Detection of pulmonary Mycoplasma pneumoniae infections in HIV-infected subjects using culture and serology

SummaryObjectiveThe true prevalence of Mycoplasma pneumoniae infections involving the respiratory tracts of HIV-infected individuals is still unclear. This study examined the prevalence of M. pneumoniae in 100 HIV-infected individuals at an AIDS care center in Chennai, India, using conventional laboratory techniques and interpretation criteria.MethodsDiagnosis was based on culture, cold agglutination test, and commercial enzyme-linked immunosorbent assay (ELISA) for the qualitative determination of IgM antibodies against M. pneumoniae. The efficacies of the different diagnostic procedures used in the study were analyzed.ResultsThe prevalence of M. pneumoniae was 31% by culture and 21% by IgM ELISA. Cough (p=0.03, OR 3.8, 95% CI 1–17.8), myalgia (p=0.04, OR 2.5, 95% CI 1–6.6), rales (p=0.04, OR 2.4, 95% CI 1–6.6), and cervical adenopathy (p=0.03, OR 2.7, 95% CI 1–7.1) were the symptoms that significantly corroborated culture positivity. Patients positive for M. pneumoniae by culture or IgM antibody had significantly greater CD4+ T-cell depletion and anemia than those without any evidence of infection.ConclusionsThis study provides the means to diagnose M. pneumoniae infection and information on the prevalence of the pathogen in HIV-infected individuals in resource constrained settings. Although modern molecular techniques may provide more insight into the prevalence of M. pneumoniae in HIV-infected individuals, conventional methods can still be used in diagnosis

Immune reconstitution inflammatory syndrome in association with HIV/AIDS and tuberculosis: Views over hidden possibilities

Gut immune components are severely compromised among persons with AIDS, which allows increased translocation of bacterial lipopolysaccharides (LPS) into the systemic circulation. These microbial LPS are reportedly increased in chronically HIV-infected individuals and findings have correlated convincingly with measures of immune activation. Immune reconstitution inflammatory syndrome (IRIS) is an adverse consequence of the restoration of pathogen-specific immune responses in a subset of HIV-infected subjects with underlying latent infections during the initial months of highly active antiretroviral treatment (HAART). Whether IRIS is the result of a response to a high antigen burden, an excessive response by the recovering immune system, exacerbated production of pro-inflammatory cytokines or a lack of immune regulation due to inability to produce regulatory cytokines remains to be determined. We theorize that those who develop IRIS have a high burden of proinflammatory cytokines produced also in response to systemic bacterial LPS that nonspecifically act on latent mycobacterial antigens. We also hypothesize that subjects that do not develop IRIS could have developed either tolerance (anergy) to persistent LPS/tubercle antigens or could have normal FOXP3+ gene and that those with defective FOXP3+ gene or those with enormous plasma LPS could be vulnerable to IRIS. The measure of microbial LPS, anti-LPS antibodies and nonspecific plasma cytokines in subjects on HAART shall predict the role of these components in IRIS

Does CD4+CD25+foxp3+ cell (Treg) and IL-10 profile determine susceptibility to immune reconstitution inflammatory syndrome (IRIS) in HIV disease?

HIV-specific T-lymphocyte responses that underlie IRIS are incomplete and largely remain hypothetical. Of the several mechanisms presented by the host to control host immunological damage, Treg cells are believed to play a critical role. Using the available experimental evidence, it is proposed that enormous synthesis of conventional FoxP3- Th cells (responsive) often renders subjects inherently vulnerable to IRIS, whereas that of natural FoxP3+ Treg cell synthesis predominate among subjects that may not progress to IRIS. We also propose that IRIS non-developers generate precursor T-cells with a high avidity to generate CD4+CD25+FoxP3+ Tregs whereas IRIS developers generate T-cells of intermediate avidity yielding Th0 cells and effector T-cells to mediate the generation of proinflammatory cytokines in response to cell-signaling factors (IL-2, IL-6 etc.). Researchers have shown that IL-10 Tregs (along with TGF-β, a known anti-inflammatory cytokine) limit immune responses against microbial antigens in addition to effectively controlling HIV replication, the prime objective of HAART. Although certain technical limitations are described herein, we advocate measures to test the role of Tregs in IRIS

Performance characteristics of an instrument-free point-of-care CD4 test (VISITECTVR CD4) for use in resource-limited settings

Objective: CD4þ T lymphocyte count remains the most common biomarker of immune status and disease progression in human immunodeficiency virus (HIV)-positive individuals. VISITECTVR CD4 is an instrument-free, low-cost point-of-care CD4 test with a cut-off of 350 CD4 cells/lL. This study aimed to evaluate VISITECTVR CD4 test’s diagnostic accuracy. Methods: Two hundred HIV-positive patients attending a tertiary HIV centre in South India were recruited. Patients provided venous blood for reference and VISITECTVR CD4 tests. An additional finger-prick blood sample was obtained for VISITECTVR CD4. VISITECTVR CD4’s diagnostic performance in identifying individuals with CD4 counts 350 cells/lL was assessed by calculating sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) taking flow cytometry as the reference. Results: The overall agreement between VISITECTVR CD4 and flow cytometry was 89.5% using venous blood and 81.5% using finger-prick blood. VISITECTVR CD4 showed better performance using venous blood [sensitivity: 96.6% (95% confidence interval: 92.1%–98.9%), specificity: 70.9% (57.1%–82.4%), PPV: 89.7% (83.9%–94.0%) and NPV: 88.6% (75.4%–96.2%)] than using fingerprick blood [sensitivity: 84.8% (77.9%–90.2%), specificity: 72.7% (59.0%–83.9%), PPV: 89.1% (82.7%–93.8%) and NPV: 64.5% (51.3%–76.3%)]. Conclusion: VISITECTVR CD4 performed well using venous blood, demonstrating its potential utility in decentralization of CD4 testing services in resource-constrained settings

Establishment of reference CD4+ T cell values for adult Indian population

<p>Abstract</p> <p>Background</p> <p>CD4+ T lymphocyte counts are the most important indicator of disease progression and success of antiretroviral treatment in HIV infection in resource limited settings. The nationwide reference range of CD4+ T lymphocytes was not available in India. This study was conducted to determine reference values of absolute CD4+ T cell counts and percentages for adult Indian population.</p> <p>Methods</p> <p>A multicentric study was conducted involving eight sites across the country. A total of 1206 (approximately 150 per/centre) healthy participants were enrolled in the study. The ratio of male (N = 645) to female (N = 561) of 1.14:1. The healthy status of the participants was assessed by a pre-decided questionnaire. At all centers the CD4+ T cell count, percentages and absolute CD3+ T cell count and percentages were estimated using a single platform strategy and lyse no wash technique. The data was analyzed using the Statistical Package for the Social Scientist (SPSS), version 15) and Prism software version 5.</p> <p>Results</p> <p>The absolute CD4+ T cell counts and percentages in female participants were significantly higher than the values obtained in male participants indicating the true difference in the CD4+ T cell subsets. The reference range for absolute CD4 count for Indian male population was 381-1565 cells/μL and for female population was 447-1846 cells/μL. The reference range for CD4% was 25-49% for male and 27-54% for female population. The reference values for CD3 counts were 776-2785 cells/μL for Indian male population and 826-2997 cells/μL for female population.</p> <p>Conclusion</p> <p>The study used stringent procedures for controlling the technical variation in the CD4 counts across the sites and thus could establish the robust national reference ranges for CD4 counts and percentages. These ranges will be helpful in staging the disease progression and monitoring antiretroviral therapy in HIV infection in India.</p

Predicting resistance as indicator for need to switch from first-line antiretroviral therapy among patients with elevated viral loads: development of a risk score algorithm

Abstract Background In resource-limited settings, where resistance testing is unavailable, confirmatory testing for patients with high viral loads (VL) delays antiretroviral therapy (ART) switches for persons with resistance. We developed a risk score algorithm to predict need for ART change by identifying resistance among persons with persistently elevated VL. Methods We analyzed data from a Phase IV open-label trial. Using logistic regression, we identified demographic and clinical characteristics predictive of need for ART change among participants with VLs ≥1000 copies/ml, and assigned model-derived scores to predictors. We designed three models, including only variables accessible in resource-limited settings. Results Among 290 participants with at least one VL ≥1000 copies/ml, 51 % (148/290) resuppressed and did not have resistance testing; among those who did not resuppress and had resistance testing, 47 % (67/142) did not have resistance and 53 % (75/142) had resistance (ART change needed for 25.9 % (75/290)). Need for ART change was directly associated with higher baseline VL and higher VL at time of elevated measure, and inversely associated with treatment duration. Other predictors included body mass index and adherence. Area under receiver operating characteristic curves ranged from 0.794 to 0.817. At a risk score ≥9, sensitivity was 14.7–28.0 % and specificity was 96.7–98.6 %. Conclusions Our model performed reasonably well and may be a tool to quickly transition persons in need of ART change to more effective regimens when resistance testing is unavailable. Use of this algorithm may result in public health benefits and health system savings through reduced transmissions of resistant virus and costs on laboratory investigations