Ultrastructural findings in the acquired immunodeficiency syndrome (AIDS)

Hairy Cell Leukemia: An Ultrastructural Study of Hairy Cells before and after Interferon Therapy

Aims and background

To test the diagnostic relevance of the presence of ribosome-lamellae complexes (RLC) in 18 hairy cell leukemia (HCL) cases, and to correlate clinical response to interferon (IFN) therapy with hairy cell ultrastructural modifications in 5 of these cases.

Methods

Peripheral blood samples of 18 HCL patients were studied by transmission electron microscopy. Five of these patients received IFN treatment and subsequently were evaluated at different intervals for ultrastructural modifications of the peripheral blood.

Results

RLC were observed in 66.66% of our 18 HCL patients, but in less than 1% of all the cases contained in the files (consisting of over 8,000 cases) of our Electron Microscopy Unit. The microvilli disappeared after IFN therapy in the patients who did not display RLC before therapy (2 cases), whereas they were fewer, shortened and blunted, but still evident, in the cases where RLC had been observed before therapy (3 cases). Moreover, in the HCL cases with pre-therapy RLC, neoplastic cells still synthesized RLC after IFN treatment, but their morphologic aspect was immature.

Conclusions

Our study suggests that: 1) the presence of RLC, when associated to the hairy aspect of the cells, has considerable diagnostic value even though RLC are observed in other rare neoplastic and non-neoplastic conditions; 2) HCL cases with pre-therapy RLC exhibited a morphologic response to IFN therapy different from that of cases without pre-therapy RLC; 3) the quantitative and qualitative modifications of RLC following IFN treatment, as yet unexplained, are probably related to IFN action, in line with a previous report.

Tubuloreticular structures in rectal biopsies of SIV-infected rhesus monkeys (Macaca mulatta)

Tubuloreticular structures (TRS) are considered to be a specific ultrastructural marker for AIDS in various organs. Experimental SIV infection in rhesus macaques is the most appropriate animal model of HIV infection. In 8 rhesus monkeys, experimentally infected with SIVmac251/MPBC, rectum biopsies were taken prior to and post infection (day 3; 1, 2, 4, 12 weeks p.i.) and were investigated by transmissionelectron microscopy to determine incidence and extent of tubuloreticular structures as well as affected cells. From the first week p.i. on TRS were found in all experimental animals as tubuli with a diameter of 20-30 nm. The tubuli were arranged in regular paracristalline formations and formed intracytoplasmatic heterogenous, polymorph accumulations, which were localized close to the endoplasmatic reticulum. In the rectal lamina propria macrophages, endothelial cells, plasma cells, lymphocytes, fibroblasts, and neutrophilic granulocytes were the affected cell types. In 5 control biopsies TRS were detected, too, but, in contrast to SIV-infected animals, they appeared only singular and very small. The results indicate that TRS are a characteristic morphologic criteria of intestinal SIV infection. They appear in very early stages of the infection. In the rectum, they can be detected as bigger, conspicuous, and abundant formations in several cells and have a restricted diagnostic and prognostic validity.

Ultrastructural studies in Langerhans cell histiocytosis: a search for evidence of viral etiology

The ultrastructure of lesional cells in biopsy material from 50 cases of Langerhans cell histiocytosis (LCH) was studied for the effects of virus and/or cytokines. Viral "footprints," which actually represent ultrastructural signs of the effects of cytokines on cells, were found in 76% of the cases. These were detected in lesional Langerhans cells, endothelial cells, and lymphocytes and consisted of tubuloreticular structures, cylindrical confronting cisternae, and curvilinear membranous formations. No virus particles or virus-specific cell products were found. These studies suggest that LCH cells are subject to cytokine stimulation but provide no evidence to implicate a virus in the disease process.

Triple retinal infection with human immunodeficiency virus type 1, cytomegalovirus, and herpes simplex virus type 1. Light and electron microscopy, immunohistochemistry, and in situ hybridization

PURPOSE

This report describes the histopathologic and virologic findings of the retina from a 55-year-old bisexual patient with the acquired immune deficiency syndrome (AIDS), who had concurrent human immunodeficiency virus type 1 (HIV-1), cytomegalovirus (CMV), and herpes simplex virus type 1 (HSV-1) retinitis, and was treated with ganciclovir.

METHODS

The eyes were obtained at autopsy and processed for light microscopy and transmission electron microscopy. Immunohistochemical stains for HSV-1, CMV, HIV-1, varicella zoster virus, and glial fibrillary acidic protein were carried out using the peroxidase-antiperoxidase and streptavidin-biotin-alkaline phosphatase techniques. For in situ hybridization, a radiolabeled CMV DNA probe (Eco-RI-Y fragment of strain AD 169) was used.

RESULTS

Results of histopathologic examination showed a full-thickness necrotizing retinitis with cytomegalic and herpes viral intranuclear inclusions in cells of the neurosensory retina, retinal vascular endothelium, and the retinal pigment epithelium. Some areas of the retina were replaced by glial tissue. The choroid contained only a few chronic inflammatory cells. Immunoperoxidase studies disclosed CMV antigens diffusely distributed throughout all layers of the retina and the retinal pigment epithelium. Herpes simplex virus type 1 antigens were present in retinal cells and the retinal vascular endothelium. Human immunodeficiency virus type 1 antigens were found in mononuclear cells in all layers of the sensory retina. Dual infections with HIV-1 and CMV of individual multinucleated giant cells of glial origin were demonstrated immunohistochemically. Transmission electron microscopy showed herpes viral particles in the vascular endothelium of the retinal vessels and the choriocapillaris. Human immunodeficiency virus particles were identified in the endothelium of the choriocapillaris.

CONCLUSIONS

The possibility of multiple viral infections of the retina, mimicking classic CMV retinitis, should be considered in the clinical and histologic differential diagnosis of necrotizing retinitis in patients with AIDS.

Concentric membranous bodies and giant mitochondria in hepatocytes from a patient with AIDS

The cytoplasm of hepatocytes in a liver biopsy from a patient with acquired immunodeficiency syndrome (AIDS) treated with sulfamethazole-trimethoprim contained concentric membranous bodies (CMB) and giant mitochondria. By light microscopy the general architecture of the liver was unaltered. By electron microscopy one to three CMB were present in random distribution within several cells in equal periportal and centrilobular localization. CMB were irregularly rounded or ovoid, loosely ribosome-studded lamellar whorls. Some were agranular or in parallel arrangement. Giant mitochondria often with paracrystalline inclusions were frequently in close association with CMB. Tubuloreticular inclusions were noted in Kupffer cell cytoplasm. Since CMB have been infrequently observed in human hepatocytes, are rare in nonneoplastic human liver, and have not been previously reported in association with AIDS, their appearance may relate to regenerative changes and/or sulfamethazole-trimethoprim therapy.

The incidence of HIV-1 and HHV-6 in corneal buttons

Twenty pairs of corneas from asymptomatic carriers of HIV-1 and seven pairs from AIDS patients were analyzed for the presence of HIV-1 and HHV-6 antigens, viral transcripts, DNA sequences, and intact and infectious particles. Although serum from all donors was positive for both HIV-1 and HHV-6 antibody by Western blot analysis, only one cornea from an asymptomatic carrier of HIV-1 was positive for HIV-1 and HHV-6. The cornea was positive when tested by tissue culture, PCR, in situ hybridization, and electron microscopy. There was no tear film contamination. These results suggest that HIV-1 and HHV-6 may be capable of invading corneal tissue.

Endemic Kaposi's sarcoma in human immunodeficiency virus type 1-seronegative persons: demonstration of retrovirus-like particles in cutaneous lesions

In 1984, Greek physicians reported on the clustering of cases of Kaposi's sarcoma (KS) on the Peloponnesus peninsula. To gain more insight into its pathogenesis, we studied the seroepidemiologic and clinicopathologic characteristics of 12 Greek KS patients (eight male/four female) five of whom were residents of an endemic area on the Peloponnesus. These patients were in good general health with ages ranging from 48 to 80 years, had no clinical signs of immunodeficiency, and combined the features of both classic and epidemic KS in that they displayed not only involvement of acral areas but also widespread mucocutaneous lesions. Routine laboratory data were within normal limits; no patient had HTLV-1 and HIV-1/2 antibodies, but all patients had antibodies to several herpesviruses. The histopathology was characteristic of KS with the peculiar feature of a dense infiltrate composed predominantly of CD4+ T lymphocytes. Immunoenzymatic/morphologic studies of the KS cells were consistent with their origin from lymphatic endothelium. Outstanding ultrastructural findings were tubuloreticular structures and cylindrical confronting cisternae, structures that are indicative of an ongoing viral infection. Indeed, extensive electronmicroscopic studies resulted in the detection of retrovirus-like particles in close association to KS cells in five of 12 patients. This in situ observation opens the possibility that this retro-virus contributes to KS development.

Lacunar dilatations of intrafusal and extrafusal terminal cisternae, annulate lamellae, confronting cisternae and tubulofilamentous inclusions within the spectrum of muscle and nerve fiber changes in myotonic dystrophy

In 3 out of 5 muscle spindles available in skeletal muscle biopsy specimens from 30 patients with myotonic dystrophy (MD) unusually large lacunar dilatations of terminal cisternae were observed that had thus far only been reported in extrafusal muscle fibers. Cytoplasmic annulate lamellae, confronting cisternae and regularly proliferated terminal cisternae, as well as intranuclear tubulovesicular inclusions were found in extrafusal muscle fibers that in combination with concentric membranous bodies seen in perineurial cells and Schwann cells generally emphasize an involvement of the endoplasmic reticulum in the pathogenesis of MD. In addition, a nuclear inclusion body was observed composed of tubulofilamentous structures with close similarity to those thought to be rather specific for inclusion body myositis. Vesicles filled with amorphous material originating from outer spindle capsule cells were suggested to indicate matrical lipidic debris leading to "ghost bodies" and calcifying globules. Light microscopical evaluation of 8 sural nerve specimens revealed a neuropathy in only 2 patients that was predominantly axonal in type and of slight to moderate severity with a secondary demyelinating component in 1 patient. These findings add to the large spectrum of muscle and nerve fiber changes in MD underlining the phenotypic multiplicity of a well defined genetic defect.

Membranous changes in primary malignant CNS lymphomas

Ultrastructural studies of 17 primary malignant CNS lymphomas revealed 6 tumors with abnormal intracytoplasmic and/or intranuclear membranous structures, most frequently associated with the endoplasmic reticulum or perinuclear envelope. In most cases, tubuloreticular inclusions and paired cisternae were present. Less frequent were accumulation of microtubules, concentric lamellar bodies, and rod-like or paracrystalline intranuclear inclusions. The specificity and significance of these membranous structures remain questionable because of their frequent occurrence in a variety of normal and pathological conditions. Some of these changes may be considered as cellular reactions to viral infections, others may indicate cellular activity or degeneration.

Hypertrophic brachial plexus neuritis: a pathological study of two cases

Two patients with brachial plexus neuropathy had recurrent symptoms for years that culminated in the development of a painful lower cervical mass. On macroscopic examination the affected nerves had a fusiform segmental enlargement, suggestive of a nerve sheath tumor, that was excised. Histologically, marked endoneurial edema, florid focal chronic inflammation, extensive onion bulb formation, and perineurial sparing were seen. Electron microscopic studies on one patient revealed microvasculitis; frequent tubuloreticular inclusions in endothelial cells, histiocytes, and lymphocytes; and cylindrical confronting cisternae in lymphocytes. We conclude that some cases of recurrent brachial plexus neuropathy are due to a localized chronic inflammation that may be related to autoimmunity or to a viral infection.

Induction of cylindrical confronting cisternae (AIDS inclusions) in Daudi lymphoblastoid cells by recombinant alpha-interferon

Cylindrical confronting cisternae (CCC), also known as test-tube and ring-shaped forms, are frequently present in the cytoplasm of lymphocytes and occasionally in other cells from patients with acquired immunodeficiency syndrome (AIDS). Recent data indicate that the presence of these cisternae and tubuloreticular structures (TRS) in lymphocytes from patients at risk for AIDS is predictive of the development of this syndrome. CCC are formed by an alteration of the membranes of the rough endoplasmic reticulum, but the mechanism by which they are formed or demonstration of their induction by specific agents has not been previously reported. We cultured Daudi lymphoblastoid cells in medium containing recombinant alpha-interferon and induced the formation of both TRS and CCC. The number of CCC formed in Daudi cells was directly proportional to the concentration of interferon used and the length of culture. CCC were in direct continuity with TRS, which were induced in cells by interferon at an earlier time. The percentage of cell sections containing TRS stayed the same or decreased somewhat after 72 hours of culture, whereas the number of CCC increased. Our results indicate that CCC could be present in various cells from patients with AIDS and other diseases as a result of elevated interferon levels in these conditions.

Malignancies in the acquired immunodeficiency syndrome

Malignancies frequently arise in patients infected with human immunodeficiency virus (HIV), including those patients classified as having the acquired immunodeficiency syndrome (AIDS). Currently, Kaposi's sarcoma and certain types of lymphoma are considered to develop as a result of HIV infection, and other cancers have also been reported in these patients. For the most part, ultrastructural study of HIV-associated malignancies has been limited to Kaposi's sarcoma; the ultrastructural features of the epidemic form of this disease are generally the same as those of the classical form. The occurrence of these cancers in HIV-infected individuals appears to be related to the immunodeficiency caused by this virus, but the basic etiologic mechanisms remain unknown. In general, only palliative treatments are presently available for HIV-associated malignancies.

Hepatic inclusions during interferon therapy in chronic viral hepatitis

Two types of cytomembranous abnormalities were identified for the first time in liver biopsies from patients with chronic active type B hepatitis during treatment with recombinant alpha-interferon. Tubuloreticular inclusions were present in the hepatic endothelial cells, Kupffer cells and perisinusoidal cells of liver biopsies from both patients, and they were absent in liver biopsies obtained before treatment. Cylindrical confronting lamellae, having "test tube" or "ring-shape" forms were observed in the cytoplasm both of Kupffer cells and macrophages in the second liver biopsy of one of the patients. The findings suggest that interferon can be involved in the pathogenesis of both cytomembranous abnormalities, but that additional biological factors may play a role in formation of the cylindrical confronting lamellae.