Rapid Diagnosis of Smear-Negative Tuberculosis Using Immunology and Microbiology with Induced Sputum in HIV-Infected and Uninfected Individuals

Rationale and Objectives. Blood-based studies have demonstrated the potential of immunological assays to detect tuberculosis. However lung fluid sampling may prove superior as it enables simultaneous microbiological detection of mycobacteria to be performed. Until now this has only been possible using the expensive and invasive technique of broncho-alveolar lavage. We sought to evaluate an immunoassay using non-invasive induced-sputum to diagnose active tuberculosis. Methods and Results. Prospective cohort study of forty-two spontaneous sputum smear-negative or sputum non-producing adults under investigation for tuberculosis. CD4 lymphocytes specific to purified-protein-derivative of Mycobacterium tuberculosis actively synthesising interferon-gamma were measured by flow cytometry and final diagnosis compared to immunoassay using a cut-off of 0.5%. Sixteen subjects (38%) were HIV-infected (median CD4 count [range] = 332 cells/mu l [103748]). Thirty-eight (90%) were BCG-vaccinated. In 27 subjects diagnosed with active tuberculosis, the median [range] percentage of interferon-gamma synthetic CD4+ lymphocytes was 2.77% [0-23.93%] versus 0% [0-2.10%] in 15 negative for active infection (p<0.0001). Sensitivity and specificity of the immunoassay versus final diagnosis of active tuberculosis were 89% (24 of 27) and 80% (12 of 15) respectively. The 3 positive assays in the latter group occurred in subjects diagnosed with quiescent/latent tuberculosis. Assay performance was unaffected by HIV-status, BCG-vaccination or disease site. Combining this approach with traditional microbiological methods increased the diagnostic yield to 93% (25 of 27) alongside acid-fast bacilli smear and 96% (26 of 27) alongside tuberculosis culture. Conclusions. These data demonstrate for the first time that a rapid immunological assay to diagnose active tuberculosis can be performed successfully in combination with microbiological methods on a single induced-sputum sample

A longitudinal examination of the relationship between trauma-related cognitive factors and internalising and externalising psychopathology in physically injured children

Cognitive models of posttraumatic stress disorder (PTSD) highlight maladaptive posttrauma appraisals, trauma memory qualities, and coping strategies, such as rumination or thought suppression, as key processes that maintain PTSD symptoms. Anxiety, depression and externalising symptoms can also present in children in the aftermath of trauma, yet there has been little empirical investigation of the potential relevance of posttrauma cognitive processes for such difficulties. Here, we examined whether: a) acute maladaptive cognitive processes (specifically, maladaptive appraisals, memory qualities, and cognitive coping) were associated with symptoms of PTSD, internalising, and externalising at 1-month posttrauma (T1); and b) changes in these cognitive processes predicted symptom change at a follow-up assessment 6 months later (T2). We recruited 132 6–13 year old children and their parents from emergency departments following the child’s experience of an acute trauma. Children self-reported on their maladaptive appraisals, trauma-memory and cognitive coping strategies, along with symptoms of PTSD, anxiety and depression. Parents also rated children’s internalising and externalising symptoms. We found each cognitive process to be robustly associated with PTSD and non-PTSD internalising symptoms at T1, and change in each predicted change in symptoms to T2. Maladaptive appraisals and cognitive coping were unique predictors of children’s posttrauma internalising. Effects were partially retained even controlling for co-occurring PTSD symptoms. There was less evidence that trauma-specific cognitive processes were associated with externalising symptoms. Findings suggest aspects of cognitive models of PTSD are applicable to broader posttrauma psychopathology, and have implications for how we understand and target children’s posttrauma psychological adjustment

Biomarkers of treatment response in clinical trials of novel antituberculosis agents

Global initiatives have been launched to develop improved tuberculosis chemotherapy. New drugs and potential treatment-shortening regimens require careful assessment in clinical trials, but existing markers of treatment outcome-clinical cure and relapse-require prolonged follow-up of patients. There is, therefore, a need to find alternative biomarkers or surrogate endpoints predictive of response. Effective treatment requires drugs with sterilising activity to produce clinical cure without relapse, and thus a useful biomarker for a drug under trial must predict the likelihood of relapse. We explore the strengths and weaknesses of existing biomarkers, which assess either host response or mycobacterial load. Change in mycobacterial burden is likely to be the best indicator of treatment outcome, but the optimum study techniques remain undefined. Finally, we propose methods to assess candidate markers, and how these candidate markers could be implemented in future clinical trials.</p

A comparison of final diagnosis against %PPD-specific CD4+IFN-γ+ responses following overnight stimulation of induced-sputum in 42 spontaneous sputum smear negative subjects with possible tuberculosis (medians shown as horizontal bars).

<p>The suggested diagnostic cut-off of 0.5% is indicated by the hatched line.</p

Immunoassay and microbiology results alone and in combination compared to final diagnosis.

<p>Subjects diagnosed with active TB are further divided according to whether this was pulmonary or non-pulmonary (italics)</p><p><u>Abbreviations</u>: AFB = acid-fast bacilli; BCG+ = Bacille-Calmette-Guerin vaccinated; HIV+ = HIV-infected; IS = induced-sputum; Mtb = Mycobacterium tuberculosis; TB = tuberculosis</p

Cytometric dot plots and ELISpot wells from a subject with active tuberculosis, demonstrating interferon (IFN)-γ synthesis in response to overnight incubation of induced-sputum with purified-protein derivative of <i>Mycobacterium tuberculosis</i> (PPD).

<p>Panel A: Proportion of CD4+ lymphocytes producing IFN-γ after incubation with no antigen (Ag) added. Panel B: Proportion of CD4+ lymphocytes producing IFN-γ after incubation with PPD. Panel C: ELISpot wells showing the IFN-γ T-cell response after incubation with no antigen added. Panel D: ELISpot wells showing the IFN-γ T-cell response after incubation with PPD.</p

Comparison of flow cytometry and ELISpot techniques in assessing PPD-specific interferon-gamma responses

<p><u>Abbreviations</u>: SFU = spot forming units; TB = tuberculosis;</p

Common or distinct pathways to psychosis? A systematic review of evidence from prospective studies for developmental risk factors and antecedents of the schizophrenia spectrum disorders and affective psychoses

Background: Identifying the unique and shared premorbid indicators of risk for the schizophrenia spectrum disorders (SSD) and affective psychoses (AP) may refine aetiological hypotheses and inform the delivery of universal versus targeted preventive interventions. This systematic review synthesises the available evidence concerning developmental risk factors and antecedents of SSD and AP to identify those with the most robust support, and to highlight remaining evidence gaps.Methods: A systematic search of prospective birth, population, high-risk, and case-control cohorts was conducted in Medline and supplemented by hand searching, incorporating published studies in English with full text available. Inclusion/exclusion decisions and data extraction were completed in duplicate. Exposures included three categories of risk factors and four categories of antecedents, with case and comparison groups defined by adult psychiatric diagnosis. Effect sizes and prevalence rates were extracted, where available, and the strength of evidencesynthesised and evaluated qualitatively across the study designs.Results: Of 1775 studies identified by the search, 127 provided data to the review. Individuals who develop SSD experience a diversity of subtle premorbid developmental deficits and risk exposures, spanning the prenatal period through early adolescence. Those of greatest magnitude (or observed most consistently) included obstetric complications, maternal illness during pregnancy (especially infections), other maternal physical factors, negative family emotional environment, psychopathology and psychotic symptoms, and cognitive and motor dysfunctions. Relatively less evidence has accumulated to implicate this diversity of exposures in AP, and many yet remain unexamined, with the most consistent or strongest evidence to date being for obstetric complications, psychopathology, cognitive indicators and motor dysfunction. Among the few investigations affording direct comparison between SSD and AP, larger effect sizes and a greater number of significant associations are commonly reported for SSD relative to AP.Conclusions: Shared risk factors for SSD and AP may include obstetric complications, childhood psychopathology, cognitive markers and motor dysfunction, but the capacity to distinguish common versus distinct risk factors/antecedents for SSD and AP is limited by the scant availability of prospective data for AP, and inconsistency in replication. Further studies considering both diagnoses concurrently are needed. Nonetheless, the prevalence of the risk factors/antecedents observed in cases and controls helps demarcate potential targets for preventative interventions for these disorders