The immunological and clinical outcome of HIV infection: 31 months of follow-up in a cohort of homosexual men

Course and Clinical Significance of CD8+ T-Cell Counts in a Large Cohort of HIV-Infected Individuals

OBJECTIVES

To examine trajectories of CD8(+) T-cell counts before and after combination antiretroviral therapy (cART) in human immunodeficiency virus (HIV)-infected individuals and associations with mortality.

METHODS

CD8(+) T-cell counts were measured in 3882 HIV-infected individuals who received care in Copenhagen during 1995-2012. Reference values were obtained from 1230 persons from the background population. Mortality rate ratios were estimated by Poisson regression.

RESULTS

CD8(+) T-cell counts were elevated during untreated HIV infection and remained elevated through 10 years of cART. A slight drop of 130 cells/µL (interquartile range, -160 to 410 cells/μL) in the median CD8(+) T-cell count was observed after cART initiation. CD8(+) T-cell counts stabilized at approximately 900 cells/µL (95th percentile of the background population, 835 cells/µL). Markedly elevated CD8(+) T-cell counts at cART initiation were associated with a poor increase in the CD4(+) T-cell count (relative risk, 2.22; 95% confidence interval [CI], 1.42-3.48). Individuals with a CD8(+) T-cell count of <500 cells/µL 1 year after cART initiation had an increased mortality rate (mortality rate ratio, 1.73; 95% CI, 1.29-2.32) and a higher proportion of deaths attributable to AIDS-related conditions, compared with individuals with CD8(+) T-cell counts of ≥500 cells/µL. After receiving cART for 10 years, a CD8(+) T-cell count of >1500 cells/µL was associated with increased non-AIDS-related mortality (mortality rate ratio, 1.82; 95% CI, 1.09-3.22), compared with a CD4(+) T-cell count of 500-1500 cells/µL.

CONCLUSIONS

CD8(+) T-cell counts are elevated during HIV infection and do not normalize despite long-term cART. Low CD8(+) T-cell counts are associated with increased AIDS-related mortality. Marked elevations in CD8(+) T-cell counts after long-term cART are associated with increased non-AIDS-related mortality.

Antibodies against the major core protein p24 of human immunodeficiency virus: relation to immunological, clinical and prognostic findings

In 79 homosexual men positive for antibody to human immunodeficiency virus (HIV), the titer and avidity of p24 antibody was determined by an indirect ELISA and the serum tested for the presence of HIV antigen. Results were examined for a possible correlation with clinical, immunological and prognostic findings. High titers and low avidity of p24 antibodies correlated significantly with a normal pokeweed mitogen response, early lymph node changes, and an asymptomatic and stable clinical condition. In HIV antigen negative patients, low titers and high avidity of p24 antibodies correlated significantly with a progressive clinical condition. The finding of primarily high avidity antibodies against p24 antigen in patients with more advanced immunodeficiency indicates that a decline of p24 antibodies during the clinical course of HIV infection may not be explained exclusively by an increased production of viral proteins.

The development of AIDS or AIDS-related conditions in a cohort of HIV antibody-positive homosexual men during a 3-year follow-up period

One hundred and thirty-three homosexual men seropositive for the antibody against human immunodeficiency virus (HIV) were enrolled in a prospective study in 1984-85. The 3-year cumulative incidences of the acquired immunodeficiency syndrome (AIDS) and AIDS-related conditions, by life-table analyses, were 18% and 34%. The cumulative incidence of immune deficiency defined as CD4 lymphocytes less than 0.5 x 10(9) l-1 was 70% at 3 years. Absence of antibodies to p24 antigen, HIV antigenaemia, CD4 lymphocytes less than 0.3 x 10 l-1 and elevated serum level of IgA were significantly associated with the development of AIDS. There was no association between disease progression and persistent generalized lymphadenopathy. When adjusted to the probable year of infection, these results are in accordance with previous cohort studies. It is concluded that most, or all, subjects seropositive for HIV will develop progressive loss of CD4 lymphocytes followed by clinical signs of immune deficiency, and that differences among previous cohorts with respect to disease progression are probably due to differences in the duration of infection.

Predictive markers of AIDS: a follow-up of lymphocyte subsets and HIV serology in a cohort of patients with lymphadenopathy

From 1982 to 1985, 89 HIV-1 seropositive men with persistent generalized lymphadenopathy (PGL) were enrolled into a prospective longitudinal study. In February 1988, after a mean observation time of 45 months, 23 patients had progressed to AIDS with opportunistic infection (AIDS/OI), 4 had developed Kaposi's sarcoma, 47 had developed HIV-related symptoms, 14 still had PGL as only symptom, and 1 was lost to follow-up. Patients with CD4 lymphocytes less than or equal to 0.40 x 10(9)/l as well as patients with HIV antigenaemia and those lacking antibodies to p24 all had a significantly higher risk of developing AIDS/OI within 30 months of observation than other patients. HIV antigen was present in 70% and antibodies to p24 were lacking in 61% of the patients at the time of AIDS/OI diagnosis. All but one (96%) of the AIDS/OI patients had CD4 numbers less than or equal to 0.20 x 10(9)/l at the same time. The estimated median time to AIDS/OI in patients with HIV antigenaemia was 21 months and in patients lacking p24 antibodies 27 months. In patients with CD4 numbers less than or equal to 0.20 and 0.40 x 10(9) cells/l the estimated median time to AIDS/OI was 14 months and longer than 30 months, respectively.

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.

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 clinical prognosis of HIV-1 infection: a review of 32 follow-up studies

Thirty-two follow-up studies of patients with HIV-1 infection, but without AIDS at baseline, were examined for information on the risk of developing AIDS or other conditions. Disease progression in asymptomatic groups was similar to that found in patients with persistent generalized lymphadenopathy (PGL) without other symptoms. Among these asymptomatic and PGL groups, the risk of developing AIDS reached 10% to 15% between 24 and 36 months of follow up. The risk of progression to AIDS continued to increase in the studies with longer follow-up periods, reaching 36% at 88 months. However, more than 40% of "high-risk" groups (characterized by the presence of constitutional symptoms, oral thrush, herpes zoster, and/or low T4 counts) developed AIDS after only 36 months of follow-up. Reliable information about progression to other states (e.g., AIDS-related complex) has not been consistently provided.

Serological response in patients with chronic asymptomatic human immunodeficiency virus infection

To examine a possible relationship between decreased immune function and serological parameters, such as human immunodeficiency virus (HIV) antigenaemia and the quality and quantity of whole virus antibodies and antibodies against the major core protein p24, we investigated 160 healthy HIV infected individuals (CDC classification II and III). According to the number of T-helper lymphocytes (CD4 cells) these were divided into two groups (CD4 cell counts above or below 500/microliter), which according to the lymphocyte transformation response to pokeweed mitogen (response above or below 20% of control value) were further subdivided into two groups. Both the presence of HIV antigen (p = 0.022) and the absence of p24 antibodies (p = 0.001) correlated to a decreased CD4 cell count. Lack of p24 antibodies was more frequent than was the presence of HIV antigen among persons with decreased CD4 cell count and decreased response to pokeweed mitogen, indicating that absence of p24 antibodies may be an earlier marker of immune dysfunction than the presence of HIV antigen. In persons with p24 antibodies present, a low such titer was associated with a decrease of both immune parameters. Presence of HIV antigen and absence of p24 antibodies thus seems to correlate with the severity of immune dysfunction in healthy HIV infected individuals.