Positive Tuberculin Reaction Research Articles

Lichen scrofulosorum- A rare case report

Lichen scrofulosorum, other name “tuberculosis cutis lichenoides” which is present as lichenoid eruption of minute papules, a rare tuberculid commonly seen in children and adolescents with tuberculosis. Mostly positive tuberculin reaction strongly associated with eruption. Diagnosis can be difficult in this type of lesion which is closely resemble to other type of dermatological conditions that are often primarily considered. Here we report a case of lichen scrofulosorum in a twenty year- old female having typical grouped lichenoid papules on the neck, hand and leg associated with itching.

Non-tuberculosis Mycobacteria (NTM) and the issue of false-reactors in tuberculination of cattle, an iranian observation

The genus Mycobacterium comprises a broad spectrum of obligate microorganisms most notably the M. tuberculosis complex bacteria; potentially-pathogenic or opportunistic species gathered under the common name of M. avium-intracellulare complex, and finally saprophytic mycobacteria. In cattle farming, Mycobacterium bovis (M. bovis) is considered as the principle cause for bovine tuberculosis (bTB). Nevertheless, non-tuberculosis mycobacteria (NTM) are potential pathogens that are increasingly reported to interfere with contemporary intradermal tuberculin tests in veterinary medicine. Therefore, these neglected mycobacteria are capable to make hurdles for bTB diagnosis. In the Iranian environment, the extent and importance of this phenomenon in regard with the public health and economical aspects is just underestimated. This work was therefore intended to isolate and characterize the mycobacterial organisms potentially involved in causing positive reactions in tuberculination of Iranian cattle. Abattoir meat inspection and laboratory microbiological investigation of slaughtered heifers from a 2,000-head Simental cattle farm with 10% of the herd positive tuberculin reactors, failed to provide any evidence of M. bovis infection. No mycobacteria was detected in bacterial culture of specimens from feedstuff, water or even the visiting feral rodents of the farm. When the farm workers were included in assessments, 22 individuals were found tuberculin-positive with 5 of them also smear-positive in their sputa assessment. Molecular identification of the five isolates from workers through sequencing of the 16SrRNA proved their identity as Mycobacterium thermoresistibile (Mth). Removing of the carrier workers from the farm vicinity, successfully ended the issue of the constantly-positive tuberculin test in the herd with no return of the problem until now. We are convinced further investigations are essential in search for interference extent and importance of NTM species in cattle tuberculination scheme in Iran.

Potential efficiency of conventional and advanced approaches used to detect Mycobacterium bovis in cattle

The present study was aimed to assess the prevalence and efficiency of techniques for the diagnosis of bovine tuberculosis (bTB) including enzyme-linked immunosorbent assay (ELISA), Gamma interferon assay (IFN-γ) and polymerase chain reaction (PCR) in comparison to skin tuberculin test and culture technique. A total of 2600 cross-breed dairy cattle in Menoufia and Daqahlia governorates were tested by the single intradermal tuberculin test where the disease prevalence was 1.8%. Serum and whole blood samples were collected from positive tuberculin reactors for ELISA and IFN-γ assay, respectively. After slaughtering of positive tuberculin reactors, the post-mortem examination was carried out and tissue samples were collected for the bacteriological examination and PCR. The percentage of visible lesions of tuberculin reactors was 78.7%, while non-visible lesions were 21.27%. Culture technique revealed that the percentage of bTB was 63.8%. The ELISA and IFN-γ assay using short-term culture filtrate (ST-CF) prepared antigen revealed higher sensitivity (72.3% and 82.9%) than the bovine purified protein derivative (PPD-B) antigen. Although prepared ST-CF antigen has great efficiency and eligibility for the diagnosis of bTB, PCR appeared to have a higher sensitivity (85.1%) than other diagnostic methods when dealing with post-mortem samples. Gamma interferon assay using ST-CF antigen is recommended for antemortem diagnosis of bTB in cattle.

Levamisole as an Adjuvant to Short-Course Therapy in Newly Diagnosed Pulmonary Tuberculosis Patients.

Background:The estimated incidence and prevalence of tuberculosis in India are 2.1 and 2.6 million cases respectively. Immunotherapy may shorten tuberculosis treatments and improve the immunity of individuals as well. Hence we study the efficacy of levamisole (LVM) (immunomodulator) as an adjuvant to chemotherapy of pulmonary tuberculosis patients.Materials and Methods:A randomized, double-blind, placebo-controlled clinical trial was conducted for 21 months in newly diagnosed sputum positive pulmonary tuberculosis patients. Patients were subjected initially to clinical examination, sputum acid-fast bacilli smear and culture, tuberculin skin test and weight record. During follow-up, above investigations were repeated. Sixty-five patients were randomly assigned into two groups to receive either tab LVM 100 mg once in a day or matching placebo, orally as a single dose, thrice a week, for 2 months with short-course antituberculosis chemotherapy.Results:Sputum negativity at 1 week was observed in 11 (44%) patients in LVM group whereas only 3 (12%) in placebo group. All the patients 25 (100%) in LVM group were sputum negative compared to 14 (56%) in placebo group by the end of 3 weeks. In LVM group, 24 (96%) and 11 (44%) patients in placebo group show radiological improvement at 2 months. A direct correlation existed between quantum of immune response and weight gain with LVM. LVM rendered all anergic patients to positive tuberculin reactors. In LVM group, patients with initial Mantoux ≥20 mm and advanced cavitary disease, there was decrease in tuberculin reaction size.Conclusion:Adjuvant immunomodulation with levamisole has the potential of shortening the total duration of antitubercular therapy.

English

Lichen scrofulosorum, also known as cutis lichenoides, is a rare tuberculid that presents as a lichenoid eruption of minute papules in children and adolescents with tuberculosis. The lesions are usually asymptomatic, closely grouped, skin-colored to reddish-brown papules, often perifollicular, and are mainly found on the abdomen, chest, back, and proximal parts of the limbs. The eruption is usually associated with a strongly positive tuberculin reaction. We report a case of lichen scrofulosorum in an adult male following Mantoux tuberculin skin test. A 33 year old male patient came with the complaints of small raised skin-colored lesions over the left forearm and back for the past one week. No history of itching associated with it. There was no history of fever, cough, anorexia, weight loss or any other systemic symptoms. No history of exposure to the risk of acquiring Sexually Transmitted Infections. He also gave history of a strong positive reaction of Mantoux test which he underwent one month back as advised by a chest physician. The raised skin-colored lesions initially started in the left forearm at the site of Mantoux test and he developed similar lesions over the back and the right forearm in the next few days. History of BCG Vaccination was present. Family history of tuberculosis is present. His father is a known case of pulmonary tuberculosis that has completed the treatment. Earlier he had gone to the chest physician for the fear of contacting Tuberculosis from his father. Chest Physician had advised Chest skiagram, Sputum for AFB, ESR and Mantoux Investigations. His Chest Skiagram was within Normal Limits and Sputum was negative for AFB. His ESR was 42mm after one hour and Mantoux Intradermal test was strongly positive (25 mm). On Dermatological examination, multiple perifollicular, skin coloured to hypo pigmented smooth scaly papules seen in groups over the left and over the back. Multiple skin coloured to hypo pigmented similar papules are seen in an annular fashion along the periphery of the Mantoux tuberculin test site. No excoriations seen. No koebnerisation seen. General Examination including lymph nodes were normal. Cardiovascular, Respiratory and Central Nervous System Examination were normal. Examination of scalp, oral cavity, genitalia, palms, soles and nails were normal. Based on the history and the classical clinical features, a diagnosis of Lichen scrofulosorum was made. Other differential diagnosis that was considered is lichen nitidus, secondary syphilis and lichenoid sarcoid. He was explained about the condition and advised skin biopsy and VDRL.

The challenge of diagnosing tuberculosis in children.

While we have made some progress towards the Millennium Development Goals( 1 ), which were agreed in 2010 by the World Health Organization - reduce by half the incidence and mortality of Tuberculosis by 2015, compared to values of 1990 -, Brazil still ranks 17th among countries with the highest TB burden in the world( 2 ). The early and effective treatment of all cases of tuberculosis is the primary measure to save around 1.5 million lives each year( 2 ). However, often, when diagnosis and treatment are being performed, many people (contacts) have already been infected, most of them children who, besides controlling less effectively the replication of the M. tuberculosis, progress more rapidly and frequently to pulmonary and extrapulmonary forms of the disease( 3 - 5 ). The identification and treatment of latent tuberculosis infection reduce the risk of progression to the active disease, particularly in high-risk groups, such as children under 5 years old, infected with HIV and on immunosuppressive therapy( 6 , 7 ). However, an early and accurate diagnosis of TB infection in children is still a great challenge. In addition to the tuberculin skin test - TST (used for over 100 years), in the last decade researchers have developed tests using peripheral blood samples that measure the release of interferon-gamma (IFN-γ) from T host cells infected by M. tuberculosis( 8 ). These tests, called Interferon-Gamma Release Assays (IGRAs), present advantages in relation to the tuberculin test: the results may be obtained in one or two days, do not require return visits for reading the skin reaction and, if repeated, do not present a booster effect. The three antigens used for the IGRA tests (ESAT-6, CFP-10, and TB7.7) are not contained in BCG vaccine and in most other mycobacteria, while tuberculin (PPD) contains more than 200 antigens, which reduces its specificity. Two commercial kits are available: QuantiFERON-TB Gold in Tube, which assesses the levels of IFN-γ produced after antigen stimulation, and the T-Spot.TB test, which quantifies the mononuclear cells producing IFN-γ after in vitro stimulation. Over the past 3 years, three systematic reviews and meta-analyzes have been published( 9 - 11 ), concerning the IGRA tests in the pediatric population, revealing a very high specificity (95-100%) - exceeding that of the Tuberculin Test (TST) -, and a lower sensitivity (80-90%), depending on the age of the subjects and their condition of imunocompetence (8-11). This suggests that the TST and the IGRAs have similar accuracy in detecting infection or disease in children, but the interpretation of results is difficult due to the absence of a definitive marker of these conditions in children. The study by Vallada et al( 12 ), published in this issue of the journal, assessed the accuracy of one Igra tests (QuantiFERON-TB Gold in Tube) in the diagnosis of tuberculosis in children and showed a positive predictive value of 81.8% (95%CI 46.3-97.4), sensitivity of 81.8% (95%CI 48.2-97.2), and specificity of 98.8% (95%CI 96-99.8). However, the small sample of children assessed with tuberculosis (latent or active disease) diminishes the power of the study in its definitive findings. A strong point of the research, however, is the low age of participants (seven of the 11 children were younger than 5 years and five presented a positive test). Only two children defined by the study criteria as infected presented a negative QuantiFERON-TB Gold in Tube test, both with active disease and under 3 years of age. Even considering that the 11 children have received BCG at birth, the test presented a good relationship with the TST, which was ≥10mm in the nine children who performed it. Important implications of the study are: the good relationship with the tuberculin skin test, even in young children, and the fact that, despite its high negative predictive value, a negative test cannot rule out the diagnosis of tuberculosis (infection or disease) in children. If we seek greater specificity in children who received the BCG vaccine, the IGRA tests are better than the TST, but if we want greater sensitivity, both tests can be performed. In immunocompromised children, including those affected with HIV, the combination of both tests should be preferred. The Interferon-Gamma Release Assays have not been validated as a routine diagnostic procedure for tuberculosis in Brazil. The possibility of excluding tuberculosis infection in children vaccinated with BCG, and the positive tuberculin reactions make the IGRAs important instruments to diagnose tuberculosis infection in our country. However, although more specific than the TST, these tests are not capable to differentiate latent tuberculosis infection from tuberculosis disease, which still requires clinical and radiological criteria for its definition.

Tuberculin Test can be Read after 24 hours in Adolescent Children

To assess readability of 24-h tuberculin response in adolescent school children. Prospective observational study in school. 601 healthy adolescent children. Tuberculin (1TU PPD RT23 Tween80) was administered and indurations at 24 and 72 h were compared. Tuberculin reaction at 24 h. One hundred twelve children (18.6%) had a positive tuberculin reaction. Prevalence of tuberculin positivity was least (14.2%) in the 10-year age-group and maximum in the 13-year age-group (21.2%). When individual values of tuberculin reaction at 24 and 72 h were compared, a significant difference was noted irrespective of the tuberculin status (t = 8.46, p = 0.001). However, when tuberculin reaction was considered as positive or negative, this difference was not significant (t = 1.89, p > 0.05). Tuberculin status in adolescents can be read as positive or negative at 24 h, irrespective of their bacillus Calmette-Guérin scar status.

Miliaire tuberculeuse aiguë du pharynx ou maladie d’Isambert : à propos d’un cas

Pharynx tuberculosis consists in a set of active lesions in granulomatous-type mucosa, resulting from Mycobacterium tuberculosis infection. In an endemic context, this diagnosis should be raised in cases of head and neck disease. A recent observation of a case of acute miliary tuberculosis gave us the opportunity to conduct a literature review of this disorder. This 9-year-old girl presented with dysphagia associated with pharyngeal discomfort, snoring, and hoarseness lasting for 8 months. This pharyngeal syndrome occurred in the context of an impaired general condition. Clinical examination found a diffuse mucosal granulation aspect in the oropharynx. The workup showed an inflammatory syndrome with a strong positive intradermal tuberculin reaction. The biopsy found an aspect of giant cell granuloma with caseous necrosis. The course was favorable on antituberculous chemotherapy. Tuberculosis is a chronic bacterial infection caused by a bacterium belonging to the M.tuberculosis complex. Pharyngeal tuberculosis remains a rare disease, but several epidemiological parameters show an upsurge of this disease, prompting us to report this observation.

Lichen scrofulosorum: A diagnosis overlooked

Lichen scrofulosorum, also known as “tuberculosis cutis lichenoides,” is a rare tuberculid that presents as a lichenoid eruption of minute papules in children and adolescents with tuberculosis. The lesions are usually asymptomatic, closely grouped, skin-colored to reddish-brown papules, often perifollicular, and are mainly found on the abdomen, chest, back, and proximal parts of the limbs. The eruption is usually associated with a strongly positive tuberculin reaction. Diagnosis of these lesions can be difficult, as they resemble many other dermatological conditions that are often primarily considered. We report a case of lichen scrofulosorum in an adult male without any focus of tuberculosis. He responded promptly to antitubercular therapy with complete clearance of lesions in one month.

The frequency profile of tuberculin skin testing among employees of a hospital

The frequency profile of tuberculin skin testing among employees of a hospital was studied. In the analysis, tuberculin skin testing was defined as "negative" if skin rash is measured < or = 9 mm, and as "positive" if skin rash is measured > or = 10 mm, and as "strongly positive" if skin rash is measured > or = 10 mm, with induration, and double skin rash or bulla. Boosting was defined as initial skin rash was measured < or = 9 mm, with second skin rash measured > or = 10 mm and at least 6 mm increase of rash than the initial one. 544 employees were tested initially, and 81 were retested. Initial tuberculin positivity was associated with older age (p < 0.001); but boosting was not associated with age and occupation. Comparing pharmacists with other groups, the adjusted odds ratio of an initial strongly positive tuberculin reaction as significantly higher, namely 2.8 (95% confidence interval 1.2-6.7), but that of a booster reaction was 4.8 (0.7-32.1) which was insignificant.

New recommendations and perspectives for the control of tuberculosis

This report summarises the ATC/CDC recommendations on the diagnosis and treatment of latent tuberculosis infection. Based on the sensitivity and specificity of the tuberculin skin test and the prevalence of TB in different groups, 3 cut-off levels have been proposed for defining a positive tuberculin reaction: > or =5 mm, >/=10 mm and > or =15 mm of induration. Treatment can be carried out mainly with Isoniazid, but there are alternatives such as Rifampin plus Pyrazinamide in the following cases: when Isoniazid-resistant M. tuberculosis appears and when the treatment is to be shortened; Rifampin alone for persons who cannot tolerate Pyrazinamide. Rifabutin can be substituted for Rifampin in HIV+ patients taking some protease inhibitors and non-nucleoside reverse transcriptase inhibitors. In persons who have been infected with multidrug resistant strains, Ethambutol and Pyrazinamide or Pyrazinamide and a fluoroquinolone can be prescribed. On the other hand, for a general prophylaxis BCG vaccination is not usually recommended due to its variable effectiveness, except in children and health care workers exposed continually to an untreated patient or to one with multidrug resistant M. tuberculosis strains. In order to achieve a new vaccine, a programme is currently being developed in the European Union called "The cluster for Tuberculosis vaccine development", which involves four main projects: optimisation and preclinical evaluation of TB vaccines, development of new live attenuated vaccines, non-protein antigens for TB vaccine and identification of mechanisms and indicators of protective immunity.

Association of Sweet’s syndrome and acute sarcoidosis: report of a case and review of the literature

Sweet's syndrome (acute febrile neutrophilic dermatosis, SS) may be considered a reactional dermatosis with numerous associated diseases. We describe a rare association between SS and acute sarcoidosis in a 55-year-old woman. The atypical feature of positive tuberculin reaction is discussed. In this association, diagnosis may be challenging with coexistent skin lesions of both diseases. Acute sarcoidosis should be considered when SS is accompanied with mediastinal lymphadenopathy, uveitis or erythema nodosum. Deep-seated nodular lesions in the context of SS are not always 'deep' SS lesions.

Smoking and tuberculosis among silicotic patients

The aim of the present study was to investigate the relationship between smoking and tuberculosis (TB) among high-risk silicotic patients in Hong Kong. A cohort of 435 silicotic patients tuberculin tested from 1995-2002 was prospectively followed-up until the end of 2005. Baseline characteristics were analysed with respect to positive tuberculin reaction (> or =10 mm) at baseline and subsequent development of TB. Smoking, alcohol use and body mass index were independent predictors of positive tuberculin reaction at baseline in multiple logistic regression analysis. Total cigarette pack-yrs did not demonstrate any significant effect. The annual incidences of TB were 1,841, 2,294 and 4,181 per 100,000 for never-, ex- and current smokers, respectively. On Cox proportional hazard analysis, current smokers have a significantly higher risk of TB than other silicotic patients (adjusted hazard ratio (95% confidence interval (CI)): 1.96 (1.14-3.35)) after controlling for age, alcohol use, tuberculin status, treatment for latent TB infection and other relevant background/disease factors. A significant dose-response relationship was also observed with the daily number of cigarettes currently smoked. Smoking cessation may reduce 32.4% (95% CI: 6.5-54.0) of the risk. Smoking increases the risk of both tuberculosis infection and subsequent development of the disease among silicotic patients.

Bacillus Calmette-Guérin vaccination and infant mortality

When the bacillus Calmette-Guérin (BCG) vaccine was introduced in the 1920s, it was suggested that BCG occasionally had nonspecific beneficial effects on mortality beyond the specific protection against tuberculosis. Considering that BCG has since then become the most used vaccine in the world, surprisingly few studies have been undertaken into the effect of BCG on general mortality and morbidity. Recent studies suggest that BCG has beneficial nontargeted effects on general infant morbidity and mortality in low-income countries, often with the most pronounced effect among girls. These observational findings are supported by early trials in which children were randomized or alternated to BCG vaccination. Furthermore, a BCG scar and a positive tuberculin reaction are related to better survival among BCG-vaccinated children in low-income countries, especially for girls. The findings are not explained by frailty bias, in other words, that healthy children are more likely to receive BCG vaccination. A nonspecific, gender-differential effect of BCG on general infant mortality may have large implications for tuberculosis vaccine research and routine vaccination policy.

Superficial thrombophlebitic tuberculide

Tuberculides are the result of immunologic reactions to hematogenously spread antigenic components of Mycobacterium tuberculosis. There are three recognized tuberculides--papulonecrotic tuberculide, erythema induratum of Bazin, and lichen scrofulosorum. In 1997, in Japan, Hara and coworkers reported five patients with what they called "nodular granulomatous phlebitis," which they proposed was a fourth type of tuberculide. We describe a patient who presented with features identical to those reported by Hara et al. in order to draw attention to the previous report and to support the concept of a fourth tuberculide which clinically resembles superficial thrombophlebitis. A black South African man presented with cord-like thickening of superficial veins on the antero-medial aspects of the lower legs. Nodular swellings were palpable along the course of these veins. There was no evidence of tuberculosis elsewhere in the body, but the patient had a strongly positive tuberculin reaction. Skin biopsies were performed for histologic examination, culture, and polymerase chain reaction (PCR). Histologic examination showed a granulomatous infiltrate localized to the veins in the subcutaneous fat. Stains for acid-fast bacilli and culture were negative, but PCR was positive for M. tuberculosis DNA. The lesions responded promptly to antituberculous therapy. Our patient showed features identical to those of cases described by Hara and coworkers and assigned as a fourth type of tuberculide. As the lesions clinically resemble superficial thrombophlebitis, we propose the term "superficial thrombophlebitic tuberculide" rather than "nodular granulomatous phlebitis."

Impact of Circulating TGF-β and IL-10 on T Cell Cytokines in Patients with Asthma and Tuberculosis

Regulatory T cells, which stimulate or inhibit the effector functions of distinct T cell subsets, are critical in the control of the immune response. We investigated the effect of TGF-β and IL-10 on T cell subsets according to the Th1/Th2 immune status. Sixty-two patients with asthma and 38 patients with pulmonary tuberculosis were included. Allergy skin tests, tuberculin tests, and chest radiography were performed. The levels of circulating IL-4, IFN-γ, TGF-β1, and IL-10 were measured using ELISA. The level of TGF-β1 was higher in patients with asthma than in those with tuberculosis, but the IL-10 levels were the same between the asthma and tuberculosis groups. Atopy was unrelated to the tuberculin response. The IFN-γ level was correlated with the IL-10 level, and the level of IL-4 was unrelated to the IL-10 or TGF-β1 level. The level of IL-10 was higher in the negative tuberculin reactors than in the positive tuberculin reactors among patients with asthma, and TGF-β1 was higher in the positive tuberculin reactors than in the negative tuberculin reactors among patients with tuberculosis. These results demonstrate that the regulatory effects of circulating TGF-β and IL-10 on T cell cytokines may be different between Th2-type asthma and Th1 tuberculosis.

Lichen scrofulosorum: current status

Lichen scrofulosorum (LS) and papulonecrotic tuberculids are unique reaction patterns – tuberculids – of the skin caused by hematogenous dissemination of the mycobacterium in those individuals possessing a high/moderately high immunity. Consequently, the bacilli are speedily destroyed in the skin, and are hard to demonstrate by smear. Accordingly, the presence of a perceptible active or concealed, systemic and/or cutaneous focus of tuberculosis is the vital prerequisite for a tuberculid. More often than not a strongly positive tuberculin reaction is indicative of tuberculids. Its histogenesis is enigmatic. However, type IV hypersensitivity reaction incited by chronic tuberculous focus may be plausible. 1,2

Comparison of ultrasound with plain radiography and CT for the detection of mediastinal lymphadenopathy in children with tuberculosis

Lymphadenopathy, with or without parenchymal abnormality, is the radiological hallmark of primary tuberculosis (TB) in children. However, lymph node enlargement may pass undetected on plain chest radiographs. Ultrasonography provides complementary information to that obtained by radiographs. To assess the clinical value of US for the detection of mediastinal lymphadenopathy in children with a positive intradermal tuberculin test. Thirty-two children with a mean age of 6 years and a positive Mantoux test underwent chest radiography (frontal and lateral) and US (suprasternal and left parasternal access routes). Chest CT was performed at the discretion of the attending physician in six cases. Eleven children had clinical symptoms and 90% a recent contact with a person with active TB. In 90.5% of children with chest radiographic images compatible with TB, coincident findings in the mediastinal US study were found. By comparison, 66.7% of those with normal chest radiography had evidence of mediastinal lymphadenopathy on the US scan. In all cases but one, US and CT findings agreed. Mediastinal US is useful for the detection of enlarged lymph nodes in children with a positive tuberculin reaction and normal chest radiography.

IL-13 over-expression in skin is not confined to IgE-mediated skin inflammation.

IL-13 is produced by T cells and, like IL-4, it can induce the production of IgE and IgG4. In order to investigate if IL-13 is a specific marker for atopic dermatitis (AD), IL-13 gene expression was analysed in chronic lichenified lesions and non-lesional skin of patients with AD, in involved and non-involved skin of patients with psoriasis, in positive tuberculin reactions in non-atopics, and in the skin of healthy control subjects. Patients with AD (n = 9) showed sensitization to common air-borne allergens (positive Phadiatop) and had total serum IgE values in the range from 10 to 4800 kU/l (median 170 kU/l). Competitive reverse transcription-polymerase chain reaction (RT-PCR) was used to assess IL-13 gene expression in skin biopsy specimens. IL-13 gene expression was markedly higher in chronic lichenified lesions of patients with AD (P < 0.01), and in the positive tuberculin reactions (P < 0.01; n = 12) than in skin from healthy control subjects (n = 10). However, there was no significant difference in IL-13 gene expression in the skin of patients with psoriasis (n = 10) and that of healthy control subjects. The dermal cell infiltrates were larger and the relative amount of CD3+ and CD4+ cells in these infiltrates was higher in the skin of subjects with a positive tuberculin reaction than in lichenified AD skin. However, these differences were not reflected in differences in IL-13 gene expression. Different triggers of IL-13 gene expression may influence the diverse patterns of inflammation seen in different inflammatory skin disorders.

BCG scar and positive tuberculin reaction associated with reduced child mortality in West Africa: A non-specific beneficial effect of BCG?

Previous studies have suggested that the bacille Calmette–Guérin (BCG) vaccine may have a non-specific beneficial effect on childhood survival in areas with high mortality. We examined whether BCG-vaccinated children with a BCG scar or a positive tuberculin reaction had better survival than children without such reactions. As part of an ongoing two-dose measles vaccine trial for which children were recruited at 6 months of age, we examined 1813 children for BCG scar at 6 months of age and 813 BCG-vaccinated children were skin-tested for delayed hypersensitivity to tuberculin, tetanus and diphtheria. We found that BCG-vaccinated children with a BCG scar had significantly lower mortality compared with BCG scar-negative children, the mortality ratio in the first 12 months of follow-up being 0.41 (0.25–0.67). BCG-vaccinated children with a positive tuberculin test had a mortality ratio of 0.45 (0.24–0.85) compared with tuberculin negative children. These results were unchanged by control for potential confounders or using different cut-off points for a tuberculin-positive response. Exclusion of dead children who had HIV antibodies did not modify the estimate (mortality rate (MR)=0.46 (0.23–0.94)). After censoring for tuberculosis (TB) exposure at home, the mortality ratios for having a scar and being tuberculin-positive were 0.46 (0.27–0.79) or 0.42 (0.21–0.84), respectively. Children positive to tetanus or diphtheria in the skin test had the same mortality as children not responding to these vaccine-related antigens. Thus, BCG scar and a positive tuberculin reaction were associated with better survival in early childhood in an area with high mortality. Since nothing similar was found for responders to diphtheria–tetanus–pertussis (DTP) vaccine, and the effect could not be explained by protection against tuberculosis, the effect of BCG vaccination could be due to non-specific immune-stimulation protecting against other infections.