Terese L. Katzenstein

Relations among CD4 lymphocyte count Nadir, antiretroviral therapy, and HIV-1 disease progression : Results from the euroSIDA study

The availability and widespread use of highly active antiretroviral therapy have led to marked decreases in the incidence of AIDS-defining illnesses and death (1-3). Highly active antiretroviral therapy substantially increases CD4 lymphocyte counts (4-6) and T-cell function (7-9). Speculation exists about the immune reconstitution and complete recovery of patients infected with HIV (10). The potential for immune reconstitution after severe immunodeficiency is of clinical significance because it may change the need for primary and secondary prophylaxis (11) and will ultimately help to determine the well-being of the patient. Viral load and CD4 cell counts have independently predicted HIV-1 disease progression (12). Clinical trials (13-15) have demonstrated that therapy-related changes in surrogate markers were associated with clinical benefit. However, the effect of a previous CD4 cell count nadir on clinical benefit in patients experiencing increases in CD4 cell count has not been addressed. In addition, an analysis of clinical benefit in patients whose CD4 cell counts have rebounded from very low levels compared with benefit in patients who do not experience such a rebound has not been reported. This information may be difficult to obtain through clinical trials and may be accessible only through large, standardized, monitored observational databases. We explored the relations among CD4 lymphocyte count, antiretroviral treatment, and clinical disease progression through an analysis of the EuroSIDA cohort study, which follows 7333 European patients infected with HIV-1. Our first objective was to investigate the effect of a previous CD4 cell count nadir on prognosis [rate of disease progression and relative hazard for disease progression] in patients who have a CD4 count of at least 200 cells/mm3. We wanted to determine whether HIV-1 disease progresses at the same rate in two types of patients: 1) patients whose previously low CD4 counts have increased to and remain greater than 200 cells/mm3 and 2) patients whose CD4 counts have never decreased to less than 150 cells/mm3 (Figure). Our second objective was to investigate the effect of a rebound in CD4 cell count after a patient has experienced severe immunosuppression. We did this by comparing the rate of disease progression in patients with current CD4 counts of at least 200 cells/mm3 who had a previous nadir of 50 cells/mm3 or less (group A, stratum 4) with the rate of progression in patients with current CD4 cell counts of 50 cells/mm3 or less (group B) (Figure). In addition, we investigated the effect of type of antiretroviral treatment on disease progression in both patient groups. Figure. Study design. solid-line graphs broken-line graph Methods The EuroSIDA study is a prospective, observational study of HIV-infected patients in 52 outpatient clinics across Europe (Appendix) (2, 16). Individual centers enrolled between 24 and 323 patients (13 centers enrolled>200 patients, 18 centers enrolled between 100 and 200 patients, and 21 centers enrolled<100 patients). Consecutive patients who made a regular appointment at least 2 weeks before recruitment were enrolled. Eligible patients were at least 16 years of age and had had a CD4 count less than 500 cells/mm3 in the previous 4 months. The EuroSIDA study has enrolled a total of 7333 patients who were recruited at three separate time points: May 1994 (cohort I; n=3121), December 1995 (cohort II; n=1369), and February 1997 (cohort III; n=2843). Information was collected on a standardized data collection form at baseline and every 6 months thereafter. This information included CD4 cell counts, starting and ending dates of each antiretroviral treatment, use of prophylaxis against opportunistic infections, and dates of diagnosis of all AIDS-defining diseases (according to the 1993 clinical definition of AIDS as determined by the Centers for Disease Control and Prevention). Members of the EuroSIDA coordinating office visited all centers to ensure that patients were selected correctly and that accurate data were provided. Statistical Analysis We identified two groups of patients. Patients in group A had CD4 counts of 200 cells/mm3 or greater; patients in group B had CD4 counts less than 50 cells/mm3. For example, a patient in group A who had a previous CD4 cell count nadir less than 50 cells/mm3 while enrolled in the study would have contributed data to group B for the period that the CD4 cell count was less than 50 cells/mm3. A single patient could thus contribute data to both groups, depending on the profile of CD4 cell counts. At recruitment, information on the four most recent CD4 counts was collected; these data were included in the analyses. Information on all CD4 cell counts measured after recruitment was also collected. We used a patient-years method of analysis to calculate incidence of AIDS-defining illness or death, unadjusted for potential confounding variables. We calculated 95% CIs using a normal approximation or a Poisson distribution when the number of events was small. For the analysis of events in group A (patients with CD4 counts 200 cells/mm3), patient follow-up was from the date on which the first CD4 count of at least 200 cells/mm3 was obtained (referred to as baseline) until the CD4 count decreased to less than 200 cells/mm3 or the patients progressed to death or to an AIDS-defining illness. For patients who had AIDS at baseline, follow-up was continued until development of a new AIDS-defining illness (recurrences of disease were not included). Patients whose CD4 cell count did not decrease to less than 200 cells/mm3 and who did not experience an event were censored at their last follow-up visit. This analysis was stratified according to the minimum CD4 cell count experienced before baseline. Four strata were defined: CD4 cell count nadirs of 150 cells/mm3 or greater (stratum 1), 100 to 149 cells/mm3 (stratum 2), 50 to 99 cells/mm3 (stratum 3), and 1 to 50 cells/mm3 (stratum 4). The incidence of disease in patients from group B (CD4 counts<50 cells/mm3) was calculated in the same way. Patient follow-up began at the date on which the first CD4 count less than 50 cells/mm3 was obtained and ended when the CD4 count increased above this level, when the patient died, or when HIV-1 disease progressed. If none of these events occurred, follow-up ended at the last office visit. To further investigate the relative hazard of disease progression according to CD4 cell count nadir in group A patients, we used Cox proportional-hazards models. We investigated the relation between disease progression and such demographic factors as age, exposure category, sex, and ethnicity. In addition, we considered the following factors at baseline: CD4 cell count, treatment regimen (no treatment, monotherapy, dual combination therapy, combination therapy with three or more drugs, or highly active antiretroviral therapy [defined as a minimum of one protease inhibitor or non-nucleoside reverse transcriptase inhibitor in combination with a minimum of two nucleoside reverse transcriptase inhibitors]), and whether AIDS had been diagnosed in a patient. With the exception of age, demographic factors were not related to disease progression in univariate models and were therefore not included in multivariate models. Variables were included in the multivariate model as fixed covariates. When measurements of CD4 cell count before recruitment to EuroSIDA were included, the analysis was left-censored at the date of recruitment. In the multivariate analysis, we also adjusted for calendar time (because of the strong relation between calendar time and the introduction of more effective therapies) and stratified by study center. We also adjusted for use of prophylaxis against Pneumocystis carinii pneumonia. All analyses were done by using SAS software, version 2 (SAS Institute, Inc., Cary, North Carolina), with one exception: The CIs were calculated on a hand calculator with the use of tables for the Poisson distribution when the number of events was small. Role of the Funding Source The sponsors of the EuroSIDA study did not influence the organization or execution of the study in general; were not involved in the design, execution, and interpretation of this analysis; and had no role in the decision to publish these findings. Results The patient samples on which the analyses are based are described in Table 1. Of a total of 7333 EuroSIDA patients, 5352 had a CD4 count of at least 200 cells/mm3 (group A) and 2514 patients had CD4 cell counts of 50 cells/mm3 or less (group B). Group A patients were stratified according to CD4 cell count nadir: Those in stratum 1 had a nadir of at least 150 cells/mm3; those in stratum 2 had a nadir of 100 to 149 cells/mm3; those in stratum 3 had a nadir of 50 to 99 cells/mm3; and those in stratum 4 had a nadir of less than 50 cells/mm3. When we compared patients from these four strata, the median baseline CD4 cell count was significantly higher in patients from stratum 1. Baseline viral loads were available for a subset of patients only. Median baseline values were greater for patients from stratum 4 and group B. Table 1. Patient Characteristics Table 2 lists the number of events, patient-years of follow-up, and incidence rates for each patient group and stratum. For patients in group A, the overall median duration of follow-up was 16 months; follow-up times decreased sharply as the nadir decreased. Patients in group B had a median follow-up duration of 6 months. The overall incidence for patients with CD4 counts of at least 200 cells/mm3 was 3.9 events per 100 patient-years of follow-up (95% CI, 3.5 to 4.3 events); within the four strata, patients from stratum 1 had the lowest incidence (3.7 events) and patients from strata 2, 3, and 4 had a higher incidence (6.0, 8.1, and 5.9 events, respectively). The incidence for patients from group B was 18-fold higher (72.9 events per 100 patient-years of follow-up [

Longitudinal serum HIV RNA quantification : correlation to viral phenotype at seroconversion and clinical outcome

Objective:To investigate the longitudinal changes in serum HIV RNA, and to clarify whether the viral load early in infection has a predictive value for the clinical outcome; also, to correlate viral phenotype at seroconversion and changes in CD4 cell counts with viral burden. Design:Twenty seroconverters with HIV isolates available at seroconversion had HIV RNA quantified by polymerase chain reaction (PCR) at seroconversion and thereafter every 6 months. Mean follow-up time was 65 months. Patients were classified according to viral phenotype at seroconversion, time to AIDS progression, serum viral load within the first year (less or more than 1.5×104 copies/ml). Results:High viral load at seroconversion was followed by a significant decline within the first months (P<0.0005). Decline to <1.5×104 copies/ml was correlated with slower progression to AIDS (P<0.05). A correlation between the rate of CD4 decline and the median viral load during the ensuing viral load plateau phase was also shown (P<0.05). Subsequent to this phase the viral burden increased. Rapid progressors had higher viral load than slow- or non-progressors; this was particularly pronounced late in infection. Harbouring syncytium-inducing (SI) virus at seroconversion was associated with faster progression to AIDS than non-SI (NSI; P<0.005). The increased in vitro replication rate of SI over NSI was not translated into significantly higher serum HIV RNA. Conclusion:Serum HIV RNA is high around the time of seroconversion. A significant decline within the first months hereafter is followed by a plateau phase, which in turn is followed by an increase in HIV RNA. HIV RNA early in infection has a predictive value for the clinical outcome. The increased virulence of SI over NSI virus did not translate into significantly higher HIV RNA values.

The relative prognostic value of plasma HIV RNA levels and CD4 lymphocyte counts in advanced HIV infection

Objective:It has been suggested that the plasma HIV RNA level is a better predictor of AIDS and death than the CD4 lymphocyte count. We assessed whether the prognostic value of plasma virus levels was different according to the CD4 count. Design:Prospective cohort study of HIV-infected patients followed for a median of 2.91 years (range, 0.02–4.54). Setting:Department of Infectious Diseases at Rigshospitalet, Copenhagen, Denmark. Participants:A group of 255 HIV-infected individuals with an initial measurement of CD4 lymphocyte count and plasma HIV RNA. Main outcome measure:Survival time. Results:The plasma HIV RNA (median 101 410 copies/ml; range (range 200–7 200 000) and the CD4 lymphocyte count (median 250 cells × 106/l; range 1–1247) were negatively correlated (Pearson r = −0.53; P < 0.00001). Of the 255 patients, 110 died during follow-up. Overall, a higher HIV RNA level was associated with increased risk of death, but the association was smaller in patients with lower CD4 lymphocyte counts (test for interaction P < 0.0001). In patients with CD4 count below 50 cells × 106/l the association between HIV RNA and risk of death was not statistically significant (relative hazard per 10-fold higher HIV RNA level was 1.53; P = 0.11; adjusted for age and CD4 count) while that between the CD4 count and risk of death was highly significant (relative hazard per 50% lower CD4 count 1.38; P = 0.005; adjusted for age and HIV RNA level). Conclusions:Patients were relatively lightly treated with antiretroviral drugs both before and during this study. In this situation, it appears that the HIV RNA level has a relatively weak association with risk of death in patients with advanced HIV infection and that the CD4 lymphocyte count is probably more useful in assessing prognosis.

Combination therapy containing ritonavir plus saquinavir has superior short-term antiretroviral efficacy: a randomized trial

OBJECTIVES To compare the efficacy and safety of indinavir 800 mg three times a day, ritonavir 600 mg twice a day, and a combination of ritonavir 400 mg twice a day and saquinavir 400 mg twice a day, when administered with two nucleoside analogues. DESIGN A randomized, open-labelled, controlled trial. Two hundred and eighty-four patients started randomized treatment. The primary end-point was the proportion of patients with HIV RNA of 200 copies/ml or less (Roche Amplicor) and HIV RNA of 20 copies/ml or less (Roche ultradirect assay) at 6 months. Analysis was performed as intent-to-treat, and missing values were accounted for as failures. RESULTS As of 1 May 1998, 269 patients should have completed 24 weeks of treatment. The proportion of patients with HIV RNA of 200 copies/ml or less was 71% (indinavir), 67% (ritonavir), and 82% (ritonavir + saquinavir), P = 0.07. In antiretroviral drug-naive patients (n = 119), the corresponding figures were 63, 57, and 89% (P < 0.01), whereas among drug-experienced patients (n = 165) 77, 74, and 77% had HIV RNA of 200 copies/ml or less (P = 0.90). The same pattern was observed in the ultradirect analysis. All three regimens were generally safe, but significantly more patients in the ritonavir group (37%) stopped treatment because of adverse drug reactions compared with the indinavir group (8%) and the ritonavir plus saquinavir group (16%) (P < 0.001). CONCLUSIONS Treatment with saquinavir plus ritonavir in combination with two nucleoside analogues is generally safe, and has superior short-term antiviral efficacy compared with indinavir and ritonavir also combined with two nucleoside analogues in antiretroviral drug-naive patients. Further follow-up is needed to determine the durability of the viral response.

Changes in use of antiretroviral therapy in regions of Europe over time

Objectives:To analyse use of antiretroviral therapy within Europe between 1994 and 1997. Design:From September 1994, the EuroSIDA study (cohorts I-III) has prospectively followed unselected HIV-infected patients from 50 clinical centres in 17 European countries (total, 7230). Methods:Patients under follow-up at half-year intervals from September 1994 (n = 2871) to September 1997 (n = 3682) were classified according to number of drugs currently used (none, one, two, three, four or more). Use of antiretroviral therapy was stratified by CD4 cell count (< 200 versus ≥ 200 × 106/1) and by region of Europe (south, central, or north). Frequency data were compared by χ2 test and logistic regression modelling. Results:The proportion of patients on antiretroviral monotherapy diminished over time (1994, 42%; 1997, 3%), as did the proportion of patients without therapy (from 37 to 9%). Over time, the proportion of patients on triple (from 2 to 55%) and quadruple (from 0 to 9%) therapy increased, whereas use of dual therapy peaked in 1996 and subsequently fell. In the three regions of Europe, changes in use of antiretroviral therapy differed substantially, However, as of September 1997, only minor differences persisted. The proportion of patients on dual, triple, and quadruple therapy were as follow: south, 33, 52 and 5%, respectively; central, 23, 55 and 14%, respectively; north, 16, 59 and 10%, respectively. In September 1997, odds for use of three or more drugs including at least one protease inhibitor did not differ significantly between regions. Conclusions:Use of antiretroviral therapy in Europe has changed dramatically towards combination treatment in the last few years. Regional differences in use of antiretroviral therapy have decreased, and by September 1997 only minor differences remained. Antiretroviral therapy with three or more drugs and use of protease inhibitors has become more common in all regions of Europe.

Epidemiology of nontuberculous mycobacteria among patients with cystic fibrosis in Scandinavia

Background Nontuberculous mycobacteria (NTM) are an emerging threat to cystic fibrosis (CF) patients but their epidemiology is not well described. Methods In this retrospective observational study we identified all Scandinavian CF patients with a positive NTM culture from airway secretions from 2000 to the end of 2012 and used national CF databases to describe microbiological and clinical characteristics. Results During the 13-year period 157 (11%) CF patients were culture positive for NTM at least once. Mycobacterium abscessus complex (MABSC) (45%) and Mycobacterium avium complex (MAC) (32%) were the predominant species with geographical differences in distribution. Younger patients were more prone to MABSC (p < 0.01). Despite treatment, less than one-third of MABSC patients with repeated positive cultures cleared their infection and a quarter had a lung transplant or died. Conclusion NTM are significant CF pathogens and are becoming more prevalent in Scandinavia. MABSC and MAC appear to target distinct patient groups. Having multiple positive cultures despite treatment conveys a poor outcome.

Soluble urokinase receptor levels in plasma during 5 years of highly active antiretroviral therapy in HIV-1-infected patients

Abstract:High blood levels of the soluble urokinase receptor (suPAR) strongly predict increased mortality in human immunodeficiency virus-1 (HIV-1)–infected patients. This study investigated the plasma concentration of suPAR in 29 treatment-naive HIV-1–infected patients during 5 years treatment with highly active antiretroviral therapy (HAART).Plasma suPAR decreased after introducing HAART, most pronounced during the first treatment year. The change in plasma suPAR was independent of changes in viral replication and CD4+ cells but it was strongly correlated with plasma levels of the soluble TNF receptor II. Compared with healthy individuals, plasma suPAR and sTN-FrII was increased in untreated patients. After initiating HAART, plasma sTNFrII remained increased whereas plasma suPAR decreased to a level comparable with healthy individuals. The present data indicate that the circulating suPAR level is linked to inflammation in untreated as well as HAART-treated HIV-1–infected patients.

Low-Level Viremia and Proviral DNA Impede Immune Reconstitution in HIV-1-Infected Patients Receiving Highly Active Antiretroviral Therapy

BACKGROUND Immunological and virological consequences of low-level viremia in human immunodeficiency virus (HIV) type 1-infected patients receiving highly active antiretroviral therapy (HAART) remain to be determined. METHODS For 24 months, 101 HAART-treated, HIV-1-infected patients with HIV RNA levels </=200 copies/mL were followed prospectively: HIV RNA level and CD4 and CD8 cell counts were investigated every 3 months, and proviral DNA and T cell subsets were investigated every 6 months. RESULTS During follow-up, 33 patients had HIV RNA levels </=20 copies/mL at all visits (uVL patients), whereas 68 patients had HIV RNA levels >20 copies/mL at >/=1 visit (dVL patients) (median increase, 81 copies/mL [interquartile range, 37-480 copies/mL]). dVL patients had higher concentrations of CD8 cells, activated and memory T cells, and proviral DNA, compared with uVL patients (P<.05). A higher HIV RNA level was independently associated with reduced CD4 gain (P<.001). A higher HIV RNA level also was associated with increases in activated CD8(+)CD38(+) and CD8(+)HLA-DR(+) cells (P<.05), and a higher level of activated CD8(+)CD38(+) cells was independently associated with reduced CD4 gain (P<.05). A higher proviral DNA level was associated with increases in CD4(+)CD45RA(-)CD28(-) effector cells and reductions in naive CD4(+)CD45RA(+)CD62L(+) and CD8(+)CD45RA(+)CD62L(+) cells (P<.05). Higher levels of activated CD4(+)HLA-DR(+) and early differentiated CD4(+)CD45RA(-)CD28(+) cells predicted increased risk of subsequent detectable viremia in patients with undetectable HIV RNA (P<.05). CONCLUSION These findings indicate that low-level viremia and proviral DNA are intimately associated with the immunological and virological equilibrium in patients receiving HAART.

Natural immunity and HIV disease progression

OBJECTIVE To investigate the clinical implications of impaired levels of the natural immunity mediated by natural killer (NK) cells and lymphokine activated killer (LAK) cells during infection with HIV-1. DESIGN Data used were from 172 individuals with an estimated measure of NK cell activity and 146 with an estimated measure of LAK cell activity. Patients had active HIV infection at the time of enrolment in the study and have been followed-up prospectively for a median of 3.0 years. METHODS The lytic activity of NK cells and LAK cells, the CD4 T lymphocyte count, and the concentration of CD16/CD56 NK cells were measured at enrolment. HIV RNA in plasma was measured retrospectively. Survival analysis was performed considering three main endpoints: CD4 cell counts below 100 x 10(6) cells/l, clinical AIDS, and death. RESULTS In unadjusted analysis and after adjustment for age, CD4 T lymphocyte count and plasma HIV RNA at enrolment, low LAK cell activity was significantly associated with higher risk of progression to a CD4 T lymphocyte count < 100 x 10(6) cells/l (crude P = 0.001; adjusted P = 0.04) and to death (crude P = 0.0002; adjusted P = 0.02). Patients with low NK cell responsiveness to interferon-alpha tended to be at higher risk of death (crude P = 0.04; adjusted P = 0.13) whereas unstimulated NK cell activity and the concentration of NK cells were of no prognostic value for patients in this cohort. CONCLUSIONS The present study suggests that low LAK cell activity and low NK cell responsiveness to interferon-alpha may be important in the pathogenesis of HIV infection.

Low level of regulatory T cells and maintenance of balance between regulatory T cells and TH17 cells in HIV-1-infected elite controllers.

Background:A subgroup of HIV-1-infected individuals, elite controllers, have spontaneous viral control and offer an exceptional opportunity to study virological and immunolocigal factors of possible involvement in control of HIV-1 infection. Methods:The frequencies of Tregs and TH17 cells was evaluated and correlated to markers of disease progression in peripheral blood mononuclear cells from 3 different groups of individuals infected with HIV-1: treatment-naive viremic individuals, individuals on successful highly active antiretroviral therapy, and elite controllers. In addition, a group of HIV-1-negative individuals were included. Results:We demonstrate that elite controllers have lower levels of Tregs compared with HIV-1-infected viremic individuals, but that the low Treg level does not differ between individuals with HIV-1 control, whether natural or therapy induced. We also show that T-cell activation and proliferation both correlate to the level of Tregs. Finally, the TH17/Treg ratio was similar in Elite Controllers and uninfected controls, whereas in viremic and treated HIV-1-infected individuals, the TH17/Treg ratio was lower compared with uninfected controls. Conclusions:We show that one feature of spontaneous HIV-1 control is a maintained balance between regulatory T cells and TH17 cells.