Background: The appearance of tuberculosis/human immunodeficiency virus co-infection and the growing number of diseases caused by nontuberculous mycobacteria, as well as the confusion that these can cause in relation to emerging multidrug-resistant strains, require more accurate and rapid laboratory results, not only in the isolation of strains but also in their identification. Objective: A comparative study evaluating a new tool of molecular identification, which uses a genetic probe based on the 16S rDNA sequence of the Mycobacterium tuberculosis gene (Gen-Probe Accuprobe® Gen Probe, Inc.), and the classic methodology. Method: Fifty-five Mycobacterium strains, isolated from the sputum of patients treated at a tuberculosis reference clinic, were selected for study. Subcultures were performed in three tubes: one submitted to genetic identification, one analyzed through classical tests (production and accumulation of niacin; growth in the Lowenstein-Jensen medium with the inhibitor agents p-nitrobenzoic acid and thiophene-2-carboxylic acid hydrazide added), and one held in reserve. Results: The probe identified 51 cases as belonging to the M. tuberculosis complex (one associated with M. kansasii) and the other 4 as nontuberculous mycobacteria, later identified as M. kansasii (3) and M. avium (1). Using traditional methods, 47 samples were identified as belonging to the M. tuberculosis complex, 4 were classified as fitting the profile of nontuberculous mycobacteria (in agreement with the genetic probe results), and 4 were unidentified, 1 of which presented the exact characteristics that 2 mycobacterium species have in common. Conclusion: The benefits of the molecular biology technique justify its implementation and routine use, in combination with classical methods, in a high-traffic clinic where complex cases of tuberculosis are treated.

Keywords: Mycobacterium tuberculosis. Molecular probe techniques.

Objective: The emergence of tuberculosis/HIV co-infection and the increase in the number of cases of infection with nontuberculous mycobacteria (NTM) require rapid laboratory test results in the isolation and identification of mycobacteria. The objective of this study was to evaluate the identification of mycobacteria by means of gene probes in comparison with that obtained using classical biochemical methods. Methods: Between 2002 and 2004, 178 mycobacterial cultures, all testing positive for acid-fast bacilli, were analyzed. Samples were obtained from clinical specimens of patients with respiratory symptoms or with clinical suspicion of pulmonary tuberculosis/mycobacteriosis who were treated in the greater metropolitan area of Santos. Results: The gene probe identified 137 samples (77%) as Mycobacterium tuberculosis complex and 41 (23%) as NTM. Discordant results between the methods (3%) were obtained only in the year of implementation (2002). When comparing the methods, the sensitivity, specificity, positive predictive value and negative predictive value of the gene probe method were 98%, 93%, 98% and 93%, respectively. Conclusions: Despite the cost, the identification of mycobacteria using the molecular technique is faster: maximum 3 h vs. 28-30 days for classical methods. The use of gene probes is a validated molecular technique. It is fast, easy to use and readily available on the market. It has high specificity and sensitivity, which justifies its implementation and routine use in referral laboratories, since it facilitates the diagnosis providing agile clinical interventions.

Keywords: Mycobacterium tuberculosis; Tuberculosis/diagnosis; Mycobacterium/classification; DNA probes.

Objective: In developing countries, sputum smear microscopy is the main tool for pulmonary tuberculosis case finding. The objective of the present study was to evaluate the diagnostic efficacy of Gabbett's staining (GS) and modified cold staining (MCS), both of which are two-step methods, in comparison with that of fluorescent staining (FS), which is a three-step method, for the detection of AFB in sputum smears. Methods: Our sample comprised 260 sputum samples collected from individuals suspected of having pulmonary tuberculosis at Kasturba Hospital, in Manipal, India. Smears were prepared in triplicate: one each for FS, MCS, and GS. The smears were randomly numbered so that the examiner was blinded to the sample identities. Results: Of the 260 samples, 16 (6.15%), 15 (5.77%), and 13 (5.00%) showed positive AFB results with FS, MCS, and GS, respectively. The sensitivity of GS and MCS, in comparison with that of FS, was 81.25% and 93.75%, respectively. The concordance of GS and MCS with FS was good (0.988 and 0.996, respectively), and no statistically significant differences were found. Conclusions: Although MCS and GS were found to be less sensitive than was FS, which is evaluated under fluorescence microscopy, the first two are promising methods for the diagnosis of tuberculosis.

Keywords: Tuberculosis, pulmonary; Diagnostic techniques and procedures; Microscopy, fluorescence; Sputum.

Objective: Nontuberculous mycobacteria (NTM) are a heterogeneous group of bacteria that are widely distributed in nature and associated with opportunistic infections in humans. The aims of this study were to identify NTM in patients with suspected tuberculosis who pre-sented positive cultures and to evaluate the genetic diversity of strains identified as Myco-bacterium avium. Methods: We studied pulmonary and extrapulmonary samples obtained from 1,248 patients. The samples that tested positive on culture and negative for the M. tu-berculosis complex by molecular identification techniques were evaluated by detection of the hsp65 and rpoB genes and sequencing of conserved fragments of these genes. All strains identified as M. avium were genotyped using the eight-locus mycobacterial interspersed repetitive unit-variable-number tandem-repeat method. Results: We found that NTM ac-counted for 25 (7.5%) of the 332 mycobacteria isolated. Of those 25, 18 (72%) were M. avium, 5 (20%) were M. abscessus, 1 (4%) was M. gastri, and 1 (4%) was M. kansasii. The 18 M. avium strains showed high diversity, only two strains being genetically related. Conclusions: These results highlight the need to consider the investigation of NTM in patients with suspected active tuberculosis who present with positive cultures, as well as to evaluate the genetic di-versity of M. avium strains.

Keywords: Mycobacterium avium; Nontuberculous mycobacteria; HIV; Genotyping techniques.

Objective: To evaluate the performance of nested PCR (nPCR) in detecting the Mycobacterium tuberculosis complex in blood samples of patients suspected of having TB, in order to determine its potential for use as an auxiliary tool in the laboratory diagnosis of TB in children. Methods: Detection of the M. tuberculosis complex in blood samples using as a target the insertion sequence IS6110 of the genomic DNA of the bacillus. Blood samples of 120 patients were evaluated. All of the patients were under 15 years of age at the time of their treatment at public hospitals in the city of Recife, Brazil (between January of 2003 and August of 2005). Attending physicians at the hospitals diagnosed TB based on the criteria recommended by the American Thoracic Society. The nPCR amplified a 123-bp fragment with outer oligonucleotides (IS1/IS2) and, in the subsequent reaction, using inner oligonucleotides (IS3/IS4), generating an 81-bp amplicon. Results: Active or latent TB was found in 65 patients, TB was ruled out in 28 suspected cases, and 27 patients were TB-free (controls). The sensitivity of nPCR was 26.15% and was significantly higher for the extrapulmonary form of the disease (55.56%) than for the pulmonary form (18.18%). The specificity was 92.73%. Conclusions: Despite the difficulties in diagnosing TB in children and the low number of cases evaluated in the present study, nPCR in blood samples proved to be a rapid and specific technique, albeit one with low sensitivity. In order to establish its true usefulness in the diagnosis of paucibacillary forms, especially extrapulmonary TB, further studies need to be carried out with a larger sample of children and analyzing biological specimens other than blood.

Keywords: Tuberculosis; Diagnosis; Blood; Polymerase chain reaction.

Objective: The rapid differentiation between Mycobacterium tuberculosis and nontuberculous mycobacteria is fundamental for patients co-infected with tuberculosis and HIV. To that end, we use two methods in our laboratory: detection of cord factor and PCR-restriction enzyme analysis (PRA). The objective of this study was to evaluate the accuracy of a screening test on solid medium as a rapid method for the presumptive identification of M. tuberculosis complex, considering costs and turnover time. Methods: A total of 152 strains were submitted to a combined screening test, consisting of the detection of cord factor under microscopy (Ziehl-Neelsen staining) and evaluation of the macroscopic aspect of colonies, as well as to PRA, which was used as the gold standard. Costs were estimated by calculating the price of all of the materials needed for each test. Results: The overall accuracy of cord factor detection alone was 95.4% (95% CI: 90.7-98.1%), and that of the combined screening test was 99.3% (95% CI: 96.4-100%). Cord factor detection costs US$ 0.25, whereas the PRA costs US$ 7.00. Results from cord factor detection are ready in 2 days, whereas PRA requires 4 days to yield results. Conclusions: The presumptive identification of M. tuberculosis using the macroscopic evaluation of colonies combined with cord factor detection under microscopy is a simple, rapid and inexpensive test. We recommend the combined screening test to rapidly identify M. tuberculosis in resource-poor settings and in less well-equipped laboratories while awaiting a definite identification by molecular or biochemical methods.

Keywords: Tuberculosis; Mycobacterium/classification; Polymerase chain reaction; Diagnostic tests, routine.

In view of the fact that the World Health Organization has recommended the use of the mycobacteria growth indicator tube (MGIT) 960 system for the diagnosis of tuberculosis and that there is as yet no evidence regarding the clinical impact of its use in health care systems, we conducted a pragmatic clinical trial to evaluate the clinical performance and cost-effectiveness of the use of MGIT 960 at two health care facilities in the city of Rio de Janeiro, Brazil, where the incidence of tuberculosis is high. Here, we summarize the methodology and preliminary results of the trial. (ISRCTN.org Identifier: ISRCTN79888843 [http://isrctn.org/])

Keywords: Controlled clinical trial; Tuberculosis; Diagnostic tests, routine.

Objective: Virulent strains of the Mycobacterium tuberculosis complex, under certain appropriate conditions, grow as characteristic ropes, bundles or serpentine cords known as cord factor or growth in cords. The objective of the present study was to evaluate cord factor detection as a method of achieving presumptive identification of the M. tuberculosis complex, comparing it to conventional typing tests. Methods: A total of 743 strains were analyzed from January of 2002 to December of 2005 in the Mycobacteria Sector of the Adolfo Lutz Institute, located in the city of Santos, Brazil. Samples were obtained from clinical specimens collected from patients with respiratory symptoms treated at basic health clinics in the greater metropolitan area of Santos. Ziehl-Neelsen-stained smears were prepared, 301 (40.5%) in MB/BacT broth and 442 (59.5%) on solid media, either Lowenstein-Jensen or Ogawa-Kudoh. Results: The sensitivity, specificity, positive predictive value and negative predictive value obtained during the performance comparison of the two methods (cord factor detection and conventional typing) using both isolation media were, respectively, 98.5, 88, 97 and 93%. The method was more sensitive on solid medium (100%), and the difference in sensitivity between the two media types was only 2.7%. Conclusions: Taking into consideration the results obtained, we conclude that, in laboratories with a high incidence of M. tuberculosis complex isolation and limited economic resources, cord factor detection is a fast and valid criterion for identifying these mycobacteria using liquid or solid medium. It also enables subsequent conclusive identification tests, as well as additional sensitivity tests when necessary.

Keywords: Laboratory techniques and procedures; Mycobacterium tuberculosis; Cord factors

We compared the nitrate reductase assay with the proportion method, which is considered the gold standard, in 57 Mycobacterium tuberculosis strains isolated from patients treated at the Federal University of Minas Gerais Hospital das Clínicas, located in the city of Belo Horizonte, Brazil. For rifampin and isoniazid, the sensitivity, specificity, and accuracy of the nitrate reductase assay were all 100%, whereas they were 100%, 88.9%, and 66.7%, respectively, for streptomycin and 98.0%, 100%, and 98.2%, respectively, for ethambutol. The mean time to results was ten days. In the study sample, the nitrate reductase assay proved highly accurate and showed excellent concordance with the gold standard.

Keywords: Mycobacterium tuberculosis; Microbial sensitivity tests; Tuberculosis, multidrug-resistant; Nitrate reductase.

Objective: To compare the performance of nested polymerase chain reaction (NPCR) with that of cultures in the detection of the Mycobacterium tuberculosis complex in pulmonary and extrapulmonary specimens. Methods: We analyzed 20 and 78 pulmonary and extrapulmonary specimens, respectively, of 67 hospitalized patients suspected of having tuberculosis. An automated microbial system was used for the identification of Mycobacterium spp. cultures, and M. tuberculosis IS6110 was used as the target sequence in the NPCR. The kappa statistic was used in order to assess the level of agreement among the results. Results: Among the 67 patients, 6 and 5, respectively, were diagnosed with pulmonary and extrapulmonary tuberculosis, and the NPCR was positive in all of the cases. Among the 98 clinical specimens, smear microscopy, culture, and NPCR were positive in 6.00%, 8.16%, and 13.26%, respectively. Comparing the results of NPCR with those of cultures (the gold standard), we found that NPCR had a sensitivity and specificity of 100% and 83%, respectively, in pulmonary specimens, compared with 83% and 96%, respectively, in extrapulmonary specimens, with good concordance between the tests (kappa, 0.50 and 0.6867, respectively). Conclusions: Although NPCR proved to be a very useful tool for the detection of M. tuberculosis complex, clinical, epidemiological, and other laboratory data should also be considered in the diagnosis and treatment of pulmonary and extrapulmonary tuberculosis.

Keywords: Tuberculosis/diagnosis; Tuberculosis/microbiology; Mycobacterium tuberculosis; Polymerase chain reaction.

Objective: To present a locally developed system of computer vision for use with HRCT images, designated SIStema para a Detecção e a quantificação de Enfisema Pulmonar (SISDEP, System to Detect and Quantify Pulmonary Emphysema), and to compare this system with a freeware system tool. Methods: Thirty-three HRCT images scanned at the apex, hilum and base of the lungs of 11 patients with COPD were analyzed. The SISDEP was compared with the Osiris Medical Imaging Software Program regarding lung parenchyma segmentation, precision of the measurement of the cross-sectional area of the lungs in mm2, mean lung density (MLD), relative area (RA) of the lung occupied by voxels with attenuation values < −950 Hounsfield units (RA −950), 15th percentile point (Perc15) and visualization of hyperinflated areas using a color mask. Results: Although both computational systems were efficient in segmenting the lungs, the SISDEP performed this task automatically and more rapidly. There were significant correlations between the two systems in terms of the results obtained for lung cross-sectional area, MLD, RA −950 and Perc15 (r2 = 0.99, 0.99, 0.99 and 1.00, respectively). The color mask tool of the SISDEP allowed excellent visualization of hyperinflated areas, discriminating them from normal areas. Conclusions: The SISDEP was efficient in segmenting the lungs and quantifying lung hyperinflation, presenting an excellent correlation with the Osiris system. The SISDEP constitutes a promising computational tool for diagnosing and assessing the progression of emphysema in HRCT images of COPD patients.

Keywords: Pulmonary disease, chronic obstructive; Emphysema; Tomography, X-ray computed; Decision making, computer-assisted.

Objective: To compare the subjective perception of asthma control reported by the patient with that measured by the score obtained on the Asthma Control Questionnaire 6-item version (ACQ-6) in patients with severe asthma and to determine whether asthma control is associated with the number of emergency room visits in the previous month. Methods: This was a cross-sectional study involving 528 patients treated at the Bahia State Asthma and Allergic Rhinitis Control Program Central Referral Clinic between August of 2008 and March of 2010, in the city of Salvador, Brazil. The patients completed the ACQ-6 and answered a specific additional question in order to evaluate their own perception of asthma control in the previous week. Results: We evaluated 423 patients who met the inclusion criteria. The sample was predominantly female (81.3%), and 64.3% had an income lower than two times the national minimum wage. The mean age was 49.85 ± 13.71 years, and the duration of asthma symptoms was 32.11 ± 16.35 years. The patients had been regularly treated via the program for 36.65 ± 18.10 months. Based on the subjective perception of asthma control, only 8% of the patients considered their asthma to be uncontrolled, whereas 38.8% had an ACQ-6 score  1.5, which indicates poor control. The kappa statistic revealed poor concordance between the two methods. There was a direct association between uncontrolled asthma and the number of emergency room visits in the previous month (p < 0.001). Conclusions: In this sample of patients, the subjective perception of asthma control differed from that measured by the ACQ-6 score, and the patients overestimated their own level of asthma control, which puts them at risk of being undertreated.

Keywords: Asthma; Health services; Questionnaires.

Background: Knowledge of the rates of drug resistance is one of the pillars of tuberculosis control program evaluation. Data from low-resource countries are scarce and results are delayed due to the techniques employed. There is therefore an urgent need for evaluation of faster and less onerous testing methods. Objective: To compare the performance of rapid colorimetric assays for phenotyping that employ oxidationreduction indicators to determine the susceptibility profile of Mycobacterium tuberculosis with the gold-standard proportion method on Lowenstein-Jensen Medium. Method: We analyzed 166 M. tuberculosis strains of known susceptibility. Minimal inhibition concentrations for isoniazid and rifampicin were determined in microplates, using a liquid medium and Alamar Blue and tetrazolium bromide indicators. To measure agreement the Kappa value was used. Cutoff values between sensitive and resistant strains were defined as 0.2µg/mL and 1.0µg/mL for isoniazid and rifampicin, respectively. Results: There was 100% concordance between Alamar Blue and tetrazolium bromide methods in the determination of minimal inhibition concentrations. Agreement between the colorimetric method and the Lowenstein-Jensen was 95% for isoniazid and rifampicin. Using the colorimetric method, results were obtained within 7 days, in contrast to the 28 days required for the conventional method. Conclusions: Assays to determine minimal inhibition concentrations in liquid medium and employing oxidationreduction indicators proved to be rapid and inexpensive. This method has the potential to become a faster, alternative method for determining susceptibility of M. tuberculosis strains in developing countries.

Keywords: Mycobacterium tubercolis. Disease susceptibility. Isoniazid/therapeutic use. Rifampin/therapeutic use.

Objective: To describe the clinical manifestations of patients with pulmonary infection caused by mycobacteria of the Mycobacterium abscessus complex (MABSC), and to compare these manifestations with those of patients infected with other nontuberculous mycobacteria (NTM). Methods: This was a retrospective cohort study involving 43 patients divided into two groups: the MABSC group, consisting of patients with pulmonary infection caused by MABSC (n = 17); and the NTM group, consisting of patients with pulmonary infection caused by NTM other than MABSC (n = 26). Patients were previously treated with a regimen of rifampin, isoniazid, pyrazinamide, and ethambutol before the diagnosis of NTM was confirmed by two culture-positive sputum samples. The nucleotide sequences of the hsp65, 16S rRNA, and/or rpoB genes were analyzed to identify the mycobacteria. Data were collected on demographic, clinical, and radiological characteristics, as well as on treatment responses and outcomes. Results: Loss of appetite was the only clinical manifestation that was significantly more common in the MABSC group than in the NTM group (p = 0.0306). The chance of having to use a second treatment regimen was almost 12 times higher in the MABSC group than in the NTM group. Treatment success was significantly higher in the NTM group than in the MABSC group (83.2% vs. 17.6%; p < 0.0001). The chance of recurrence was approximately 37 times higher in the MABSC group than in the NTM group. Conclusions: In the study sample, treatment response of pulmonary disease caused by MABSC was less favorable than that of pulmonary disease caused by other NTM.

Keywords: Nontuberculous mycobacteria/classification; Nontuberculous mycobacteria/drug effects; Lung diseases.

Objective: To determine, based on international guidelines for asthma management, the appropriateness of the treatment that the Unified Health Care System provides to patients with asthma. Methods: This was a cross-sectional study involving patients suspected of having asthma and referred to the Pulmonology Clinic of the Federal University of Minas Gerais Hospital das Clínicas, Brazil, between November of 2006 and October of 2007. Results: A total of 102 patients were included, and 70 were diagnosed with asthma. The previous treatment was consistent with the guidelines in 18.6% of the patients; 50.0% of the patients had previously been submitted to spirometry, and 34.3% had previously been submitted to PEF. The most frequently prescribed medication was short-acting β2 agonists (90.3%). Conclusions: The results show that the majority of non-specialized physicians working within the public health care system do not manage the treatment of patients with asthma in accordance with the guidelines. This situation calls for continuing medical education programs that prioritize primary care.

Keywords: Asthma; Guideline adherence; Therapeutics; Public health.

Studies published by Brochard et al. and by Esteban et al. came to different conclusions about the best technique of weaning from mechanical ventilation. Although the association of synchronized intermittent mandatory ventilation (SIMV) with pressure support ventilation (PSV) is frequently used and considered as a physiologic form of weaning, no prospective randomized study compared this technique to synchronized intermittent mandatory ventilation or to pressure support ventilation used singly. The authors compared these three weaning methods to determine the one that is associated with the shortest weaning time and the smallest frequency of unfavorable outcome. Methods: The authors analyzed prospectively 72 consecutive patients submitted to mechanical ventilation for at least 24 hours and that had clinical, gasometric, and respiratory criteria for weaning. The patients were randomized in three groups (SIMV, PSV, SIMV+PSV). Stringent criteria were used in the application of each technique to define success or failure of the procedure. Results: The groups (SIMV = 21, PSV = 25 and SIMV+PSV = 26 patients) were similar with respect to age, score APACHE III and diseases. Mean duration of weaning was 1.7 ± 1.2 days with SIMV, 2.5 ± 1.6 days with PSV, and 2.1 ± 1.5 days with SIMV+PSV. Four (19.0 %) patients failled to wean in the SIMV group, nine (36.0%) in PSV and two (7.7%) in SIMV+PSV. Conclusions: This study shows a good performance of SIMV+PSV for weaning patients from mechanical ventilation and unfavorable results with support ventilation that can not be attributed to homogeneity between the groups, nor to the methodologies or equipments used.

Keywords: Weaning. Synchronized intermittent mandatory ventilation. Pressure support ventilation.

Malignant mesothelioma (MM) is a highly aggressive form of cancer, has a long latency period, and is resistant to chemotherapy. It is extremely fatal, with a mean survival of less than one year. The development of MM is strongly correlated with exposure to asbestos and erionite, as well as to simian virus 40. Although various countries have banned the use of asbestos, MM has proven to be difficult to control and there appears to be a trend toward an increase in its incidence in the years to come. In Brazil, MM has not been widely studied from a genetic or biochemical standpoint. In addition, there have been few epidemiological studies of the disease, and the profile of its incidence has yet to be well established in the Brazilian population. The objective of this study was to review the literature regarding the processes of malignant transformation, as well as the respective mechanisms of tumorigenesis, in MM.

Keywords: Occupational diseases; Mesothelioma; Genes, tumor suppressor; Oncogenes; Signal transduction.

Objective: To evaluate the accuracy of determining specific IgA to HspX recombinant antigen in pleural fluid and serum samples for the diagnosis of pleural tuberculosis in patients with pleural effusion. Methods: This was a cross-sectional study. Serum and pleural fluid samples of patients with pleural effusion and suspected of having pleural tuberculosis were tested with indirect ELISA in order to determine the optical density of specific IgA to HspX. Results: We evaluated serum and pleural fluid samples from 132 patients: 97 diagnosed with pleural tuberculosis (study group) and 35 diagnosed with pleural effusion due to other causes (control group). The determination of IgA in pleural fluid satisfactorily discriminated between pleural tuberculosis patients and control patients. The sensitivity of the test in pleural fluid and in serum was 69% and 30%, respectively, whereas the specificity was 83% and 84%, respectively. Conclusions: Our data suggest that this test can be used in the diagnosis of pleural tuberculosis. Further studies, involving larger patient samples and different epidemiological scenarios, are warranted.

Keywords: Pleural effusion; Tuberculosis/diagnosis; Enzyme-linked immunosorbent assay.

Objective: Silicosis is a pneumoconiosis characterized by fibrosis of the lung parenchyma caused by inhalation of silica particles. Genetic factors might play a role in the severity silicosis. We sought to evaluate the influence of polymorphisms in the ACE, FAS, FASLG, NOS2, IL1RN, FAM13A, TGFB1, and TNF genes on the severity of silicosis. Methods: Nine polymorphisms were genotyped by PCR in a sample of 143 patients with silicosis in the state of Rio de Janeiro, Brazil. Results: Fifty-seven patients (40%) were classified as having simple silicosis and 86 (60%) were classified as having complicated silicosis. The TT genotype of rs1800469 in the TGFB1 gene showed a protective effect for complicated silicosis (OR = 0.35; 95% CI, 0.14-0.92; p = 0.028) when compared with the other two genotypes (CC+CT). The polymorphic T allele of rs763110 in the FASLG gene (OR = 0.56; 95% CI, 0.31-0.99; p = 0.047), as well as a dominant model for the T allele (TT+CT: OR = 0.37; 95% CI, 0.15-0.96; p = 0.037), also showed a protective effect. When patients with simple silicosis despite having been exposed to silica for a longer time (> 44,229 hours) were compared with patients with complicated silicosis despite having been exposed to silica for a shorter time, the T allele of rs763110 in the FASLG gene (OR = 0.20; 95% CI, 0.08-0.48; p < 0.0001), as well as dominant and recessive models (OR = 0.06; 95% CI, 0.00-0.49; p = 0.01 and OR = 0.22; 95% CI, 0.06-0.77; p = 0.014, respectively), showed a protective effect against the severity of silicosis. Conclusions: It appears that rs1800469 polymorphisms in the TGFB1 gene and rs763110 polymorphisms in the FASLG gene are involved in the severity of silicosis. Given the lack of studies relating genetic polymorphisms to the severity of silicosis, these results should be replicated in other populations.

Keywords: Silicosis; Polymorphism, genetic; Genetic association studies; Cytokines.