Free and antibody-complexed antigen and antibody profile in apparently healthy HIV seropositive individuals and in AIDS patients.

The pattern of free and antibody-complexed HIV antigen and the antibody profile were investigated retrospectively in 305 serum samples taken from 22 AIDS patients before and during the development of AIDS and from 40 apparently healthy seropositive individuals. Most AIDS patients were found positive for both free and complexed antigen and had high gp41 antibody titres but low or undetectable p24 antibody. Four different patterns of HIV antigenaemia were observed: 1) positive for both free and complexed antigen; 2) negative for free HIV antigen at first, but always positive for complexed antigen; 3) positive for free antigen without complexed antigen; and 4) negative for both free and complexed antigen. The development of immune complexes preceded the appearance of free antigen and might reflect the ongoing viral replication with antigen excess and binding of anticore antibodies. No correlation was found between the development of AIDS symptoms and either the duration of free antigen positivity or the level of antigenaemia. A different pattern was observed in apparently healthy seropositive individuals: 90% of whom had high antibody titres to p24 and gp41 and were persistently negative for free and complexed HIV antigen. This study demonstrates that testing HIV markers in sequentially collected serum samples from HIV seropositive individuals is a useful and simple tool for early identification of persons at risk of developing AIDS.

Neutralizing antibody and clinical status of human immunodeficiency virus (HIV)-infected individuals.

An assay based on inhibition of cytopathic effect of human immunodeficiency virus (HIV) strains in Molt 4 cells was developed to quantitate neutralizing antibodies (NA) in sera of HIV-infected individuals. The assay was specific and gave results comparable to those obtained by the inhibition of immunofluorescence (IFI) and reverse transcriptase (RT) activity. Attempts were made to correlate the presence and the antibody titres with the clinical status of HIV-infected individuals classified according to Walter Reed staging classification scheme. NA titres correlated inversely with the stage of HIV infection: Compared with acquired immunodeficiency syndrome (AIDS) patients, HIV-infected subjects at stage WR1 had significantly higher NA titres. Moreover, a decrease in NA titre in relation to clinical deterioration was noted in sequential sera of eight of 11 AIDS patients, retrospectively examined, for NA. The symptomless subjects showed either the same level of NA or a trend towards an increasing antibody titre with time. Different isolates of HIV strains showed a variability in the extent of sensitivity to neutralization by sera obtained from different HIV-infected individuals.

Further isolation of HIV strains in Palermo: some biological properties of the new isolates.

21 HIV strains were isolated from peripheral mononuclear cells of 31 adult and pediatric patients with AIDS or ARC and 10 apparently healthy HIV seropositive individuals. Viral isolation rate was correlated to the clinical status of patients, being very high in patients with AIDS or ARC, and lower in apparently healthy individuals. 4 isolates were propagated in cultures of a T-cell continuous line (Molt 4) and their biological properties were compared. The capacity to establish a chronic infection on Molt 4 cells and the extent of cytopathic effect of the infected cultures varied among the different strains. Moreover, differences in endpoint titrations of the supernatants and variable effects on cell multiplication and viability of Molt 4 cells were also observed. Our results further substantiate the existence of a wide heterogeneity of HIV strains.

Main routes of transmission of human immunodeficiency virus (HIV) infection in a family setting in Palermo, Italy.

A cross-sectional seroepidemiologic study was carried out on household contacts and sexual partners of human immunodeficiency virus (HIV) antibody-positive intravenous drug abusers in Palermo, Italy, in 1985 to evaluate factors that influenced HIV transmission. A total of 43 index cases, 36 spouses or heterosexual partners, 28 children, and 55 adult household members were enrolled. None of the household members without sexual contact, who had shared items and facilities and had interacted with the index cases, contracted HIV infection. However, six of 36 sexual partners had antibodies to HIV. It was observed that the risk of HIV infection was significantly associated with the frequency of sexual intercourse with the seropositive partner. Four children were also found to be infected: two had acquired immunodeficiency syndrome-related complex, and the other two were clinically and immunologically normal. Furthermore, one other child had evidence of passive transfer of maternal antibodies. The infection was confined to the younger children (ranging in age from eight months to three years). The data support a high rate of vertical transmission from mother to infant, an intermediate rate of transmission to sexual partners, and no transmission attributable to household contact.

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.

Isolation of HTLV III/LAV from drug addicts in Palermo.

The new human retroviruses HTLV III/LAV, implicated as the causative agent of AIDS, have been isolated from peripheral blood lymphocytes of 5 of 13 drugs abusers with acquired immunodeficiency syndrome-related complex (ARC). In one patient the virus was also found in cell-free plasma. No HTLV III/LAV was detected in or isolated from 5 clinically healthy drug abusers. The lymphocytes were cultured with interleukin 2 and expressed either a transcriptase reverse activity or HTLV III/LAV antigens within 2-3 weeks of cultivation. The viruses were also transmitted into normal lymphocytes from cord blood of human newborns. At the present state of development, virological investigation, other than seroepidemiological survey, seems a suitable marker for human retroviruses tracing in epidemiological studies.

HBV infection risk in hospital workers.

Prevalence of HBV infection markers and its association with some risk factors has been studied on hospital staff of the University Polyclinic of Palermo. The results show that male sex, job category (technicians, nurses, cleaners) and age are significantly associated with a higher prevalence of HBV infection markers; length of service and working in departments with a presumably higher exposure to blood did not result as a risk factor of higher prevalence of HBV infection when submitted to multiple regression logistic analysis. It is suggested that results of this study may be affected by the elevated spread of HBV infection in this area, and extra risk associated to hospital exposure is too small to be demonstrated.