title: Toll-like receptor signaling is impaired in dendritic cells from patients with X-linked agammaglobulinemia.
abstract: Bruton's tyrosine kinase (BTK), which is defective in patients with X-linked agammaglobulinemia (XLA), is expressed not only in B cells but also in monocytes and dendritic cells (DCs). DCs play a crucial role in the innate immune response against infections by sensing pathogens through Toll-like receptors (TLRs). However, it is not known whether BTK deficiency in XLA might impair TLR-mediated signaling in DCs, which are susceptible to various infections. The phenotypic maturation and cytokine production mediated by TLRs were examined in monocyte-derived DC from XLA patients and normal controls. The TLR expression in DCs was analyzed by flow cytometry. TLR-mediated signaling in DCs was evaluated for the phenotypic maturation based on CD83 expression and production of cytokines, such as TNF-alpha, IL-6 and IL-12p70. TLR levels in DCs were similar between XLA and controls. TLR2, TLR4 and TLR7/8 ligands elicited less phenotypic maturation of DCs from XLA patients than normal controls based on CD83 expression. Stimulation with TLR2, TLR4 and TLR7/8 ligands, as well as TLR3 ligand, resulted in significantly lower production of TNF-alpha, but neither IL-6 nor IL-12p70, by DCs from XLA patients in comparison to normal controls. These findings suggest that BTK may thus be required for TLR signaling in DCs. The impaired TLR signaling in DCs may therefore be partly responsible for the occurrence of severe infections with bacteria and some viruses in XLA patients.
authors.affiliation: Department of Pediatrics, Graduate School of Medicine, University of Toyama, Toyama, Japan.
authors.forename: Hiromichi
authors.initials: H
authors.lastname: Taneichi
authors.forename: Hirokazu
authors.initials: H
authors.lastname: Kanegane
authors.forename: Mostafa Mohamed
authors.initials: MM
authors.lastname: Sira
authors.forename: Takeshi
authors.initials: T
authors.lastname: Futatani
authors.forename: Kazunaga
authors.initials: K
authors.lastname: Agematsu
authors.forename: Masahiro
authors.initials: M
authors.lastname: Sako
authors.forename: Hideo
authors.initials: H
authors.lastname: Kaneko
authors.forename: Naomi
authors.initials: N
authors.lastname: Kondo
authors.forename: Tsuneyasu
authors.initials: T
authors.lastname: Kaisho
authors.forename: Toshio
authors.initials: T
authors.lastname: Miyawaki
mesh_terms: D000077329:Agammaglobulinaemia Tyrosine Kinase; D000361:Agammaglobulinemia / Q000276:immunology* / Q000378:metabolism; D015703:Antigens, CD / Q000276:immunology / Q000378:metabolism; D002648:Child; D002675:Child, Preschool; D041321:Chromosomes, Human, X; D016207:Cytokines / Q000276:immunology / Q000378:metabolism*; D003713:Dendritic Cells / Q000276:immunology*; D040181:Genetic Diseases, X-Linked / Q000276:immunology* / Q000378:metabolism; D006801:Humans; D007136:Immunoglobulins / Q000276:immunology / Q000378:metabolism; D007223:Infant; D008024:Ligands; D008562:Membrane Glycoproteins / Q000276:immunology / Q000378:metabolism; D011505:Protein-Tyrosine Kinases / Q000172:deficiency / Q000378:metabolism*; D015398:Signal Transduction; D051193:Toll-Like Receptors / Q000276:immunology / Q000378:metabolism*; D000097802:CD83 Antigen
chemical_list: D000077329:Agammaglobulinaemia Tyrosine Kinase; D015703:Antigens, CD; D016207:Cytokines; D007136:Immunoglobulins; D008024:Ligands; D008562:Membrane Glycoproteins; D011505:Protein-Tyrosine Kinases; D051193:Toll-Like Receptors; D000097802:CD83 Antigen; C000625949:BTK protein, human