Increased IL-17 production by peripheral T helper cells after tumour necrosis factor blockade in rheumatoid arthritis is accompanied by inhibition of migration-associated chemokine receptor expression.

OBJECTIVES: The contribution of IL-17-producing Th17 cells to the pathogenesis of T-cell-mediated inflammatory disorders such as RA and atopic dermatitis (AD) has to be viewed in relation to the role of Th1/Th2 cells and long-recognized key cytokines like TNF. We aimed to study the frequency and migration-associated phenotype of peripheral Th17, Th1 and Th2 cells in healthy individuals, RA and AD patients, and to study the influence of anti-TNF therapy in RA. METHODS: Intracellular IL-17, IFN-γ and IL-4 production and CC-chemokine receptor CCR4 and CCR6 expression were analysed flow cytometrically in peripheral memory Th cells from healthy individuals, AD and RA patients. The latter were grouped by disease activity and presence or absence of adalimumab therapy. In RA patients initiating anti-TNF therapy, cytokine production by in vitro-stimulated peripheral mononuclear cells was measured by cytometric bead array. RESULTS: The peripheral Th17 cell frequency is elevated in AD but not in RA. In RA, Th17 cells and IL-17 production increase after anti-TNF therapy, irrespective of disease activity. Th1 cells and IFN-γ production are elevated in remission and under anti-TNF therapy. CCR6 expression is up-regulated in Th17 cells, but RA patients in remission under anti-TNF therapy have significantly lower expression than those with active disease. CONCLUSIONS: The increase in peripheral Th17 cells in RA patients after anti-TNF therapy is accompanied by a decrease in Th17-specific CCR6 expression, which might prevent homing of these potentially pro-inflammatory cells to the synovium.

Hereditary angioedema in childhood: an approach to management.

Hereditary angioedema (HAE) is an inherited disorder characterized by recurrent, circumscribed, non-pitting, non-pruritic, and rather painful subepithelial swelling of sudden onset, which fades during the course of 48-72 hours, but can persist for up to 1 week. Lesions can be solitary or multiple, and primarily involve the extremities, larynx, face, esophagus, and bowel wall. Patients with HAE experience angioedema because of a defective control of the plasma kinin-forming cascade that is activated through contact with negatively charged endothelial macromolecules leading to binding and auto-activation of coagulation factor XII, activation of prekallikrein to kallikrein by factor XIIa, and cleavage of high-molecular-weight kininogen by kallikrein to release the highly potent vasodilator bradykinin. Three forms of HAE have currently been described. Type I and type II HAE are rare autosomal dominant diseases due to mutations in the C1-inhibitor gene (SERPING1). C1-inhibitor mutations that cause type I HAE occur throughout the gene and result in truncated or misfolded proteins with a deficiency in the levels of antigenic and functional C1-inhibitor. Mutations that cause type II HAE generally involve exon 8 at or adjacent to the active site, resulting in an antigenically intact but dysfunctional mutant protein. In contrast, type III HAE (also called estrogen-dependent HAE) is characterized by normal C1-inhibitor activity. The diagnosis of HAE is suggested by a positive family history, the absence of accompanying pruritus or urticaria, the presence of recurrent gastrointestinal attacks of colic, and episodes of laryngeal edema. Estrogens may exacerbate attacks, and in some patients attacks are precipitated by trauma, inflammation, or psychological stress. For type I and type II HAE, diminished C4 concentrations are highly suggestive for the diagnosis. Further laboratory diagnosis depends on demonstrating a deficiency of C1-inhibitor antigen (type I) in most kindreds, but some kindreds have an antigenically intact but dysfunctional protein (type II) and require a functional assay to establish the diagnosis. There are no particular laboratory findings in type III HAE. Prophylactic administration of either 17alpha-alkylated androgens or synthetic antifibrinolytic agents has proven useful in reducing the frequency or severity of attacks. Plasma-derived C1-inhibitor concentrate, recombinant C1-inhibitor, ecallantide (DX88; a plasma kallikrein inhibitor) and icatibant (a bradykinin B(2) receptor antagonist) have demonstrated significant efficacy in the treatment of acute attacks, whereas the C1-inhibitor concentrate has also provided a significant benefit as long-term prophylaxis. However, these drugs are not licensed in all countries and are not always readily available.

P38 mitogen-activated protein kinase signal transduction in the diagnosis and follow up of immunotherapy of wasp venom allergy.

BACKGROUND: P38 mitogen-activated protein kinase (MAPK) is known to govern IgE-mediated basophil activation. Intracellular phosphorylated p38 MAPK (Pp38 MAPK) in IgE-activated basophils can be quantified flow cytometrically. OBJECTIVES: To study whether Pp38 MAPK constitutes a potential novel read-out for flow-assisted diagnosis of hymenoptera venom allergy and to investigate whether this marker allows follow-up of successful venom immunotherapy (VIT). METHODS: Fifty-two patients with documented wasp venom allergy and seven wasp-stung asymptomatic control individuals were enrolled. Wasp venom-induced basophil activation was analyzed flow cytometrically with anti-IgE, anti-CD63, and anti-Pp38 MAPK to assess their activation status before starting immunotherapy. To assess whether p38 MAPK constitutes a candidate marker for monitoring VIT, we repeated the basophil activation test (BAT) in 25 patients on the fifth day of a build-up immunotherapy. In addition, we investigated whether the Pp38 MAPK-based BAT could contribute in the decision of discontinuing VIT in a cross-sectional analysis in 13 patients receiving treatment for 3 years and 14 patients receiving treatment for 5 years. RESULTS: Patients exhibited a dose-dependent basophil activation with phosphorylation of p38 MAPK and upregulation of downstream CD63. In contrast, stung controls demonstrated a dose-dependent but "abrogated" signal transduction in basophils with less and shorter duration of the phosphorylation of p38 MAPK and without subsequent upregulation of CD63. When repeated after 5 days of VIT and when investigated cross-sectionally after 3 years or 5 years of maintenance therapy, no effect of VIT on the phosphorylation of p38 MAPK was demonstrable. CONCLUSIONS: This study discloses that not only basophils from patients, but also from the stung control individuals, respond to wasp venom stimulation with phosphorylation of p38 MAPK, although to a lesser extend. No clear effect of VIT on the phosphorylation of p38 MAPK was shown. Thus, although p38 MAPK provides an additional tool in the diagnosis of wasp venom allergy, it does not contribute to the decision whether to stop successful VIT. © 2010 International Clinical Cytometry Society.