HIV and hepatitis C co-infection: the role of HAART in HIV/hepatitis C virus management

Chapter XX Antiviral Treatment and Cancer Control

Hepatitis B virus (HBV), hepatitis C virus (HCV), human papilloma virus (HPV), Epstein-Barr virus (EBV), human T-cell lymphotropic virus type 1 (HTLV-1), Kaposi's sarcoma-associated herpesvirus (KSHV), and Merkel cell polyomavirus (MCV) contribute to about 10-15% global burden of human cancers. Conventional chemotherapy or molecular target therapies have been used to treat virus-associated cancers. However, a more proactive approach would be the use of antiviral treatment to suppress or eliminate viral infections to prevent the occurrence of cancer in the first place. Antiviral treatments against chronic HBV and HCV infection have achieved this goal, with significant reduction in the incidence of hepatocellular carcinoma in treated patients. Antiviral treatments for EBV, KSHV, and HTLV-1 had limited success in treating refractory EBV-associated lymphoma and post-transplant lymphoproliferative disorder, KSHV-associated Kaposi's sarcoma in AIDS patients, and HTLV-1-associated acute, chronic, and smoldering subtypes of adult T-cell lymphoma, respectively. Therapeutic HPV vaccine and RNA interference-based therapies for treating HPV-associated infection or cervical cancers also showed some encouraging results. Taken together, antiviral therapies have yielded promising results in cancer prevention and treatment. More large-scale studies in a real-world setting are necessary to confirm the efficacy of antiviral therapy. Further investigation for more effective and convenient antiviral regimens warrants more attention.

The cost-effectiveness of treating triple coinfection with HIV, tuberculosis and hepatitis C virus

OBJECTIVES

The objective of this study was to estimate the cost-effectiveness of treating patients infected with HIV and simultaneously coinfected with tuberculosis (TB) and hepatitis C virus (HCV).

METHODS

A mathematical model for HIV coinfection with TB and HCV is introduced. The model was designed to incorporate parameters of control for the coverage of care, which makes it useful for performing cost-effectiveness analysis of public policies. A cost-effectiveness analysis of early medical care of patients with TB and HCV coinfection, with coverage of 0 (basal), 25, 50, 75 and 100%, was performed for the whole cohort of patients and a special analysis was performed in a selected population with triple infection.

RESULTS

The cost per resolved infection and the cost per year of life gained were found to be very cost-effective for the population with triple infection, for all different coverages.

CONCLUSIONS

It is known that treating patients with HIV who are coinfected with TB or HCV implies high cost and low efficacy, but it is possible that the population with triple infections could achieve important benefits in terms of years of life gained.

Hepatic Safety of Rilpivirine/Emtricitabine/Tenofovir Disoproxil Fumarate Fixed-Dose Single-Tablet Regimen in HIV-Infected Patients with Active Hepatitis C Virus Infection: The hEPAtic Study

OBJECTIVES

The aim of this study was to evaluate the frequency of transaminase elevations (TE) and total bilirubin elevations (TBE) during the first year of therapy with a single tablet regimen including RPV/FTC/TDF (EPA) in HIV/hepatitis C virus (HCV)-coinfected subjects in clinical practice.

METHODS

In a retrospective analysis, HIV/HCV-coinfected subjects who started EPA at 17 centres throughout Spain were included as cases. Subjects who started an antiretroviral therapy (ART) other than EPA during the study period at the same hospitals were randomly selected as controls in a 1:2 ratio. Primary outcome variables were grade (G) 3-4 TE and G4 TBE.

RESULTS

Of the 519 subjects included, 173 individuals started EPA. Nine (5.2%) subjects of the EPA group and 49 (14.2%) controls were naïve to ART. The median (Q1-Q3) follow-up was 11.2 (9.7-13.9) months. TE was observed in 2 [1.2%; 95% confidence interval (CI): 0.14%-4.1%] subjects receiving EPA and 11 (3.2%; 95%CI: 1.6%-5.6%) controls (p = 0.136), all events were G3. No patient discontinued ART due to TE. One (0.6%; 95%CI: 0.01%-3.1%) subject on EPA and 8 (2.3%; 95%CI: 1%-4.5%) subjects in the control group developed TBE (p = 0.141), without developing any other hepatic event during follow-up. Three (2.3%) subjects with cirrhosis versus 10 (3.1%) without cirrhosis showed G3-4 TE (p = 0.451).

CONCLUSION

The frequency of severe liver toxicity in HIV/HCV-coinfected subjects receiving EPA under real-life conditions is very low, TE were generally mild and did not lead to drug discontinuation. All these data suggest that EPA can be safely used in this particular subpopulation.

Differential predictors of ART adherence among HIV-monoinfected versus HIV/HCV-coinfected individuals

Although adherence is an important key to the efficacy of antiretroviral therapy (ART), many people living with HIV (PLWH) fail to maintain optimal levels of ART adherence over time. PLWH with the added burden of Hepatitis C virus (HCV) coinfection possess unique challenges that potentially impact their motivation and ability to adhere to ART. The present investigation sought to (1) compare ART adherence levels among a sample of HIV/HCV-coinfected versus HIV-monoinfected patients, and (2) identify whether ART-related clinical and psychosocial correlates differ by HCV status. PLWH receiving ART (N = 215: 105 HIV/HCV-coinfected, 110 HIV-monoinfected) completed a comprehensive survey assessing ART adherence and its potential correlates. Medical chart extraction identified clinical factors, including liver enzymes. Results demonstrated that ART adherence did not differ by HCV status, with 83.7% of coinfected patients and 82.4% of monoinfected patients reporting optimal (i.e., ≥95%) adherence during a four-day recall period (p = .809). Multivariable logistic regression demonstrated that regardless of HCV status, optimal ART adherence was associated with experiencing fewer adherence-related behavioral skills barriers (AOR = 0.56; 95%CI = 0.43-0.73), lower likelihood of problematic drinking (AOR = 0.15; 95%CI = 0.04-0.67), and lower likelihood of methamphetamine use (AOR = 0.14; 95%CI = 0.03-0.69). However, among HIV/HCV-coinfected patients, optimal adherence was additionally associated with experiencing fewer ART adherence-related motivational barriers (AOR = 0.23; 95%CI = 0.08-0.62) and lower likelihood of depression (AOR = 0.06; 95%CI = 0.00-0.84). Findings suggest that although HIV/HCV-coinfected patients may face additional, distinct barriers to ART adherence, levels of adherence commensurate with those demonstrated by HIV-monoinfected patients might be achievable if these barriers are addressed.

Liver Damage in Patients with HCV/HIV Coinfection Is Linked to HIV-Related Oxidative Stress

HIV infection aggravates the progression of liver damage in HCV-coinfected patients, with the underlying pathogenesis being multifactorial. Although high level of oxidative stress has been observed frequently in patients infected with HIV or HCV, the status of oxidative stress in HIV/HCV coinfection and its contribution to HCV liver damage have not been determined. This study involved 363 HBsAg-negative, anti-HCV-positive former blood donors recruited from a village in central China in July 2005; of these, 140 were positive for HIV. Of these 363 subjects, 282 were successfully followed up through July 2009. HIV/HCV-coinfected subjects had higher rates of end-stage liver disease-related death than those monoinfected with HCV. Liver ultrasound manifestations were poor in HIV-positive than in HIV-negative individuals, in both chronic HCV carriers and those with resolved HCV. Serum concentrations of total glutathione (tGSH), malondialdehyde (MDA), glutathione peroxidase (GSH-Px), GSSG, and reduced GSH were higher in HIV-positive than HIV-negative subjects. GSSG concentrations were higher in HIV-infected subjects with abnormal ALT/AST levels than in those with normal ALT/AST levels and were associated with poorer liver ultrasound manifestations. These finding indicated that HIV infection accelerated HCV-associated liver damage in HIV/HCV-coinfected individuals. Increased oxidative stress, induced primarily by HIV coinfection, may contribute to aggravated liver damage.

Peginterferon-alfa mono-therapy in the treatment of acute hepatitis C in HIV-infection

The ongoing epidemic of acute hepatitis C (AHC) infection among MSM highlights the need to identify factors allowing for optimal treatment outcome in HIV co-infected individuals. Cohort study of 105 HIV-infected patients with AHC infection from five centres in two European countries was carried out. Choice of treatment with pegIFN-alfa alone (group 1; n = 36) or pegIFN-alfa and ribavirin (RBV) (group 2; n = 69) was at the discretion of the investigator. Outcome was evaluated as RVR and SVR. Fisher's exact and Mann Whitney U tests were used for statistical analysis. All patients were male, median age was 39 years, main route of transmission MSM (91%). In 69% of patients, clinical signs of acute hepatic infection were missing, dominant HCV genotypes were 1 (64%) and 4 (16%) and mean baseline HCV-RNA was 3.559.085 IU/mL. 60% received HAART and CD4 cell count was 469/mm(3) . Overall SVR rate was 64.8% (68/105). SVR was reached in 69% of treated patients in group 1 and in 63% of treated patients in group 2 (P = 0.67) while RVR was seen in 61% and 49%, respectively (P = 0.35). Interestingly, by univariate analysis, SVR rates in group 1 were significantly higher in patients initiating therapy within 4 weeks of AHC diagnosis compared to patients initiating therapy within 5-36 weeks after diagnosis (P = 0.03). PegIFN-alfa alone or in combination with ribavirin results in similar response rates in HIV-infected patients with AHC. In particular, when treatment is initiated within 4 weeks of diagnosis, pegIFN mono-therapy might be sufficient to allow for an optimal treatment response.

Quantification of hepatic FOXP3+ T-lymphocytes in HIV/hepatitis C coinfection

Coinfection with HIV adversely impacts every stage of hepatitis C (HCV) infection. Liver damage in HCV infection results from host antiviral responses rather than direct viral pathogenesis. Despite depressed cellular immunity, coinfected patients show accelerated hepatic fibrosis compared with HCV monoinfected patients. This paradox is poorly understood. T-regulatory (Treg) cells (CD4+ and FOXP3+) are hypothesized to limit hepatic damage in HCV. Our hypothesis was that reduced frequency of hepatic Treg in HIV/HCV coinfection compared with HCV monoinfection may explain poorer outcomes. We quantified FOXP3+, CD4+, CD8+ and CD20+ cells in liver biopsies of 35 male subjects matched by age and ISHAK fibrosis score, 12 HIV monoinfected, 11 HCV monoinfected and 12 HIV/HCV coinfected. Cell counts were performed using indirect immunohistochemical staining and light microscopy. HIV/HCV coinfected subjects had fewer hepatic FOXP3+ (P = 0.031) and CD4+ cells (P = 0.001) than HCV monoinfected subjects. Coinfected subjects had more hepatic CD8+ cells compared with HCV monoinfected (P = 0.023), and a lower ratio of FOXP3+ to CD8+ cells (0.08 vs 0.27, P < 0.001). Multivariate analysis showed number of CD4+ cells controlled for differences in number of FOXP3+ cells. Fewer hepatic FOXP3+ and CD4+ cells in HIV/HCV coinfection compared with HCV monoinfection suggests lower Treg activity, driven by an overall loss of CD4+ cells. Higher number of CD8+ cells in HIV/HCV coinfection suggests higher cytotoxic activity. This may explain poorer outcomes in HIV/HCV coinfected patients and suggests a potential mechanism by which highly active antiretroviral therapy may benefit these patients.

Hepatitis B and C co-infection among HIV-infected adults while on antiretroviral treatment: long-term survival, CD4 cell count recovery and antiretroviral toxicity in Cambodia

Background

Despite the high burden, there is a dearth of (long-term) outcome data of hepatitis B virus (HBV) and hepatitis C virus (HCV) co-infected patients receiving antiretroviral treatment (ART) in a clinical setting in resource-constrained settings, particularly from Asia.

Methods

We conducted a retrospective cohort study including all adults initiating standard ART (non-tenofovir-based) between 03/2003 and 09/2012. HBV infection was diagnosed by HBV surface antigen detection. HCV diagnosis relied on antibody detection. The independent effect of HBV and HCV on long-term (≥5 years) ART response in terms of mortality (using Cox regression), severe livertoxicity (using logistic regression) and CD4 count increase (using mixed-effects modelling) was determined.

Results

A total of 3089 adults were included (median age: 35 years (interquartile range 30–41); 46% male), of whom 341 (11.0%) were co-infected with HBV and 163 (5.3%) with HCV. Over a median ART follow-up time of 4.3 years, 240 individuals died. Mortality was 1.6 higher for HBV co-infection in adjusted analysis (P = 0.010). After the first year of ART, the independent mortality risk was 3-fold increased in HCV co-infection (P = 0.002). A total of 180 (5.8%) individuals discontinued efavirenz or nevirapine due to severe livertoxicity, with an independently increased risk for HBV (hazard ratio (HR) 2.3; P<0.001) and HCV (HR 2.8; P<0.001). CD4 recovery was lower in both HBV and HCV co-infection but only statistically significant for HBV (P<0.001).

Discussion

HBV and HCV co-infection was associated with worse ART outcomes. The effect of early ART initiation and providing effective treatment for hepatitis co-infection should be explored.

Hepatic safety and tolerability of raltegravir among HIV patients coinfected with hepatitis B and/or C

BACKGROUND

Potential liver toxicity is an important consideration for antiretroviral selection among patients coinfected with HIV and viral hepatitis (B and/or C). We sought to describe the hepatic safety profile of raltegravir in this population.

METHODS

Using data from HIV clinical cohorts at Johns Hopkins University and the University of North Carolina at Chapel Hill, we evaluated factors associated with liver enzyme elevations (LEEs) and calculated adverse event incidence rates for patients initiated on raltegravir-containing regimens prior to 1 January 2010. LEEs were graded according to Division of AIDS definitions.

RESULTS

During the study period, 456 patients received raltegravir - of whom 36% were hepatitis-coinfected (138 HCV, 17 HBV, 11 HBV+HCV). Coinfected patients were more likely to have baseline abnormal LEEs and developed severe (grade 3-4) LEEs at a rate 3.4× that of HIV-monoinfected patients (95% CI 1.28, 9.61). Among all participants, the incidence rate for first occurrence of severe LEEs was 5 per 100 person-years (95% CI 3, 7). In adjusted analyses, coinfected patients had a 2.7-fold increased hazard of severe LEEs (95% CI 1.03, 7.04). 60% of severe abnormalities occurred within 6 months after starting raltegravir; the drug was discontinued in 3 (1.3%) coinfected patients and 18 (6.2%) monoinfected patients.

CONCLUSIONS

Compared with HIV-monoinfected patients, those with HIV-hepatitis coinfection are at increased hazard of developing LEEs on raltegravir, at a level similar to other antiretrovirals. Severe events were uncommon, rarely leading to raltegravir discontinuation. With appropriate monitoring, raltegravir-based therapy is safe in hepatitis-coinfected patients.

Anti-viral treatment and cancer control

Hepatitis B virus (HBV), hepatitis C virus (HCV), human papillomavirus (HPV), and Epstein-Barr virus (EBV) contribute to about 10-15 % global burden of human cancers. Conventional chemotherapy or molecular target therapies have been used to treat virus-associated cancers. However, a more proactive approach would be the use of antiviral treatment to suppress or eliminate viral infections to prevent the occurrence of cancer in the first place. Antiviral treatments against chronic HBV and HCV infections have achieved this goal, with significant reduction in the incidence of hepatocellular carcinoma in treated patients. Antiviral treatments for EBV, Kaposi's sarcoma-associated herpesvirus (KSHV), and human T-cell lymphotropic virus type 1 (HTLV-1) had limited success in treating refractory EBV-associated lymphoma and post-transplant lymphoproliferative disorder, KSHV-associated Kaposi's sarcoma in AIDS patients, and HTLV-1-associated acute, chronic, and smoldering subtypes of adult T-cell lymphoma, respectively. Therapeutic HPV vaccine and RNA-interference-based therapies for treating HPV-associated cervical cancers also showed some encouraging results. Taken together, antiviral therapies have yielded promising results in cancer prevention and treatment. More large-scale studies are necessary to confirm the efficacy of antiviral therapy. Further investigation for more effective and convenient antiviral regimens warrants more attention.

Liver fibrosis progression in HIV-HCV-coinfected patients treated with distinct antiretroviral drugs and impact of pegylated interferon/ribavirin therapy

BACKGROUND

Advanced liver fibrosis frequently develops in patients with chronic hepatitis C coinfected with HIV. Non-invasive techniques for staging liver fibrosis, such as transient elastometry, may allow both periodic monitoring and examination of large patient populations.

METHODS

A programme of liver fibrosis assessment using transient elastometry has been ongoing at our institution since 2004. All HIV-HCV-coinfected patients having ≥2 examinations separated by >18 months were included. Liver fibrosis progression (LFP) was defined as an increase in liver stiffness from <9.5 kPa (Metavir F0-F2) to >9.5 kPa (Metavir F3-F4), or an increase >30% in patients with baseline Metavir F3-F4.

RESULTS

A total of 545 HIV-HCV-coinfected patients were analysed (mean age 41 years, 71% male, 81% intravenous drug users, mean body mass index 23.3 kg/m(2), 4.2% hepatitis B surface antigen-positive, 8.4% alcohol abuse, mean CD4(+) T-cell count 519 cells/μl). At baseline, 527 patients were on antiretroviral therapy, with the most frequent third drug being atazanavir (19.7%), efavirenz (15.9%), lopinavir (13.1%) or nevirapine (7.2%). A total of 99 (18%) patients experienced LFP during a mean (sd) follow-up of 70.9 (15.7) months. Use of protease inhibitors (OR 4.93, 95% CI 1.73, 14.0; P=0.03) and male gender (OR 5.12, 95% CI 1.37, 19.1; P=0.01) were associated with LFP. By contrast, the achievement of HCV clearance following pegylated interferon/ribavirin (PEG-IFN/RBV) therapy (OR 0.27, 95% CI 0.1, 0.79; P=0.02) was protective. Lopinavir exposure was significantly associated with LFP (OR 1.02, 95% CI 1.0, 1.04; P=0.03), whereas nevirapine was protective (OR 0.94, 95% CI 0.9, 0.99; P=0.02).

CONCLUSIONS

The use of protease inhibitors, mainly lopinavir, is associated with increased LFP in HIV-HCV-coinfected patients. By contrast, nevirapine therapy and, particularly, HCV clearance with PEG-IFN/RBV significantly reduce LFP.

Effect of HCV infection on cause-specific mortality after HIV seroconversion, before and after 1997

BACKGROUND & AIMS

Individuals with human immunodeficiency virus (HIV) infection frequently also are infected with hepatitis C virus (HCV) (co-infection), but little is known about its effects on the progression of HIV-associated disease. We aimed to determine the effects of co-infection on mortality from HIV and/or acquired immune deficiency syndrome (AIDS), and hepatitis or liver disease, adjusting for the duration of HIV infection.

METHODS

We analyzed data from the 16 cohorts of the Concerted Action on Seroconversion to AIDS and Death in Europe (CASCADE) collaboration, which included information on HCV infection and cause of death. A competing-risks proportional subdistribution hazards model was used to evaluate the effect of HCV infection on the following causes of death: HIV- and/or AIDS-related, hepatitis- or liver-related, natural, and non-natural.

RESULTS

Of 9164 individuals with HIV infection and a known date of seroconversion, 2015 (22.0%) also were infected with HCV. Of 718 deaths, 395 (55.0%) were caused by HIV infection and/or AIDS, and 39 (5.4%) were caused by hepatitis or liver-related disease. Among individuals infected with only HIV or with co-infection, the mortality from HIV infection and/or AIDS-related causes and hepatitis or liver disease decreased significantly after 1997, when combination antiretroviral therapy became widely available. However, after 1997, HIV and/or AIDS-related mortality was higher among co-infected individuals than those with only HIV infection in each risk group: injection drug use (adjusted hazard ratio [aHR], 2.43; 95% confidence interval [CI], 1.14-5.20), sex between men and women or hemophilia (aHR, 3.43; 95% CI, 1.70-6.93), and sex between men (aHR, 3.11; 95% CI, 1.49-6.48). Compared with individuals infected with only HIV, co-infected individuals had a higher risk of death from hepatitis or liver disease.

CONCLUSIONS

Based on analysis of data from the CASCADE collaboration, since 1997, when combination antiretroviral therapy became widely available, individuals co-infected with HIV and HCV have had a higher risk of death from HIV and/or AIDS, and from hepatitis or liver disease, than patients infected with only HIV. It is necessary to evaluate the effects of HCV therapy on HIV progression.

Substance abuse, HIV-1 and hepatitis

During the course of human immunodeficiency virus type 1 (HIV-1) disease, the virus has been shown to effectively escape the immune response with the subsequent establishment of latent viral reservoirs in specific cell populations within the peripheral blood (PB) and associated lymphoid tissues, bone marrow (BM), brain, and potentially other end organs. HIV-1, along with hepatitis B and C viruses (HBV and HCV), are known to share similar routes of transmission, including intravenous drug use, blood transfusions, sexual intercourse, and perinatal exposure. Substance abuse, including the use of opioids and cocaine, is a significant risk factor for exposure to HIV-1 and the development of acquired immune deficiency syndrome, as well as HBV and HCV exposure, infection, and disease. Thus, coinfection with HIV-1 and HBV or HCV is common and may be impacted by chronic substance abuse during the course of disease. HIV- 1 impacts the natural course of HBV and HCV infection by accelerating the progression of HBV/HCV-associated liver disease toward end-stage cirrhosis and quantitative depletion of the CD4+ T-cell compartment. HBV or HCV coinfection with HIV-1 is also associated with increased mortality when compared to either infection alone. This review focuses on the impact of substance abuse and coinfection with HBV and HCV in the PB, BM, and brain on the HIV-1 pathogenic process as it relates to viral pathogenesis, disease progression, and the associated immune response during the course of this complex interplay. The impact of HIV-1 and substance abuse on hepatitis virus-induced disease is also a focal point.

Impact of hepatitis C virus on HIV response to antiretroviral therapy in Nigeria

The effect of hepatitis C virus (HCV) on antiretroviral therapy (ART) response in patients in sub-Saharan Africa is unknown. We studied 1431 HIV-infected ART initiators in Jos, Nigeria, of whom 6% were HCV coinfected. A similar proportion of HIV/HCV-coinfected and HIV-monoinfected patients achieved HIV RNA <400 copies per milliliter after 24 and 48 weeks of ART (P > 0.05). Hepatotoxicity was uncommon (0.8% and 0.33% at 24 and 48 weeks, respectively) but was more common in the HIV/HCV-coinfected group at 24 (adjusted odds ratio = 19.3; 95% confidence interval: 4.41 to 84.4) and 48 weeks (adjusted odds ratio = 56.7; 95% confidence interval: 5.03 to 636.92). HCV did not significantly impact ART response in this Nigerian cohort.

Different HCV genotype distributions of HIV-infected individuals in Henan and Guangxi, China

Background

Due to shared transmission routes, hepatitis C virus (HCV) infection is highly prevalent among people infected with human immunodeficiency virus (HIV). Highly active antiretroviral therapy (HAART) is associated with hepatotoxicity, leading to the negative effects on patients with HIV/HCV co-infection. In order to provide valuable information for HCV management in this particular population, we investigated the HCV genotypes in HIV-infected individuals from Henan and Guangxi, the two provinces with the most HIV-infected cases in China.

Methods

Individuals, who acquired HIV infection through various risk routes, were recruited from Henan and Guangxi. Test of antibodies against HCV (anti-HCV) was conducted, and detection of HCV RNA was performed by PCR amplification. HCV subtypes were determined by direct sequencing of amplicons, followed by phylogenetic analysis.

Results

We recruited a total of 1,112 HIV-infected people in this present study. Anti-HCV was detected from 218 (50.1%) patients from Henan and 81 (12.0%) patients from Guangxi, respectively. The highest prevalence of HIV/HCV co-infection was observed from FBDs (former blood donors) (87.2%) in Henan and IDUs (intravenous drug users) (81.8%) in Guangxi, respectively. The seroprevalence rate of HCV among people with sexual contact was significantly higher in Henan than in Guangxi (18.7% vs. 3.5%, P<0.05). The positive rate of HCV RNA in Henan and Guangxi was 30.6% (133/435) and 11.2% (76/677), respectively. Moreover, we found that 20 anti-HCV negative samples were HCV positive by PCR amplification. HCV subtype 1b (52.7%) was predominant in Henan, followed by subtype 2a (41.9%). The most frequently detected subtypes in Guangxi were 6a (35.6%) and 3b (32.9%).

Conclusion

The HCV genotype distributions were different in HIV-infected people from Henan and Guangxi. HIV/HCV co-infection was not only linked to the transmission routes, but also associated with the geographic position.

Immune reconstitution inflammatory syndrome: immune restoration disease 20 years on

Restoration of immune responses against opportunistic pathogens after commencing antiretroviral therapy (ART) may cause immune restoration disease (IRD) in about 10%-40% of HIV patients with low CD4(+) T-cell counts and usually presents clinically as a type of immune reconstitution inflammatory syndrome (IRIS). IRIS may be associated with many different opportunistic pathogens, but types associated with Mycobacterium tuberculosis, BCG, cryptococci, JC polyomavirus (the cause of progressive multifocal leukoencephalopathy [PML]), hepatitis C virus and hepatitis B virus infection are the most informative about disease pathogenesis and management. A CD4(+) T-cell count of < 50/μL and a high pathogen load are the most commonly identified risk factors for IRIS. Recovery of pathogen-specific T-cell responses and perturbations of innate immune responses before and after ART appear to cause immunopathological abnormality in tissues infected by the pathogen. Prevention of IRIS may be influenced by the timing of ART: The risk of tuberculosis (TB)-associated-IRIS can be reduced by commencing ART after 8 weeks of TB treatment, but rates of AIDS or death are lower if ART is commenced during the first 4 weeks of TB treatment. Outcomes for patients with HIV and treated cryptococcal or TB meningitis may be improved by deferring ART until the opportunistic infection is fully suppressed, but data are inadequate. As ART is currently the only effective treatment for PML in patients with HIV, PML-associated IRIS cannot be prevented by manipulating the timing of ART. A greater understanding of the immunopathogenesis of IRIS may lead to targeted therapies.

Glances in Immunology of HIV and HCV Infection

Since the identification of HIV and HCV much progress has been made in the understanding of their life cycle and interaction with the host immune system. Despite these viruses markedly differ in their virological properties and in their pathogenesis, they share many common features in their immune escape and survival strategy. Both viruses have developed sophisticated ways to subvert and antagonize host innate and adaptive immune responses. In the last years, much effort has been done in the study of the AIDS pathogenesis and in the development of efficient treatment strategies, and a fatal infection has been transformed in a potentially chronic pathology. Much of this knowledge is now being transferred in the HCV research field, especially in the development of new drugs, although a big difference still remains between the outcome of the two infections, being HCV eradicable after treatment, whereas HIV eradication remains at present unachievable due to the establishment of reservoirs. In this review, we present current knowledge on innate and adaptive immune recognition and activation during HIV and HCV mono-infections and evasion strategies. We also discuss the genetic associations between components of the immune system, the course of infection, and the outcome of the therapies.

Interplay between HIV-1 and Host Genetic Variation: A Snapshot into Its Impact on AIDS and Therapy Response

As of February 2012, 50 circulating recombinant forms (CRFs) have been reported for HIV-1 while one CRF for HIV-2. Also according to HIV sequence compendium 2011, the HIV sequence database is replete with 414,398 sequences. The fact that there are CRFs, which are an amalgamation of sequences derived from six or more subtypes (CRF27_cpx (cpx refers to complex) is a mosaic with sequences from 6 different subtypes besides an unclassified fragment), serves as a testimony to the continual divergent evolution of the virus with its approximate 1% per year rate of evolution, and this phenomena per se poses tremendous challenge for vaccine development against HIV/AIDS, a devastating disease that has killed 1.8 million patients in 2010. Here, we explore the interaction between HIV-1 and host genetic variation in the context of HIV/AIDS and antiretroviral therapy response.