Human immunodeficiency virus (HIV) proteins in neuropathogenesis of HIV dementia

Human immunodeficiency virus (HIV) infection of the nervous system is unique when compared with other viral encephalitides. Neuronal cell loss occurs in the absence of neuronal infection. Viral proteins, termed "virotoxins," are released from the infected glial cells that initiate a cascade of positive feedback loops by activating uninfected microglial cells and astrocytes. These activated cells release a variety of toxic substances that result in neuronal dysfunction and cell loss. The virotoxins act by a hit and run phenomenon. Thus, a transient exposure to the proteins initiates the neurotoxic cascade. High concentrations of these proteins likely occur in tight extracellular spaces where they may cause direct neurotoxicity as well. The emerging concepts in viral protein-induced neurotoxicity are reviewed as are the neurotoxic potential of each protein. Future therapeutic strategies must target common mechanisms such as oxidative stress and dysregulation of intracellular calcium involved in virotoxin-mediated neurotoxicity.     

Human immunodeficiency virus type 2 (HIV2)

In the mid 1980's a second human retrovirus, capable of causing the acquired immunodeficiency syndrome (AIDS), was isolated from patients of West African origin. This virus, now called human immunodeficiency virus type 2 (HIV2), was found to be distinct from human immunodeficiency virus type 1 (HIV1) but closely related to simian immunodeficiency viruses (SIV). Although the genomes of HIV1 and HIV2 are similar there are significant differences in nucleotide and amino acid sequences, most marked with the envelope genes and proteins. Both viruses, however, bind to the same CD4 cellular receptor. HIV2 is largely confined to West Africa where it is the dominant HIV, though patients infected with HIV2 have been described in Europe and America. Its transmission, clinical features and immunological effects are similar to those associated with HIV1 infection. However, there is some suggestion that the incubation period from infection to clinical disease may be longer than with HIV1 and that HIV2 may be less pathogenic. Patients with sera that react with both HIV1 and HIV2 antigens have been described, but it is unclear whether this represents serological cross reactivity or true double virus infection. Testing for HIV2 antibodies may become increasingly necessary in HIV2 non-endemic areas.     

Human immunodeficiency virus (HIV) seropositivity among uninfected HIV vaccine recipients

Since 1987, >10,000 individuals worldwide have received immunizations with human immunodeficiency virus (HIV) preventive vaccine constructs. Many constructs elicit antibodies detected by standard serologic tests (enzyme immunoassays, rapid tests, and Western blots) and result in vaccine recipients' serum being identified as reactive and indicative of HIV infection. To determine the frequency of vaccine-induced HIV antibody among uninfected HIV vaccine trial participants and to identify factors associated with these results, serum samples from HIV-uninfected participants from selected United States phase I/II HIV-1 vaccine trials were tested with 6 serologic screening tests. Reactive specimens were tested by use of Western blot. Overall, 490 serum specimens from 461 vaccine recipients were tested; 100 (20.4%) reacted on at least 1 serologic test, and 65 (13%) were determined to be positive by Western blot. Canarypox or vaccinia vaccine recipients' serum with or without HIV envelope glycoprotein (gp120 or gp160) boosts accounted for all positive Western blot results; no positive Western blot results were obtained from gp120 subunit recipients. The potential for vaccine recipients being misclassified as HIV infected increased with vaccine complexity.     

Human immunodeficiency virus (HIV) infection and the kidney

Since the first report on the acquired immunodeficiency syndrome (AIDS) in 1981, organ involvement of AIDS has increased. We discuss the effect of human immunodeficiency virus (HIV) infection, the causative agent of AIDS, on the field of nephrology. Hyponatremia, the commonest fluid and electrolyte abnormality, is caused by various pathophysiologic mechanisms, including adrenal insufficiency. The renal parenchymal complications are diverse, but a new entity, HIV-associated nephropathy, is becoming recognized because of its characteristic clinical and pathologic features, including the fact that it causes irreversible renal failure. HIV infection in patients with end-stage renal failure, both before and after initiation of maintenance dialysis, is a significant problem. The present methods of preventing spread of virus in dialysis units seem successful. Few patients who are infected with HIV or who have AIDS have had renal transplantation, although unsuspected viral infection of cadaveric organs remains a concern.     

Human immunodeficiency virus (HIV) and the occupational physician

This paper reviews the issues concerning occupational physicians in relation to HIV infection and AIDS, including the epidemiology and the indications for HIV antibody testing in employment. The role of the occupational physician in caring for employees infected with HIV and in educating the workforce is discussed.     

Human immunodeficiency virus (HIV) infection of the uterine cervix

Human immunodeficiency virus (HIV) has been detected in cervical secretions from HIV-infected women. We report the isolation of HIV from four cervical biopsy specimens. Cervicitis was shown by immunohistochemical staining in cervical biopsy specimens from four HIV-seropositive women; cervicitis was not found in cervical biopsy specimens from four HIV-seronegative women. We found HIV antigens in monocyte-macrophages and endothelial cells within the submucosa of three of these cervices by specific immunohistochemical staining. Small numbers of HIV-infected cells resembling lymphocytes also were found in the cervical mucosa. The virus was not shown by culture or immunohistochemistry in cervical biopsy specimens from the four HIV-seronegative women. These findings suggest that HIV enters cervical secretions from selected infected cell populations within the cervical tissue. The HIV-infected cells in cervical tissue may be involved in transmission of HIV by heterosexual contact and to neonates born to HIV-infected women.     

Human immunodeficiency virus (HIV) circulating immune complexes in infected children

Circulating immune complexes (CIC) were studied for the presence of human immunodeficiency virus (HIV) antigens (HIV-Ag) in 55 children infected by the human immunodeficiency virus type 1 (HIV-1). CIC were elevated in 85% of patients. In 33 of 55 patients CIC included at least one HIV-Ag (HIV-Ag-CIC). Sixty percent of patients had p17 antigen, 50% had p24 antigen, and 16% had gp120 associated with CIC. Levels of HIV-Ag-CIC did not correlate with free serum HIV antigens. Patients with high HIV-Ag-CIC had a more severe clinical course and 90% of those with markedly elevated HIV-Ag-CIC (greater than 3+) have died within 6 to 24 months. HIV-Ag-CIC were also present in some patients including neonates and young infants in whom free HIV-Ag was undetectable. Monitoring of HIV-Ag in isolated CIC may be of value for early detection of HIV infection and for monitoring of disease outcome.     

Human immunodeficiency virus (HIV) infection in brains with AIDS-related leukoencephalopathy

In addition to central nervous system (CNS) opportunistic infections and neoplasms, patients with acquired immunodeficiency syndrome (AIDS) develop unexplained dementia and encephalopathy and degeneration of the white matter. We studied autopsied brains from 20 adult patients who expired from AIDS to determine the relationship of human immunodeficiency virus (HIV) infection to white matter lesions and to clinical findings. In four patients with dementia/encephalopathy and abnormalities of the white matter, there was evidence of HIV infection as shown by in situ hybridization. In contrast, the remaining 16 patients who had no evidence of white matter degeneration revealed no hybridization to the HIV probe. The cells infected with HIV included endothelial cells, perivascular macrophages/monocytes, and multinucleated giant cells and were found in or adjacent to white matter degeneration. These results demonstrate a correlation between HIV-infected cells and AIDS leukoencephalopathy and provide further evidence for HIV-related dementia/encephalopathy.     

HIV treatment in developing countries

Diagnostic, prognostic and therapeutic advances have had a major impact on HIV at both the individual and community levels in wealthy nations. However, more than 95% of HIV infections occur in developing countries, where personal or national economies cannot support these measures. Therefore, HIV treatment in developing countries must focus on particular aspects of infection, especially prevention and treatment of those opportunistic infections for which inexpensive antimicrobial agents are available and effective. At present, the focus in developing countries is on tuberculosis, Pneumocystis carinii pneumonia (PCP), and pneumococcal pneumonia. The spread of antimicrobial resistance in mycobacteria and pneumococci is of special concern for developing countries, and strategies to limit the spread of resistance should take high priority. The use of specific antiretroviral agents is limited, because of cost, to prevention of mother-to-child transmission, and notable successes have been achieved. While it is unlikely that these agents will become widely available to the general population, targeting treatment at high-risk groups, through a program of post-exposure prophylaxis, may be an affordable strategy in some situations.     

HIV (human immunodeficiency virus) and HIV-associated diseases

The discovery of the Human Immunodeficiency Virus (HIV), the characterization of its molecular biology and the development of serologic methods for detecting antibodies have led to a better understanding of HIV-associated clinical syndromes. Recently, the Centre of Disease Control has proposed a classification of HIV-related conditions. This classification forms the basis for this review. It is completed by remarks on antiviral and immunomodulating drugs and its effects on HIV. Difficulties in development of vaccines are discussed.     

Human immunodeficiency virus (HIV) associated non-Hodgkin's lymphomas in Denmark: report of three cases

High grade malignant non-Hodgkin's lymphoma (NHL) was the presenting manifestation of the acquired immunodeficiency syndrome (AIDS) in 3/81 reported cases of AIDS in Denmark (by April 2, 1986). Asymptomatic HIV infection, 1 and 5 yr prior to the onset of lymphoma, was documented in 2 cases. 1 patient became infected by Factor VIII treatment, 2 were male homosexuals. 2 patients had an uncommon tumour presentation in the oral cavity, 1 patient presented with an abdominal mass. The histologic subtypes were immunoblastic (2), and small noncleaved cell, Burkitt's (1). Helper/suppressor T-cell ratio was decreased at onset of lymphoma in 2 cases. All 3 patients have died, 4, 6, and 24 months after diagnosis of NHL. Only 1 patient died of NHL, 1 died of an unclassified pneumonia and the third developed progressing supranuclear HIV-associated polyneuropathy without evidence of CNS lymphoma. Thus, high grade malignant B-cell NHL is a regular initial manifestation of AIDS, and may develop after years of asymptomatic HIV infection.     

Human immunodeficiency virus infection (HIV)–associated rheumatic manifestations in thepre- and post-HAART eras

Clinical Rheumatology - Rheumatic manifestations remain an important clinical manifestation associated to HIV. To date after 4 decades of the onset of the HIV/AIDS pandemic, almost 37 million...