Pulmonary Densitovolumetry Using Computed Tomography in Patients with Nontuberculous Mycobacteria: Correlation with Pulmonary Function Tests.

BACKGROUND: Since nontuberculous mycobacterial pulmonary disease (NTM-PD) is a condition with increasing morbidity, a more detailed knowledge of radiological aspects and pulmonary function plays a relevant role in the diagnosis and appropriate therapeutic management of these patients. OBJECTIVES: The purpose of this study was to evaluate changes in lung parenchyma through computed tomography (CT) densitometry and, secondarily, to analyze its correlation with pulmonary function testing (PFT) in patients with NTM-PD. METHODS: This is a cross-sectional study in which 31 patients with NTM-PD and 27 controls matched by sex, age, and body mass index underwent CT pulmonary densitovolumetry and pulmonary function tests including spirometry and body plethysmograph. RESULTS: Based on the total lung volume (TLV) and total lung mass (TLM) measurements, the cumulative mass ratios were calculated for 3% (M3), 15% (M15), 85% (M85), and 97% (M97) of the TLV. We also calculated the complement, which is represented by TLM (100%) minus the mass of 15% (C85) or 3% (C97) of the TLV. Patients with NTM-PD presented lower values of M3 and M15 than controls, with greater significant differences in the apical third and middle third measurements. Compared to controls, patients with NTM-PD showed higher values of C85 and C97, although significant differences were observed only in the basal third measurements. There were negative correlations of total lung capacity with M3 and M15 in the middle third and apical third measurements. There were positive correlations of residual volume and airway resistance with M3 at the apical third measurement. CONCLUSIONS: Patients with NTM-PD show reduced lung mass and increased lung mass in the apical and basal regions of the lungs, respectively. Furthermore, there is a relationship between lung mass measurements and pulmonary function parameters.

IgG subclasses' response to a set of mycobacterial antigens in different stages of Mycobacterium tuberculosis infection.

Despite the reported high heterogeneity of the human immune response to tuberculosis (TB), new studies may contribute to the understanding of Mycobacterium tuberculosis immunopathogenesis. To investigate the patterns of humoral response during latent (LTBI) and active TB, we evaluated specific IgG subclasses' response, by ELISA, to a set of mycobacterial antigens (Rv2029c, Rv2031c, Rv2034, Rv2628, Rv3353c ESAT6:CFP10, and the new chimeric PstS1(285-374):CFP10) in plasma samples from exposed uninfected controls (ExC, n = 24), LTBI (n = 61), and TB (n = 15) donors. In general, the TB group showed statistically higher levels of IgG1, and lower levels of IgG3. Keeping specificities ≥90%, the highest sensitivity for TB detection was observed for IgG1-ESAT6:CFP10 (93.3%), followed by IgG2-Rv3353 (86.7%), IgG1-Rv3353 (69.2%) and IgG1-PstS1(285-374):CFP10 (53.3%). The combinatory of high IgG1-ESAT6:CFP10, followed by low IgG2-Rv3353c titers increased the specificity for TB detection to 100%. Only IgG3-ESAT6:CFP10 showed statistical differences between ExC and LTBI, detecting 50% of the LTBI donors. For the first time, higher levels of IgG2-PstS1(285-374):CFP10 and IgG2-Rv3353 were observed in LTBI and ExC, as compared with a lower or absent immunoreactivity among TB. This study demonstrates differential modulation of subclasses' profiles for the stages of infection, which may contribute to the further development of new diagnostic tools.

Close contact interferon-gamma response to the new PstS1(285-374):CPF10: a preliminary 1-year follow-up study.

BACKGROUND: The available diagnostic tools for latent tuberculosis (TB) infection (LTBI) via interferon-gamma (IFN-g) release assays (IGRA) are based on ESAT6:CFP10 stimulation. However, the mycobacterial antigen PstS1 is also highly immunogenic and some of its fragments, such as PstS1(285-374), have shown higher immunoreactivity in LTBI than in active TB. PstS1(285-374), therefore, could increase the accuracy of the existing IGRA to detect LTBI. Thus, a new chimeric protein has recently been developed (PstS1(285-374):CFP10) showing potential for LTBI screening of recent close contacts (rCt) exposed to Mycobacterium tuberculosis. The aim of this study was to analyze the PstS1(285-374):CFP10 longitudinal IFN-g profile in comparison to ESAT6:CFP10 and full PstS1/CFP10 stimulation in a rCt cohort and correlate the responses to these in-house IGRA with any clinical changes/interventions that might occur. METHODS: A free-of-cost, one-year follow up was offered to 120 rCt recruited in Rio de Janeiro, RJ, Brazil. Whole blood short-term (WBA), long-term stimulation (LSA) assays, and the tuberculin skin test (TST) were performed during follow up. RESULTS: Among the enrolled rCt, 44.2% (53/120) returned for re-evaluation and the control group (TST negative, n = 17) showed low IFN-g reactivity to all antigen stimulations during the entire follow up, except for one participant who had shown radiological evidence of past TB/LTBI. Both incident cases were detected by IGRA-PstS1(285-374):CFP10 during LTBI and after disease progression. Moreover, subsequent to the prophylactic treatment for LTBI (tLTBI), a significant regression in the LSA response was predominantly observed through stimulation of the new chimeric protein (8/10, 80%) followed by ESAT6:CFP10 (5/10, 50%) and PstS1/CFP10 (4/10, 40%). No clinical or epidemiological characteristics were exclusively shared among IGRA convertors. CONCLUSION: It was demonstrated that the TST negative rCt without radiological evidence of LTBI/TB did not develop an IGRA-PstS1(285-374):CFP10 response during the one-year follow up. Moreover, all incident cases were detected by our new IGRA; and a significant decrement of LSA-PstS1(285-374):CFP10 reactivity post-prophylactic tLTBI was found. To our knowledge, this is the first study to monitor changes in the immune response profile of IGRA-PstS1(285-374):CFP10 among rCt during a consecutive one-year period, thus providing additional evidence of its potential in the detection of LTBI.

Profile of interferon-gamma response to latency-associated and novel in vivo expressed antigens in a cohort of subjects recently exposed to Mycobacterium tuberculosis.

Recently some latency-associated antigens (LAA) of Mycobacterium tuberculosis were described, as Rv2029c, Rv2031c, Rv2034, Rv2628 and Rv3353c. Of which, the Rv2034 and Rv3353c also demonstrated in vivo expression. Therefore evaluating the immune response to these antigens may help to understand their role in latent TB infection. In a 1-year longitudinal study, IFN-γ response by in vitro peripheral blood mononuclear cells stimulation with LAA was investigated in subjects recently exposed to TB, classified by IFN-γ release assay (IGRA) using RD1 antigens (ESAT-6:CFP-10) and tuberculin skin test (TST) response. Except for Rv3353c, all the LAA triggered higher mean IFN-γ response in IGRA-RD1(+) groups (p < 0.05). Combining the IFN-γ-responders to Rv2029c, Rv2031c plus Rv2034 detected 90.3% (28/31) of IGRA-RD1(+) and 66.7% (24/36) of TST(+) contacts, while 95% (19/20) and 11% (2/17) were identified by classifying them according to a TST and IGRA-RD1 double-positive or double-negative response, respectively. In the follow-up, the TST convertors (negative to positive) also demonstrated an IFN-γ conversion to Rv2029c and Rv2031c, whereas the unique TB incident case was exclusively detected via IGRA-Rv2029c and TST before developing TB. A reversion rate to LAA (60%-100%) after prophylactic treatment was observed at TST(+)/IGRA-RD1(+) group. Further studies into the performance of these antigens are thus warranted.

Yield of close contact tracing using two different programmatic approaches from tuberculosis index cases: a retrospective quasi-experimental study.

BACKGROUND: Being a contact of a pulmonary tuberculosis (TB) case is a risk factor for active and latent TB. The objective of this study is to determine the contact tracing yield using two different programmatic definitions of close contact in the city of Rio de Janeiro, Brazil. METHODS: This is a retrospective quasi-experimental study. Data were obtained by reviewing the medical records from TB index cases and their close contacts admitted to the Outpatient TB Clinic of the Institute of Thoracic Diseases, University of Rio de Janeiro. From January 2001 to December 2004, a close contact was defined as an individual who shared an enclosed space with a TB index case for a total period of ≥ 100 hours, whereas from January 2005 to December 2008 the definition of close contact was changed to an individual who shared an enclosed space with a TB index case ≥ 4 hours a week. The primary outcome of this study was newly diagnosed pulmonary TB cases and the secondary outcome was the prevalence of latent TB infection (LTBI) among close contacts during both periods. RESULTS: From 2001-2004, 810 close contacts from 257 index cases were evaluated and the prevalence of active TB and LTBI were 2% (16/810) and 62% (496/794), respectively. From 2005-2008, 1,310 close contacts from 369 index cases were identified and the prevalence of active TB and LTBI were 2.7% (35/1,310) and 69% (877/1,275), respectively. There was not a statically significant difference in the detection of active TB (p = 0.3) between the 2 time periods, but the detection of LTBI was significant higher (p = 0.003). The number needed to screen (contacts/new cases) decreased from 50 to 37 and the number need to contact trace (index cases/new cases) decreased from 16 to 10 from 2001-2004 to 2005-2008. CONCLUSION: In conclusion, the findings of this study suggest that the less conservative definition of TB close contacts (sharing space ≥ 4 h/week) can be a helpful tool for increasing the rate of diagnosis for newly active pulmonary TB cases and for the detection of LTBI among contacts of active pulmonary TB cases.

Genetic polymorphisms of NAT2, CYP2E1 and GST enzymes and the occurrence of antituberculosis drug-induced hepatitis in Brazilian TB patients.

Isoniazid (INH), one of the most important drugs used in antituberculosis (anti-TB) treatment, is also the major drug involved in hepatotoxicity. Differences in INH-induced toxicity have been attributed to genetic variability at several loci, such as NAT2, CYP2E1, GSTM1 and GSTT1, that code for drug-metabolising enzymes. Our goal was to examine the polymorphisms in these enzymes as susceptibility factors to anti-TB drug-induced hepatitis in Brazilian individuals. In a case-control design, 167 unrelated active tuberculosis patients from the University Hospital of the Federal University of Rio de Janeiro, Brazil, were enrolled in this study. Patients with a history of anti-TB drug-induced acute hepatitis (cases with an increase to 3 times the upper limit of normal serum transaminases and symptoms of hepatitis) and patients with no evidence of anti-TB hepatic side effects (controls) were genotyped for NAT2, CYP2E1, GSTM1 and GSTT1 polymorphisms. Slow acetylators had a higher incidence of hepatitis than intermediate/rapid acetylators [22% (18/82) vs. 9.8% (6/61), odds ratio (OR), 2.86, 95% confidence interval (CI), 1.06-7.68, p = 0.04). Logistic regression showed that slow acetylation status was the only independent risk factor (OR 3.59, 95% CI, 2.53-4.64, p = 0.02) for the occurrence of anti-TB drug-induced hepatitis during anti-TB treatment with INH-containing schemes in Brazilian individuals.

Genetic polymorphisms of NAT2, CYP2E1 and GST enzymes and the occurrence of antituberculosis drug-induced hepatitis in Brazilian TB patients

Isoniazid (INH), one of the most important drugs used in antituberculosis (anti-TB) treatment, is also the major drug involved in hepatotoxicity. Differences in INH-induced toxicity have been attributed to genetic variability at several loci, such as NAT2, CYP2E1, GSTM1 and GSTT1, that code for drug-metabolising enzymes. Our goal was to examine the polymorphisms in these enzymes as susceptibility factors to anti-TB drug-induced hepatitis in Brazilian individuals. In a case-control design, 167 unrelated active tuberculosis patients from the University Hospital of the Federal University of Rio de Janeiro, Brazil, were enrolled in this study. Patients with a history of anti-TB drug-induced acute hepatitis (cases with an increase to 3 times the upper limit of normal serum transaminases and symptoms of hepatitis) and patients with no evidence of anti-TB hepatic side effects (controls) were genotyped for NAT2, CYP2E1, GSTM1 and GSTT1 polymorphisms. Slow acetylators had a higher incidence of hepatitis than intermediate/rapid acetylators [22 percent (18/82) vs. 9.8 percent (6/61), odds ratio (OR), 2.86, 95 percent confidence interval (CI), 1.06-7.68, p = 0.04). Logistic regression showed that slow acetylation status was the only independent risk factor (OR 3.59, 95 percent CI, 2.53-4.64, p = 0.02) for the occurrence of anti-TB drug-induced hepatitis during anti-TB treatment with INH-containing schemes in Brazilian individuals.

Cell proliferation and interferon-gamma response to recombinant MBP-3, NarL, MT-10.3, and 16kDa Mycobacterium tuberculosis antigens in Brazilian tuberculosis patients

Human pulmonary tuberculosis (TB) is a worldwide public health problem. In resistant individuals, control of the infection mainly requires development of a Th1 cell immune response with production of cytokines, of which interferon-gamma (IFN-gamma)plays an important role. Several antigens from Mycobacterium tuberculosis complex has been described for use in vaccine development or for diagnostic purposes, however little evaluation has been done in endemic area for TB. The proliferative and IFN-gamma human T cell immune responses, to four recombinant proteins (MBP-3, NarL, MT-10.3, 16 kDa) and PPD, of 38 Brazilian TB patients (6 untreated and 32 treated) and 67 controls (38 positive and 29 negative tuberculin skin test - TST) were compared. The highest reactivity mean rate was obtained with PPD followed by 16 kDa in TB patients. While most of the patients (87 percent) and controls (> 64 percent) respond to the PPD, 16kDa was more specifically recognized (> 21 percent) although less sensitive (54 percent). When TB patients were divided according to treatment status, opposite to PPD, higher average level of IFN-gamma was induced by 16kDa in untreated (505 pg/ml) compared to treated TB patients and TST+ (269.8 pg/ml x 221.6pg/ml, respectively), although the difference was not significant. These data show that in contrast with the other recombinant proteins, the stimulatory potency of 16kDa to induce proliferative and INF-gamma response was more effective and is more recognized by active TB untreated patients, eliciting in control individuals a more selective immune response than PPD.