Tuberculin Skin Test Reactivity Research Articles

THE ASSESSMENT OF TUBERCULOSIS IN PATIENTS WITH INFLAMMATORY RHEUMATIC DISEASES TREATED WITH BLOCKERS OF THE TUMORAL NECROSIS ALPHA FACTOR: A RETROSPECTIVE OBSERVATIONAL MULTICENTRE STUDY

Aim. To achieve extensive information (regional) in relation with the tuberculosis identified in current clinical practice in patients with inflammatory rheumatic diseases treated with biological agents. Patients and methods. Twenty seven rheumatologists from 11 Romanian medicale center agreed to participate voluntarily and provide required data on tuberculosis (TB) occurring between January 1999 and June 2011 in their patients with rheumatoid arthritis (RA), ankylosing spondylitis (AS) and psoriatic arthropathy (PsA) in relation with anti-TNFα agent. This observational research included 693 patients (RA n=492, SA n=137, AP n= 64). All patients were screen for latent Mycobacterium tuberculosis infection (LTBI) before they start anti-TNFα treatment. Chemoprophylaxis with isoniazid before anti-TNFα therapy is recommended if the diameter of tuberculin skin test reaction is more than 5 mm (before 2005 only if indurations was more than 10 mm). We recorded the demographic characteristics, and complex information about disease, treatment, tuberculosis diagnosis and the comorbidities. Incidence rate of TB are presented as events/1,000 person-years with associated 95% confidence interval [95%CI]. Results. Fifteen patients were diagnosed with TB, most (60%) were born in rural areas and 40% in areas with higher incidence (≥ 80%ooo) of TB. The incidence of TB was 1.65‰ (IC95% [11.54-34.63]). The extra pulmonary sites were present in 53.3% of the cases. Cultures were positive for Mycobacterium tuberculosis in 11 cases (73.3%). Suspicion of TB was confirmed histological in 6 cases (40%). The average duration of developing TB after initiation of TNF inhibitor was 23.26 months (range one month to 120 months). In 7/12 TB cases treated with IFX the incidence appeared in the first year of treatment. Any of known risk factors don’t have a significant influence in our cohort. Conclusions. The risk of reactivation of a latent TB during biologic therapy is greater in patients with rheumatic inflammatory diseases living in geographical areas with high endemicity of TB infection. Reduced compliance to chemoprophylaxis may be responsible for the occurrence of these cases.

Factors Affecting the Tuberculosis Risk in Patients Receiving Anti-Tumor Necrosis Factor-α Treatment

Background: Tumor necrosis factor (TNF)-α inhibitors are known to increase the risk of tuberculosis (TB). Objectives: To examine the factors associated with an increased risk of TB in patients receiving anti-TNF-α treatment (aTNF-α-T). Method: Of 3,094 patients who received aTNF-α-T between 2003 and 2013, a total of 1,964 subjects with a follow-up time longer than 6 months were identified and included in this retrospective analysis. Potential risk factors for the development of TB in patients receiving aTNF-α-T were evaluated. Results: Of the 1,964 patients, 1,009 (51%) were male and 955 (49%) were female, with a mean age of 39.7 ± 13.9 years. The primary conditions requiring aTNF-α-T included ankylosing spondylitis (n = 875), rheumatoid arthritis (n = 711), Behçet's disease (n = 83), and others (n = 295). Sixteen patients [8 (50%) males and 8 (50%) females; 5 (31.2%) with pulmonary TB and 11 (68.8%) with extrapulmonary TB] developed TB, with a corresponding TB incidence of 466/100,000. No significant associations were found between age, gender, smoking history, pack-years of smoking, isoniazid (INH) chemoprophylaxis, type of anti-TNF-α agent, use of other immunosuppressive drugs, and the risk of TB (p > 0.05). Multivariate logistic regression analysis showed a significantly higher risk of TB in patients diagnosed with Behçet's disease, and a significantly lower risk of TB in patients with a tuberculin skin test wheal ≥10 mm in diameter (p < 0.05). Conclusion: aTNF-α-T is associated with an increased risk of pulmonary or extrapulmonary TB, even when follow-up protocols and INH chemoprophylaxis are implemented, and TB often develops in the later stages of treatment. The risk of TB was higher in patients with Behçet's disease and lower in patients who had a strong tuberculin skin test reaction.

Current tuberculin reactivity of schoolchildren in the Central African Republic.

BackgroundThe tuberculin skin test (TST) is the recommended method for screening for Mycobacterium tuberculosis infection in many countries. We used this technique to assess bacillus Calmette-Guérin (BCG) status and to estimate the current prevalence and annual rate of latent tuberculosis infection in schoolchildren in the Central African Republic.MethodsTwo tuberculin units of 0.1 ml purified protein derivative TR23 were injected intradermally into the left forearm of 2710 children attending school in Bangui and Ombella M’Poko. The induration size was interpreted at cut-off points of ≥5 mm, ≥10 mm and ≥15 mm. The annual infection rate was estimated as the average number of infections in the study sample each year between birth and the time of the survey.ResultsOverall, there was no reaction to the TST (no induration) in 71.7 % (95 CI, 68.3–75.3 %) of BCG-vaccinated children and 82.9 % (95 CI, 74.1–91.4 %) of non-vaccinated children. The proportions of children who gave a TST reaction above ≥10 mm and ≥15 mm cut-off was 18.4 % (95 % CI, 16.8–20.1 %) and 8.9 % (95 % CI, 7.8–10.0 %), respectively. The proportions of TST reaction above these cut-offs were 19.6 % (95 % CI, 17.4–21.9 %) and 8.1 % (95 % CI, 6.7–9.6 %), respectively. The annual infection rate was 0.8 % at the cut-off point of ≥15 mm.ConclusionThis study provides updated data on rates of tuberculosis infection in the Central African Republic. It is remarkable that most of the children had negative tuberculin reactivity. More studies are required to understand the factors that determine the low tuberculin reactivity in this population.

Regulatory T-cell subsets in response to specific Mycobacterium tuberculosis antigens in vitro distinguish among individuals with different QTF and TST reactivity

Regulatory T cells (Tregs), a subset of CD4+ T cells related with immune regulation, have been associated with active and latent tuberculosis infection (LTBI). Treg frequencies were evaluated by multicolor flow cytometry (FC) in peripheral blood mononuclear cells (PBMCs) stimulated with mycobacterial antigens ESAT-6, CFP-10, and TB7.7 to assess their capacity to distinguish subjects with different reactivity to the QuantiFERON-TB® Gold In-Tube (QFT-IT) test and the tuberculin skin test (TST). Increased frequencies of CD4+CD25highCD39+ cells were found for the [TST+, QTF+] compared with the [TST+, QTF−] group. Also, higher frequencies were observed for the [TST+, QTF+] compared with the [TST+, QTF−] and [TST−, QTF−] groups in CD4+CD25highFoxp3+ and CD4+CD25highCD39+Foxp3+ populations. Receiver operating characteristics (ROC curve) analysis confirmed these discriminating results. QFT–IT and TST quantitative values correlated with several Treg population frequencies.

Scar formation and tuberculin conversion following BCG vaccination in infants: A prospective cohort study.

Background:There is considerable variation in BCG scar failure rate on available data and correlation between BCG scar and tuberculin conversion remains controversial. Through this study we aimed to determine the scar failure rate and tuberculin conversion in term infants vaccinated with BCG within the first month.Materials and Methods:A prospective cohort study was conducted among 85 consecutive infants weighing >2 kg attending the immunization clinic of a medical college hospital. Fifteen subjects who could not complete the follow up were excluded. Total of 70 cases were analyzed. All babies were administered 0.1 ml of BCG and examined at 3 months (+1 week) for scar. Tuberculin test was done with 5TU PPD. An induration of >5 mm was considered positive. Statistical analysis was done using Microsoft Excel and SPSS-22.Results:Out of the 70 infants, 41 (58.6%) were males. Although majority (72.9%) of infants were vaccinated within 7 days, only 18 (25.7%) received BCG within 48 hours of birth. Sixty-four (91.4%) had a visible scar at 12 weeks post vaccination representing a scar failure rate of 8.6%. Tuberculin test was positive in 50 (71.4%). The mean ± s.d. for scar and tuberculin skin test (TST) reaction size was 4.93 ± 2.01 mm and 6.01 ± 3.22 mm, respectively. The association between scar formation and tuberculin positivity was highly significant (P < 0.001). There was significant correlation between scar size and TST size (r = 0.401, P = 0.001)Conclusions:Less than 10% of infants fail to develop a scar following BCG vaccination. There is good correlation between scar positivity and tuberculin conversion.

Children exposed to multidrug-resistant tuberculosis at a home-based day care centre: a contact investigation.

In high tuberculosis (TB) burden settings, day care centres may be an underestimated source of exposure of children to infectious drug-susceptible (DS) and drug-resistant (DR) TB cases. To describe the results of a contact investigation of children exposed to an adult with DR-TB at a South African home-based day care centre. Retrospective descriptive community-based cohort study. Mycobacterium tuberculosis resistant to isoniazid (INH), rifampicin and amikacin was cultured from the sputum of an adult index case residing in a home-based day care centre. Of 38 children aged <15 years identified during routine contact investigation, consent was obtained for 34; the median age was 3.9 years (IQR 2.9-5.2); 23/34 were aged <5 years, none were human immunodeficiency virus infected. The median contact score was 4/10, 8 had a reactive tuberculin skin test (⩾10 mm) and none had TB. Of the 34 study children, 24 received 6 months of DR-TB preventive therapy comprising ofloxacin, ethambutol and high-dose INH; 21 completed 12 months' follow-up and none developed TB. TB at day care centres may result in many exposed young children with high TB contact scores, similar to household contact investigations. Active identification and initiation of preventive treatment may be able to avert DR-TB cases.

Tuberculin skin test negativity is under tight genetic control of chromosomal region 11p14-15 in settings with different tuberculosis endemicities.

A substantial proportion of subjects exposed to a contagious tuberculosis case display lack of tuberculin skin test (TST) reactivity. We previously mapped a major locus (TST1) controlling lack of TST reactivity in families from an area in South Africa where tuberculosis is hyperendemic. Here, we conducted a household tuberculosis contact study in a French area where the endemicity of tuberculosis is low. A genome-wide analysis of TST negativity identified a significant linkage signal (P < 3 × 10−5) in close vicinity of TST1. Combined analysis of the 2 samples increased evidence of linkage (P = 2.4 × 10−6), further implicating genetic factors located on 11p14-15. This region overlaps the TNF1 locus controlling mycobacteria-driven tumor necrosis factor α production.

Cytokine gene polymorphisms are associated with susceptibility to tuberculosis in an Amerindian population.

Cytokines play an important role in anti-tuberculosis immune response, combined with antigen-presenting cells and lymphocytes. Immune response gene polymorphisms have been reported to be associated with tuberculosis (TB) susceptibility in some but not all studies. To evaluate the association of immune response genes with susceptibility to tuberculin skin test (TST) reactivity and/or TB. Fourteen single nucleotide polymorphisms were genotyped in 96 individuals of the Aché, a native Paraguayan population, by allelic discrimination using real-time polymerase chain reaction. Univariate and multivariate Poisson regression were employed to assess risk genotypes. A higher prevalence of purified protein derivative reactivity was associated with the TNF-α CCA/TCG haplotype (PR 1.298, 95%CI 1.059-1.589) and with the IL-10 AT/CC diplotype (PR 1.181, 95% CI 1.024-1.362), and the presence of the IL-8 rs4073 T allele was associated with protection against TB (PR 0.482, 95%CI 0.273-0.851). These results suggest that polymorphisms in genes associated with immune response are involved in TST reactivity and susceptibility to TB in the Aché population.

Vitamin D deficiency and tuberculin skin test reaction in old age home residents in Romania

Vitamin D deficiency and tuberculin skin test reaction in old age home residents in Romania

The effect of topical calcipotriol or zinc on tuberculin skin tests in hospitalised South African children

The tuberculin skin test (TST) is used to help diagnose tuberculosis (TB) in acutely ill hospitalised children. OBJECTIVE To investigate the potential augmentative effect of topical calcipotriol (a vitamin D analogue) or zinc on TST induration. Three TSTs were performed among 64 hospitalised children; each site was covered with topical aqueous cream (control), calcipotriol or zinc and assessed 24 and 48 h later by investigators blinded to all topical applications. TSTs were reactive in 15 (23.4%) children, of whom 13 (20.3%) were TST-positive. Topical calcipotriol and zinc induced TST positivity in two children with reactive but negative control TSTs. These treatments, however, did not significantly increase TST positivity rates. In children with reactive TSTs, the median 48 h induration diameter was not significantly different between the control, calcipotriol- or zinc-treated groups, which were respectively 12.0 (25%-75% IQR 5.0 - 18.0), 14.0 (25%-75% IQR 10.0 - 15.0) and 12.0 (25%-75% IQR 8.0 - 15.0) mm. Topical treatments did not induce TST reactivity or TST positivity in children with culture-confirmed TB disease (n = 4), human immunodeficiency virus infection (n= 18) or kwashiorkor (n = 9). Topical calcipotriol or zinc does not induce TST reactivity or significantly increase TST positivity rates in acutely ill hospitalised children. However, further studies are required to assess the effects of topical treatments on TST positivity in severely malnourished children.

Added value of interferon-gamma release assays in screening for tuberculous infection in the Netherlands

Interferon-gamma release assays (IGRAs) are reported to be more specific for the diagnosis of latent tuberculous infection (LTBI) than the tuberculin skin test (TST). The two-step procedure, TST followed by an IGRA, is reported to be cost-effective in high-income countries, but it requires more financial resources. To assess the added value of IGRA compared to TST alone in the Netherlands. Test results and background data on persons tested with an IGRA were recorded by the Public Municipal Health Services in a web-based database. The number of persons diagnosed with LTBI using different screening algorithms was calculated. In those tested with an IGRA, at least 60% of persons who would have been diagnosed with LTBI based on TST alone had a negative IGRA. Among those with a TST reaction below the cut-off for the diagnosis of LTBI, 13% had a positive IGRA. For 41% of persons tested with an IGRA after TST, the IGRA influenced whether or not an LTBI diagnosis would be made. With the IGRA as reference standard, a high proportion of persons in low-prevalence settings are treated unnecessarily for LTBI if tested with TST alone, while a small proportion eligible for preventive treatment are missed. Incremental costs of the two-step strategy seem to be balanced by the improved targeting of preventive treatment.

Infliximab Does Not Lead to Reduction in the Interferon-gamma and Lymphoproliferative Responses of Patients with Moderate to Severe Psoriasis

Treatment of patients with immune-mediated inflammatory diseases with anti-tumour necrosis factor (anti-TNF) agents increases the risk of tuberculosis reactivation, suggesting that it may affect their cellular immune responses. We evaluated cellular immune responses of 12 severe psoriasis patients before and during infliximab treatment. Peripheral blood mononuclear cells were stimulated with phytohaemagglutinin, the superantigen enterotoxin B (SEB), a cytomegalovirus lysate (CMV), and Mycobacterium tuberculosis (Mtb) antigens. The lymphocyte proliferative and IFN-γ responses were evaluated. Treatment with infliximab did not lead to reduction in the IFN-γ and lymphoproliferative responses: it rather increased the overnight release of IFN-γ in phytohaemagglutinin and SEB stimulated cultures. This effect was most noted at the peak of the anti-TNF clinical effect and less prominent at its nadir. Immunoreactivity to CMV was also either unaffected or slightly increased by the anti-TNF. Of note, the IFN-γ and proliferative responses to Mtb by the two tuberculin skin test-reactors were also increased at the peak of infliximab, declining at its nadir. The deleterious consequences of TNF blockade in severe psoriasis patients undergoing infliximab treatment are apparently attenuated by the abbreviation of the immunosuppressive effect of TNF overexpression.

Pleuro-peritoneal lymphomatosis with concurrent tonsillar involvement in T-cell nonHodgkin′s lymphoma: Clinical presentation mimicking disseminated tuberculosis

A young male patient had been evaluated for pleural effusion at another center wherein on the basis of exudative, lymphocyte predominant pleural effusion with high pleural fluid adenosine deaminase (ADA) levels and tuberculin skin test (TST) reactivity, antituberculous medications had been administered. Reevaluation in view of worsening symptoms led to confirmation of the diagnosis of T-cell lymphoblastic lymphoma with pleuro-peritoneal lymphomatosis and tonsillar involvement. This case highlights the fact that elevated ADA levels should not be taken as surrogate for a diagnosis of TB in the absence of histopathological/microbiological confirmation even in countries with high tuberculosis (TB) prevalence. Tonsil in an uncommon site of involvement in patients with T-cell lymphoma. As the diagnosis in our patient was confirmed from biopsy of a tonsillar mass, a thorough physical examination should be performed in all patients with a suspected diagnosis of lymphoma.

Assessment of tuberculin reactivity of BCG-vaccinated infants in Zaria, Nigeria

Introduction: Tuberculosis (TB) is a serious public health problem associated with high morbidity and mortality. BCG vaccination as part of TB prevention strategy is faced with many challenges. The study sought to determine post BCG vaccination scarring and tuberculin reactivity, which may serve as useful indicators of routine BCG vaccination in infants. Materials and Methods: The study was descriptive cross-sectional. Infants were selected and physically examined for presence and size of BCG scar. Mantoux test was performed. Data were analyzed using statistical package for the social sciences software (SPSS version 16.0). Chi-square and Fisher's exact tests were used for association between categorical variables while Pearson's correlation co-efficient was used for the correlation between BCG scar size and Mantoux reaction. P ≤ 0.05 was considered significant. Results: The male:female ratio of the subjects was 1.6:1.0 with a mean birth weight of 3.2 ± 0.4kg.Mean age at Mantoux test was 19.0 ± 3.0 weeks and the prevalence of BCG scar was 81.5% with a mean scar size of 5.3 ± 3.2mm. Mantoux test was positive in 202 (56.7%), negative in 133 (37.4%), and indeterminate in 21 (5.9%) infants. The Mantoux reaction was significantly associated with the age interval between BCG administration and time of Mantoux test (χ2 = 54.17, P < 0.05), the infants' gender (χ2 = 31.23, P < 0.05) and their nutritional status (χ2 = 22.60, P < 0.05). The reaction was not significantly associated with the social class of the infants' parents. Conclusion: The study demonstrated high prevalence of BCG scar and high Tuberculin skin test reaction. Regular evaluation of BCG vaccination is recommended using TST and scar observation as adjuncts to strengthen BCG vaccination processes for effective tuberculosis prevention.

Factores asociados a la adherencia en el tratamiento de la infección tuberculosa

ObjectiveTo analyze adherence to treatment of tuberculosis infection and to identify risk factors for its compliance. DesignAn observational historical cohort study. SettingHospital Universitari Sant Joan d’Alacant (Alicante). ParticipantsAll patients with a tuberculin skin test (TST) done during tuberculosis contact tracing during 6 years. ResultsWe included 764 tuberculosis contacts in the analysis. 59.7% of the 566 patients who completed the contact tracing, had tuberculosis infection (TI). Of the patients with TI, 45.6% had not started treatment for tuberculosis infection (TTBI). Factors associated with not starting TTBI were: age (36-65 years, RR: 5.8; 95% CI: 1.2-27.5, and > 65 years, RR: 11.3; 95% CI: 2.0-64.0), the social relationship with TB case (RR: 2.2; 95% CI 1.2-3.8), and the TST reaction (≥ 15mm; RR: 0.5; 95% CI: 0.3-0.9). The completion rate for TTBI was 80.4% among people who started therapy. The treatment regimen was associated with greater compliance to TTBT (7-9H, RR: 12.7; 95% CI: 1.5-107.3). ConclusionsThe treatment compliance rate of Tuberculosis infection was high among people who started therapy. Almost a half of the contacts with TI did not start treatment, and associated factors were: age, social relationship, and the TST reaction. The treatment regimen was associated with greater compliance. It is important to know the factors associated with adherence to treatment of TI in each health area, and focus efforts on risk groups; thereby approaching the global control of tuberculosis.

Prevalence of tuberculosis symptoms and latent tuberculous infection among prisoners in northeastern Malaysia

There are currently no routine screening procedures for active tuberculosis (TB) or latent tuberculous infection (LTBI) in Malaysian prisons. To determine the prevalence and correlates of LTBI and active TB symptoms among Malaysian prisoners with and without human immunodeficiency virus (HIV) infection using the tuberculin skin test (TST) and the World Health Organization TB symptom-based screening instrument. A cross-sectional survey of 266 prisoners was performed in Kelantan, Malaysia. Consenting participants underwent two-step TST and were screened for active TB symptoms. Standardized cut-offs of respectively ≥5 and ≥10 mm were used to define reactive TST among prisoners with and without HIV. Clinical and behavioral data were assessed and HIV-infected prisoners were stratified by CD4 status. Overall LTBI prevalence was 87.6%, with significantly lower TST reactivity among HIV-infected than non-HIV-infected prisoners (83.6% vs. 91.5%, P < 0.05); however, TB symptoms were similar (16.9% vs. 10.1%, P = 0.105). On multivariate analysis, previous incarceration (aOR 4.61, 95%CI 1.76-12.1) was the only significant correlate of LTBI. Increasing age (aOR 1.07, 95%CI 1.01-1.13), lower body mass index (aOR 0.82, 95%CI 0.70-0.96) and TST-reactive status (aOR 3.46, 95%CI 1.20-9.97) were correlated with TB symptoms. LTBI is highly prevalent, associated with previous incarceration, and suggests the need for routine TB screening on entry to Malaysian prisons.

Cellular immune response of Curraleiro Pé-duro and Nellore calves following Mycobacterium bovis-BCG vaccination

The present study aimed to assess the CD4, CD8 and γδ blood levels for Curraleiro Pé-duro, as well as the specific IFN-γ response after BCG vaccination using flow cytometry. The specific immune response against BCG was also evaluated by tuberculin skin test, performed before and 45 days after the vaccination. For comparison purposes, the same parameters were investigated on Nellore calves, an exotic bovine with resistance previously demonstrated. Naturally, Curraleiro Pé-duro animals had greater levels of CD4, CD8 and γδ lymphocytes (p&lt;0.05). In response to vaccine, Curraleiro Pé-duro showed greater ability to respond specifically to BCG, generating resistance profile (Th1), evidenced by greater number of antigen specific CD4+ cells producing IFN-γ (p&lt;0.05) and also higher tuberculin skin test reaction (p&lt;0.05). Additionally, vaccinated Curraleiro Pé-duro calves had higher CD4 cells numbers than both Nellore control (p&lt;0.05) and vaccinated groups (p&lt;0.05). Curraleiro Pé-duro calves' higher basal lymphocytes blood level and stronger response in both IFN-γ and tuberculin skin test parameters probably play a positive role on protection/resistance to Mycobacterium bovis.

Subcutaneous emphysema as the first relevant clinical sign of complicated tubercular lymph node disease in a child

BackgroundChildren make up a significant proportion of the global tuberculosis (TB) caseload, and experience considerable TB-related morbidity and mortality. Unfortunately, it is not easy to diagnose TB in the first years of life because of the diversity of its clinical presentation and the non-specific nature of most of its symptoms.Case presentationA 26-month-old male child was admitted to hospital because of the sudden onset of rapidly increasing swelling of the neck, face and upper trunk a few hours before. Upon admission, his temperature was 36.5°C, pulse rate 120/min, respiratory rate 36/min, and O2 saturation 97% in air. Palpation revealed subcutaneous emphysema (SE) over the swollen skin areas, and an examination of the respiratory system revealed crepitations in the left part of the chest without any significant suggestion of mediastinal shift. Chest radiography showed enlargement of the left lung hilum with pneumomediastinum and diffuse SE. Bronchoscopy was carried out because of the suspicion that the SE may have been due to the inhalation of a peanut. This excluded the presence of a foreign body but showed that the left main bronchus was partially obstructed with caseous material and showed significant signs of granulomatous inflammation on the wall. Contrast-enhanced computed tomography of the lungs confirmed the SE and pneumomediastinum, and revealed bilateral hilum lymph node disease with infiltration of the adjacent anatomical structure and a considerable breach in the left primary bronchus wall conditioning the passage of air in the mediastinum and subcutaneous tissue. As a tuberculin skin test and polymerase chain reaction for Mycobacterium tuberculosis on bronchial material and gastric aspirate were positive, a diagnosis of TB was made and oral anti-TB therapy was started, which led to the elimination of M. tuberculosis and a positive clinical outcome.ConclusionsThis is the first case in which SE was the first relevant clinical manifestation of TB and arose from infiltration of the bronchial wall secondary to caseous necrosis of the hilum lymph nodes. Physicians should be aware of the fact that SE is one of the possible initial signs and symptoms of early TB infection, and act accordingly.

Strategy to Better Select HIV-Infected Individuals for Latent TB Treatment in BCG-Vaccinated Population

ObjectiveTo evaluate the T-SPOT.TB interferon-γ releasing assay and the tuberculin skin test (TST), for the diagnosis of latent tuberculosis infection(LTBI) and the development of subsequent active tuberculosis, in BCG-vaccinated HIV-infected individuals.MethodsHIV-infected individuals without clinical suspicion of active TB or a past history of TB were enrolled from 1 January 2008 to 30 November 2010. Both T-SPOT.TB test and TST were offered to the participants whom were followed up prospectively until April 30, 2012 for development of TB.ResultsAmong the 909 participants, 25% had positive TST reactions with cut-off point of 5 mm and 15% had positive T-SPOT.TB results. After a median follow-up of 2.97 years, there were 5 cases developed culture-confirmed active TB (all had dual positive TST and T-SPOT.TB results), and the incidence was 0.17 per 100 person-years. The relative risks (RRs) for subsequent active TB in HIV-infected individuals with positive TST results, positive T-SPOT.TB results and dual positive results compared with the risk for individuals with negative results were 40.6 (95% CI 2.1–767.9), 73.9 (95% CI 3.9–1397.7) and 226.5 (95% CI 12.0–4284), respectively. The number needed to treat to prevent one subsequent TB case among patients with a positive TST, a positive T-SPOT.TB and dual positive results was 35, 22 and 8 respectively.ConclusionsAdopting positive results of the TST and T-SPOT.TB to screen LTBI among BCG-vaccinated HIV-infected individuals might be feasible. Number needed to treat for isoniazid preventive therapy could be reduced significantly by using dual positive strategy.

AB0518 High percentage of dermoconversion in patients with rheumatoid arthritis under biological therapy

BackgroundMexico is a high burden tuberculosis (Tb) country. Inflammatory rheumatic diseases such as rheumatoid arthritis have an increased risk of Tb associated with both RA activity itself and treatment requirement,...