Winston Cavert

Quantitative Image Analysis of HIV-1 Infection in Lymphoid Tissue

Tracking human immunodeficiency virus-type 1 (HIV-1) infection at the cellular level in tissue reservoirs provides opportunities to better understand the pathogenesis of infection and to rationally design and monitor therapy. A quantitative technique was developed to determine viral burden in two important cellular compartments in lymphoid tissues. Image analysis and in situ hybridization were combined to show that in the presymptomatic stages of infection there is a large, relatively stable pool of virions on the surfaces of follicular dendritic cells and a smaller pool of productively infected cells. Despite evidence of constraints on HIV-1 replication in the infected cell population in lymphoid tissues, estimates of the numbers of these cells and the virus they could produce are consistent with the quantities of virus that have been detected in the bloodstream. The cellular sources of virus production and storage in lymphoid tissues can now be studied with this approach over the course of infection and treatment.

Cd4+ count and risk of non-aids diseases following initial treatment for Hiv infection

Background:Reductions in AIDS-related morbidity and mortality following the advent of combination antiretroviral therapy have coincided with relative increases in chronic non-AIDS end-organ diseases among HIV+ patients. Objective:To examine the association of latest CD4+ counts with risk of non-AIDS diseases in a cohort of 1397 patients who initiate antiretroviral therapy. Methods:CD4+ counts and HIV RNA levels along with fatal, and non-fatal, AIDS and non-AIDS diseases (liver, cardiovascular, renal, and cancer) were assessed over a median follow-up of 5 years. Cox proportional regression models were used to study risk associations. Results:A total of 227 patients experienced an AIDS event and 80 patients developed a non-AIDS disease event. Both AIDS and non-AIDS diseases rates (events/100 person-years), respectively, declined with higher latest CD4+ counts: 13.8 and 2.1 with latest CD4+ counts less than 200 cells/μl; 2.0 and 1.7 for counts of 200–350 cells/μl; and 0.7 and 0.7 for counts greater than 350 cells/μl. After adjusting for baseline covariates and the latest HIV RNA level, risk of AIDS and non-AIDS diseases were lowered by 44% (95% confidence interval for hazard ratio 0.50–0.62, P < 0.01) and 14% (95% confidence interval for hazard ratio 0.77–0.96, P = 0.01), respectively, for each 100 cell/μl higher latest CD4+ count. Conclusion:Higher CD4+ counts on antiretroviral therapy are associated with lower rates of non-AIDS diseases and AIDS. These findings expand our understanding of the implications of HIV-related immunodeficiency and motivate randomized studies to evaluate the effects of antiretroviral therapy on a broad set of clinical outcomes at CD4+ counts greater than 350 cells/μl.

A Prospective Clinical Study of Epstein‐Barr Virus and Host Interactions during Acute Infectious Mononucleosis

BACKGROUND Characterizing virus-host interactions during self-limited infectious mononucleosis could explain how Epstein-Barr virus (EBV) replication is normally controlled and provide insight into why certain immunocompromised patients fail to contain it. METHODS University students had an average of 7 clinical and virologic evaluations during acute infectious mononucleosis. EBV was quantified in 697 samples of oral wash fluid, whole blood, peripheral blood mononuclear cells (PBMCs), and plasma by a real-time (TaqMan) polymerase chain reaction (qEBV) assay developed in our laboratory. RESULTS Twenty of 25 subjects had serologically confirmed primary EBV infection. EBV was cleared from whole blood by a first-order process with a median half-life of 3 days, and its quantity was associated with severity of illness (r2=0.82). Oral shedding persisted at a median of >or=1x104 copies/mL for 32 weeks and was unrelated to severity of illness. Subjects with nonprimary EBV infection shed virus intermittently, and median quantities for all samples became undetectable within 4 weeks. CONCLUSIONS Using a novel qEBV assay, we demonstrated that young adults with primary EBV infection rapidly cleared virus from blood but not from the oropharynx. High oral concentrations of EBV in asymptomatic persons who have resumed normal activities support the concept that infectious mononucleosis is most likely acquired by kissing.

Intensification and Stimulation Therapy for Human Immunodeficiency Virus Type 1 Reservoirs in Infected Persons Receiving Virally Suppressive Highly Active Antiretroviral Therapy

Highly active antiretroviral therapy (HAART) has led to significant changes in mortality and morbidity in the human immunodeficiency virus type 1 (HIV-1) epidemic. Nevertheless, because of molecular mechanisms of viral persistence, HAART does not eradicate HIV-1. Didanosine and hydroxyurea were added to the antiretroviral regimens of 3 HIV-1-infected men who were receiving stable HAART and who had HIV-1 RNA levels <50 copies/mL at the initiation of the study protocol, as a novel intensification to attack cryptic viral replication; low-dose OKT3 was then administered, followed by a course of interleukin-2, to stimulate latent provirus. Replication-competent virus was undetectable after treatment, and plasma viral RNA was either undetectable or <5 copies/mL. In trial periods during which no antiretroviral therapy was administered, the patients developed plasma viral rebound. This translational approach combines novel intensification and stimulation therapy to deplete residual HIV-1 reservoirs. Additional experimental approaches must be developed if HIV-1 eradication is to become possible in patients receiving virally suppressive HAART.

The National NeuroAIDS Tissue Consortium: a new paradigm in brain banking with an emphasis on infectious disease.

The National NeuroAIDS Tissue Consortium (NNTC) was founded in 1998, in response to the scientific need for well‐characterized central nervous system (CNS) and peripheral nervous system (PNS) tissues and fluids from HIV‐infected individuals. In addition to performing the routine functions of non‐transplant anatomic tissue banks, the Consortium offers a unique model for the integration of independent research entities in order to provide well‐characterized tissues and fluids for the international research community. Herein, we describe the structure of the Consortium, pointing out the inherent strengths of linking together multiple independent sites for the purpose of banking HIV‐infected nervous system tissues. We describe the neuropathology protocol that was adopted and successfully implemented at the four participating banks of the Consortium.

Poor Initial CD4+ Recovery With Antiretroviral Therapy Prolongs Immune Depletion and Increases Risk for AIDS and Non-AIDS Diseases

Background:Low CD4+ increases risk for both AIDS- and non-AIDS-related morbidity and mortality. The magnitude of CD4+ recovery early after initial antiretroviral therapy (ART) is important in the ultimate duration of immune depletion. Methods:We examined CD4+ recovery among 850 participants in the Community Program for Clinical Research on AIDS Flexible Initial Retrovirus Suppressive Therapies study with virologic suppression (ie, achieved an HIV RNA level <400 copies/mL) with 8 months of initial ART and determined subsequent risk for AIDS, non-AIDS diseases (non-AIDS cancers and cardiovascular, end-stage renal, and liver diseases), or death using Cox regression during a median 5-year follow-up. Results:Mean pretreatment CD4+ was 221 cells/μL; 18% (n = 149) had a poor CD4+ recovery (<50 cells/μL) after 8 months of effective ART, resulting in lower CD4+ over 5 years. Older age (hazard ratio 1.34/10 yrs, P = 0.003) and lower screening HIV RNA (hazard ratio 0.65 per log10 copies/mL higher, P = 0.001), but not screening CD4+, were associated with a poor CD4+ recovery. After 8 months of effective ART, 30 patients experienced the composite outcome of AIDS, non-AIDS, or death among participants with a poor CD4+ recovery (rate = 5.8/100 person-years) and 74 patients among those with an adequate recovery (≥50 cells/μL; rate = 2.7/100 person-years) (adjusted hazard ratio = 2.24, P < 0.001). The risk of this composite outcome associated with a poor CD4+ recovery declined when ART was initiated at higher CD4+ counts (P < 0.01). Conclusions:Impaired immune recovery, despite effective ART, results in longer time spent at low CD4+, thereby increasing risk for a broad category of HIV-related morbidity and mortality conditions.

Evidence of human immunodeficiency virus type 1 infection of nestin-positive neural progenitors in archival pediatric brain tissue

Human immunodeficiency virus type 1 (HIV-1) central nervous system (CNS) infection in children is associated with impaired brain growth and neurodevelopmental delays. Neural progenitors are critical for neurogenesis. Human multipotential neural progenitors grown in culture are permissive for HIV-1 infection, but it is not known if infection of these cells occurs in vivo. Brain tissue from pre-highly active antiretroviral therapy (HAART) era pediatric acquired immunodeficiency syndrome (AIDS) patients was examined for evidence of HIV-1 infection of nestin-positive neural progenitors by in situ hybridization; or after laser microdissection harvest, DNA extraction, and polymerase chain reaction (PCR). HIV-1 or viral DNA was identified in nestin-positive cells in four of seven HIV-1-infected children, suggesting in vivo infection of neural progenitors.

A randomized crossover study to determine bioequivalence of generic and brand name nevirapine zidovudine and lamivudine in HIV-negative women in India.

Low-cost generic antiretroviral drugs are available in resource-limited settings for treatment of HIV infections. However, few bioequivalence data in specific populations in which these generics are likely to be used are available. We conducted a randomized crossover bioequivalence study of generic and brand name formulations of nevirapine, zidovudine, and lamivudine in HIV-negative Indian women using US Food and Drug Administration (FDA) criteria. Subjects took single doses of all formulations separated by a 14-day washout period. Plasma concentrations were measured over 96 hours during each study period. Average bioequivalence was determined using natural log-transformed maximum concentration (Cmax) and area-under-the-concentration-time curve (AUC) mean ratio data. Fifteen Indian women were enrolled. The 90% confidence intervals for nevirapine (14 subjects) and lamivudine (15 subjects) Cmax, AUC from 0 to the last measurable time point (AUC0-t), and AUC from 0 to infinity (AUC0-∞) mean ratios and zidovudine (15 subjects) AUC0-t and AUC0-∞ mean ratios were all within 0.80 to 1.25. However, the 90% confidence interval for zidovudine Cmax mean ratio was 0.70 to 1.46. Generic and brand name nevirapine and lamivudine met FDA average bioequivalence criteria. Lack of average bioequivalence for zidovudine was found for Cmax but is not expected to be clinically significant, because the total AUC values were similar between formulations.

Malassezia: is it a pulmonary pathogen in the stem cell transplant population?

Abstract: Malassezia furfur is a yeast that can cause a variety of infections, most commonly in normal hosts, and also in immunocompromised hosts. This yeast typically colonizes the skin, and is the causative agent of tinea versicolor. However, in immunocompromised hosts, it can more commonly cause catheter‐related fungemia or folliculitis. Pulmonary infections from Malassezia have not been commonly recognized. Unlike many other common opportunistic fungal infections in immunocompromised hosts, neutropenia and the use of broad‐spectrum antibiotics do not appear to be significant risk factors for Malassezia infections in the stem cell transplant (SCT) population. Additionally, disseminated infection, despite fungemia, is uncommon. A series of patients who underwent SCT at the University of Minnesota between 2004 and 2006 were reviewed for the occurrence of suspected Malassezia infections in the post‐transplant period. Four cases of possible pulmonary M. furfur infection were identified in our SCT recipients. The clinical characteristics of these patients, the infections, treatment, and outcome are described. In addition, we discuss the possible pathogenicity of this yeast in the pulmonary setting.

VIRAL INFECTIONS IN HUMAN IMMUNODEFICIENCY VIRUS DISEASE

A number of the herpesviruses as well as representatives of other viral genera can produce serious opportunistic infections in persons infected with HIV. Although some, such as JC virus, HHV-6, and HHV-8, remain essentially untreatable at this time, others are readily treatable or can be retarded with chemoprophylaxis. Further therapeutic advances for some of these viral superinfections, particularly CMV, HSV, VZV, HHV-8, and human genital papillomavirus, will considerably improve the longevity and quality of life of persons with AIDS.