Tuberculin skin testing: determinants and reaction

Effect of nutritional status on Tuberculin skin testing

OBJECTIVES

To evaluate Tuberculin skin test (TST) results in a population of immigrants and internationally adopted children from several geographical areas; to analyze whether nutritional status can modify TST results.

METHODS

This cross-sectional observational study included adopted children and immigrants evaluated in the authors' unit between January 2003 and December 2008. Children diagnosed with tuberculosis, or vaccinated with live attenuated virus 2 mo earlier, HIV-infected, chronically ill or under treatment with immunosuppressive agents were excluded. TST was considered as dependent variable. Independent variables were gender, age, geographical origin, BCG scar, nutritional status, immune status and intestinal parasitism.

RESULTS

One thousand seventy four children were included; 69.6 % were girls. There was a BCG scar in 79 % of children. Mantoux = 0 mm was found in 84.4 %, <10 mm in 4.1 %, and ≥10 mm in 11.4 % of children. Nutrition (McLaren's classification) was normal (≥90 %) in 26.7 % of the subjects, with mild malnutrition (80-89 %) in 36 %, moderate (70-79 %) in 23.2 % and severe (≤69 %) in 14.1 %. There was no difference in TST results among different nutritional status children.

CONCLUSIONS

The nutritional status, measured by McLaren's classification, does not changes the results of TST. McLaren's classification only grades protein-caloric malnutrition, so in authors' experience this type of malnutrition does not interfere with TST results. Implementing other nutritional parameters could help to determine whether nutritional status should be taken into account when interpreting TST results.

Six Mantoux tuberculin skin tests with 1, 2, 5, 10, 20, and 50 units in a healthy male without side-effects - is skin reaction a linear function of tuberculin dose?

BACKGROUND

Tuberculosis remains a serious disease worldwide. Anti-tuberculosis campaigners many times face negative tuberculin skin tests after Bacille Calmette Guérin vaccination. Increasing tuberculin units might be a solution. However, is skin reaction a linear function of tuberculin dose? Are there any side-effects when higher tuberculin doses are administered?

CASE PRESENTATION

Six simultaneous Mantoux tuberculin skin tests, using 1, 2, 5, 10, 20, and 50 tuberculin units (88 altogether) of purified protein derivative RT23 per 0.1 mL were applied in a healthy male Greek 35-years-old, with known natural Mycobacterium tuberculosis primary infection since five years. Skin indurations 72 hours later were 15, 22, 23, 19, 23, and 27 mm respectively.

CONCLUSION

No linear relation between tuberculin dose and skin reaction observed; skin reaction increased as tuberculin dose increased but with a decreasing rate, especially after 2 TUs, which seem correctly defined for detection of natural infection. No side-effects occurred.

Tuberculin survey among school-aged children in Ahvaz, Iran, 2006

BACKGROUND AND OBJECTIVE

The tuberculin test is widely used for the diagnosis of tuberculosis (TB) in children, as it is the only one to provide evidence of infection with Mycobacterium tuberculosis. Our objective was to estimate the prevalence of TB infection, the annual risk of infection (ARI), and the incidence of active TB in school children.

METHODS

A cross-sectional study was carried out in Ahvaz, a city of southern Iran, in 2006. A questionnaire was used to collect information, including demographic characteristics, bacillus Calmette-Guérin (BCG) vaccination history, and household contact with active TB. Tuberculin testing was performed. Reactivity that measured < 5 mm was considered negative, between 5 and 9 mm was considered doubtful, and > or = 10mm was considered positive. Chest radiographs were obtained as part of the evaluation for children with a positive result.

RESULTS

A total of 3906 children with a mean+/-standard deviation (SD) age of 10.59+/-2.63 years (51% female, 49% male) were entered into our study. Of these, 3338 children (85.5%) did not develop a reaction (0mm), 243 (6.2%) had reactivity of 1-4mm, 238 (6.1%) had reactivity of 5-9 mm, and 87 (2.2%) had reactivity of > or = 10 mm. More than 90% of the children had received the BCG vaccine in the first week of life. The ARI rate was 0.5% and the estimated case of smear-positive TB was approximately 25 per 100000 population. Only three children were diagnosed with active TB, a prevalence of 75 per 100000 population.

CONCLUSIONS

Tuberculin testing using 5TU-PPD (5 tuberculin units of purified protein derivative) is a valuable diagnostic test for latent TB and active TB in childhood. BCG vaccination has no remarkable effect on the interpretation of tuberculin reactivity. The incidence rate of active pulmonary TB in children in the region of study is of concern.

The Effect of Neonatal Bacille Calmette-Guérin Vaccination on Purified Protein Derivative Skin Test Results in Canadian Aboriginal Children

BACKGROUND

The effect that neonatal bacille Calmette-Guérin (BCG) vaccination has on tuberculin skin test (TST) results is not well evaluated in preschool children.

METHODS

This was a retrospective cohort study of TST results in aboriginal children in Saskatchewan reserve communities. Records from the centralized provincial tuberculosis program were searched for aboriginal children aged 0 to 4 years during the time period 1991 to 1999. Only the first TST result reported as part of infant and preschool screening programs was considered. Children with active tuberculosis and those evaluated as part of a contact-tracing program were excluded. The BCG-vaccinated and unvaccinated groups were compared using wheal size cut points of 5 mm, 10 mm, and 15 mm.

RESULTS

Data from 1,086 children with neonatal BCG vaccination and 1,867 unvaccinated children were analyzed. The rate of TST reactions was higher in vaccinated children at all ages, using a cut point of 5 mm. The rate of TST reactions was no different in vaccinated children >or= 1 year old when using a cut point of 15 mm. When using a cut point of 10 mm, the rate of TST reactions was higher at age 1 year but not different at age 4 years in the vaccinated children.

CONCLUSION

The rate of TST reactions in preschool aboriginal children living on a reserve who have received neonatal BCG vaccination is affected by the cut point and age. The BCG vaccination status and age should therefore be considered when interpreting TST reactivity in the clinical assessment of aboriginal children participating in a tuberculosis control program.

Comparison of tuberculin skin test response after three modalities of neonatal BCG vaccination

The aim of this study was to determine the tuberculin skin test (TST) response to three different BCG modalities [0.1 ml Tokyo (n=104), 0.05 ml Pasteur-Mérieux (n=137) and 0.1 ml Pasteur-Mérieux (n=100)] in a cohort of healthy newborns 5 months after vaccination at birth in Santiago, Chile. Among the 341 infants, 91.2% had a response to TST, and the mean+/-SD TST reaction size was significantly larger in infants receiving the Tokyo strain than in those receiving the 0.05 ml or 0.1 ml Pasteur-Mérieux strains (4.4+/-2.0, 3.5+/-1.3 and 3.1+/-1.4 mm, respectively; P<0.0001). The mean+/-SD of the BCG scar size was significantly lower in infants vaccinated with the Tokyo strain than in those vaccinated with the 0.1 ml Pasteur-Mérieux strain (3.9+/-1.2 vs. 4.3+/-1.1 mm; P=0.03) and no significant difference was found between infants receiving the Tokyo strain and the 0.05 ml Pasteur-Mérieux strain. However, the differences in TST size induced by diverse BCG vaccination modalities may not reflect the quality of the immunologically induced response in terms of TB protection.

BCG vaccination at three different age groups: response and effectiveness

BACKGROUND: The protection, which some BCG vaccines could confer against the development of tuberculosis (TB) in childhood, might be indirectly reflected by the subsequent development of BCG immune response. The objectives of the study were to examine effectiveness and possible differences of post-vaccination reaction to a lyophilized BCG at different age groups and to evaluate its protection against TB in a decade's period. METHODS: We studied the post-vaccination PPD-skin reaction and scar formation at three different school levels, corresponding to ages of 6, 12 and 15 years old, vaccinated by a lyophilized BCG vaccine (Pasteur Institute), currently used in our country. During a 10-year follow up the reported TB cases in vaccinated and non-vaccinated adolescences up to 24-years old were analyzed and compared to the number of cumulative cases observed in the adult population of two neighboring territories (vaccinated and non-vaccinated). RESULTS AND DISCUSSION: There was a significant correlation (r2 = 0.87, p < 0.0001) between tuberculin induration and scar formation. There was no statistically significant difference between the three age groups (6, 12, and 15 year-old, respectively) in regard to the diameter of tuberculin induration or scar formation. Although 34% of 10-year later indurations were unpredictably related to the initial ones (increased or decreased), they were significantly correlated (r2 = 0.45, p = 0.009). The relative percentage of TB for the 14-24 years-age group to the adult studied population was significantly lower among the immunized children compared to the non-immunized population of the same age group (17/77, 22% vs. 71/101, 70%, p < .0001). CONCLUSION: Our data suggest that the lyophilized BCG vaccine used for BCG programs at different age groups is equally effective and may confer satisfactory protection against tuberculosis in puberty.

A prospective study of bacillus Calmette-Guérin scar formation and tuberculin skin test reactivity in infants in Lima, Peru

OBJECTIVES

To determine the sensitivity of the bacillus Calmette-Guérin (BCG) scar as an indicator of previous vaccination and to ascertain the tuberculin skin test (TST) response in infancy after vaccination in a community from an area hyperendemic for tuberculosis (TB).

METHODS

In a birth cohort of healthy term infants from Lima, Peru, a single dose of BCG vaccine was administered within the first month of life. Scar formation was assessed biweekly during the first 6 months and again at 3 years after vaccination. TST response was evaluated 6 months after vaccination.

RESULTS

Six months after vaccination, 99% (68) of the newborns exhibited a BCG scar (>2 mm). Scar size did not differ by sex, birth weight, age at vaccination, or nutritional status in the first 2 months. Eighty percent of the participants were found 3 years after vaccination, and all of them had a BCG scar. Mean TST reaction size 6 months after vaccination was 2.9 +/- 0.3 mm. No association was found between sex or age at BCG vaccination and TST size. Only 3 children had a TST >10 mm, and the 3 had a TB contact at home.

CONCLUSIONS

The BCG scar was a sensitive indicator of vaccination status up to 3 years after the administration of the vaccine in the first month of life. Although nearly a quarter of the children had a TST response >5 mm 6 months after vaccination, TST reactions >10 mm did not occur in the absence of exposure to a person with tuberculosis. A cutoff of 10 mm should be used for disease control purposes in people who are born in countries where TB is endemic.

Orofacial granulomatosis with gingival onset

BACKGROUND, AIMS

Orofacial granulomatosis (OFG) is a descriptive term used for granulomatous disorders of the face and oral cavity that may occur for a variety of reasons, some of which result in significant morbidity and mortality. Although rarely, a granular enlargements of the gingiva may be the first clinical manifestation of OFG, preceding other local or systemic manifestations.

METHOD

We will report a case of OFG that showed an atypical and monosymptomatic onset with a generalized hyperplastic gingivitis that preceded other facial and mucosal features by several weeks.

RESULT

Considering the variable clinical onset of OFG and its apparent increase in incidence, we emphasize that in some cases, the periodontologist, as first consulted health care professional, plays an important role to detect this disorder. Early diagnosis of OFG is a crucial step to prevent and cure its unsightly sequelae and sometimes avoid progression of systemic potentially life-threatening OFG-related diseases.

CONCLUSION

Thus, when none of the common causes of gingival enlargement can be detected, OFG diagnosis should be suspected.