Staining qualities of cytomegalovirus inclusions in the lungs of patients with the acquired immunodeficiency syndrome: a potential source of diagnostic misinterpretation

Aberrant staining with Grocott's methenamine silver: utility beyond fungal organisms

INTRODUCTION

Historically, Grocott's methenamine silver (GMS) stain has been used in cytopathology to highlight Pneumocystis jiroveci and other fungal organisms. Several nonfungal organisms, however, can show distinct GMS staining patterns that are important to recognize.

MATERIALS AND METHODS

We prospectively and retrospectively identified nonfungal pathogenic organisms on GMS-stained liquid-based and cytospin preparations of respiratory cytologic specimens. The organisms included parasitic worms, viruses, and assorted bacteria. Nine cases were identified, including two cases each of Strongyloides stercoralis, Cytomegalovirus, Mycobacterium tuberculosis, Nocardia species, as well as one case of anthrax-like Bacillus cereus.

RESULTS

The nonfungal organisms had silver deposition in varying locations including the internal organs and/or cuticle of Strongyloides stercoralis larvae, the intranuclear inclusions of Cytomegalovirus infected cells, the surfaces of partially acid-fast Nocardia species and acid-fast Mycobacterium tuberculosis, and the cell walls and central endospores of Bacillus cereus. In 3 of the 9 cases, organisms were not clinically suspected. It was the aberrant GMS staining that pointed to the diagnosis and led to the performance of the definitive stain, culture, or other test.

CONCLUSIONS

GMS is a chromic acid, sodium bisulfate stain that precipitates silver ions in fungal polysaccharide walls, producing the characteristic black stain on light microscopy. It is helpful to recognize aberrant GMS staining to avoid misdiagnosis of fungal elements. GMS stains several nonfungal human pathogens and may be a particularly useful diagnostic aid when the infectious condition is not clinically suspected or the number of organisms is sparse and otherwise difficult to visualize by routine staining methods.

Pneumocystis jiroveci Pneumonia

Pneumocystis pneumonia (PCP) is one of the most common pulmonary infections in persons with impaired cell-mediated immunity, and particularly those infected with human immunodeficiency virus (HIV).1–7 Pneumocystis was first described in the lungs of guinea pigs, during experiments on American trypanosomiasis by Carlos Chagas8 in 1909 and by Antonio Carinii9 in 1910. Both considered the cysts of Pneumocystis as part of the trypanosome’s life cycle. Shortly afterward the Delanoes10 found identical forms in the lungs of rats that had not been infected with trypanosomes and recognized the organism as a separate species. The name Pneumocystis carinii, was given to this organism as a generic name (Greek:pneumon, “lung”; kystis, “cyst”), honoring Carinii.11

Viral Infections of the Lung

The lungs are among the most vulnerable to microbial assault of all organs in the body. From a contemporary vantage, lower respiratory tract infections are the greatest cause of infection-related mortality in the United States, and rank seventh among all causes of deaths in the United States.2,3 From a global and historic perspective, the scope and scale of lower respiratory tract infection is greater than any other infectious syndrome, and viral pneumonias have proven to be some of the most lethal and dramatic of human diseases. The 1918–1919 influenza pandemic, perhaps the most devastating infectious disease pandemic in recorded history, resulted in an estimated 40 million deaths worldwide, including 700,000 deaths in the U.S.4 The global outbreak of severe acute respiratory syndrome (SARS) during 2003, although considerably smaller in scale, resulted in 8098 cases and 774 deaths5 and is a dramatic contemporary example of the ability of viral pneumonias to rapidly disseminate and cause severe disease in human populations.

Visualization of human herpesvirus type 8 in Kaposi's sarcoma by light and transmission electron microscopy

BACKGROUND

Human herpesvirus type 8 (HHV-8) has been associated with Kaposi's sarcoma, body cavity-based lymphoma (BCBL), and multicentric Castleman's disease through DNA, in situ hybridization, and serologic studies. HHV-8 has been visualized only in HHV-8-positive/Epstein-Barr virus (EBV)-negative/ cytomegalovirus (CMV)-negative BCBL cell lines, but not in HHV-8-positive/EBV-negative/ CMV-negative Kaposi's sarcoma lesions.

DESIGN

Kaposi's sarcoma of the skin, lymph node, and spleen from three patients with AIDS were analysed for HHV-8, EBV and CMV DNA by polymerase chain reaction (PCR), for HHV-8 RNA (Tl.1 riboprobe) by in situ hybridization (ISH), for viral inclusions by light microscopy, and for herpesviruses by transmission electron microscopy (TEM). Sections were also labeled with Tl.1 counterstained with CD34, an endothelial cell marker.

RESULTS

The skin lesion was DNA PCR-positive for HHV-8 and CMV (nested, but not single PCR), the lymph node was positive for HHV-8 and EBV, and the spleen was positive for only HHV-8. TEM revealed infection by a virus displaying the typical morphology and cytopathicity of herpesviruses. Hexagonal nucleocapsids and mature enveloped virions were present in vasoformative spindle cells and mononuclear cells, often resembling lymphocytes. Extrapolating from TEM to standard light microscopy on hematoxylin and eosin-stained paraffin sections, eosinophilic, targetoid intranuclear inclusions were identified within spindle cells which often lined vascular lumina. The Tl.1-riboprobe labeled CD34+ spindle cells containing intranuclear inclusions, as well as mononuclear cells within Kaposi's sarcoma and residual lymphoid tissue.

CONCLUSION

The herpesvirus visualized in Kaposi's sarcoma lesions has morphologic and cytopathic features typical of human herpesviruses, productively infects vasoformative spindle cells and mononuclear cells, and is consistent with HHV-8. It can also form intranuclear inclusions that are identifiable by light microscopy in hematoxylin and eosin sections and by ISH.

Detection of human cytomegalovirus DNA from allogeneic bone marrow transplant recipients with interstitial pneumonitis

Interstitial pneumonitis (IP) due to human cytomegalovirus (HCMV) infection can kill patients who receive allogeneic bone marrow transplants (BMT). However, making a definitive diagnosis of HCMV-associated IP is difficult, except in pathologically defined cases. The authors tried to detect HCMV DNA amplified by the polymerase chain reaction with nonradioactive Southern blot analysis from paraffin-embedded lung tissue. Human cytomegalovirus DNA was detected in all of ten BMT recipients with IP and all of three non-BMT recipients with histologically diagnosed HCMV IP. Clinical diagnoses indicated that three of ten allogeneic BMT recipients had HCMV IP, and they showed amplified HCMV DNA despite the lack of histologic viral inclusions. However, HCMV DNA was not detected in 11 immunosuppressed patients with non-HCMV pneumonitis who were included as controls. These observations indicate that the polymerase chain reaction and Southern blot analysis used with lung tissue is more sensitive than histologic examination, and that these tests may be applicable to transbronchial lung biopsy specimens for the early specific diagnosis of HCMV IP. Further analysis of allogeneic BMT recipients showed that four patients who died of HCMV IP fewer than 90 days after BMT had higher quantities of HCMV DNA, whereas six patients who died of HCMV IP more than 90 days after BMT showed lower quantities of HCMV DNA. THis result suggests that HCMV IP in the late phase after MBT might not be attributable to active virus replication alone but rather to the immune response involved in the graft-versus-host reaction.

Concurrent oral cytomegalovirus and herpes simplex virus infection in association with HIV infection. A case report

Recurrent oral herpes simplex virus lesions are common in both immunocompetent and immunocompromised persons. In contrast, cytomegalovirus-associated intraoral lesions are rarely seen, even in the immunocompromised host. We report a case of concurrent oral herpes simplex virus and cytomegalovirus infection, appearing as an ulcerative lesion of the labial mucosa in a patient with acquired immunodeficiency syndrome. Herpes simplex virus type 1 was shown to be present in the lesion by culture tests, histopathologic examination, immunohistochemistry findings and a direct immunofluorescence assay, and cytomegalovirus by histopathologic examination and immunohistochemistry findings. We deduce that the lesion was due to concurrent herpes simplex virus-1 and cytomegalovirus infection. The patient responded well to 2 weeks of treatment with a high dose of acyclovir.

Oral CMV lesions and the HIV infected. Early recognition can help prevent morbidity

Although they are rare, oral ulcers caused by cytomegalovirus infection can occur in immunocompromised people, including those infected with HIV. Once recognized, however, oral CMV lesions can be successfully treated in most cases. Moreover, early recognition permits prompt evaluation for CMV retinitis or disseminated CMV infection, and may help prevent morbidity caused by CMV.

The value of immunohistochemistry and in situ hybridization in detecting cytomegalovirus in bone marrow transplant recipients

Autopsy tissues of 19 patients with complications after bone marrow transplantation (BMT) were analysed for the presence of cytomegalovirus (CMV) using histochemical methods. CMV antigens were detected by antibodies to CMV Immediate Early Antigen (IEA) or CMV Late Antigen (LA). CMV-DNA was detected by DNA in situ hybridization (DISH). IEA was detected in one or more tissues in 79% of 14 patients from whom frozen tissue was available. CMV-DNA was detected on paraffin sections in 84% of all 19 patients. CMV components were present in all organs studied; the highest incidence was found in lung, gastrointestinal tract and kidney. In histology, only 37% of patients showed signs of CMV infection by the presence of cytomegalic cells with nuclear inclusions (or so called "owl eye cells"). In tissue culture, only 33% of 15 patients were CMV positive. Serologically, 68% of all patients had active CMV infection, as indicated by a rise in antibody titres. We conclude that the quick detection of CMV IEA and CMV-DNA has a high sensitivity and predictive value, which is comparable to or exceeds the serological detection of CMV.

EBV and HSV infections in a patient who had undergone bone marrow transplantation: oral manifestations and diagnosis by in situ nucleic acid hybridization

The course of infections with herpes simplex virus and Epstein-Barr virus in an immunosuppressed patient who had undergone bone marrow transplantation and had tested seronegative for human immunodeficiency virus is described. The clinical oral manifestations were unusual, as they included hairy leukoplakia-like lesions and extensive mucosal ulceration. Histologic examination disclosed unique features consisting of both lichenoid and viral cytopathic changes. The association of the lesions with both Epstein-Barr virus and herpes simplex virus was confirmed by in situ hybridization histochemistry. The importance of recognition of the symptoms, specific diagnosis by DNA hybridization, and implications for antiviral prophylaxis and therapy are emphasized.

A review of pulmonary cytopathology in the acquired immunodeficiency syndrome

Over the past 6 yr, we have observed an increase in cytologic specimens from the respiratory tract in patients suspected or known to have AIDS, from 7 of 81,031 cases in 1982 to 1,231 of 55,333 in 1987. Based on our experience with 1,140 patients, this article reviews the technical and morphologic evaluation of pulmonary cytologic specimens from AIDS patients.

[Cytomegalovirus infection as a cause of intestinal perforation]

Three male patients with the acquired immunodeficiency syndrome revealed perforations of the intestine (jejunum-ileum; colon ascendens; coecum). The cause was necrosis due to cytomegalovirus infection. The characteristic findings were cytomegalic inclusion bodies in endothelial cells of the capillaries. These lesions caused alterations of the microcirculation. Therefore it seems reasonable to conclude that in these cases necrosis and perforation were due to ischemia. Cytomegalovirus infection must be taken into consideration in any patient with the acquired immunodeficiency syndrome and gastrointestinal ulcerations.

Viral infections in the acquired immunodeficiency syndrome

The following communication is a tripartite synopsis of the role of viral infection in the acquired immunodeficiency syndrome (AIDS). The first section describes the impact of viral opportunistic infection in AIDS; for each virus, clinical presentation and diagnosis, laboratory diagnostic approaches (with emphasis on electron microscopy), and therapeutic interventions attempted to date are discussed. The second segment explores current theories on the pathogenesis of AIDS, and describes diagnostic and therapeutic approaches to the syndrome itself. The final section catalogues ultrastructural anomalies in the cells of AIDS patients, many of which have been mistakenly identified as etiologic agents.

Oral mucosal cytomegalovirus as a manifestation of the acquired immune deficiency syndrome

Cytomegalovirus (CMV) infection presenting as a painful palatal gingival ulcer was one of the initial clinical manifestations of the acquired immune deficiency syndrome (AIDS) in a male homosexual patient. The diagnosis of oral CMV infection was established when large intranuclear and smaller cytoplasmic CMV inclusions were observed in endothelial cells at the base of the mucosal ulcer. The identification of intranuclear and intracytoplasmic herpes-type viral particles in the infected cells was confirmed by electron microscopy. Cytoplasmic viral particles coexisted with paranuclear dense bodies resembling lysosomes. These features are characteristic of CMV-infected cells. A review of the English-language literature disclosed only three previously reported cases of CMV infection involving the oral mucous membranes. A vasculitis associated with the CMV-infected endothelial cells appears to be the underlying mechanism responsible for development of the oral ulcer. CMV should be considered a possible causative agent when oral ulcers are detected in immunocompromised patients. Likewise, the finding of CMV in oral ulcers should alert one to the possibility of an immunocompromised state.