Bryan E. Shepherd

Cellular Recognition of Mycobacterium tuberculosis ESAT-6 and KatG Peptides in Systemic Sarcoidosis

ABSTRACT Sarcoidosis is an enigmatic disease with a pathology similar to that of tuberculosis. We detected Th-1 immune responses to Mycobacterium tuberculosis ESAT-6 and KatG peptides from peripheral blood mononuclear cells from 15/26 sarcoidosis, 1/24 purified-protein-derivative-negative (PPD−) (P < 0.0001, Fishers exact test), and 7/8 PPD-positive (PPD+) subjects (P = 0.21). This finding provides immunologic links between mycobacteria and systemic sarcoidosis.

Race and Sex Differences in Antiretroviral Therapy Use and Mortality among HIV-Infected Persons in Care

BACKGROUND There are conflicting data regarding race, sex, and mortality among persons infected with human immunodeficiency virus (HIV). We studied all-cause mortality among persons in care during the highly-active antiretroviral therapy (HAART) era. METHODS This retrospective cohort study included patients who made>or=1 clinic visit from January 1998 through December 2005. RESULTS Of 2605 patients (with 6657 person-years of follow-up), 38% were black and 24% were female. The percentage of time in care while receiving HAART was lower for blacks than for nonblacks (47% vs. 76%; P<.001) and for females than for males (57% vs. 71%; P=.01). There were 253 deaths (38 per 1000 person-years). After adjustment for characteristics at baseline, death was associated with black race (hazard ratio [HR], 1.33; P .04), female sex (HR, 1.53; P .007), injection drug use (IDU) as a risk factor for HIV infection (HR, 1.61; P .009), older age (HR, 1.45 per 10 years; P<.001), a lower CD4 cell count (HR, 0.59 for 200 vs. 350 cells/mm3; P<.001) and a higher HIV type 1 RNA level (HR, 1.35; P<.001). After adjustment for the length of time that HAART was received, black race (HR, 1.00; P .99) and IDU (HR, 1.37; P .09) were no longer associated with death, but female sex was (HR, 1.62; P=.002). CONCLUSIONS Race-associated differences in mortality likely resulted from HAART use. Women had an increased risk of death even after adjustment for HAART use. Addressing racial disparities will require improved HAART utilization. Increased mortality among women requires further study.

Respiratory syncytial virus uses a Vps4-independent budding mechanism controlled by Rab11-FIP2.

Respiratory syncytial virus (RSV) infects polarized epithelia, which have tightly regulated trafficking because of the separation and maintenance of the apical and basolateral membranes. Previously we established a link between the apical recycling endosome (ARE) and the assembly of RSV. The current studies tested the role of a major ARE-associated protein, Rab11 family interacting protein 2 (FIP2) in the virus life cycle. A dominant-negative form of FIP2 lacking its N-terminal C2 domain reduced the supernatant-associated RSV titer 1,000-fold and also caused the cell-associated virus titer to increase. These data suggested that the FIP2 C2 mutant caused a failure at the final budding step in the virus life cycle. Additionally, truncation of the Rab-binding domain from FIP2 caused its accumulation into mature filamentous virions. RSV budding was independent of the ESCRT machinery, the only well-defined budding mechanism for enveloped RNA viruses. Therefore, RSV uses a virus budding mechanism that is controlled by FIP2.

Mortality during the first year of potent antiretroviral therapy in HIV-1-infected patients in 7 sites throughout Latin America and the Caribbean.

Background:Although nearly 2 million people live with HIV in Latin America and the Caribbean, mortality rates after initiation of highly active antiretroviral therapy (HAART) have not been well described. Methods:Five thousand one hundred fifty-two HIV-infected, antiretroviral-naive adults from clinics in Argentina, Brazil, Chile, Haiti, Honduras, Mexico, and Peru starting HAART during 1996-2007 were included. First-year mortality rates and their association with demographics, regimen, baseline CD4, and clinical stage were assessed. Results:Overall 1-year mortality rate was 8.3% [95% confidence interval (CI): 7.6% to 9.1%], although variable across sites: 2.6%, 3.7%, 6.0%, 13.0%, 10.8%, 3.5%, and 9.8% for clinics in Argentina, Brazil, Chile, Haiti, Honduras, Mexico, and Peru, respectively. Eighty percent of deaths occurred within the first 6 months. Median baseline CD4 was 107 cells per milliliter, ranging from 79 (Peru) to 163 (Argentina). Mortality estimates adjusting for CD4 were similar across sites (1.1%-2.8% for CD4 = 200), except for Haiti, 7.5%, and Honduras, 7.0%. Death was associated with lower CD4 [adjusted hazard ratio for CD4 = 200 vs. CD4 = 50 was 0.58; 95% CI: 0.40 to 0.85] and clinical AIDS (hazard ratio = 3.1; 95% CI: 2.1 to 4.5). Conclusions:Mortality rates were similar to those reported elsewhere for resource-limited settings. Disease stage at HAART initiation, treatment eligibility criteria, program age, and background mortality rates may explain some variability in prognosis between sites.

Venezuelan Equine Encephalitis Virus Replicon Particles Encoding Respiratory Syncytial Virus Surface Glycoproteins Induce Protective Mucosal Responses in Mice and Cotton Rats

ABSTRACT Respiratory syncytial virus (RSV) is an important viral pathogen that causes severe lower respiratory tract infection in infants, the elderly, and immunocompromised individuals. There are no licensed RSV vaccines to date. To prevent RSV infection, immune responses in both the upper and lower respiratory tracts are required. Previously, immunization with Venezuelan equine encephalitis virus replicon particles (VRPs) demonstrated effectiveness in inducing mucosal protection against various pathogens. In this study, we developed VRPs encoding RSV fusion (F) or attachment (G) glycoproteins and evaluated the immunogenicity and efficacy of these vaccine candidates in mice and cotton rats. VRPs, when administered intranasally, induced surface glycoprotein-specific virus neutralizing antibodies in serum and immunoglobulin A (IgA) antibodies in secretions at the respiratory mucosa. In addition, fusion protein-encoding VRPs induced gamma interferon (IFN-γ)-secreting T cells in the lungs and spleen, as measured by reaction with an H-2Kd-restricted CD8+ T-cell epitope. In animals vaccinated with F protein VRPs, challenge virus replication was reduced below the level of detection in both the upper and lower respiratory tracts following intranasal RSV challenge, while in those vaccinated with G protein VRPs, challenge virus was detected in the upper but not the lower respiratory tract. Close examination of histopathology of the lungs of vaccinated animals following RSV challenge revealed no enhanced inflammation. Immunization with VRPs induced balanced Th1/Th2 immune responses, as measured by the cytokine profile in the lungs and antibody isotype of the humoral immune response. These results represent an important first step toward the use of VRPs encoding RSV proteins as a prophylactic vaccine for RSV.

A Mechanistic Role for Type III IFN-λ1 in Asthma Exacerbations Mediated by Human Rhinoviruses

RATIONALE Human rhinoviruses (HRV) are the leading cause of upper respiratory infections and have been postulated to trigger asthma exacerbations. However, whether HRV are detected during crises because upper respiratory infections often accompany asthma attacks, or because they specifically elicit exacerbations, is unclear. Moreover, although several hypotheses have been advanced to explain virus-induced exacerbations, their mechanism remains unclear. OBJECTIVES To determine the role of HRV in pediatric asthma exacerbations and the mechanisms mediating wheezing. METHODS We prospectively studied 409 children with asthma presenting with upper respiratory infection in the presence or absence of wheezing. Candidate viral and immune mediators of illness were compared among children with asthma with different degrees of severity of acute asthma. MEASUREMENTS AND MAIN RESULTS HRV infections specifically associated with asthma exacerbations, even after adjusting for relevant demographic and clinical variables defined a priori (odds ratio, 1.90; 95% confidence interval, 1.21-2.99; P = 0.005). No difference in virus titers, HRV species, and inflammatory or allergic molecules was observed between wheezing and nonwheezing children infected with HRV. Type III IFN-λ(1) levels were higher in wheezing children infected with HRV compared with nonwheezing (P < 0.001) and increased with worsening symptoms (P < 0.001). Moreover, after adjusting for IFN-λ(1), children with asthma infected with HRV were no longer more likely to wheeze than those who were HRV-negative (odds ratio, 1.18; 95% confidence interval, 0.57-2.46; P = 0.66). CONCLUSIONS Our findings suggest that HRV infections in children with asthma are specifically associated with acute wheezing, and that type III IFN-λ(1) responses mediate exacerbations caused by HRV. Modulation of IFN- λ(1) should be studied as a therapeutic target for exacerbations caused by HRV.

Cellular Responses to Mycobacterial Antigens Are Present in Bronchoalveolar Lavage Fluid Used in the Diagnosis of Sarcoidosis

ABSTRACT Considerable evidence supports the concept that CD4+ T cells are important in sarcoidosis pathogenesis, but the antigens responsible for the observed Th1 immunophenotype remain elusive. The epidemiologic association with bioaerosols and the presence of granulomatous inflammation support consideration of mycobacterial antigens. To explore the role of mycobacterial antigens in sarcoidosis immunopathogenesis, we assessed the immune recognition of mycobacterial antigens, the 6-kDa early secreted antigenic protein (ESAT-6) and catalase-peroxidase (KatG), by T cells derived from bronchoalveolar lavage (BAL) fluid obtained during diagnostic bronchoscopy. We report the presence of antigen-specific recognition of ESAT-6 and KatG in T cells from BAL fluid of 32/44 sarcoidosis subjects, compared to 1/27 controls (P < 0.0001). CD4+ T cells were primarily responsible for immune recognition (32/44 sarcoidosis subjects), although CD8+ T-cell responses were observed (25/41 sarcoidosis subjects). Recognition was significantly absent from BAL fluid cells of patients with other lung diseases, including infectious granulomatous diseases. Blocking of Toll-like receptor 2 reduced the strength of the observed immune response. The presence of immune responses to mycobacterial antigens in cells from BAL fluid used for sarcoidosis diagnosis suggests a strong association between mycobacteria and sarcoidosis pathogenesis. Inhibition of immune recognition with monoclonal antibody against Toll-like receptor 2 suggests that induction of innate immunity by mycobacteria contributes to the polarized Th1 immune response.

Absolute Count and Percentage of CD4+ Lymphocytes Are Independent Predictors of Disease Progression in HIV-Infected Persons Initiating Highly Active Antiretroviral Therapy

BACKGROUND Highly active antiretroviral therapy (HAART) is recommended when the absolute CD4(+) T lymphocyte count is <200 cells/mm(3), and it should be considered when that count is > or =200, although the optimal timing when it is > or =200 is unclear. Because preliminary data had suggested that a low CD4(+) T lymphocyte percentage (%CD4) is associated with disease progression in persons initiating HAART who have a higher absolute CD4, we sought to further characterize the predictive utility of %CD4. METHODS We conducted an observational study of persons in Collaborations in HIV Outcomes Research/US cohort who initiated their first HAART regimen between 1997 and 2004, received > or =30 days of therapy, and had baseline values of absolute CD4, %CD4, and HIV-1 RNA. Cox proportional-hazards models determined associations between %CD4 and disease progression (to either a new AIDS-defining event [ADE] or death). RESULTS Of 1891 persons, 11% were female and 18% were African American; the median age was 38 years. Median follow-up was 55 months (interquartile range, 23-83 months), and 468 (25%) had disease progression. Multivariable analysis including age, race, sex, HIV-1 RNA, prior antiretroviral therapy, probable route of infection, prior ADE, absolute CD4, and %CD4 was performed; prior ART (P<.0001), injection-drug use (P=.04), lower absolute CD4 (P=.002), and lower %CD4 (P=.002) predicted disease progression. CONCLUSIONS %CD4 at initiation of the first HAART regimen predicted disease progression independent of absolute CD4; %CD4 may be used to determine the timing of HAART.

Cross-Sectional Analysis of Late HAART Initiation in Latin America and the Caribbean: Late Testers and Late Presenters

Background Starting HAART in a very advanced stage of disease is assumed to be the most prevalent form of initiation in HIV-infected subjects in developing countries. Data from Latin America and the Caribbean is still lacking. Our main objective was to determine the frequency, risk factors and trends in time for being late HAART initiator (LHI) in this region. Methodology Cross-sectional analysis from 9817 HIV-infected treatment-naïve patients initiating HAART at 6 sites (Argentina, Chile, Haiti, Honduras, Peru and Mexico) from October 1999 to July 2010. LHI had CD4+ count ≤200cells/mm3 prior to HAART. Late testers (LT) were those LHI who initiated HAART within 6 months of HIV diagnosis. Late presenters (LP) initiated after 6 months of diagnosis. Prevalence, risk factors and trends over time were analyzed. Principal Findings Among subjects starting HAART (n = 9817) who had baseline CD4+ available (n = 8515), 76% were LHI: Argentina (56%[95%CI:52–59]), Chile (80%[95%CI:77–82]), Haiti (76%[95%CI:74–77]), Honduras (91%[95%CI:87–94]), Mexico (79%[95%CI:75–83]), Peru (86%[95%CI:84–88]). The proportion of LHI statistically changed over time (except in Honduras) (p≤0.02; Honduras p = 0.7), with a tendency towards lower rates in recent years. Males had increased risk of LHI in Chile, Haiti, Peru, and in the combined site analyses (CSA). Older patients were more likely LHI in Argentina and Peru (OR 1.21 per +10-year of age, 95%CI:1.02–1.45; OR 1.20, 95%CI:1.02–1.43; respectively), but not in CSA (OR 1.07, 95%CI:0.94–1.21). Higher education was associated with decreased risk for LHI in Chile (OR 0.92 per +1-year of education, 95%CI:0.87–0.98) (similar trends in Mexico, Peru, and CSA). LHI with date of HIV-diagnosis available, 55% were LT and 45% LP. Conclusion LHI was highly prevalent in CCASAnet sites, mostly due to LT; the main risk factors associated were being male and older age. Earlier HIV-diagnosis and earlier treatment initiation are needed to maximize benefits from HAART in the region.

Mycobacterium tuberculosis Antigen 85A Induces Th-1 Immune Responses in Systemic Sarcoidosis

Sarcoidosis is a granulomatous disease of unknown etiology, characterized by a Th-1 immunophenotype. Although humoral immune responses by sarcoidosis subjects to mycobacterial proteins have been detected, mycobacterial antigens capable of inducing cellular immune responses in sarcoidosis subjects have not been reported. We used the enzyme-linked immunospot assay to assess for recognition of the Mycobacterium tuberculosis mycolyl transferase, Antigen 85A, by peripheral blood mononuclear cells from 25 sarcoidosis subjects, 22 PPD− (purified protein derivative) healthy volunteers, and 16 PPD+ healthy subjects. Reactivity to Ag85A whole protein was observed in 15 of 25 sarcoidosis subjects compared to 2 of 22 PPD− subjects (p=0.0006, Fisher’s exact test) and to 14 of 16 PPD+ subjects (p=0.084, Fisher’s exact test). Monoclonal antibody against HLA-DR inhibited recognition. In addition to immune recognition of Ag85A whole protein, peptide-mapping studies identified four immunogenic Ag85A peptides, which induced Th-1 immune responses in individual sarcoidosis subjects, suggesting that multiple epitopes from a mycobacterial protein may have a role in sarcoidosis immunopathogenesis.