Tuberculosis and atopy: A study in an endemic area

The impact of pulmonary tuberculosis treatment on the prevalence of allergic rhinitis

Atopy is a syndrome characterized by immediate hypersensitivity reactions to common environmental antigens. The "hygiene hypothesis" stipulates that childhood infections are associated with a lower risk of allergies. Not much has been published about the effects that the treatment of pulmonary tuberculosis (TB) has on allergies, specifically allergic rhinitis. We conducted a study to investigate the prevalence of allergic rhinitis in patients with pulmonary TB before and after treatment of their TB. Our initial study group was made up of 121 patients with confirmed pulmonary TB who were followed up by questionnaire. In addition to demographic data, they provided information about their personal and family history of atopy and their current status with regard to allergic rhinitis. After providing informed consent, all patients underwent skin-prick testing with Dermatophagoides pteronyssinus, Dermatophagoides farinae, and Blomia tropicalis allergens before and after TB treatment. Stool samples were obtained to identify patients with worm infestation, and they were excluded from the study. In all, 94 patients completed treatment and follow-up, and their data were included in the final analysis. Of this group, 31 patients (33.0%) exhibited symptoms of allergic rhinitis prior to TB treatment, and 26 (27.7%) had a positive skin-prick test. Following treatment, only 12 patients (12.8%) reported allergic rhinitis symptoms (p = 0.004), but there was no significant reduction in the number of patients with a positive skin-prick test (n = 20 [21.3%]; p = 0.555). We conclude that the treatment of pulmonary TB results in significant relief of atopy, particularly allergic rhinitis symptoms.

Pediatric allergy and immunology in Turkey

Allergic diseases constitute a significant health problem in Turkey. According to a recent multicenter study, which used the ISAAC questionnaire, the mean prevalence of wheezing, rhinoconjunctivitis, and eczema in 10-yr-old school children during the past year was 15.8%, 23.5%, and 8.1%, respectively. A healthcare level system, regulated by Ministry of Health, is available in Turkey. Pediatric allergists and pediatric immunologists provide patient care at the tertiary level. Currently, 48 centers deliver care for allergic and immunologic diseases in children. There are 136 pediatric and 61 adult allergists/immunologists. Although the number of allergy/clinical immunology specialists is limited, these centers are capable of delivering many of the procedures required for the proper management and diagnosis of allergy/immunology. Pediatric allergy and/or immunology is a subspecialty lasting 3 yr and follows a 4-yr pediatric specialist training. Fellow training involves gaining knowledge in basic and clinical allergy and immunology as well as the performance and interpretation of laboratory procedures in the field of allergy and clinical immunology. The Turkish National Society of Allergy and Clinical Immunology (TNSACI) was officially established in 1989 and currently has 356 members. The society organizes a national congress annually and winter schools for fellowship training as well as training courses for patients and their relatives. TNSACI also has a strong representation in European Academy of Allergy and Clinical Immunology (EAACI) and European Society for Immunodeficiencies (ESID) through its participation in the executive committee, consensus reports, and initiatives in the diagnosis of allergic and immunologic diseases of children. The 30th Congress of the EAACI is also due to be held in Istanbul, Turkey, between June 11 and 15, 2011.

Lack of an inverse association between tuberculosis infection and atopy: by T-cell-based immune assay (RD1-ELISpot)

The association between mycobacterial exposure, vaccination with bacillus Calmette-Guerin (BCG) in early life and atopy remains controversial. Distinguishing between environmental mycobacterial exposure, TB infection and BCG-vaccination is not possible with the tuberculin skin test (TST) but new accurate blood-tests for TB infection present an opportunity to differentiate TB infection from environmental mycobacterial exposure and BCG-vaccination. We used a new blood test in parallel with TST to investigate whether Mycobacterium tuberculosis infection and/or BCG vaccination are associated with development of atopy in children with prior household TB contacts. All children who had contact with adult active pulmonary TB during the last 6 months underwent TST, chest radiography, and RD1-ELISpot assay. The presence of a BCG scar was documented, and assessment of atopy was carried out by International Study of Asthma and Allergies in Childhood questionnaire, allergy skin prick testing (SPT) and evaluation of serum total IgE. Among 361 children enrolled 39 (11%) had a positive SPT, 236 (63%) positive TST, and 189 (52%) positive RD1-ELISpot. The frequency of SPT positivity, ever wheezing, allergic rhinitis, doctor-diagnosed asthma, high serum IgE level, and median total serum IgE levels did not differ significantly different by TST or RD1-ELISpot status. On the other hand, presence of BGC scar was associated with lower median total serum IgE level (p = 0.01) and lower frequency of high IgE (p = 0.003). M. tuberculosis infection whether measured by TST or RD1-ELISpot, was not associated with atopy in children with household TB contact. Presence of a BCG vaccination scar was inversely associated with atopy, as measured by serum IgE.

The damage-response framework of microbial pathogenesis and infectious diseases

Historical and most currently held views of microbial pathogenesis and virulence are plagued by confusing and imprecise terminology and definitions that require revision and exceptions to accommodate new basic science and clinical information about microbes and infectious diseases. These views are also inherently unable to account for the ability of some microbes to cause disease in certain, but not other hosts, because they are grounded in singular, either microbe-or host-centric views. The damage-response framework is an integrated theory of microbial pathogenesis that puts forth the view that microbial pathogenesis reflects the outcome of an interaction between a host and a microbe, with each entity contributing to the nature of the outcome, which in turn depends on the amount of host damage that results from the host-microbe interaction. This view is able to accommodate new information and explain why infection with the same microbe can have different outcomes in different hosts. This chapter describes the origins and conceptual underpinnings of and the outcomes of infection put forth in, the damage-response framework.

Do vaccines modify the prevalence of asthma and allergies?

Epidemiological studies suggest the hypothesis that the increase in asthma and allergies in the industrialized world can be explained by a decline in the number of infectious diseases occurring during childhood. In the context of this 'hygiene hypothesis', is immunization in early life a risk factor for promoting allergic diseases? The majority of studies, especially those conducted with more extensive populations, have not found an increased risk, and although 'not finding an increased risk' is not the same as 'the non-existence of any risk at all', it seems that the evidence is tipped in favor of the absence of risk. Conversely, although some surveys have described a protective effect of vaccination, the majority refuted this result. If there is any effect, it is probably a weak one.