Essentials for starting a pediatric clinical study (2): Role of environment and immunity in the development of childhood allergic and immunologic disorders.
Regulatory T- (T(REG)) cells are considered to inhibit the development of both type 1 and type 2 helper T (T(H1) and (TH2)) cells. However, the number of T(REG) cells in patients with allergic diseases who have high levels of serum IgE and blood eosinophils is reduced as compared to individuals who have similarly high levels of IgE and eosinophils but are asymptomatic. Therefore, T(REG) cells may suppress the onset of allergic disease by downregulating other types of immune cells besides T(H1) and T(H2) cells. The newly discovered interleukin (IL-)17-producing helper T- (T(H17)) cells responsible for autoimmune inflammatory diseases may counteract with T(REG) cells even in allergic diseases. T(H2) cells capable of producing of high levels of tumor necrosis factor (TNF)-alpha may also be involved in the inflammation in allergic diseases. In this review, the role of T(H1), T(H2), T(H17) and T(REG) cells in allergic diseases is further discussed by using the balancing square model and the factors differentiating between patients with clinical manifestations of allergic symptomatic versus atopic individuals who are sensitized but asymptomatic.
Saito
Hirohisa
H
Department of Allergy and Immunology, National Research Institute for Child Health, Development, Setagaya, Tokyo, Japan. hsaito@nch.go.jp
D002648:Child; D016207:Cytokines; D015536:Down-Regulation; D004804:Eosinophils; D006801:Humans; D006967:Hypersensitivity / Q000276:immunology*; D007154:Immune System Diseases / Q000276:immunology*; D007073:Immunoglobulin E; D020381:Interleukin-17; D008407:Mast Cells / Q000276:immunology; D050378:T-Lymphocytes, Regulatory / Q000276:immunology*; D018417:Th1 Cells / Q000276:immunology*; D018418:Th2 Cells / Q000276:immunology*; D014409:Tumor Necrosis Factor-alpha; D000094632:Thymic Stromal Lymphopoietin
D016207:Cytokines; D020381:Interleukin-17; D014409:Tumor Necrosis Factor-alpha; D007073:Immunoglobulin E; D000094632:Thymic Stromal Lymphopoietin