died shortly thereafter. Autopsy revealed hemorrhagic pancreatitis and fulminant hepatic necrosis. Both the pancreas and liver contained intranuclear inclusions consistent with adenovirus; electron microscopy confirmed that there were, indeed, adenoviral particles. This report of adenoviral pancreatitis emphasizes the diversity of manifestations seen with adenoviral infection.

In situ hybridization and immunohistochemical analysis of cytomegalovirus-associated ileal perforation

A patient with the acquired immunodeficiency syndrome (AIDS) with a cytomegalovirus (CMV) infection localized in the area of an ileal Kaposi sarcoma resulting in perforation is described. Because only one case of such an association of Kaposi sarcoma with CMV leading to perforation has been reported, the presence and distribution of CMV-related nucleic acids and proteins in the affected segment of intestine were evaluated. By using in situ hybridization and immunocytochemical analyses the presence of CMV was shown within epithelial, endothelial, smooth muscle, and inflammatory cells at the site of perforation. This study not only confirmed that CMV can be detected in virtually all components of the intestinal wall despite the absence of distinctive cytomegalic changes, but also generated critical information that illustrates the usefulness of immunohistochemistry and in situ hybridization in elucidating the pathogenesis of CMV-associated lesions. These findings lend further support to the concept that CMV plays a pivotal role in the pathogenesis of intestinal perforation and emphasize the critical importance of in situ hybridization in gaining insight into the mechanisms of CMV-induced injury.

Participation of immune complexes in adenovirus infection

To determine the participation of immune complexes during adenovirus infection, we evaluated serum and necropsy specimens of patients with confirmed adenovirus infection of the lower respiratory tract. In lung and kidney from seven dead patients, immunofluorescence revealed the presence of hexon, immunoglobulins and complement. These patients had clinical manifestations of kidney dysfunction. In dead patients (3/3 in whom serum was available) neither anti-adenovirus antibodies nor adenovirus-specific immune complexes could be found in the final stage of the infection. However, two of these patients had anti-adenovirus antibodies and immune complexes in samples obtained early in the infection. Most patients (16/19) who survived the infection had circulating anti-adenovirus antibodies. Half also had immune complexes specific for adenovirus in some moment of the illness. This suggests that immune complexes arise during respiratory infection by adenovirus, probably contributing to its clinical picture.

Adenovirus infection of the large bowel in HIV positive patients

AIMS

To describe the microscopic appearance of adenovirus infection in the large bowel of human immunodeficiency virus (HIV) positive patients with diarrhoea.

METHODS

Large bowel biopsy specimens from 10 HIV positive patients, eight of whom were also infected with other gastrointestinal pathogens, with diarrhoea were examined, together with six small bowel biopsy specimens from the same group of patients. Eight of the patients had AIDS. The biopsy specimens were examined by light microscopy performed on haematoxylin and eosin stained and immunoperoxidase preparations, the latter using a commercially available antibody (Serotec MCA 489). Confirmation was obtained with electron microscopy.

RESULTS

The morphological appearance of cells infected with adenovirus showed characteristic nuclear and cellular changes, although the inflammatory reaction was non-specific. Immunoperoxidase staining for adenovirus was sensitive and specific, and the presence of viral inclusions consistent with adenovirus was confirmed by electron microscopy.

CONCLUSIONS

The light microscopic features of adenovirus infection are distinctive and immunocytochemistry with a commercially available antibody is a sensitive and specific means of confirming the diagnosis. Further studies of the role of adenovirus in causing diarrhoea in these patients are indicated.

Adenoviruses in the immunocompromised host

Adenoviruses are among the many pathogens and opportunistic agents that cause serious infection in the congenitally immunocompromised, in patients undergoing immunosuppressive treatment for organ and tissue transplants and for cancers, and in human immunodeficiency virus-infected patients. Adenovirus infections in these patients tend to become disseminated and severe, and the serotypes involved are clustered according to the age of the patient and the nature of the immunosuppression. Over 300 adenovirus infections in immunocompromised patients, with an overall case fatality rate of 48%, are reviewed in this paper. Children with severe combined immunodeficiency syndrome and other primary immunodeficiencies are exposed to the serotypes of subgroups B and C that commonly infect young children, and thus their infections are due to types 1 to 7 and 31 of subgenus A. Children with bone marrow and liver transplants often have lung and liver adenovirus infections that are due to an expanded set of subgenus A, B, C, and E serotypes. Adults with kidney transplants have viruses of subgenus B, mostly types 11, 34, and 35, which cause cystitis. This review indicates that 11% of transplant recipients become infected with adenoviruses, with case fatality rates from 60% for bone marrow transplant patients to 18% for renal transplant patients. Patients with AIDS become infected with a diversity of serotypes of all subgenera because their adult age and life-style expose them to many adenoviruses, possibly resulting in antigenically intermediate strains that are not found elsewhere. Interestingly, isolates from the urine of AIDS patients are generally of subgenus B and comprise types 11, 21, 34, 35, and intermediate strains of these types, whereas isolates from stool are of subgenus D and comprise many rare, new, and intermediate strains that are untypeable for practical purposes. It has been estimated that adenoviruses cause active infection in 12% of AIDS patients and that 45% of these infections terminate in death within 2 months. In all immunocompromised patients, generalized illness involving the central nervous system, respiratory system, hepatitis, and gastroenteritis usually have a fulminant course and result in death. Treatments for adenovirus infections are of little proven value, although certain purine and pyrimidine analogs have shown beneficial effects in vitro and may be promising drugs.

Necrotizing tubulointerstitial nephritis associated with adenovirus infection

We report 10 autopsy cases of necrotizing tubulointerstitial nephritis induced by adenovirus (ADV). Hemorrhagic, necrotizing tubulitis with intranuclear inclusion bodies was observed in the kidneys of five bone marrow transplant recipients and five patients treated with intensive chemotherapy for malignancies (four cases of leukemia and one case of lung cancer). It was histopathologically demonstrated that necrobiotic tubular cells had inclusion-bearing cells of three types: "smudge cells," Cowdry A intranuclear inclusion cells, and full-type intranuclear-containing cells. Immunofluorescent examination with anti-ADV antibody demonstrated specific fluorescence on the affected tubular cells of all 10 kidneys. Specific antigens for ADV type 11 were also revealed in all but one case by an immunofluorescent test using type-specific antiserum and convalescent serum containing high titer antibody to this serotype. Electron microscopy revealed intranuclear crystalline arrays of viral particles, 75 to 80 nm in diameter, in each of the seven cases examined. Extrarenal involvement, indicated by ADV-induced cytopathologic change, was confined to bladder or prostate. Hemorrhagic cystitis was recorded in all the bone marrow transplant cases as well as in one leukemia case. Adenovirus type 11 was isolated from urine in all five cases tested during these episodes. Renal failure was ascribed to ADV infection in two of five patients who died from renal dysfunction. The presence of hemorrhagic cystitis and localization of invasive infection in urogenital organs suggested that renal infection might occur by ascending route from the bladder. We propose that ADV should be added as a viral agent to the pathogenetic list of tubulointerstitial nephritis.

Adenovirus colitis in the acquired immunodeficiency syndrome

Adenovirus was identified in colonic tissue by transmission electron microscopy or culture in 5 of 67 (7.4%) homosexual men seropositive for human immunodeficiency virus (51 with the acquired immunodeficiency syndrome) with diarrhea. Colonoscopy showed the mucosa to be normal in 3 cases and mildly inflamed in 2. Light microscopy showed foci of mucosal necrosis that contained chronic inflammatory cells and degenerating and necrotic epithelial cells with amphophilic nuclear inclusions. By transmission electron microscopy, hexagonal viral particles characteristic of adenovirus were identified within the inclusions. Only 1 patient was concomitantly infected by a second potential enteric pathogen. It was concluded that adenovirus, an uncommon enteric pathogen in immunocompetent adults, causes intestinal pathology and may be associated with diarrheal illness in persons with the acquired immunodeficiency syndrome.

Nucleic acid hybridization in viral diagnosis

Since 1982, numerous studies have been published utilizing a variety of hybridization techniques to detect viral nucleic acid directly in clinical specimens and in tissue sections. However, hybridization techniques are still not widely used in the clinical laboratory. Other recent advances, such as the development of monoclonal antibodies for virus identification and ELISA kits for virus detection, and the introduction of centrifugation cultures for rapid diagnosis, have postponed the clinical application of hybridization techniques. Furthermore, the use of hybridization for diagnosis has been limited by its insensitivity when compared to cell culture, the need for radioisotopes to increase sensitivity, and the difficulties inherent in transferring a basic research tool to the clinical laboratory. Nevertheless, with recently developed amplification techniques and further advances in nonradioactive labelling of probes, it can be expected that nucleic acid hybridization will be an established technique in diagnostic laboratories in the near future.

Enzyme linked immunosorbent assay: determination of anti-adenovirus antibodies in an infant population

In order to define an accurate assay for anti-adenovirus antibody detection, a recently developed ELISA was compared with IFA and CF. On 58 sera, the ELISA was more sensitive than both CF and IFA, which showed relative sensitivities of 63% and 94%, respectively. It was not possible to determine the exact specificity of the tests because of the lack of a gold standard. Furthermore, the ELISA was used to define the prevalence of adenovirus antibodies in 116 infants between 1 and 24 months old (mean 7.28). The data showed that maternal antibodies waned by the age of 5 to 6 months and that more than 80% of the children had been infected by adenoviruses by the age of 10 months.

Evaluation of immunofluorescent reagents, centrifugation, and conventional cultures for the diagnosis of adenovirus infection

In this study we have evaluated four fluorescent antibody reagents, three monoclonal and one polyclonal, for identification of adenovirus isolates and compared four conventional cultures (human embryonic kidney, A549, HEp-2, and MRC-5 cells) with centrifugation culture for rapid diagnosis. For identification of adenovirus isolates by immunofluorescence, CDC reagent and Adenoclone, both monoclonal antibodies to the hexon group-reactive antigen, were more sensitive and easier to interpret than the other two reagents tested. HEK and A549 cells were the most sensitive for isolation of adenovirus. Although A549 cells were an inexpensive alternative to HEK, A549 cell monolayers deteriorated more rapidly and passages were more often required. Centrifugation cultures with A549 cells detected 77% of positives within 2 days and 100% within 5 days, whereas isolation in conventional culture required up to 10 days for HEK and up to 20 days for MRC-5 cells.