Demonstration of antibodies to human T-lymphotropic retrovirus type III in lymphoadenopathy syndrome patients and in individuals at risk for acquired immune deficiency syndrome (AIDS) in Italy

Enhancement of human immunodeficiency virus type 1 (HIV-1) infection via increased membrane fluidity by a cationic polymer

Cationic polymers are known to have potent activity against bacteria, but their effects on viral activity have been little studied. We investigated the effect of one such polymer, polyethyleneimine (PEI), on HIV-1 infection. Although virus-cell binding was significantly inhibited by PEI, HIV-1 infection in human T-cell lines such as MT-4 and MOLT-4 was accelerated conversely when the drug treatment was carried out, after the virus had attached to the cells or PEI was simultaneously added to the virus and cell culture system. This paradoxical effect of PEI on HIV-1 infection was examined using HIV-1 chronically infected cells (MOLT-4/HIV-1). Dissociation of the glycoprotein gp120 (as revealed by exposure of transmembrane protein gp41) from MOLT-4/HIV-1 cells and the resultant fusion of these cells was shown to be induced by the addition of PEI. Accordingly, it was suggested that the binding inhibition of HIV-1 to CD4-positive cells by PEI was due to the shedding of gp120 from HIV-1 particles, and this PEI rather promoted membrane fusion between the virus and cells leading to the enhancement of HIV-1 infection. Similarly, dissociation of gp120 from MOLT-4/HIV-1 was also induced by sCD4. The effect of these reagents on changes in membrane fluidity was evaluated by polarization (p) measurements, and it was observed that the acceleration of membrane fluidity occurred only in the PEI system. Therefore, it is likely that PEI accelerates HIV-1 infection by facilitating virus entry into the host cells through an increase in membrane fluidity.

Immunological, Clinical and Epidemiological Aspects of an HIV-1 Positive Drug Abuser Cohort

We analyzed a cohort of intravenous drug abusers with HIV-1 disease attending our institute in the years 1985–1993. We focused particular attention on the epidemiological analysis of patients, and their clinical, immunological and infectious conditions. The significance of biological markers, particulary CD4+ lymphocyte count and the occurence of other viral infections such as Cytomegalovirus, Epstein-Barr virus, Herpes Simplex virus and Hepatitis B and C viruses in the progress of HIV-1 disease were evaluated. At least two-thirds of the patients at different stages of HIV-1 were treated with antiretroviral drugs: zidovudine (AZT) from 1987 up to the present and more recently didanosine (DDI) alone or in combination with AZT. Psychological and behavioral aspects of our HIV-1 infected drug abusers, in particular needle exchange and condom use, were analyzed.

The epidemiology of acquired immunodeficiency syndrome and associated tumours in Europe

By the end of September 1991, more than 60,000 cases of acquired immunodeficiency syndrome (AIDS) had been reported to the World Health Organization (WHO) by 31 countries in the WHO European region. Most of the cases (58,280/60,485-96%) were recorded in western Europe, chiefly in five countries: France (16,552 cases), Italy (10,584), Spain (10,101), Germany (6,968) and the United Kingdom (5,065). From the first reports in 1981 of European cases of AIDS until 1987, AIDS spread faster in the northern and central areas than elsewhere in the European region. Since then, the spread of the epidemic has been remarkably more rapid in southern Europe, while in eastern Europe AIDS is still in an early phase. More than 70% of the cases among homosexual or bisexual men were from the northern part of Europe, while the cases among intravenous drug users (IVDUs) were concentrated in the southern European countries, principally Italy and Spain. Over time, an increasing proportion of cases was recorded among IVDUs and in heterosexuals. More than 10,000 patients in Europe were diagnosed as having Kaposi's sarcoma (KS) (14% of all AIDS cases) or non-Hodgkin's lymphoma (NHL) (3%) as the presenting clinical manifestation of AIDS. The possibility of predicting the evolution of the epidemic in Europe depends heavily on the development of unbiased monitoring systems for HIV infection in the general population (i.e. anonymous unlinked testing).

Human immunodeficiency virus (HIV) seropositivity in intravenous (i.v.) drug abusers in three cities of Italy: possible natural history of HIV infection in i.v. drug addicts in Italy

The prevalence of human immunodeficiency virus (HIV) antibodies and the symptoms induced [persistent generalized lymphadenopathy (PGL), AIDS-related complex (ARC), acquired immunodeficiency syndrome (AIDS)] was evaluated in several groups of intravenous (IV) drug abusers in three large Italian cities (Milan, Bologna, and Rome). The earliest evidence of seropositivity in sera collected from patients with acute viral hepatitis dates back to 1979 in Milan and to 1981 in Bologna with peaks in 1983 in both cities. In two groups of IV drug addicts on methadone-maintenance treatment at assistance centers, the prevalence of seropositivity differed sharply between Rome (33.3%) and Milan (69.3%) in 1985. Rates of seroconversion were also found to be higher in Milan than in Bologna and Rome. When a population of IV drug abusers voluntarily attending centers for surveillance of AIDS and/or ARC were investigated, high levels (range 55.2-81.5%) of seropositivity were found in the three cities. ARC prevalence among seropositives was very high (range 48.1-64.2% in 1985) in the three cities. The evolution rate to AIDS in Milan was higher among those attending a center for AIDS surveillance (7.4%) than among those attending an assistance center for methadone treatment (0.9%). These data are compatible with the hypothesis that virus infection among IV drug abusers originated in and then spread widely in Northern Italy (Milan first and then Bologna). Both the first appearance and subsequent spread of virus infection are in keeping with the reported occurrence of AIDS cases in the corresponding three regions of Milan, Bologna, and Rome.

AIDS in Sicily: prevalence of antibodies to human immunodeficiency virus (HIV) in low and high risk groups

A seroepidemiological survey, carried out to evaluate the prevalence of antibodies to HIV in patients with ARC and in healthy individuals at risk for AIDS, showed the infection to be widespread in the groups at risk, namely in drug abusers and hemophiliacs. However, remarkable difference existed between the prevalence of antibodies to HIV in drug abusers of the city of Palermo and those of other Sicilian provinces. Spread of the virus among Sicilian thalassemics, however, was very low and quite similar in all geographic areas. Antibodies were found very rarely (0.06%) in unpaid voluntary blood donors. The spread of the virus is still confined in high risk groups, and the major part of the seropositive blood donors were identified a posteriori as drug abusers.

Characterization of specific immune complexes in HIV-related disorders

Eighty-seven seropositive subjects with HIV (human immunodeficiency virus) infection together with 20 normal controls with no history of any illness were investigated for the presence of circulating immune complexes (CIC) by the conglutinin binding assay (KgBA) and further studied for isotype characterization of CIC. Six out of 87 patients showing very high values for immune complexes (CIC) were studied for the presence of free antigen. In 3 out of 6 (1, IVc1; 1, III; 1, IVa) we could detect by ultracentrifugation analysis the presence of specific HIV (p15) anti-HIV (anti-p15) and gp41-anti-gp41 CIC. Evidence in favour of this finding is supported by: the presence of specific CIC (p15-anti-p15 or gp41-anti-gp41) seen only at pH 7.2; the apparent presence of free antigen and specific HIV antibodies were only at pH 4.0. The relevance of this finding lies in the attempt to explain the occurrence of false seronegativity seen occasionally in symptomatic patients. Thus, the presence of CIC might perhaps interfere in the routine assay (i.e. ELISA) making the diagnosis difficult. All these considerations will have to be taken into account in the future handling of this disease.

Transmission of human immunodeficiency virus (HIV/HTLV-III/LAV): a review

The literature on the transmission of human immunodeficiency virus (HIV/HTLV-III/LAV) is reviewed. HIV spreads by vertical transmission and by iatrogenic transmission (transfer of blood or blood-containing products), by infected needles among i.v. drug users and, more rarely, among health care workers, but mainly by sexual contact. In Western countries the virus is mainly spread by passive anal intercourse among homosexuals and seldom by heterosexual intercourse. In African countries, however, the virus is mainly spread by heterosexual intercourse, probably because of other, concurring sexually transmitted diseases. Some preventive measures are discussed.

Screening and confirmatory tests for antibody to HTLV-III/LAV retrovirus in individuals at risk for AIDS

The prevalence of specific antibodies to HTLV-III/LAV retrovirus was investigated during 1985 in a large group of subjects at risk for AIDS living in the Florence area. Two hundred and thirty-two of 774 (29.9%) intravenous drug users (IDU), 40 of 164 homosexuals (24.3%), 43 of 147 hemophiliacs (29.2%), 7 of 10 children born from IDU mothers and 4 of 88 heterosexual partners of IDU were found to be seropositive using different ELISA kits. The positivity in all serum samples showing low antibody titres and/or discordant results with different sandwich ELISA kits was confirmed by a competition ELISA assay and the Western blot technique. Serum samples from 4 of 210 hemodialyzed and from one of 17 polytransfused patients also showed positive reactions in the assays based on the sandwich principle, but gave negative results in both the competition ELISA assay and the Western blot technique. In addition, all these sera showed positive reactions using immunofluorescence and ELISA procedures that control for reactivity with H9 human cell line material used for culturing the HTLV-III/LAV retrovirus. These data demonstrate that exposure to HTLV-III/LAV retrovirus is widespread in groups of subjects at risk for AIDS living in the Florence area. Furthermore, the results of the present study suggest that, in addition to the Western blot technique, the competition ELISA assay as well as assays that control reactivity with H9 human cell line material may be of value for detecting false positive reactions due to antibody cross-reactive with human cellular components.