Unusual cytoplasmic body in lymphoid cells of homosexual men with unexplained lymphadenopathy. A preliminary report

High level of coreceptor-independent HIV transfer induced by contacts between primary CD4 T cells

Cell-to-cell virus transmission is one of the most efficient mechanisms of human immunodeficiency virus (HIV) spread, requires CD4 and coreceptor expression in target cells, and may also lead to syncytium formation and cell death. Here, we show that in addition to this classical coreceptor-mediated transmission, the contact between HIV-producing cells and primary CD4 T cells lacking the appropriate coreceptor induced the uptake of HIV particles by target cells in the absence of membrane fusion or productive HIV replication. HIV uptake by CD4 T cells required cellular contacts mediated by the binding of gp120 to CD4 and intact actin cytoskeleton. HIV antigens taken up by CD4 T cells were rapidly endocytosed to trypsin-resistant compartments inducing a partial disappearance of CD4 molecules from the cell surface. Once the cellular contact was stopped, captured HIV were released as infectious particles. Electron microscopy revealed that HIV particles attached to the surface of target cells and accumulated in large (0.5-1.0 microm) intracellular vesicles containing 1-14 virions, without any evidence for massive clathrin-mediated HIV endocytosis. The capture of HIV particles into trypsin-resistant compartments required the availability of the gp120 binding site of CD4 but was independent of the intracytoplasmic tail of CD4. In conclusion, we describe a novel mechanism of HIV transmission, activated by the contact of infected and uninfected primary CD4 T cells, by which HIV could exploit CD4 T cells lacking the appropriate coreceptor as an itinerant virus reservoir.

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.

Lennert's lymphoma with giant multivesicular lysosomal bodies optically visible

A case of a 43-year-old male patient with lymphoepithelioid lymphoma is discussed. During the 10-year follow-up of this patient, different biopsy specimens were obtained. Immunohistochemical studies with a complete paraffin panel determined a T-cell nature of the specimens. Electron microscopy showed a peculiar finding in the cytoplasms of the tumoral cells that correlated with optical inclusions observed in optical imprints; these imprints corresponded to lysosomic multivesicular bodies, whose significance is discussed.

Ultrastructural pathology of human immunodeficiency virus infection

The electron microscope has been used with great skill in many aspects of the acquired immunodeficiency syndrome. It has played a critical role in classifying the human immunodeficiency virus, in characterizing the morphogenesis and gene products of the virus, and in elucidating the host cell targets and interactions. With the aid of the electron microscope, new opportunistic pathogens are being identified, and particularly difficult diagnoses are being made. Extrapolations from observations made at the ultrastructural level to the light microscopic level have provided criteria for the diagnosis of several infectious agents. As with any powerful scientific tool, observations must be interpreted with great care by scientists experienced in electron microscopy.

Confronting cisternae and ciliated cells in malignant pleural mesothelioma: an ultrastructural study

The incidence of malignant mesothelioma of the pleura has recently increased in Japan, and ultrastructural and immunohistochemical studies can help in the histopathologic diagnosis. Confronting cisternae consist of dense laminae between the cisternae of rough endoplasmic reticula. Cylindric confronting cisternae have recently been found in patients with acquired immunodeficiency syndrome. The pathologic significance of this unusual structure is still obscure, but it has been proposed that trapped ribosomes on the confronting unit membranes of rough endoplasmic reticula produce the dense laminae. In this study, prominent confronting cisternae were found in more than half the tumor cells, and accumulation of an electrondense fine granular substance surrounded by Golgi vesicles (so-called vesicular rosettes) were noted and found to be continuous with the dense laminae. The nature and origin of the vesicular rosettes are important with regard to the formation and significance of confronting cisternae. Oligocilia have been found in various metaplastic and neoplastic cells and are thought to be nonspecific. There has been only one report of ciliated cells and confronting cisternae in a malignant peritoneal mesothelioma, however, indicating that these unusual cytoplasmic structures might be related to some epithelial-type mesotheliomas.

Crystalline inclusions in epithelial cells of hairy leukoplakia: a new ultrastructural finding

Hairy leukoplakia is often the first manifestation of an HIV infection. In the present study we have investigated the ultrastructural features of hairy leukoplakia in two HIV seropositive male homosexual patients. Ultrastructurally EBV particles were found in the upper prickle and keratinized epithelial cells, whereas papilloma virus particles were not found. Candida albicans were also seen in the keratinized layer. In addition two types of inclusions which have not previously been reported in hairy leukoplakia were commonly seen in the epithelial cells containing the EBV. The first was a crystalline microtubular structure which may take the form of several arrays. The second was an elongated multivesicular structure consisting of membrane-bound rounded vesicles embedded in a background of fine filaments. The vesicles were similar to the empty looking EBV particles and their mean diameter was 100 nm. Further investigations are needed to elucidate the exact nature of these structures and their relationship to the Epstein-Barr virus.

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.

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.

Unusual crystalline inclusions in a case of AIDS-related complex

A lymph node of a patient with AIDS-related complex was studied with light and electron microscopic techniques. In numerous plasma cells and follicular center cells amorphous and unusual crystalline structures which probably consist of abnormal immunoglobulin could be found.

Ultrastructural alterations and virus-like particles in lymph nodes of drug addicts with lymphadenopathy syndrome (LAS)

Lymph node biopsies from 16 cases of intravenous drug addicts with lymphadenopathy syndrome (LAS) have been examined at the electron microscope. The main ultrastructural alterations observed in the lymphocytes, dendritic reticulum cells and endothelial cells were tubulo-reticular structures (TRS), test tube and ring shaped forms (TRF) and nuclear pockets (NP). Images suggesting virus budding from lymphocytes and virus-like particles have also been found in 9 out of the 16 cases. The possibility to correlate the latter findings with a better knowledge of LAS evolution and prognosis is discussed.

LAV-like viral particles in lymph node germinal centers in patients with the persistent lymphadenopathy syndrome and the acquired immunodeficiency syndrome-related complex: an ultrastructural study of 30 cases

The detection of LAV- or HTLV III-type viral particles in lymph node germinal centers from patients with the persistent lymphadenopathy syndrome (LAS) or the acquired immunodeficiency syndrome (AIDS)-related complex (ARC) is an important diagnostic factor in the prodromal stages of AIDS. These particles, the morphology of which is defined, are situated solely in the extracellular spaces delimited by cytoplasmic extensions of the dendritic reticular cells. Often few in number, they were found in 26 of the 30 lymph nodes studied, selected uniquely on the basis of light microscopic criteria (predominantly follicular lymphoid hyperplasia). The four negative nodes contained no, or fewer than two, germinal centers in the samples taken for ultrastructural study. The diagnosis of the LAS or the ARC was always confirmed clinically and biologically. Thus, lymph node biopsy and the corresponding ultrastructural study are important steps in the diagnosis of AIDS.

Head and neck presentations of acquired immunodeficiency syndrome

Since December 1980, over 3000 cases of acquired immunodeficiency syndrome (AIDS) have been reported. The charts of 102 patients admitted to the New York University Medical Center with a diagnosis of AIDS were reviewed with particular emphasis on presenting signs, symptoms, and laboratory values. Symptoms tended to be nonspecific and most often resembled those of an upper respiratory infection. Over 71% of the patients presented with at least two of the following four signs: diffuse adenopathy, oral and facial lesions consistent with Kaposi's sarcoma, white oral lesions, and anergy. Laboratory findings included leukopenia, increased erythrocyte sedimentation rate, thrombocytopenia, and anemia. The in-hospital mortality rate was 26%. The current status of our knowledge concerning AIDS is reviewed and discussed. The frequency and types of presenting signs and symptoms in the head and neck are reported to alert the otolaryngologic community to this entity.

Lymph node modification in patients with the acquired immunodeficiency syndrome (AIDS) or with AIDS related complex (ARC). A histological, immuno-histopathological and ultrastructural study of 45 cases

The authors present the results of a histopathological study on the lymph-nodes taken from 45 subjects suffering from either an AIDS or from a chronic adenopathy corresponding to the definition of AIDS related complex (ARC). The various aspects observed were classed as type I to type IV. The lymph-node modifications observed in the 29 patients with an ARC could be divided into three principle groups: an extensive follicular hyperplasia associated with other elementary lesions or type IA (25 lymph-nodes from 23 patients); changes resembling a multicentric Castleman syndrome or type IB (1 case); angioimmunoblastic-like (AIL) lesions or type II (2 cases) and an association of lesions of type II (7 lymph-nodes from 6 patients). During AIDS, the adenopathy usually disappears, and the small lymph-nodes removed, especially on autopsy, show an extensive lymphoid depletion (type III) with systematic sclerosis (15 lymph-nodes from 14 patients). When adenopathy persists, it is due to infections complications (tuberculosis, cryptococcosis, avian mycobacteriosis and Whipple's disease like lesions). Of the 10 patients in whom a Kaposi's sarcoma was observed, only 6 showed lymph-node involvement, or type IV. The different histopathological lesions seem to appear according to an evolving succession, proven by certain association of lesions and by successive biopsies. In our series, 17% of subjects with an ARC evolved to AIDS. Lymph-node biopsy allows a possible ARC to be implicated on the association of the following simple lesions: follicular hyperplasia with partial or total destruction of the perifollicular lymphocytic cisterna, infiltration of the germinative centres by streams of small lymphocytes, evolving to an aspect of a "burst" germinative centre and various sinusal reactions with, in particular, the presence of neutrophilic polynuclear cells. The biopsy also allows the forms with bad prognosis to be recognized: those with AIL-like aspect or multicentric Castleman-like syndrome, which seems to represent a particular evolutive form. Finally, it also detects, in certain cases, the localization of a Kaposi syndrome, signalling the passage to AIDS. The immunopathological studies present a double interest. Firstly, they offer arguments in favour of the diagnosis: increase in the number of T8 lymphocytes in the germinative centres with the formation of small clusters and disruption of the network of dendritic reticular cells, and the inversion of the T4/T8 ratio in the extra-follicular cortical regions, by either a decrease in T4 lymphocytes or by an increase in T8 lymphocytes.(ABSTRACT TRUNCATED AT 400 WORDS)

AIDS and parasitic infections, including Pneumocystis carinii and cryptosporidiosis

AIDS is a disorder that the pediatrician must consider when evaluating children with a variety of clinical conditions, including overwhelming infection with a number of parasites. This article discusses these opportunistic parasitic infections, focusing on their link with AIDS.

Serum lactate dehydrogenase levels in adults and children with acquired immune deficiency syndrome (AIDS) and AIDS-related complex: possible indicator of B cell lymphoproliferation and disease activity. Effect of intravenous gammaglobulin on enzyme levels

Twenty-seven of 33 patients with the acquired immune deficiency syndrome (AIDS) or AIDS-related complex (16 adults and 17 children) demonstrated significant elevation of serum lactate dehydrogenase activity, occurring in the isomorphic distribution. Serum lactate dehydrogenase activity was the highest in all nine patients with acute Pneumocystis carinii pneumonitis, in seven of whom extensive interstitial pulmonary infiltrates with lymphocytes and plasma cells were documented. Lactate dehydrogenase activity was also significantly elevated on a long-term basis in all 17 pediatric patients with non-Pneumocystis lymphoid interstitial pneumonitis. Clinical resolution of Pneumocystis carinii pneumonitis was associated with a decline in lactate dehydrogenase activity. Periodic intravenous gammaglobulin was more effective than conventional therapy (trimethoprim/sulfamethoxazole and pentamidine) in achieving clinical and immunologic improvement and reduction of serum lactate dehydrogenase activity in patients with Pneumocystis carinii pneumonitis. Intravenous gammaglobulin was also more effective in patients with AIDS and non-Pneumocystis carinii pneumonitis and lymphoid interstitial pneumonitis. Lactate dehydrogenase activity declined to normal, at least temporarily, in nine of 12 intravenous gammaglobulin-treated patients as compared with only two of 12 untreated patients. Six adult patients with AIDS or AIDS-related complex and no interstitial pneumonitis exhibited normal lactate dehydrogenase levels. These findings suggest that serum lactate dehydrogenase activity in patients with AIDS or AIDS-related complex may be a useful indicator of pulmonary interstitial inflammation. As such, it may be utilized to predict disease course and monitor response to intravenous gammaglobulin treatment.

The acquired immunodeficiency syndrome: an ultrastructural study

Blood and a variety of tissues from 97 patients with the acquired immunodeficiency syndrome (AIDS) and 25 with the AIDS prodrome were studied ultrastructurally. Tubuloreticular structures (TRS) were found in 85 per cent of the patients with AIDS and in 92 per cent of those with the prodrome. Test tube and ring-shaped forms (TRF), found in 41 per cent of the patients with AIDS and in 8 per cent of those with the prodrome, increased with disease progression. Among the patients with AIDS, as the number of sites examined per case increased, the incidence of TRS and TRF tended to approach 100 per cent, suggesting that they are present in all patients with AIDS. Other changes seen frequently were immunologic capping of blood lymphocytes, intramitochondrial iron in blood reticulocytes and marrow normoblasts, megakaryocytic immaturity and platelet phagocytosis, collections of membranous rings in hepatocytic cytoplasm, suggestive of non-A, non-B hepatitis, and proliferations and engorgement of hepatic Ito cells with lipid. The data suggest that TRS and TRF can be used as diagnostic and prognostic markers.

Electron microscopy of the intestine and rectum in acquired immunodeficiency syndrome

To provide a better understanding of the morphologic changes that take place in the intestine and colon in acquired immunodeficiency syndrome (AIDS), electron microscopy was performed on intestinal or colonic biopsy specimens obtained from 6 patients with AIDS and from 2 patients with AIDS-related lymphadenopathy syndrome. Cryptosporidia were attached to the plasma membrane of epithelial cells in 2 patients and were noninvasive. An invasive protozoan organism identified as Microsporidia was found in 1 patient. Evidence for epithelial cell injury was limited. Unusually prominent secretory granules in colonic epithelial cells (a morphologic counterpart of secretion) was found in 2 patients. Tubuloreticular structures were observed in 7 patients. The structures were found in endothelial cells, lymphocytes, monocytes, intraepithelial lymphocytes, and free in the capillary lumen. Tube- and ring-shaped forms were observed in 2 patients, prominent intraepithelial mast cells in 4 patients, rectal spirochetosis in 1 patient, and pseudomembranous colitis in 1 patient with intestinal and systemic shigellosis. Vesicular rosettes, retroviruses, other viruses, and Mycobacterium avium-intracellulare were not observed. These observations expand our knowledge of morphologic changes in the colonic and intestinal mucosa in patients with AIDS. Tubuloreticular structures are so prominent, in contrast to our previous electron-microscopic observations in other disease and normal states of the intestine and colon, that their finding (though clearly nonspecific) may be a clue to the diagnosis of AIDS in an otherwise equivocal situation.

Ultrastructural findings in the acquired immunodeficiency syndrome (AIDS)

Ultrastructural studies have made significant contributions in evaluating the pathology and pathogenesis of AIDS. Three distinct types of abnormal cytomembranous inclusions in tissue specimens or peripheral blood mononuclear cells from AIDS patients are described--vesicular rosettes (VR), tubuloreticular inclusions (TRI), and cylindrical confronting lamellae (CCL).

A surgical oncology perspective on AIDS

During the summer of 1981 reports of unusual opportunistic infections among male homosexuals first began to appear in the literature and by December 1983, 3000 cases has been reported to the Center for Disease Control in Atlanta, Georgia. Homosexual and bisexual men comprise 71% of the reported cases, while 17% are known intravenous drug users, and the remaining 12% made up of persons with other risk factors. Approximately 80% of AIDS patients with Kaposi's sarcoma have identifiable gastrointestinal lesions. Specific risk factors for Kaposi's sarcoma in AIDS patients have not been exclusively identified, but it is thought that repeated sexual involvement with multiple partners exposes the victim to the immunosuppressive effect of cytomegalovirus and allogenic sperm, which may in turn impair lymphoid cells. The immunological abnormalities associated with AIDS have included striking changes in T-cell ratios, with more profound changes in the Kaposi-AIDS groups. Increases in IgG, decreased antibody production by B-cells to challenge antigen, decreased B-cell proliferative responses to B-cell mitogens, abnormalities in macrophage function, and increased serum thymosin levels have been found. Various opportunistic infections afflict the patient with AIDS. Antimicrobial therapy, various interferons, interleukin-2, and immunomodulation with thymosin have all been used without much success. The distribution and transmission of AIDS parallels hepatitis B virus infection which is transmitted sexually and parenterally. On the whole the same precautions as for hepatitis B should be taken for AIDS. Health care personnel treating patients with AIDS should also wear masks and eye protection against the splatter of body fluids and secretions.(ABSTRACT TRUNCATED AT 250 WORDS)

Pathology of suspected acquired immune deficiency syndrome in children: a study of eight cases

Biopsy and/or autopsy material from lymphoreticular and other organs was studied in 8 children with suspected acquired immune deficiency syndrome (AIDS). One or both parents of each of these children had one or more of the recognized risk factors for AIDS, such as intravenous drug abuse, prostitution, Haitian origin. The following histologic patterns were noted in the lymph nodes: (1) follicular hyperplasia with normocellular paracortex, (2) follicular hyperplasia with depletion of paracortex, and (3) atrophy of follicles with depletion of paracortex. Lymphoid interstitial pneumonitis (LIP), a previously unreported lesion in AIDS, was present in 4 cases. It is suggested that the pulmonary lymphoid lesion may be part of a more generalized lymphoid hyperplasia involving B cells. The gross and microscopic features of the thymus, available in 2 of the 8 cases, indicated that the immunologic defect in these children was not of congenital type. Pathologic findings can be helpful in the diagnosis of the syndrome when correlated with clinical and immunologic features of suspected cases and of the pulmonary lesion. The latter is of importance in deciding the type of therapy to be given for the pulmonary disease process.

Homosexual men in London: lymphadenopathy, immune status, and Epstein-Barr virus infection

By November 7, 1983, 24 cases of AIDS in the United Kingdom had been reported to the Communicable Disease Surveillance Centre. At the same time an increasing number of homosexual men with unexplained lymphadenopathy syndrome (LAS) have been seen in our department. Between December 1982 and July 1983, 14 homosexual men with LAS and 11 healthy homosexual men were studied. Patients with LAS had a high number of lifetime episodes of sexually transmitted diseases, a history of recent sexual activity in the United States (9 of 14), sexual contact with British AIDS patients or other persons with LAS (7 of 14), and hypergammaglobulinemia. Low T-helper/T-suppressor ratios (less than 0.8), due mainly to a decrease in T-helper cells, were found in both groups. Lymph node biopsies showed follicular hyperplasia and hypocellular pattern. All 25 patients studied had antibodies to Epstein-Barr virus capsid antigen (anti-VCA) and 11 had antibodies to early antigen (anti-EA); 13 of 17 were excreting the virus; and two showed no Epstein-Barr-virus-specific regression. Peripheral blood immunoglobulin-producing B-cells from six patients with hypergammaglobulinemia were negative for the Epstein-Barr virus nuclear antigen (EBNA). Five lymph node biopsies showed no EBNA-positive cells. Epstein-Barr virus reactivation is common in the patients with LAS and healthy homosexual men in London, but would not seem to be the cause of the polyclonal B-cell activation or lymphadenopathy.

Transfusion-associated acquired immune deficiency syndrome in infants

Two preterm infant boys not known to be at risk developed clinical, laboratory, and pathologic features of acquired immune deficiency syndrome (AIDS) after receiving multiple blood transfusions in the neonatal period. Their clinical courses were characterized by failure to thrive, recurrent otitis media, hepatomegaly, and fatal interstitial pneumonia. Laboratory evaluation revealed progressive lymphopenia, reversed T helper/suppressor ratios, increased percentages of B-lymphocytes, decreased lymphoproliferative responses to mitogens, hyperimmunoglobulinemia, and high levels of circulating immune complexes. At postmortem examination thymic involution, lymphocyte depletion in spleen and lymph nodes, and micronodular mineralization in the central nervous system were seen. The findings were not specific for other known congenital immune deficiencies and were most indicative of AIDS. The lack of other risk factors suggests transmission of AIDS via blood transfusions in the neonatal period.

A distinctive follicular hyperplasia in the acquired immune deficiency syndrome (AIDS) and the AIDS related complex. A pre-lymphomatous state for B cell lymphomas?

The histological features of a distinctive follicular hyperplasia observed in twenty-nine male patients with AIDS or the AIDS related complex are described. The group includes four patients with Kaposi's sarcoma, five with lymphoma, 16 with persistent generalized lymphadenopathy, and four with hemophilia. Histopathology is correlated with lymphocyte phenotyping and clinical findings and a model for the pathogenesis of this unique syndrome is presented.

Distribution of T-cell phenotypic subsets and surface immunoglobulin-bearing lymphocytes in lymph nodes from male homosexuals with persistent generalized adenopathy: an immunohistochemical and ultrastructural study

Lymph nodes from homosexual men with persistent generalized adenopathy were evaluated for distribution of T-cell phenotypic subsets and surface immunoglobulin(SIg)-bearing lymphocytes. Electron microscopy revealed tubulovesicular structures within lymphocytes but no multivesicular rosettes. Eight to 33 per cent of the lymphocytes within germinal centers were suppressor T cells, compared with germinal centers from control lymph nodes, in which these cells were rare (P = 0.002). Significantly greater percentage of suppressor/cytotoxic T lymphocytes were also present in the paracortex and follicular mantles of lymph nodes from the homosexual group (P = 0.002 and 0.007, respectively). Percentages of helper T lymphocytes were significantly decreased in germinal centers (P = 0.008) and paracortical regions (P = 0.002). Florid follicular hyperplasia with aberrations in follicular architecture was the most common histologic pattern, but one node with diffuse hyperplasia and subtotal effacement of architecture revealed depletion of SIg-bearing lymphocytes and increased numbers of suppressor T cells. Reversed helper-to-suppressor T-cell ratios in lymph nodes from homosexuals with generalized adenopathy may be related to viral infection and contribute to immune deficiency in this group.

Viral infections of the nervous system

Neurotropic viruses cause a number of important infectious syndromes including encephalitis, myelitis, meningitis, and radiculopathy. In this review, the biology of conventional and unconventional viruses is examined. The host immune response to viruses is discussed, and patterns of viral pathogenesis are explained. The clinical features, laboratory findings, management of important viral infections, such as herpes simplex encephalitis and epidemic encephalitis, are presented. Post-infection syndromes, such as the Guillain-Barré syndrome, and chronic viral infections, such as those causing progressive multifocal leukoencephalopathy and subacute sclerosing panencephalitis, are discussed. Current knowledge concerning the nature of unconventional virus-like agents of the spongiform encephalopathies, including kuru and Creutzfeldt-Jakob disease, is summarized. Finally, viral infections of immunocompromised patients and the possible role of viruses in the newly described acquired immunodeficiency syndrome (AIDS) are examined.

Speculations on the viral etiology of acquired immune deficiency syndrome and Kaposi's sarcoma

The acquired immune deficiency syndrome (AIDS) appeared in the United States in late 1978 and has spread at an epidemic rate through the four major coastal cities of this country. The disease appears to show the same epidemiologic distribution as hepatitis B virus infection, and for this reason, most investigators feel that this new disease is caused by a blood-borne sexually transmitted virus. A number of viral agents have been suggested as the cause of AIDS, but to date, no virus has been consistently isolated. The most likely candidate is a retrovirus that has recently been introduced into the human population and has found its way into two extremely high-risk groups, namely, promiscuous male homosexuals and intravenous drug abusers. The relationship between Kaposi's sarcoma and cytomegalovirus is still unclear, but evidence is mounting that cytomegalovirus may be the agent that initiates this multifocal malignancy. Multiple factors must be involved in this process. It is known that some immunosuppressed individuals develop Kaposi's sarcoma, which completely resolves when the immunosuppression is reversed; however, in individuals with classical Kaposi's sarcoma, the profound degree of helper T-cell depression that characterizes the acquired immune deficiency syndrome is not seen.

Is cancer communicable?

Recent developments in cancer epidemiology have led to the possibility of an exceedingly complex communicable factor(s) in cancer etiology. The transmission of such an agent(s) may require a susceptible genotype and/or other promotional events. Likely candidates which support this supposition include: Epstein-Barr virus (nasopharyngeal carcinoma, Burkitt's lymphoma, salivary gland tumor among Eskimos, X-linked lymphoproliferative syndrome of Purtilo); human T-cell leukemia virus (adult T-cell leukemia); acquired immune deficiency syndrome (AIDS), complicated by Kaposi's sarcoma (etiologic agent remains elusive, though epidemiology suggests possible infectious transmission); abnormal immune phenomena in households of Hodgkin's disease patients; and clustering of various types of cancer in spouses, the general population, and families. We have selectively reviewed the literature and evolved an etiologic hypothesis which integrates a communicable agent(s) in concert with genetic and/or environmental carcinogenic interaction which could conceivably explain a significant fraction of the total cancer burden.

Precocious thymic involution manifest by epithelial injury in the acquired immune deficiency syndrome

Thymuses from six heterosexual Haitian patients with the acquired immune deficiency syndrome (AIDS) were studied by light microscopy and the findings were compared with those from three control groups. The control groups included 1) five age-matched Haitian hospital patients; 2) ten age- and sex-matched Montreal patients who had died suddenly or had had brief illnesses; and 3) 20 middle-elderly Montreal patients who had experienced chronic, wasting illnesses or prolonged hospitalization. Thymuses from patients with AIDS demonstrated pronounced involution, effacement of the cortex and medulla, marked thymocyte depletion, variable degrees of plasma cell infiltration and fibrosis, and, above all, absence of Hassall's corpuscles. Thymuses from Haitian and Montreal control subjects who had died suddenly or had brief illnesses demonstrated minimal involution and abundant Hassall's corpuscles. Although thymuses from 12 of the chronically ill control subjects demonstrated marked involution, architectural effacement, and absence of Hassall's corpuscles, partial architectural preservation and variable numbers of Hassall's corpuscles were observed in eight of these subjects. Thus, the extent of thymic involution observed in patients with AIDS antedates that incurred with aging and supersedes that induced by sustained stress and inanition. The loss of Hassall's corpuscles in patients with AIDS suggests that the thymic epithelium either incurs a form of injury or undergoes precocious involution during the illness. Whether this lesion is central to the pathogenesis of AIDS or merely a reflection of intense, sustained stress coupled with accelerated physiologic involution is unknown. It is possible that the disappearance of Hassall's corpuscles may indicate important, although as yet cryptic events within the thymic microenvironment in this syndrome.

Respiratory tract fluids: analysis of content and contemporary use in understanding lung diseases

Respiratory tract fluid, produced from an enormous area spanning the mucosa of the nose to the alveolar surface, is a complex mixture of serum transudate and locally secreted proteins and glycomucoproteins and of inflammatory and immune effector cells intermingled. Its analysis is important in understanding the pathogenesis of respiratory diseases and remains essential for the clinical diagnosis of most lung disorders. Many basic facts about the formation and composition of this fluid remain unknown, and little information exists about absorptive mechanisms along the airways. Respiratory fluid is not homogeneous but has unique regional characteristics that are becoming better appreciated as more selective sampling methods are devised. Above all, it is a dynamic substance in healthy airways and diseased ones, and any specimen is just a point-in-time sample that can change in composition, often making serial analysis and comparisons necessary. Nasal fluids currently have limited diagnostic application except in allergic rhinitis. Expectorant (sputum) telescopes fluid and cells from all areas and is not from a specific locale, so the trend is to retrieve more selective and regional specimens of airways fluids. Technology largely does not exist to collect area specimens, except for bronchoalveolar lavage, which generally samples the alveolar surface. Clearly, bronchoalveolar lavage fluid analysis has been the favored way to characterize the peripheral air-spaces for the past 10 years or so, and most of this monograph has been devoted to normal data derived from lavage specimens and to a few examples of lung disease that reflect this burgeoning application. In many respects, results obtained from lavage fluid are virtually in catalogue form at present, and it remains to the future to know how some of the observations will help make diagnosis better or elucidate pathogenic mechanisms. Generally, bronchoalveolar lavage fluid analysis has led to better concepts of immunopathology of many diseases and provided new ways to monitor the evolution of certain diseases, especially the diffuse interstitial lung disorders, but development of specific criteria for diagnosis has been less rewarding. However, certain patterns of lymphocyte-predominant alveolitis, suggesting sarcoidosis or hypersensitivity diseases, recognition of specific T lymphocyte defects and opportunistic microorganisms as in AIDS, and the use of microprobe electron analysis to identify cellular particulates all point to more precision of diagnosis. Alveolar proteinosis and histiocytosis X may be detected from lavage fluid components. The prospects are truly exciting.(ABSTRACT TRUNCATED AT 400 WORDS)

Acquired immune deficiency syndrome

Acquired Immune Deficiency Syndrome (AIDS) occurs as a result of a defect in cell mediated immunity with a comparatively normal humoral immunity. Originally diagnosed in four distinct groups, AIDS is now recognized in six high-risk groups. Many theories of etiology exist; the most accepted etiologic agent is the Human T-lymphotropic retrovirus (HTLV). Clinical presentations are that of an opportunistic infection or a nonspecific illness. Once AIDS is diagnosed, medicine has little to offer the AIDS victim. CDC recommendations for health personnel and AIDS patients are reviewed.

A comparative ultrastructural study of virions in human pre-AIDS and simian AIDS

Virions resembling the AIDS-associated retroviruses HTLV-III and LAV were identified between pseudopods of dendritic reticulum cells in lymph nodes from 3 patients with prodromal AIDS. The virions are morphologically distinguishable from HTLV-I and HTLV-II and also from D-type retroviruses that are associated with the simian acquired immune deficiency syndrome. Budding forms resembling incomplete nucleoids of maturing D-type retrovirus were found in neutrophils in a lymph node from another patient with prodromal AIDS. The significance of these structures is unknown.

Studies of cellular immunity in male homosexuals in London

97 symptom-free homosexuals were studied clinically, serologically, and with in-vivo and in-vitro tests of cellular immune function in the context of the acquired immunodeficiency syndrome (AIDS). A high proportion of these men showed abnormalities: lymphopenia (33%), decreased T-helper/T-suppressor (Th/Ts) cell ratios (43%), both these abnormalities (12%), decreased total T-helper cells (15%), monocyte chemotactic (10%) and phagocytic (27%) defects, anergy to three recall antigens (32%), and anergy to purified protein derivative despite BCG inoculation (55%). The lymphocyte abnormalities and anergy characteristic of AIDS were seen in 5%. No clear clinical or serological associations were seen for the AIDS-like defects. Trends of association were seen between higher lymphocyte counts, lower Th/Ts ratios, more T-suppressor cells and serological evidence of previous virus infection. The combination of lymphocyte abnormalities and anergy observed in these symptom-free homosexuals may represent a latent phase of AIDS.