The dissociation between virological and immunological responses to HAART

Thymic Exhaustion and Increased Immune Activation Are the Main Mechanisms Involved in Impaired Immunological Recovery of HIV-Positive Patients under ART

Decades of studies in antiretroviral therapy (ART) have passed, and the mechanisms that determine impaired immunological recovery in HIV-positive patients receiving ART have not been completely elucidated yet. Thus, T-lymphocytes immunophenotyping and cytokines levels were analyzed in 44 ART-treated HIV-positive patients who had a prolonged undetectable plasma viral load. The patients were classified as immunological non-responders (INR = 13) and immunological responders (IR = 31), according to their CD4+ T cell levels. Evaluating pre-CD4+ levels, we observed a statistically significant trend between lower CD4+ T cell levels and INR status (Z = 3.486, p < 0.001), and during 18 months of ART, the CD4+ T cell levels maintained statistical differences between the INR and IR groups (WTS = 37.252, p < 0.001). Furthermore, the INRs were associated with an elevated age at ART start; a lower pre-treatment CD4+ T cell count and a percentage that remained low even after 18 months of ART; lower levels of recent thymic emigrant (RTE) CD4+ T cell (CD45RA + CD31+) and a naïve CD4+ T cell (CD45RA + CD62L+); higher levels of central memory CD4+ T cells (CD45RA-CD62L+); and higher immune activation by CD4+ expressing HLA-DR+ or both (HLA-DR+ and CD38+) when compared with IRs. Our study demonstrates that thymic exhaustion and increased immune activation are two mechanisms substantially implicated in the impaired immune recovery of ART-treated HIV patients.

Rapid CD4 decline prior to antiretroviral therapy predicts subsequent failure to reconstitute despite HIV viral suppression

HIV-1 infection is characterized by loss of CD4T cells, leading to immunodeficiency. Initiation of antiretroviral therapy (ART) results in suppression of the viral load and increased CD4 counts. Both viral and host factors determine CD4 cell responses to ART with approximately 15-30% of individuals having suboptimal increase of CD4T cell count, most commonly due to lack of compliance to ART. A smaller fraction of patients will have immune reconstitution failure and suboptimal CD4 increase despite suppression of HIV replication, and these individuals are at risk for adverse health outcomes. We sought to characterize the factors associated with decreased immunological response among Manitoba's HIV patient population. This retrospective case-control study included HIV patients with immune reconstitution failure despite suppression of HIV replication by ART. The immune reconstitution failure was defined by CD4 cell count increase from baseline of less than 100 CD4 cells/mm³ or lack of increase to above 200 CD4 cells/mm³ within one year of viral load suppression. Age and nadir CD4 cell counts are known risk factors associated with immune reconstitution failure. We chose controls (Patients with immune reconstitution success) of similar age and CD4 nadir cell with cases (Patients with immune reconstitution failure). We explored the potential effects of gender, HLA type, presence of co-infection, ethnicity, ART type, and rate of pre-treatment CD4 decline among cases and controls. Of more than 550 patients followed by our HIV clinic, 42 individuals met our definition of immune reconstitution failure and they were assigned to the cases group. 31 patients, comprising a range of ages and CD4 nadirs similar to those of the cases, were assigned to the control group. Our primary analysis was a regression model, predicting post-ART change in CD4 over time. After controlling for age and nadir CD4 cell counts, the only potential predictor that appears consistently associated with the rate of post-ART rise in CD4 over time in our cohort, regardless of the other variables that we have controlled for, is the rate of decline in CD4 pre-ART initiation. Several factors have been variably correlated with immune reconstitution failure of CD4 T cell count. Age and low CD4 nadir are factors previously shown to correlate with immune reconstitution failure; and we have controlled for them in our study. Another possible predictor is the rate of decline in CD4 pre-ART, which can serve as an additional marker of reconstitution failure and necessitate prioritizing individuals to ART initiation or identification of a subset of individuals that may be targeted for future adjunct strategies to improve immune recovery.

Addition of maraviroc to antiretroviral therapy decreased interferon-γ mRNA in the CD4+ T cells of patients with suboptimal CD4+ T-cell recovery

The CCR5 antagonist, maraviroc (MVC), is associated with an enhanced CD4+ T-cell response independent of virological suppression; however, its mechanism of action has not been elucidated. In this study, we confirmed the effect of MVC on CD4+ T-cell count recovery in immunological non-responders, and compared the conventional combination antiretroviral therapy (cART) with MVC-intensified cART. We also investigated the effect of MVC on interferon-γ (IFN-γ) production in CD4+ T cells in vitro and in vivo, and evaluated the relationship between the mRNA level of IFN-γ and the degree of CD4+ T-cell count recovery. In vitro analysis indicated that MVC significantly decreased mRNA levels of IFN-γ in HIV-Tat stimulated CD4+ T cells from healthy donor peripheral blood mononuclear cells. Of the 18 HIV-infected patients treated with MVC-intensified cART, 12 had a significantly increased CD4+ T-cell count after 24 weeks of additional treatment with MVC. In patients exhibiting a response in CD4+ T-cell counts, mRNA levels of IFN-γ in CD4+ T cells were lower than those in patients showing a non-response at baseline and at week 24, while mRNA levels of IFN-γ decreased in both groups at 24 weeks. In conclusion, MVC decreased the mRNA level of IFN-γ in CD4+ T cells in vitro and in vivo, especially in patients whose CD4+ T-cell count increased significantly. We also found that the lower baseline IFN-γ mRNA level and the larger decreased rate of IFN-γ mRNA in CD4+ T cells were associated with a good response to MVC regarding CD4+ T-cell recovery.

Factors associated with long-term CD4 cell recovery in HIV-infected patients on successful antiretroviral therapy

OBJECTIVES

The aim of the study was to study the factors associated with immunological recovery in HIV-infected patients with suppressed viral load.

METHODS

Nadir and current CD4 cell counts were recorded in 821 patients, as well as many demographic, epidemiological, lifestyle, clinical, therapeutic, genetic, laboratory, liver fibrosis and viral hepatitis parameters.

RESULTS

The median age of the patients was 44.4 years [interquartile range (IQR) 40.3-48.0 years], the median time since HIV diagnosis was 15.3 years (IQR 10.5-18.9 years), the median time of suppressed viral load was 7.0 years (IQR 4.0-10.0 years) and the median time on the current antiretroviral regimen was 2.8 years (IQR 1.4-4.7 years). The median nadir and current CD4 counts were 193.0 (IQR 84.0-301.0) and 522.0 (IQR 361.0-760) cells/μL, respectively, separated by a median period of 10.2 years (IQR 5.9-12.9 years). The median CD4 count gain during follow-up was 317.0 (IQR 173.0-508.0) cells/μL. Many variables were associated with CD4 cell gains in univariate analyses, including age, gender, epidemiology, prior clinical conditions, fibrosis stage, transient elastometry, aspartate aminotransferase (AST), nadir CD4 count and hepatitis B and C virus infections and genotypes, as well as the durations of follow-up since nadir CD4 count, overall antiretroviral treatment, current antiretroviral regimen, protease inhibitor therapy and suppression of viral load. Multivariate analysis revealed that longer duration of HIV suppression (P < 0.0001), more advanced clinical Centers for Disease Control and Prevention (CDC) stages (P < 0.0001), younger age (P = 0.0003), hepatitis C virus genotypes 1 and 4 (P = 0.003), sexual acquisition of HIV (P = 0.004), and lower transient elastometry values (P = 0.03) were independent predictors of CD4 cell gains. Overall, the model accounted for 14.2% of the variability in CD4 count.

CONCLUSIONS

In addition to the duration of HIV suppression, HIV-related diseases, HIV epidemiology, age, hepatitis C virus genotypes, and liver fibrosis were independently associated with long-term immunological recovery.

Association between hepatitis B vaccine antibody response and CD4 reconstitution after initiation of combination antiretroviral therapy in HIV-infected persons

Background

Hepatitis B virus (HBV) vaccine antibody response has been associated with reduced risk of AIDS or death. However, it is unknown whether HBV vaccine responsiveness is associated with improved immune reconstitution during treatment with combination antiretroviral therapy (cART). We evaluated the relationship between HBV vaccine response status and CD4 reconstitution on cART in the U.S Military HIV Natural History Study.

Methods

Participants with viral load <400 copies/mL within 1 year on initial cART and documented HBV vaccination and surface antibody (anti-HBs) prior to cART were included. Participants were characterized as HBV vaccine responders (anti-HBs ≥10 IU/L) or non-responders (<10 IU/L) and further divided into 2 groups based on vaccine administration before or after HIV diagnosis. Linear mixed regression was used to model CD4 reconstitution during the first year of cART.

Results

Of the 307 and 169 participants vaccinated before or after HIV diagnosis, HBV vaccine response occurred in 288 (94%) and 74 (44%), respectively. For those vaccinated before HIV diagnosis, CD4 counts increased by a median 190 [IQR 99–310] cells/mm³ for responders and 186 [IQR 116–366] cells/mm³ for non-responders during the first year (P = 0.684). Participants vaccinated after HIV diagnosis had median increases of 185 [IQR 76–270] and 143 [IQR 47–238] cells/mm³ for responders and non-responders, respectively (P = 0.134). In contrast to those with CD4 > 350 cells/mm³ at cART initiation, participants with CD4 < 200 and 200–350 cells/mm³ had significantly reduced CD4 gains in both groups by longitudinal mixed models, but there was no difference in CD4 recovery according to HBV vaccine seroresponse.

Conclusions

Although HBV vaccine responsiveness is associated with a reduction in HIV disease progression, HBV vaccine responders do not achieve greater CD4 gains during the first year of cART. Additional clinical markers are needed to predict the magnitude of post-cART immune recovery.

Factors Associated with Immunological Discordance in HIV-Infected Patients Receiving Antiretroviral Therapy with Complete Viral Suppression in a Resource-Limited Setting

"Immunological discordance," i.e., immunological failure despite complete viral suppression in human immunodeficiency virus (HIV)-infected patients receiving antiretroviral therapy (ART), is associated with increased risk of AIDS or death. To evaluate risk factors for immunological discordance in a resource-limited setting in which patients usually present late with low CD4 cell counts, we conducted a case-control study among HIV-infected patients receiving ART and having undetectable HIV RNA. The study included patients with immunological discordance (cases), which was defined as CD4 cell count < 30% above baseline and absolute CD4 cell count < 200 cells/mm(3) at the first 12 months of undetectable HIV RNA (<50 copies/mL). Patients without immunological discordance were included as controls. Of 142 patients (44 cases; 98 controls), the mean age was 38.6 ± 9.4 years and 67.6% were men; 65.5% had history of opportunistic infections. In multivariate analysis, only baseline CD4 cell count < 100 cells/mm(3) (odd ratio [OR], 2.53; 95% confidence interval [CI], 1.04-6.14; P = 0.040) and history of lost to follow-up (OR, 11.04; 95% CI, 2.87-42.46; P < 0.001) were significantly associated with immunological discordance. Early initiation of ART and intervention to improve regular clinic visit compliance and adherence to ART are crucial to prevent immunological discordance among HIV-infected patients.

Treatment outcome of HAART-treated patients in a resource-limited setting: the Belgrade Cohort Study

INTRODUCTION

We evaluated the effects of highly-active-antiretroviral-therapy (HAART) in a resource-limited settings.

METHODS

A cross-sectional study was performed in patients who had initiated HAART at the HIV/AIDS-Center, Belgrade, Serbia. Treatment response was considered favorable in case of the achievement of undetectable HIVRNA plasma-viral-load (pVL<50 copies/μL), and with the CD4+ T-cell counts increased above 350cells/μL. The treatment failure was defined as pVL over 1.7 log10 copies/mL, regardless of immunological improvement.

RESULTS

Eight hundred and forty HIV infected patients were followed-up for 8.2±3.4years. Out of 697 patients available for follow-up, 113 (16.2%) patients died, 44 (6.3%) experienced treatment failure, while 540 (77.5%) had sustained undetectable viremia. In 419 (60.1%) favorable treatment response was achieved, while the dissociation between immunological and virological responses to HAART occurred in 121 (14.4%). A baseline CD4+ T-cell counts above 200 cells/μL was the single independent predictor of a favorable treatment response (HR=2, 95%CI=1.69-2.61, P=0.001), while pre-treatment with ART, HCV co-infection and AIDS at the time of treatment initiation, were all factors preventing a favorable response (HR=0.27, 95%CI=0.19-0.36, P=0.001; HR=0.75, 95%CI=0.56-0.95, P=0.02; HR=0.73, 95%CI=0.17-0.95, P=0.018, respectively). A sustained viral suppression was an independent predictor of survival (HR=0.2, 95% CI 0.07-0.61, P=0.004). HAART treated HIV-infected patients who reach and maintain undetectable viremia, have an 80% probability of a 14-years survival (P=0.08, log-rank).

CONCLUSION

If patient with advanced HIV-related immunodeficiency reach and maintain optimal viral suppression during HAART, regardless of the level of immune recovery, and if they continue to maintain this, their prognosis may be fairly good even in the resource-limited settings.

Virologic and immunologic outcome of HAART in Human Immunodeficiency Virus (HIV)-1 infected patients with and without tuberculosis (TB) and latent TB infection (LTBI) in Addis Ababa, Ethiopia

BACKGROUND

HIV/TB coinfection remains a major challenge even after the initiation of HAART. Little is known about Mycobacterium tuberculosis (Mtb) specific immune restoration in relation to immunologic and virologic outcomes after long-term HAART during co-infections with latent and active TB.

METHODS

A total of 232 adults, including 59 HIV patients with clinical TB (HIV + TB+), 125 HIV patients without clinical TB (HIV + TB-), 13 HIV negative active TB patients (HIV-TB+), and 10 HIV negative Tuberculin Skin TST positive (HIV-TST+), and 25 HIV-TST- individuals were recruited. HAART was initiated in 113 HIV + patients (28 TB + and 85 TB-), and anti-TB treatment for all TB cases. CD4+ T-cell count, HIV RNA load, and IFN-γ responses to ESAT-6/CFP-10 were measured at baseline, 6 months (M6), 18 months (M18) and 24 months (M24) after HAART initiation.

RESULTS

The majority of HIV + TB- (70%, 81%, 84%) as well as HIV + TB + patients (60%, 77%, 80%) had virologic success (HIV RNA < 50 copies/ml) by M6, M18 and M24, respectively. HAART also significantly increased CD4+ T-cell counts at 2 years in HIV + TB + (from 110.3 to 289.9 cells/μl), HIV + TB- patients (197.8 to 332.3 cells/μl), HIV + TST- (199 to 347 cells/μl) and HIV + TST + individuals (195 to 319 cells/μl). Overall, there was no significant difference in the percentage of patients that achieved virologic success and in total CD4+ counts increased between HIV patients with and without TB or LTBI. The Mtb specific IFN-γ response at baseline was significantly lower in HIV + TB + (3.6 pg/ml) compared to HIV-TB + patients (34.4 pg/ml) and HIV + TST + (46.3 pg/ml) individuals; and in HIV-TB + patients compared to HIV-TST + individuals (491.2 pg/ml). By M18 on HAART, the IFN-γ response remained impaired in HIV + TB + patients (18.1 pg/ml) while it normalized in HIV + TST + individuals (from 46.3 to 414.2 pg/ml).

CONCLUSIONS

Our data show that clinical and latent TB infections do not influence virologic and immunologic outcomes of ART in HIV patients. Despite this, HAART was unable to restore optimal TB responsiveness as measured by Mtb specific IFN-γ response in HIV/TB patients. Improvement of Mtb-specific immune restoration should be the focus of future therapeutic strategies.

Immune reconstitution inflammatory syndrome and the influence of T regulatory cells: a cohort study in The Gambia

Objective

The factors associated with the development of immune reconstitution inflammatory syndrome in HIV patients commencing antiretroviral therapy have not been fully elucidated. Using a longitudinal study design, this study addressed whether alteration in the levels of T regulatory cells contributed to the development of IRIS in a West African cohort of HIV-1 and HIV-2 patients. Seventy-one HIV infected patients were prospectively recruited to the study and followed up for six months. The patients were categorized as IRIS or non-IRIS cases following published clinical guidelines. The levels of T regulatory cells were measured using flow cytometry at baseline and all follow-up visits. Baseline cytokine levels of IL-2, IL-6, IFN-γ, TNF-α, MIP-1β, IL-1, IL-12, IL-13, and IL-10 were measured in all patients.

Results

Twenty eight percent of patients (20/71) developed IRIS and were predominantly infected with HIV-1. Patients developing IRIS had lower nadir CD4 T cells at baseline (p = 0.03) and greater CD4 T cell reconstitution (p = 0.01) at six months post-ART. However, the development of IRIS was not influenced by the levels of T regulatory cells. Similarly, baseline cytokine levels did not predict the onset of IRIS.

Conclusion

The development of IRIS was not associated with differences in levels of T regulatory cells or baseline pro-inflammatory cytokines.

Reduced thymic output is a major mechanism of immune reconstitution failure in HIV-infected patients after long-term antiretroviral therapy

BACKGROUND

Approximately 20% of human immunodeficiency virus type 1 (HIV-1)--infected adults do not normalize their CD4(+) T lymphocytes after long-term effective highly active antiretroviral therapy (HAART). The mechanistic basis for this failure is unclear.

METHODS

Seventy-four patients were followed up regularly for 3-7 years. Patients with undetectable plasma viral load (<50 copies/mL) for over 12 months were further classified into 2 groups: (1) immunological nonresponders, whose CD4(+) T-cell count was < 200/μL or <20% compared with baseline; and (2) immunological responders, whose CD4(+) T-cell count was > 300/μL or >30% compared with baseline.

RESULTS

Compared with 17 immunological responders, 13 immunological nonresponders had a lower magnitude of naive CD4(+) T-cell increase, a lower percentage of recent thymic immigrants (CD31(+)%), and a higher percentage of activated CD8(+) T cells. Furthermore, unlike CD4(+) T cells, which increased along with the decrease of viral load, the percentage of recent thymic immigrants (CD31(+)%) had little change in the majority of patients. These data were fit into a mathematical model, , from which we deduced that the initial rate of CD4(+) T-cell restoration is associated significantly with the percentage of recent thymic immigrants (CD31(+)%).

CONCLUSIONS

Our data indicate that the failure to restore CD4(+) T-cell count following HAART was associated primarily with a defect in recent thymic immigrants, which suggests the existence of thymus exhaustion.

Predictors of suboptimal virologic response to highly active antiretroviral therapy among human immunodeficiency virus-infected adolescents: analyses of the reaching for excellence in adolescent care and health (REACH) project

OBJECTIVE

To examine the prevalence and biopsychosocial predictors of suboptimal virologic response to highly active antiretroviral therapy (HAART) among human immunodeficiency virus-infected adolescents.

DESIGN

Population-based cohort study.

SETTING

Sixteen academic medical centers across 13 cities in the United States.

PARTICIPANTS

One hundred fifty-four human immunodeficiency virus-infected adolescents who presented for at least 2 consecutive visits after initiation of HAART.

MAIN OUTCOME MEASURES

Viral load (plasma concentration of human immunodeficiency virus RNA) and CD4(+) lymphocyte count.

RESULTS

Of the 154 adolescents enrolled in the study, 50 (32.5%) demonstrated early and sustained virologic suppression while receiving HAART. The remaining 104 adolescents (67.5%) had a poor virologic response. Adequate adherence (>50%)-reported by 70.8% of respondents-was associated with 60% reduced odds of suboptimal virologic suppression in a multivariable logistic regression model (adjusted odds ratio = 0.4; 95% confidence interval, 0.2-1.0). Exposure to suboptimal antiretroviral therapy prior to HAART, on the other hand, was associated with more than 2-fold increased odds of suboptimal virologic response (adjusted odds ratio = 2.6; 95% confidence interval, 1.1-5.7).

CONCLUSIONS

Fully two-thirds of human immunodeficiency virus-infected adolescents in the current study demonstrated a suboptimal virologic response to HAART. Nonadherence and prior single or dual antiretroviral therapy were associated with subsequent poor virologic responses to HAART. These predictors of HAART failure echo findings in pediatric and adult populations. Given the unique developmental stage of adolescence, age-specific interventions are indicated to address high rates of nonadherence and therapeutic failure.

African Australians living with HIV: a case series from Victoria

Background: This research aimed to describe the characteristics of African-born Victorians living with HIV, identify associations with delayed HIV diagnosis and describe their response to combination antiretroviral therapy (cART). Methods: A case series of African-born adults living with HIV in Victoria was conducted. Data was collected in interviews and reviews of case notes. Associations with delayed HIV diagnosis (CD4 below 200 cells µL–1 at diagnosis and/or AIDS within 3 months of HIV diagnosis) were explored using univariate regression. AIDS-defining illnesses and response to cART were described. Results: Fourteen males and six females were included. Ten were born in the Horn of Africa (nine in Ethiopia). Sixteen had sexual exposure (12 heterosexual; four male-to-male sex). Seven reported acquiring HIV in Australia. Median CD4 count at diagnosis was 145 cells µL–1. Ten had delayed HIV diagnosis, of whom eight were born in the Horn of Africa. Delayed HIV diagnosis was associated with birth in the Horn of Africa (odds ratio: 11.56). Nine had a diagnosis of AIDS, including three cases of tuberculosis, three of Pneumocystis jiroveci pneumonia and two of cerebral toxoplasmosis. Eighteen had received cART, of which 16 achieved virological suppression and 15 achieved a CD4 count above 200 cells µL–1. Clinical failure and virological failure occurred in seven and five cases, respectively. Conclusions: HIV prevention strategies for Victoria’s African communities should address HIV exposure in Australia. Ethiopian-born Victorians with HIV appear to be at particular risk of delayed diagnosis. Response to cART in this series was comparable to that observed in other industrialised countries.

The prognosis of highly active antiretroviral therapy (HAART) treated HIV infected patients in Serbia, related to the time of treatment initiation

BACKGROUND

With the introduction of highly active antiretroviral treatment (HAART) an impressive improvement in patient survival and quality of life has bee observed. However, the optimal timing of initial HAART is still under consideration.

OBJECTIVE

To investigate the prognosis of HAART treated patients in Serbia, related to the timing of HAART initiation.

STUDY DESIGN

A series of 563 patients on HAART was retrospectively analyzed to investigate treatment response and survival.

RESULTS

After a mean of 6 years (range 1-14) of treatment with PI-based and/or NNRTI-based regimens, a favorable response was achieved in 72.4%, treatment failure occurred in 7.9%, while 19.7% had a dissociative immunological/virological response. If treatment was initiated during primary HIV infection it took a shorter time to achieve a favorable response than in patients who began HAART in chronic HIV infection (2.7+/-2.2 years vs. 6.9+/-2.7 years, P<0.01). A higher proportion of patients with primary HIV infection then those treated in the chronic phase achieved a favorable response to HAART (88.4% vs. 71.9%, P=0.045). Patients who initiated HAART when their CD4 cell counts were below 200 cells/microL needed longer treatment for favorable response (8 years vs. 6 years, log rank P<0.01). Forty-seven (8.3%) patients died. The overall estimated survival was 13 years. Patients older then 40 and IVDU were more likely to die during HAART (OR 2.6, 95% CI 1.1-5.9, P=0.016, and OR 2.0, 95% CI 1.0-3.7, P=0.02, respectively). However, reaching and maintaining undetectable viremia was an independent predictor of longer survival (OR 11.3, 95% CI 4.6-27.7, P<0.01).

CONCLUSION

Reaching and maintaining undetectable viremia during HAART predicted longer survival, even if sub-clinical immunodeficiency remained.

Impact of adding maraviroc to antiretroviral regimens in patients with full viral suppression but impaired CD4 recovery

We reviewed the effect of adding maraviroc on CD4 cell counts in nine patients on antiretroviral therapy with full viral suppression but impaired CD4 cell recovery. There were no significant differences in changes in CD4 cell count, percentage of CD4 cells, or in the ratio of CD4/CD8 cells at 30 days and 25 weeks of maraviroc therapy. Plasma endotoxin levels measured in four patients before and during maraviroc treatment also showed no significant differences.

CD4 responses in the setting or suboptimal virological responses to antiretroviral therapy: features, outcomes, and associated factors

The factors associated with discordant viroimmunological responses following antiretroviral therapy are unclear. We studied 1380 patients who initiated a protease inhibitor (PI)-based antiretroviral regimen and who fulfilled the criteria for inclusion. Of them, 255 (18.5%) had CD4 increases > or =100 cells/microl after 1 year of therapy despite detectable viral load (immunological responders); they were compared with 669 patients (48.5%) who had CD4 increases <100 cells/microl regardless of their final viral load (immunological nonresponders). Immunological responders had higher rates of sexual acquisition of HIV (p = 0.03), lower rates of clinical progression (p = 0.02), higher probabilities of being naive to antiretroviral therapy (p = 0.006) or to PI if antiretroviral experienced (p = 0.03), higher rates of receiving only nucleoside reverse transcriptase inhibitors in addition to the PI (p = 0.04), and lower baseline CD4 counts (p = 0.007) and higher viral loads (p = 0.009), as compared with nonresponders. Multivariate analysis revealed that sexual transmission of HIV (homosexual p = 0.004, heterosexual p = 0.03), no prior PI experience (p = 0.005), absence of clinical progression (p = 0.02), and lower baseline CD4 counts (p = 0.03) were independently associated with immunological response. However, these factors differed according to the patients' prior antiretroviral status, as higher baseline viral load was also associated with immunological response in antiretroviral-experienced patients (p = 0.02), whereas baseline CD4 count (p = 0.007) was the only predictive parameter in antiretroviral-naive patients. We conclude that immunological responses despite suboptimal viral suppression are common. Prior PI experience, HIV transmission category, baseline CD4 counts, and clinical progression were independently predictive of this condition, although the associated factors were different depending on the patient's prior antiretroviral history.

The incidence of and risk factors for HIV-associated cognitive-motor complex among patients on HAART

BACKGROUND

While highly active antiretroviral therapy (HAART) allows for the considerable decline in the incidence of HIV-related opportunistic infections and tumors, its effect on treating HIV infection of the brain, such as HIV-associated dementias (HADs), remains unclear.

METHODS

A cross-sectional study of consecutive series of 96 patients from the Serbian HIV/AIDS cohort, treated with HAART in our HIV unit was performed to evaluate the incidence of and risk factors for cognitive/motor complex during HAART. CD4+T cell counts and pVL values at the time of neurological evaluation were parameters of the response to HAART. The mini-mental test and neurologic examination were performed at one point of time during treatment to reveal cognitive and/or motor disorders.

RESULTS

After mean HAART duration of 47 months, unimpaired cognition, minor cognitive impairment, and HIV-associated dementia were recorded in 56 (58.3%), 27 (28.1%), and 13 (13.5%), respectively. Motor abnormalities had 39 (40.6%) patients. Of these, 21, 12, and 6 patients belong to the subgroups with normal cognition, minor cognitive impairment and HAD patients, respectively. Factors predictive for HAD were age over 40 (OR 3.7, 95% CI 1.07-13.28, P=0.039), and AIDS diagnosis prior to HAART initiation (OR 14.19, 95% CI 1.76-114.16, P=0.013). Conversely, factors shown to be protective against HAD were the usage of AZT and NNRTIs, as components of HAART regimens (OR 0.18, 95% CI 0.046-0.76, P=0.019, and OR 0.14, 95% CI 0.034-0.6, P=0.008).

CONCLUSION

Cognitive/motor complex has still remained a significant neuropathology among late presenters and elder HIV/AIDS patients. Certain HAART regimens containing AZT, and/or NNRTIs, could be protective for these patients.

Regulatory T cells and HIV-1 infection

Recently, it has been emphasized that chronic generalized immune activation is a leading event in the pathogenesis of HIV-1 infection. Supporting evidence comes from observations that in cases of lack of activation, infected subjects maintain a high number of T cells and do not develop AIDS-related events. Despite intensive studies, the exact mechanisms of T-cell activation are still not well understood and options for their control are limited. Very promising in this direction is a recently described T-cell subpopulation--regulatory T cells. Their functional activity and vitality are strongly dependent on the presence of IL-2. Better understanding of the mechanisms of T-cell activation, as well as the contribution of regulatory T cells to its control will increase therapeutic options for HIV-1-infected subjects. The application of immune-based therapy together with highly active antiretroviral therapy will lend a helping hand to the natural regulatory mechanisms in the control of infection.

The metabolic syndrome, an epidemic among HIV-infected patients on HAART

BACKGROUND

HAART has dramatically changed the prognosis of AIDS, but has led to long-term toxicities of antiretroviral drugs. A major chronic complication is the metabolic syndrome (MS), including hyperlipidemia, lipodystrophy (LD), and impaired glucose metabolism.

METHODS

A cross-sectional study of a series of 582 patients from the Serbian HIV/AIDS cohort, treated with HAART for a mean period of 3.3+/-2.1 years (range 1-10), was performed to evaluate the prevalence and risk factors for MS during HAART.

RESULTS

The prevalence of LD was 29.1%, with a 100% probability of development after 10 years of treatment. Risk factors for LD included female gender (OR 1.7, 95% CI 1.0-2.7, P=0.02), age>40 (OR 1.7, 95% CI 1.1-2.7, P=0.01) and AIDS at HAART initiation (OR 1.9, 95% CI 1.2-2.2, P<0.01), as well as prolonged usage of NRTIs (OR 2.7, 95% CI 1.6-4.5, P<0.01). The NNRTI-based regimens were less likely to induce LD than those PI-based (OR 1.87, 95% CI 1.2-2.9 vs. OR 3.7, 95% CI 2.3-6.1, respectively). Hyperlipidemia occurred in 47% of the patients, and was associated with male gender (OR 2.2, 95% CI 1.4-3.5, P<0.01) and prolonged usage of PI+NNRTI HAART (OR 3.0, 95% CI 1.8-4.9, P<0.01). In contrast, regimens composed of 2 NRTI+NNRTI were less likely to induce hyperlipidemia (OR 0.4, 95% CI 0.3-0.7, P=0.03). Glucose intolerance and/or diabetes mellitus was recorded in 9.6%, if with AIDS at HAART initiation (OR 3.7, 95% CI 1.2-11.4, P<0.01), male gender (OR 5.2, 95% CI 1.8-15.1, P<0.01) and age>40 (OR 2.6, 95% CI 1.1-6.3, P=0.02).

CONCLUSION

MS seems an inevitable consequence of long-term successful HAART.

Utility of CD4 cell counts for early prediction of virological failure during antiretroviral therapy in a resource-limited setting

BACKGROUND

Viral load monitoring is not available for the vast majority of patients receiving antiretroviral therapy in resource-limited settings. However, the practical utility of CD4 cell count measurements as an alternative monitoring strategy has not been rigorously assessed.

METHODS

In this study, we used a novel modelling approach that accounted for all CD4 cell count and VL values measured during follow-up from the first date that VL suppression was achieved. We determined the associations between CD4 counts (absolute values and changes during ART), VL measurements and risk of virological failure (VL > 1,000 copies/ml) following initial VL suppression in 330 patients in South Africa. CD4 count changes were modelled both as the difference from baseline (DeltaCD4 count) and the difference between consecutive values (CD4 count slope) using all 3-monthly CD4 count measurements during follow-up.

RESULTS

During 7093.2 patient-months of observation 3756 paired CD4 count and VL measurements were made. In patients who developed virological failure (n = 179), VL correlated significantly with absolute CD4 counts (r = - 0.08, P = 0.003), DeltaCD4 counts (r = - 0.11, P < 0.01), and most strongly with CD4 count slopes (r = - 0.30, P < 0.001). However, the distributions of the absolute CD4 counts, DeltaCD4 counts and CD4 count slopes at the time of virological failure did not differ significantly from the corresponding distributions in those without virological failure (P = 0.99, P = 0.92 and P = 0.75, respectively). Moreover, in a receiver operating characteristic (ROC) curve, the association between a negative CD4 count slope and virological failure was poor (area under the curve = 0.59; sensitivity = 53.0%; specificity = 63.6%; positive predictive value = 10.9%).

CONCLUSION

CD4 count changes correlated significantly with VL at group level but had very limited utility in identifying virological failure in individual patients. CD4 count is an inadequate alternative to VL measurement for early detection of virological failure.

Indinavir influences biological function of dendritic cells and stimulates antifungal immunity

In this study, we analyzed the possibility that Indinavir (IDV), a well-known protease inhibitor (PI) used in highly active antiretroviral therapy, could affect immune response against the opportunistic fungus Cryptococcus neoformans. In particular, the quality of dendritic cell (DC) response was analyzed. The results reported here show that IDV treatment induces an expansion of DC with CD8alpha phenotype in spleens of infected hosts. Splenic CD11c+ DC expressed elevated costimulatory molecules such as CD40 and CD80, showed an increased expression of mRNA for proinflammatory cytokines, and secreted abundant IL-12. Integration of all aforementioned regulatory effects results in development of an efficient, T cell-protective response that reflects a consistent reduction in fungus colonization at a cerebral level. These results could help to elucidate the immunoregulatory activity of PI and point out the beneficial effects of IDV in regulating DC functions and antifungal activity. Therefore, although new PI are being introduced in the clinical setting, nevertheless, given its low cost and proven efficacy, IDV could still be considered a potential key compound in the treatment of HIV in resource-limited settings.

Factors associated with poor immunologic responses despite viral suppression in markedly immunosuppressed patients

To determine the factors associated with poor immunologic responses despite viral suppression in markedly immunocompromised patients (</=200 CD4 cells per microliter at baseline), individuals with less than 100 CD4 increases after 12 months of nelfinavir-based highly active antiretroviral therapy (HAART; n = 114) were compared to those with 100 or more CD4 increases (n = 338). Responders were more likely to be naïve to antiretroviral therapy (p = 0.009) and to protease inhibitors (p< 0.001), less likely to have undetectable viral load at baseline (p = 0.01), to be infected through injection drug use (p = 0.02), to receive two versus three daily nelfinavir doses (p = 0.05), and to have higher viral load (p< 0.001) and lower CD4 counts (p = 0.03) at baseline than nonresponders. Logistic regression analysis revealed that baseline viral load (odds ratio [OR] 0.76, 95% confidence interval [CI] 0.64-0.91), two daily nelfinavir doses (OR 1.85, 95% CI 1.12-3.03) and prior treatment with protease inhibitors (OR 1.85, 95% CI 1.11-3.07) were significantly predictive of poor immunologic responses. On the contrary, viral load had no predictive role in antiretroviral therapy (ART)-naïve patients (p = 0.7). We conclude that poor immunologic responses are common in these patients. Lower viral load at baseline is associated with poorer responses, which could be related to suboptimal prior antiretroviral therapy. In patients taking nelfinavir, administration in two versus three daily doses is also associated with worse immunologic responses.

Long-term survival of HIV-infected patients treated with highly active antiretroviral therapy in Serbia and Montenegro

BACKGROUND

Highly active antiretroviral therapy (HAART) has dramatically changed the prognosis of HIV disease, even in terminally ill patients. Although these patients may survive many years after the diagnosis of AIDS if treated with HAART, some still die during treatment.

METHODS

A retrospective study in a cohort of 481 HIV-infected patients treated with HAART between January 1998 and December 2005 was conducted to compare subgroups of long-term survivors (LTSs) and patients who died during treatment.

RESULTS

A total of 48 patients survived for more than 72 months (mean 83.8+/-standard deviation 5.6 months). Thirty patients died during treatment (mean 35.3+/-25.0 months), of whom nine died from non-AIDS-related causes, 18 died from AIDS-related causes, and three died as a result of HAART toxicity. Although LTSs were significantly (P=0.015) younger at HAART initiation, age below 40 years was not a predictor of long-term survival. The subgroups did not differ in the proportion of clinical AIDS cases at HAART initiation, in the prevalence of hepatitic C virus (HCV) coinfection, or in pretreatment and end-of-follow-up CD4 cell counts. In contrast, the viral load achieved during treatment was lower in the survivors (P=0.03), as was the prevalence of hepatitis B virus (HBV) coinfection (P=0.03). Usage of either protease inhibitor (PI)-containing regimens [odds ratio (OR) 9.0, 95% confidence interval (CI) 2.2-35.98, P<0.001] or all three drug classes simultaneously (OR 7.4, 95% CI 2.2-25.1, P<0.001) was associated with long-term survival. Drug holidays incorporated in structured treatment interruption (STI) were also associated with a good prognosis (OR 14.9, 95% CI 2.9-75.6, P<0.001).

CONCLUSIONS

Long-term survival was associated with PI-based HAART regimens and lower viraemia, but not with the immunological status either at baseline or at the end of follow up. STI when CD4 counts reach 350 cells/microL, along with undetectable viraemia, was a strong predictor of long-term survival.