ABSTRACT
Background: The global prevalence of chronic hepatitis C is estimated at 2.8%. There is markedly higher prevalence in the Middle East about 14.7% in Egypt. Dendritic cells [DCs] are one of the major Antigen presenting cells in the body. They bridge innate and adaptive immunity and impact priming of HCV-specific immune responses. The current study was aimed to investigate the DC activation status, and their role in interaction with natural killer [NK] cells utilizing different setups with healthy NK and HCV+ DC, HCV+ NK and healthy DC, healthy DC and healthy NK and finally HCV+ NK and HCV+ DC in the presence of HCV peptides and a ratio of 5 NK: 1DC
Results: DC-NK interaction in chronic HCV infection is mainly affected by the affection of DCs by HCV leading to a maturation defect [decreased expression of HLA DR, CD 86 and CD 83]. Healthy NK cells were able to stimulate the maturation of DCs particularly with core peptide whereas NS3-4 had no effect. When DCs were healthy, all peptides were able to produce significant maturation of DCs even when co-cultured with HCV+ NK cells. Co-cultured HCV+ NK cells and HCV+ DCs showed significantly higher apoptosis of both cells. This could be attributed to the immature moDCs more with chronic HCV infection due to the fact that immature DCs typically under express HLA-class I molecules that would protect from NK-mediated lysis
Conclusion: Cross-talk between DCs and NK cells plays an important role in the induction of both the innate and adaptive immune systems. HCV infection was found to impair the maturation of DCs. Thus consequently affecting its antigen presentation and T cell allostimulatory capacity and rendering them more liable to NK mediated lysis which could explain the persistence of infection and chronicity
ABSTRACT
Background: Various populations of regulatory T cells play a central role in the development of peripheral tolerance to allergens. Culturing of CD4+ T cells isolated from peripheral blood of allergic patients with vitamin D induces the generation of stable IL-10 producing CD4+CD25+ Treg cells suppressing the proliferation of T helper cells obtained from the same patients. The immune regulatory role of vitamin D in allergic patients has been controversial and obviously needs a more clarifying research work
Aim of the work: to determine the percentage of induced T regulatory cells producing interleukin 10 after stimulation of T regulatory cells with cow milk allergen in the presence of vitamin D in culture. This aims to further in-vitro study the immune regulatory role of vitamin D in cow milk allergic patients
Results: there is association between decreased level of vitamin D and milk-allergy, as serum level of 25[OH] D3 was insufficient in 16 [80 %] patients [10- 29.9 ng/ml] while 4 [20%] patients were sufficient [30-100 ng/ml]. Addition of vitamin D, in culture, induces the production of CD4+ CD25hi Foxp3+ IL10+. Treg cells within peripheral blood mononuclear cells [PMNCs] isolated from allergic children who had insufficient vitamin D, but not in allergic children who had normal level of vitamin D
Conclusion: this work provides further evidence for an important role of 1,25[OH]2D3 as an immune-modulatory molecule and suggests that supplementation of vitamin-D-deficient individuals, who are reported to have reduced numbers of circulating and Foxp3+ IL10+ Treg cells, may represent an attractive therapy for enhancing endogenous populations of Treg cells in allergy