Varicella vaccination in HIV-1-infected children after immune reconstitution

Immunogenicity and safety of live attenuated and recombinant/inactivated varicella zoster vaccines in people living with HIV: A systematic review

Few papers focus their attention on VZV vaccination effectiveness among people living with HIV (PLWH). Flanking the live attenuated vaccine (VZL) available, a newly recombinant vaccine (RZV) was recently introduced and approved for HZ prevention among adults. PLWH represents a population on which a particular attention should be applied, in order to guarantee the vaccine efficacy and safety. We performed a literature search in USNLM, PubMed, PubMed Central, PMC and Cochrane Library. From all the publications found eligible, data were extracted and processed per population, vaccine type, immunogenicity and ADRs. The review of the 13 included studies shows that both RZV and VZL are immunogenic and have an acceptable safety profile in adults and children living with HIV. However, given the lack of research available about vaccine efficacy in preventing VZV and HZ in PLWH, additional studies need to be performed, in order to achieve a full completeness of data.

The Impact of HIV on B Cell Compartment and Its Implications for COVID-19 Vaccinations in People with HIV

HIV causes intense polyclonal activation of B cells, resulting in increased numbers of spontaneously antibody-secreting cells in the circulation and hypergammaglobulinemia. It is accompanied by significant perturbations in various B cell subsets, such as increased frequencies of immature/transitional B cells, activated memory B cells, atypical memory B cells, short-lived plasmablasts and regulatory B cells, as well as by decreased frequencies of resting memory and resting naïve B cells. Furthermore, both memory and antigen-inexperienced naïve B cells show exhausted and immune-senescent phenotypes. HIV also drives the expansion and functional impairment of CD4+ T follicular helper cells, which provide help to B cells, crucial for the generation of germinal center reactions and production of long-lived plasma and memory B cells. By suppressing viral replication, anti-retroviral therapy reverses the virus-induced perturbations and functional defects, albeit inadequately. Due to HIV's lingering impact on B cells, immune senescence and residual chronic inflammation, people with HIV (PWH), especially immune non-responders, are immunocompromised and mount suboptimal antibody responses to vaccination for SARS-CoV-2. Here, we review how functionally and phenotypically distinct B cell subsets are induced in response to a vaccine and an infection and how HIV infection and anti-retroviral therapy (ART) impact them. We also review the role played by HIV-induced defects and perturbations in B cells in the induction of humoral immune responses to currently used anti-SARS-CoV-2 vaccines in PWH on ART. We also outline different strategies that could potentially enhance the vaccine-induced antibody responses in PWH. The review will provide guidance and impetus for further research to improve the immunogenicity of these vaccines in this human population.

Recombinant Simian Varicella Virus-Simian Immunodeficiency Virus Vaccine Induces T and B Cell Functions and Provides Partial Protection against Repeated Mucosal SIV Challenges in Rhesus Macaques

HIV vaccine mediated efficacy, using an expanded live attenuated recombinant varicella virus-vectored SIV rSVV-SIVgag/env vaccine prime with adjuvanted SIV-Env and SIV-Gag protein boosts, was evaluated in a female rhesus macaques (RM) model against repeated intravaginal SIV challenges. Vaccination induced anti-SIV IgG responses and neutralizing antibodies were found in all vaccinated RMs. Three of the eight vaccinated RM remained uninfected (vaccinated and protected, VP) after 13 repeated challenges with the pathogenic SIVmac251-CX-1. The remaining five vaccinated and infected (VI) macaques had significantly reduced plasma viral loads compared with the infected controls (IC). A significant increase in systemic central memory CD4+ T cells and mucosal CD8+ effector memory T-cell responses was detected in vaccinated RMs compared to controls. Variability in lymph node SIV-Gag and Env specific CD4+ and CD8+ T cell cytokine responses were detected in the VI RMs while all three VP RMs had more durable cytokine responses following vaccination and prior to challenge. VI RMs demonstrated predominately SIV-specific monofunctional cytokine responses while the VP RMs generated polyfunctional cytokine responses. This study demonstrates that varicella virus-vectored SIV vaccination with protein boosts induces a 37.5% efficacy rate against pathogenic SIV challenge by generating mucosal memory, virus specific neutralizing antibodies, binding antibodies, and polyfunctional T-cell responses.

HIV-1 Persistence in Children during Suppressive ART

There is a growing number of perinatally HIV-1-infected children worldwide who must maintain life-long ART. In early life, HIV-1 infection is established in an immunologically inexperienced environment in which maternal ART and immune dynamics during pregnancy play a role in reservoir establishment. Children that initiated early antiretroviral therapy (ART) and maintained long-term suppression of viremia have smaller and less diverse HIV reservoirs than adults, although their proviral landscape during ART is reported to be similar to that of adults. The ability of these early infected cells to persist long-term through clonal expansion poses a major barrier to finding a cure. Furthermore, the effects of life-long HIV persistence and ART are yet to be understood, but growing evidence suggests that these individuals are at an increased risk for developing non-AIDS-related comorbidities, which underscores the need for an HIV cure.

Health Considerations for HIV-Infected International Travelers

PURPOSE OF THE REVIEW

International travel continues to steadily increase, including leisure travel, travel to one's country of origin to visit friends and relatives, travel for service work, and business travel. Travelers with HIV may have an increased risk for travel-associated infections. The pre-travel medical consultation is an important means of assessing one's risk for travel-related health issues. The aim of this review is to provide an update on key health considerations for the HIV-infected traveler.

RECENT FINDINGS

Like all travelers, the HIV-infected traveler should adhere to behavioral precautions, including safety measures with food and water consumption, safe sexual practices, and arthropod bite avoidance. HIV is a risk factor for venous thromboembolism and patients should be educated regarding this risk. Most pre-travel vaccines are safe and immunogenic in HIV-infected individuals, though live vaccines should be avoided in patients with low CD4 counts. Malaria chemoprophylaxis is strongly recommended in patients with HIV traveling to endemic areas and no significant interactions exist between the commonly used prophylactic anti-malarial agents and anti-retroviral therapy (ART). Travelers with HIV, particularly those who are not on ART or who have low CD4 cell counts, may have increased risk for tuberculosis, malaria, enteric infections, visceral leishmaniasis, American trypanosomiasis, and endemic mycoses such as histoplasmosis, talaromycosis, and coccidioidomycosis. The immune status of the HIV-infected traveler should be assessed prior to travel along with the duration, itinerary, and activities planned during travel in order to carefully consider individual risk for travel-related health issues.

Studies with herpes zoster vaccines in immune compromised patients

INTRODUCTION

The active component of the herpes zoster vaccine (ZVL), licensed for people ≥50 years of age, is a live attenuated varicella-zoster virus. ZVL is contraindicated for immune compromised individuals, with limited regard to the degree of immunosuppression. Areas covered: This review evaluates phase I and II and observational studies for ZVL, and published reports of the off-label use of ZVL, for conditions and therapies for which investigators considered the risk-benefit for using ZVL to be favorable. It also discusses exploratory trials of ZVL for additional immune compromising conditions, and summarizes clinical guidelines from many countries and professional societies that are based upon recent investigations. Studies in immune compromised patients of investigational vaccines that do not contain live virus are reviewed. Expert commentary: It is likely that past and ongoing research with ZVL will define immune compromising diseases and/or therapies for which the risk-benefit for using ZVL vaccine is favorable. The main variables to consider in this assessment in immune compromised patients are safety, immunogenicity, protection against herpes zoster, and persistence of protection. Vaccination against herpes zoster prior to suppressing immunity is an important clinical strategy, although efficacy of this approach has not been evaluated in a clinical trial.

Immunisation practices in centres caring for children with perinatally acquired HIV: A call for harmonisation

BACKGROUND

Current national immunisation schedules differ between countries in terms of vaccine formulation, timing of vaccinations and immunisation programme funding and co-ordination. As a result, some HIV infected paediatric population may be left susceptible to vaccine preventable infections. Vaccines used in healthy population should be subjected to high quality ethical research and be explicitly validated for use in children with special vaccination needs such as those infected with HIV. This survey was completed to assess current vaccination practices and attitudes toward vaccination among pediatricians who care for vertically HIV infected children.

METHODS

An online questionnaire was completed by 46 experts in paediatric HIV-infection from the Paediatric European Network for Treatment of AIDS (PENTA). Data were collected between November 2013 and March 2014.

RESULTS

46units looking after 2465 patients completed the questionnaire. The majority of units (67%) reported that common childhood immunisation were administered by the family doctor or local health services rather than in the HIV specialist centre. Vaccination histories were mostly incomplete and difficult to obtain for 40% of the studied population. Concerns were reported regarding the use of live attenuated vaccines, such as varicella and rotavirus, and these were less frequently recommended (61% and 28% of the units respectively). Monitoring of vaccine responses was employed in a minority of centres (41%). A range of different assays were used resulting in diverse units of measurement and proposed correlates of protection.

CONCLUSION

Vaccination practices for perinatally HIV-infected children vary a great deal between countries. Efforts should be made to improve communication and documentation of vaccinations in healthcare settings and to harmonise recommendations relating to additional vaccines for HIV infected children and the use of laboratory assays to guide immunisation. This will ultimately improve coverage and vaccine induced immunity in this vulnerable patient group.

[Guidelines for vaccination of immunocompromised individuals]

Immunosuppression of various origins is associated with an increased risk of infection; therefore the prevention of infectious diseases by vaccination is especially important in immunocompromised patients. However, the response to vaccinations is often reduced in these risk groups and the application of live vaccines is contraindicated during immunosuppression.In the following expert statement, recommendations for vaccination were created on the basis of current evidence and theoretical/immunological considerations. A first, general part elaborates on efficacy and safety of vaccinations during immunosuppression, modes of action of immunosuppressive medications and recommended time intervals between immunosuppressive treatments and vaccinations. A core piece of this part is a graduation of immunosuppression into three stages, i. e. no relevant immunosuppression, mild to moderate and severe immunosuppression and the assignment of various medications (including biologicals) to one of those stages; this is followed by an overview of possible and necessary vaccinations in each of those stages.The second part gives detailed vaccination guidelines for common diseases and therapies associated with immunosuppression. Primary immune deficiencies, chronic kidney disease, diabetes mellitus, solid and hematological tumors, hematopoetic stem cell transplantation, transplantation of solid organs, aspenia, rheumatological-, gastroenterologic-, dermatologic-, neurologic diseases, biologicals during pregnancy and HIV infection are dealt with.These vaccination guidelines, compiled for the first time in Austria, aim to be of practical help for physicians to facilitate and improve vaccination coverage in immunocompromised patients and their household members and contact persons.

Prevalence and Persistence of Varicella Antibodies in Previously Immunized Children and Youth With Perinatal HIV-1 Infection

BACKGROUND

Two doses of live-attenuated varicella-zoster vaccine are recommended for human immunodeficiency virus 1 (HIV-1)-infected children with CD4% ≥ 15%. We determined the prevalence and persistence of antibody in immunized children with perinatal HIV (PHIV) and their association with number of vaccinations, combination antiretroviral therapy (cART), and HIV status.

METHODS

The Adolescent Master Protocol is an observational study of children with PHIV and perinatally HIV-exposed but uninfected (PHEU) children conducted at 15 US sites. In a cross-sectional analysis, we tested participants' most recent stored sera for varicella antibody using whole-cell and glycoprotein enzyme-linked immunosorbent assay. Seropositivity predictors were identified using multivariable logistic regression models and C statistics.

RESULTS

Samples were available for 432 children with PHIV and 221 PHEU children; 82% of children with PHIV and 97% of PHEU children were seropositive (P < .001). Seropositivity after 1 vaccine dose among children with PHIV and PHEU children was 100% at <3 years (both), 73% and 100% at 3-<7 years (P < .05), and 77% and 97% at ≥ 7 years (P < .01), respectively. Seropositivity among recipients of 2 vaccine doses was >94% at all intervals. Independent predictors of seropositivity among children with PHIV were receipt of 2 vaccine doses, receipt of 1 dose while on ≥ 3 months of cART, compared with none (adjusted odds ratio [aOR]: 14.0 and 2.8, respectively; P < .001 for overall dose effect), and in those vaccinated ≥ 3 years previously, duration of cART (aOR: 1.29 per year increase, P = .02).

CONCLUSIONS

Humoral immune responses to varicella vaccine are best achieved when children with PHIV receive their first dose ≥ 3 months after cART initiation and maintained by completion of the 2-dose series and long-term cART use.

Immunoglobulin VH gene diversity and somatic hypermutation during SIV infection of rhesus macaques

B cell functional defects are associated with delayed neutralizing antibody development in pathogenic lentivirus infections. However, the timeframe for alterations in the antibody repertoire and somatic hypermutation (SHM) remains unclear. Here, we utilized the SIV/rhesus macaque (RM) model to investigate the dynamics of immunoglobulin V(H) gene diversity and SHM following infection. Three RMs were infected with SIVmac239, and V(H)1, V(H)3, and V(H)4 genes were amplified from peripheral blood at 0, 2, 6, 24, and 36 weeks postinfection for next-generation sequencing. Analysis of over 3.8 million sequences against currently available RM germline V(H) genes revealed a highly biased V(H) gene repertoire in outbred RMs. SIV infection did not significantly perturb the predominant IgG1 response, but overall immunoglobulin SHM declined during the course of SIV infection. Moreover, SHM at the AID deamination hotspot, WRC, rapidly decreased and was suppressed throughout SIV infection. In contrast, a transient increase in mutations at the APOBEC3G deamination hotspot, CCC, coincided with a spike in APOBEC3G expression during acute SIV infection. The results outline a timetable for altered V(H) gene repertoire and IgG SHM in the SIV/RM model and suggest a burst of APOBEC3G-mediated antibody SHM during acute SIV infection.

Vaccines for post-exposure prophylaxis against varicella (chickenpox) in children and adults

BACKGROUND

The prevention of varicella (chickenpox) using live attenuated varicella vaccines has been demonstrated both in randomised controlled trials (RCTs) and in population-based immunisation programmes in countries such as the United States and Australia. Many countries do not routinely immunise children against varicella and exposures continue to occur. Although the disease is often mild, complications such as secondary bacterial infection, pneumonitis and encephalitis occur in about 1% of cases, usually leading to hospitalisation. The use of varicella vaccine in persons who have recently been exposed to the varicella zoster virus has been studied as a form of post-exposure prophylaxis (PEP).

OBJECTIVES

To assess the efficacy and safety of vaccines for use as PEP for the prevention of varicella in children and adults.

SEARCH METHODS

We searched CENTRAL (2014, Issue 1), MEDLINE (1966 to March week 1, 2014), EMBASE (January 1990 to March 2014) and LILACS (1982 to March 2014). We searched for unpublished trials registered on the clinicaltrials.gov and WHO ICTRP websites.

SELECTION CRITERIA

RCTs and quasi-RCTs of varicella vaccine for PEP compared with placebo or no intervention. The outcome measures were efficacy in prevention of clinical cases and/or laboratory-confirmed clinical cases and adverse events following vaccination.

DATA COLLECTION AND ANALYSIS

Two review authors independently extracted and analysed data using Review Manager software.

MAIN RESULTS

We identified three trials involving 110 healthy children who were siblings of household contacts. The included trials varied in study quality, vaccine used, length of follow-up and outcomes measured and, as such, were not suitable for meta-analysis. We identified high or unclear risk of bias in two of the three included studies. Overall, 13 out of 56 vaccine recipients (23%) developed varicella compared with 42 out of 54 placebo (or no vaccine) recipients (78%). Of the vaccine recipients who developed varicella, the majority only had mild disease (with fewer than 50 skin lesions). In the three trials, most participants received PEP within three days following exposure; too few participants were vaccinated four to five days post-exposure to ascertain the efficacy of vaccine given more than three days after exposure. No included trial reported on adverse events following immunisation.

AUTHORS' CONCLUSIONS

These small trials suggest varicella vaccine administered within three days to children following household contact with a varicella case reduces infection rates and severity of cases. We identified no RCTs for adolescents or adults. Safety was not adequately addressed.

Immune reconstitution and vaccination outcome in HIV-1 infected children: present knowledge and future directions

Current evidence on routine immunization of HIV-1 infected children point out the need for a special vaccine schedule in this population. However, optimal strategies for identifying individuals susceptible to infections, and then offering them sustained protection through appropriate immunization schedule, both in terms of timing and number of vaccine doses, still remain to be elucidated. Understanding the degree of immune recovery after HAART initiation is important in guiding administration of routine vaccination in HIV-1 infected children. Although quantitative measures (e.g., CD4+ T-cell counts and immunoglobulin levels) are frequently performed to evaluate immune parameters, these measures do not fully mirror functional immune recovery. Here, we will review the status of single mandatory and recommended vaccines for HIV-1 infected children in relation to immune recovery after HAART initiation with the aim of identifying new means to help design personalized vaccine schedules for this population.

Vaccination in HIV-infected individuals

Vaccinations are key to limiting the increased risk of severe infectious diseases in HIV-infected patients for whom the risk–benefit ratio has been re-evaluated. Vaccine safety and immunogenicity depend on both vaccine type and immune deficiency, while vaccine-induced immune activation promotes a transient increase in viral load. Vaccine immunogenicity is reduced and wanes more rapidly, strengthening the need for revaccination. While inactivated vaccines are safe, attenuated vaccines are theoretically contraindicated, but the risk of infectious diseases outweighs the risks of severe adverse events in endemic areas, where the majority of HIV-infected individuals live, thus allowing their use when immune deficiency is moderate. Immune reconstitution with HAART has improved vaccine immune response, highlighting the importance of global access to and early initiation of therapy.

The immunogenicity and safety of live attenuated varicella-zoster virus vaccine in human immunodeficiency virus-infected children

BACKGROUND

The live attenuated varicella vaccine is recommended for HIV-infected children who are not severely immunosuppressed. This study aimed to assess the immunogenicity and safety of varicella vaccination among HIV-infected children who had severe immunosuppression before receiving antiretroviral therapy.

METHODS

Sixty HIV-infected children with no history of chickenpox or herpes zoster infection with CD4 T lymphocyte counts ≥ 15% or ≥ 200 cell/mm were enrolled. Two doses of varicella vaccine were administered at the time of enrollment and at 3 months. Varicella zoster virus (VZV) antibody was tested at baseline and 3 months after each dose by the enzyme-linked immunosorbent assay technique. An antibody titer >20 HU/mL was regarded as protective.

RESULTS

The median (interquartile range) of age, CD4 nadir, and current CD4 percentage were 11.2 (8.5-12.8) years, 9.5% (3-14), and 28% (22-32), respectively. Fifty-seven children (95%) received antiretroviral therapy for a median of 27 months. Among 34 children (57%) who were VZV seronegative at baseline, 11.8% (95% CI, 3.3%-27.5%) and 79.4% (95% CI, 62.1%-91.3%) were VZV seroconverted after first and second dose of vaccine, respectively. Children who had VZV seroconversion were more likely to have HIV RNA <1.7 copies/mL (92.6% vs. 71.4%, P = 0.18). Among 26 children who were seropositive at baseline, the geometric mean titers were increased from 56.7 to 107.9 and 134.6 unit/mL, respectively. Local and systemic reactions of grade 1 and 2 were reported in 13% and 4% of children, respectively. There was a trend toward better response among children with younger age, high CD4, and viral suppression.

CONCLUSIONS

Administration of the 2 doses of varicella vaccine resulted in high seroconversion rates without serious adverse reactions. Varicella vaccination for HIV-infected children should be encouraged.

Recombinant varicella vaccines induce neutralizing antibodies and cellular immune responses to SIV and reduce viral loads in immunized rhesus macaques

The development of an effective AIDS vaccine remains one of the highest priorities in HIV research. The live, attenuated varicella-zoster virus (VZV) Oka vaccine, safe and effective for prevention of chickenpox and zoster, also has potential as a recombinant vaccine against other pathogens, including human immunodeficiency virus (HIV). The simian varicella model, utilizing simian varicella virus (SVV), offers an approach to evaluate recombinant varicella vaccine candidates. Recombinant SVV (rSVV) vaccine viruses expressing simian immunodeficiency virus (SIV) env and gag antigens were constructed. The hypothesis tested was that a live, attenuated rSVV-SIV vaccine will induce immune responses against SIV in the rhesus macaques and provide protection against SIV challenge. The results demonstrated that rSVV-SIV vaccination induced low levels of neutralizing antibodies and cellular immune responses to SIV in immunized rhesus macaques and significantly reduced viral loads following intravenous challenge with pathogenic SIVmac251-CX-1.

Determinants of vaccine immunity in the cohort of human immunodeficiency virus-infected children living in Switzerland

BACKGROUND

Human immunodeficiency virus (HIV)-infected children are at increased risk of infections caused by vaccine preventable pathogens, and specific immunization recommendations have been issued.

METHODS

A prospective national multicenter study assessed how these recommendations are followed in Switzerland and how immunization history correlates with vaccine immunity.

RESULTS

Among 87 HIV-infected children (mean age: 11.1 years) followed in the 5 Swiss university hospitals and 1 regional hospital, most (76%) had CD4 T cells >25%, were receiving highly active antiretroviral treatment (79%) and had undetectable viral load (60%). Immunization coverage was lower than in the general population and many lacked serum antibodies to vaccine-preventable pathogens, including measles (54%), varicella (39%), and hepatitis B (65%). The presence of vaccine antibodies correlated most significantly with having an up-to-date immunization history (P<0.05). An up-to-date immunization history was not related to age, immunologic stage, or viremia but to the referral medical center.

CONCLUSIONS

All pediatricians in charge of HIV-infected children are urged to identify missing immunizations in this high-risk population.

A phase I-II study of live attenuated varicella-zoster virus vaccine to boost immunity in human immunodeficiency virus-infected children with previous varicella

Herpes zoster, may be severe and recurrent in HIV-infected children. We determined the safety and immunogenicity of live attenuated varicella-zoster virus (VZV) vaccine in 46 HIV-infected children who had experienced varicella. There were no serious adverse events. Two years after vaccination 82% of subjects remained VZV-antibody positive and 60% had VZV-specific cell-mediated immunity. No child developed herpes zoster.

Vaccines for post-exposure prophylaxis against varicella (chickenpox) in children and adults

BACKGROUND

Live attenuated varicella vaccines for the prevention of varicella (chickenpox) has been demonstrated both in randomised controlled trials (RCTs) and in population-based immunisation programmes in countries such as the United States. However, many countries do not routinely immunise children against varicella, and exposures continue to occur. Although the disease is often mild, complications such as secondary bacterial infection, pneumonitis and encephalitis occur in about 1% of cases, usually leading to hospitalisation. The use of varicella vaccine in persons who have recently been exposed to the varicella zoster virus has been studied as a form of post-exposure prophylaxis (PEP).

OBJECTIVES

To assess the efficacy and safety of vaccines for use as PEP for the prevention of varicella in children and adults.

SEARCH STRATEGY

We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library, 2008, Issue 1); MEDLINE (1966 to February 2008); and EMBASE (January 1990 to February 2008).

SELECTION CRITERIA

RCTs and quasi-RCTs of varicella vaccine for PEP compared with placebo or no intervention. The outcome measures were efficacy in prevention of clinical cases and/or laboratory-confirmed clinical cases and adverse effects following vaccination.

DATA COLLECTION AND ANALYSIS

Two review authors independently extracted and analysed data using Review Manager software.

MAIN RESULTS

Three studies involving 110 healthy children who were siblings of household contacts were identified as suitable for inclusion. The studies varied in quality, study design, vaccine used, and outcomes measured and, as such, were not suitable for meta-analysis. Overall, 13 out of 56 vaccine recipients (18%) developed varicella compared with 42 out of 54 placebo (or no vaccine) recipients (78%). Of the vaccine recipients who developed varicella, the majority only had mild disease (with less than 50 skin lesions). In the three studies, most subjects received PEP within three days following exposure; too few subjects were vaccinated four to five days post exposure to ascertain the efficacy of vaccine given more than three days after exposure. No included studies reported on adverse events following immunisation.

AUTHORS' CONCLUSIONS

These small trials suggest varicella vaccine administered within three days to children following household contact with a varicella case reduces infection rates and severity of cases. No RCTs for adolescents or adults were identified. However safety was not adequately addressed.

A splenic marginal zone-like peripheral blood CD27+B220- B cell population is preferentially depleted in HIV type 1-infected individuals

Peripheral blood CD27(+) B cells are reduced in HIV-1-infected individuals. In healthy individuals, the human peripheral blood CD27(+) B cell pool consists of two subsets defined by the expression, or lack thereof, of the CD45 isoform B220. We investigated the presence of circulating B220(+) and B220(-) memory B cells in HIV(+) individuals and found that the reduction in CD27(+) memory B cells occurs primarily among CD27(+)B220(-) B cells. Studies conducted using healthy controls indicate that CD27(+)B220(-) B cells have a splenic marginal zone like the immunophenotype IgM(hi)IgD(lo)CD21(+)CD23(-), express TLR9, and proliferate and secrete IgG and IgM in response to B cell-specific ODN. CD27(+)B220(+) B cells have the immunophenotype IgM(lo)IgD(hi)CD21(+)CD23(+), express activation-induced cytidine deaminase, and proliferate in response to SAC but do not secrete immunoglobulin. The AICD expression, along with CD86 expression, by CD27(+)B220(+) suggests these cells are of germinal center origin. The preferential depletion of CD27(+)B220(-) B cells mirrors alterations in spleen morphology and resident B cell populations due to HIV infection reported by other investigators and may play an important role in the defective B cell immunity against T-independent pathogens such as pneumococcus observed in HIV-1-infected individuals.

Primary varicella and herpes zoster among HIV-infected children from 1989 to 2006

OBJECTIVES

The primary objective of this study was to determine the incidence of herpes zoster in perinatally HIV-infected children. Secondary objectives included assessing the impact of highly active antiretroviral therapy and varicella zoster virus immunization on primary varicella and herpes zoster incidence and identifying risk factors for herpes zoster. We hypothesized that the incidence of herpes zoster has decreased in this population as a result of highly active antiretroviral therapy and routine varicella zoster virus immunization.

PATIENTS AND METHODS

This retrospective cohort study included HIV-infected children at a pediatric HIV clinic from 1989 to 2006. Incidence rates for 3 intervals (1989-1996, 1997-1999, and 2000-2006) were compared on the basis of introduction of highly active antiretroviral therapy (1996) and varicella zoster virus vaccination (1999). A Cox proportional-hazards regression model was developed for the time to herpes zoster among the subset of patients with primary varicella infection.

RESULTS

In 356 patients followed for 1721 person-years, the incidence of herpes zoster according to period was 30.0 per 1000 person-years in 1989-1996, 31.9 per 1000 person-years in 1997-1999, and 6.5 per 1000 person-years in 2000-2006. There was no difference in incidence-rate ratio between 1989-1996 and 1997-1999. However, there was a significant difference in herpes zoster incidence when comparing 1989-1999 with 2000-2006. The incidence of primary varicella zoster virus infection and herpes zoster in the 57 patients who received the varicella zoster virus vaccine was 22.3 per 1000 and 4.5 per 1000 person-years, respectively. Highly active antiretroviral therapy at the time of primary varicella zoster virus infection was protective against herpes zoster and increased herpes zoster-free survival.

CONCLUSIONS

The incidence of herpes zoster has decreased since 1989. The decline occurred after 2000, likely representing the combined effect of immunization and highly active antiretroviral therapy. The use of highly active antiretroviral therapy at the time of primary varicella zoster virus infection decreased the risk of herpes zoster and increased herpes zoster-free survival. Varicella zoster virus immunization was effective in preventing both primary varicella zoster virus and herpes zoster in this cohort.

B cell immunopathology during HIV-1 infection: lessons to learn for HIV-1 vaccine design

Induction of broad HIV-1 neutralizing antibodies should be a major goal of an effective HIV-1 vaccine. However, B cells are severely damaged during HIV-1 infection with loss of memory B cells and decline of serological memory. The molecular events leading to B cell damage must be further characterized with the aim of selecting vaccine components allowing preservation of B cell functions. This review focuses on B cell damage and antibody responses in HIV-1-infected patients during vaccination studies with viral and bacterial antigens. In addition novel data indicate that B cell activation may be at the basis of impaired immune responses.