Bjarne Ørskov Lindhardt

T-cell subset alterations and lymphocyte responsiveness to mitogens and antigen during severe primary infection with HIV: a case series of seven consecutive HIV seroconverters.

Seven consecutive patients who presented with a severe acute mononucleosis-like illness associated with HIV seroconversion were evaluated by T-cell subset enumerations and measurements of lymphocyte transformation responses to mitogens and antigen during both their primary illness and a 1-year follow-up period. We observed a characteristic pattern of response to primary HIV infection; initial lymphopenia was followed by CD8 lymphocytosis and inversion of the CD4:CD8 ratio. During follow-up, the CD8 count gradually returned to normal, whereas the CD4:CD8 ratio remained inverted because of a relatively low number of CD4 lymphocytes. Primary infection was followed by prolonged and severe cellular hyporesponsiveness to both mitogens and antigen. At the last follow-up, responses to pokeweed mitogen were still severely impaired, with a median 19% (range 7-50%) of that observed in healthy controls. We conclude that severe primary HIV infection may be followed by sustained lymphocyte hyporesponsiveness, a sustained low percentage of CD4 lymphocytes and sustained inversion of the CD4:CD8 ratio.

Investigation of immunosuppressive properties of inactivated human immunodeficiency virus and possible neutralization of this effect by some patient sera

Retroviral infections are accompanied by immunosuppression in a variety of species. For feline leukemia virus, the immunosuppression has been ascribed to the transmembrane envelope protein, p15E, which suppresses the proliferative responses of cat, mouse, and human lymphocytes. A similar suppressive effect has been shown for a lysate of human immunodeficiency virus (HIV), strain HTLV-IIIB. Here we determined that detergent-disrupted HTLV-IIIB lystate exerted a strong suppressive effect on PHA-stimulated lymphocytes. Preparations of whole virions, a lysate of a local HIV isolate grown on MP-6 cells, and a commercially obtained UV and psoralene-inactivated lysate were examined and demonstrated to have a similar suppressive effect. The HIV lysate was not directly cytotoxic to lymphocytes and did not contain tumor necrosis factor or lymphotoxin. The HIV lysate specifically suppressed the proliferation of a range of hemopoietic cell lines from man and mouse including three EBV transformed CD4- and IL-2 receptor-negative B-cell lines. The lysate also suppressed the formation of human bone marrow colonies, whereas the lysate had only a slight or no effect on fibroblasts. The suppression of lymphocyte proliferation was not abrogated by addition of IL-2 or IL-1 and the HIV lysate inhibited the expression of IL-2 receptors on suboptimal PHA-stimulated mononuclear cells. The suppressive factor(s) has not been characterized in molecular terms, but suppressive activity was recovered in fractions with a molecular weight of about 67,000 and in both the glycoprotein fraction and in the glycoprotein-depleted fraction of the HIV lysate. Sera from one-third of a small series (N = 13) of individuals with antibodies to HIV seem to be able to neutralize the suppressive properties of HIV lysate in cultures.

Prognostic value of immunologic abnormalities and HIV antigenemia in asymptomatic HIV-infected individuals: proposal of immunologic staging

The prognostic value of various immunologic tests was investigated in 150 HIV-seropositive homosexual men, who were initially without HIV-related symptoms or AIDS and who were followed for a median of 12 months (range 3-28 months). The laboratory investigations included HIV antigen in serum, total lymphocyte count, T-helper (CD4) and T-cytotoxic/suppressor (CD8) counts, and lymphocyte transformation responses to the mitogens phytohemagglutinin (PHA) and pokeweed mitogen (PWM), and to antigenic extracts from Candida albicans and cytomegalovirus. 24 individuals developed HIV-related symptoms or AIDS (11 cases). All parameters except the CD8 count were of prognostic value, but a multivariate analysis of symptom-free survival showed that HIV antigenemia, a CD4 count less than 0.5 x 10(9)/l, and relative response to PWM below 25% of controls contained all the prognostic information. Individuals abnormal at entry for these 3 variables had a theoretical 36 times as high hazard of developing symptoms within the observation period as had individuals with normal parameters. There was no significant covariation between HIV antigenemia on the one hand and CD4 count and response to PWM on the other. Although, the latter 2 variables covaried, each of them provided independent information, and both were used to classify the degree of the immunodeficiency in 3 stages: Im-0 with normal values, Im-1 with one, and Im-2 with both tests abnormal. Individuals in stage Im-2 had a 10 times increased risk of developing symptoms. The immunologic staging correlated significantly with the clinical grouping (CDC criteria). This staging improved in only 1, but deteriorated in half of 36 individuals observed for at least 18 months. Thus, the staging is likely to prove useful when attempts to arrest the immunodeficiency of HIV-infected individuals has to be monitored.

The Immunological and Clinical Outcome of HIV Infection: 31 Months of Follow-up in a Cohort of Homosexual Men

T-cell subsets, antibodies (Ab) against human immunodeficiency virus (HIV) and clinical status were evaluated during a 31 (24-35) month follow-up study of homosexual men. The study group included 50 homosexual men, with many sexual partners, who by 1982-83 were without symptoms and had a prevalence of HIV Ab of 38%. Among the men who were seropositive on the initial investigation a significant decrease occurred in the absolute number of CD4+ lymphocytes (p less than 0.01). 88% of these men experienced a decrease, and by follow-up 59% had CD4+ lymphocytes below the normal range. Also the men who seroconverted during the study had a significant decrease in CD4+ lymphocytes, while no changes were observed in the seronegative group. None of the subgroups had significant changes in CD8+ lymphocyte number. AIDS or AIDS related complex developed in 33% of the men seropositive at inclusion. None of these clinical syndromes developed in the seroconverting or the seronegative group. The men who eventually developed clinical symptoms did not differ significantly from the healthy HIV Ab positive persons, with respect to lifestyle parameters, presence of lymphadenopathy and isolation of cytomegalovirus. However, they had significantly lower CD4+ cells and CD4/CD8 ratio (p less than 0.01) at inclusion. It is concluded that in the majority of persons infected with HIV, phenotypic T-cell alterations will occur with a latency of years, but it remains to be seen if the alterations necessarily will result in clinical manifestations. Further, T-cell subset determination among healthy HIV Ab positive persons will provide prognostic information.

Neutralizing antibodies against two HIV-1 strains in consecutively collected serum samples: cross neutralization and association to HIV-1 related disease

97 sera collected during a 10-year period from 10 HIV-1 infected individuals were tested for neutralizing capacity against a virus isolate FICPH-22 obtained from a Danish AIDS patient, and the laboratory strain HTLV-IIIB. Three patterns of serum neutralizing activity were demonstrated: (a) patients developing high neutralizing activity against both HIV strains; (b) patients developing high neutralizing activity against the Danish virus isolate; and (c) patients developing only low titers of neutralizing antibodies (NA) against both HIV strains. The HTLV-IIIB strain was less sensitive to serum neutralization than the FICPH-22 isolate and the appearance of NA against HTLV-IIIB was typically lacking several years behind that against FICPH-22 indicating a broadening of the NA response over time. No difference in clinical outcome was observed comparing patients reaching high titers of NA and patients with low titers. Development of AIDS among patients reaching high titers of NA was preceded by a decline in NA titers, indicating an association of high titers of NA with the healthy carrier state and of declining or low titers of NA with disease progression. The majority of the neutralizing activity was mediated by IgG, but some neutralizing activity was demonstrated in the IgG depleted serum, indicating the presence of additional neutralizing substances in serum.

Antibody to HIV in Patients with Acute Hepatitis B in the Period 1975–1984

In order to elucidate the time when HIV was introduced into a population of patients with acute hepatitis B, serum samples collected in the period 1975-1984 from 331 patients with hepatitis B were analysed for the presence of antibody to HIV (anti-HIV). Anti-HIV was not detected in any of the serum samples from 97 females. 5/234 serum samples from males (2%) were repeatedly positive. Anti-HIV was first demonstrated in 1978, 3 years before the first patients with AIDS were recognized in Denmark. None of the 4 Danish patients with anti-HIV developed AIDS during a follow-up period of 1-7 years. However, at the time of follow-up in 1985 3 had decreased cell mediated immunity. The hepatitis B infection had an uncomplicated course in 4/5 patients with anti-HIV. One patient had a protracted delta hepatitis and was a HBsAg carrier before as well as after the acute hepatitis. Thus, the HIV infection did not cause any complicated course in this study.

HIV-2 Infection in Denmark

A collection of 3019 selected serum samples (ss), comprising 329 ss from intravenous drug abusers, 558 ss from homosexual men, 682 samples from persons attending a STD clinic, 100 ss from individuals of African origin, 300 ss from sexual contacts to Africans, 650 ss from Danish blood donors who resided in Africa greater than 2 years prior to donating the ss, and 400 ss with equivocal antibody reactions in an HIV-1 Western blot was tested for antibodies against HIV-2 by in-house HIV-2 ELISA and Western blot. Four ss were positive for antibodies against HIV-2. Three of the ss originated from West African men, the fourth belonged to the spouse of one of these men. Three of the samples presented with an uncharacteristic reaction in a HIV-1 Western blot. The study indicates that HIV-2 infection is not yet widespread in Denmark and that it remains closely related to West Africa.

HIV Neutralizing Antibodies: Development and Association with HIV Related Disease

Serum neutralization was measured in 72 sera collected during a 5.5-year period from 10 HIV infected individuals. Neutralizing antibodies (NA) were present in all sera. NA titers ranging from greater than 40 to greater than 640 were detected in sera from 4 patients, who all remained healthy and further an increase with time of NA was observed in these 4 patients. Progression to disease was observed in 3 persons with NA titers less than or equal to 40 who also lacked or lost anti-gag antibodies. Two of these patients were HIV antigenaemic prior to development of disease, whereas antigen was not detected in the remaining 7 healthy persons. A weak positive correlation (R(S) = +0.643, p less than 0.001) was found between titers of NA and whole virus antibody (WVA), with the ratios between titers (NA titer/WVA titer) varying a 100-fold. The results suggest that the presence of NA in some cases might be related to a healthy carrier state and that a combination of low titer NA with decline of anti-gag antibodies and/or HIV antigenaemia is associated with progression to clinical disease.

Serological Markers of Primary HIV Infection

39 persons with an incidentally discovered seroconversion from HIV antibody negative (Ab-) to antibody positive (Ab+) state as measured by an enzyme-linked immunosorbent assay (ELISA) were investigated for the presence of (1) HIV antigen (Ag) and (2) immunoblotting test (IBT) Ab in serum samples collected within the year before seroconversion. 13 (33%) of the patients were HIV Ag+ at some time before seroconversion. However, the collection of samples was not done systematically and the samples from patients who had at least 1 sample collected within 3 months before seroconversion were thus compiled separately. This group consisted of 58 samples from 19 patients and among these none were HIV Ag+ earlier than 11 weeks before seroconversion, but the prevalence of HIV Ag+ samples was rising towards seroconversion and 10 patients (53%, 95% confidence limits: 29-76%) became HIV Ag+ in this 11-week period. Further, among all patients 13 (33%) were IBT Ab+ 4-50 days (median: 14 days) before seroconversion. Finally, among 18 patients with signs and symptoms consistent with an acute HIV infection 10 were HIV Ag+, as opposed to 4 HIV Ag+ patients among 21 without symptoms (p = 0.041).