| Background: Chronic gastritis,a kind of common disease of the digestive system,is about gastric mucosa inflammation caused by different reasons.Helicobacter pylori(H.pylori)infection is the most common etiologic factor of chronic gastritis.H.pylori can initiate a robust host immune response and subsequently results in chronic inflammation in the gastric mucosa.The mononuclear macrophages are important immune cells involved in the inflammatory response,with functions of clearing pathogens and antigen-presenting.They play an important role in the body’s natural immune response.Mononuclear macrophages can be divided into classical activation type(classically activated,M1)and alternative activation type(alternatively activated,M2).The M1 mononuclear macrophages can secrete a variety of proinflammatory cytokines such as IL-12,for removing bacteria and tumor cells.M2-like mononuclear macrophages can produce anti-inflammatory cytokines,such as IL-10 and other immune regulatory factors,helping tissue repair and promoting the growth of tumor.Mononuclear macrophages are in different polarization states in different diseases,so as to play different roles.Mononuclear macrophages are the first line of immune defense for H.pylori.H.pylori state of survival or replication is closely related to the function of macrophages.However,polarization state of mononuclear macrophages and its role in the pathogenesis of H.pylori infection are poorly understood.Monocytes and macrophages,on the other hand,are involved in tumor immunity by promoting tumor growth,invasion and metastasis.Monocytes could reflect the activation state of the tumor associated macrophages.In patients with gastric cancer,especially H.pylori-associated gastric cancer,whether circulating monocyte subsets can help judging the disease severity and prognosis or not remains unclear.Aims: We aimed to study the numbers,phenotypic characterization of different monocyte subsets and the levels of related serum cytokines in patients with newly H.pylori infected gastritis.Moreover,we investigated the potential correlation between these subsets and clinical data in patients with H.pylori infection.This study is aimed at figuring out the role of monocyte subsets in the pathogenesis of H.pylori infection.In addition,we explored the quantitative change of M2-like monocytes in patients with gastric cancer,especially H.pylori positive ones,as well as the relationship between the M2-like subsets and disease severity and prognosis.Methods:(1)H.pylori was determined by 14C-urea breath test and serum western blot method.Peripheral blood from 40 patients with new-onset H.pylori infection,15 patients with uninfected chronic gastritis and 14 health controls was examined for monocyte subsets in peripheral blood mononuclear cells(PBMC)by flow cytometry.The levels of serum IL-12 and IL-10 were measured using cytometric bead array(CBA).CD64+ and CD163+ macrophages in gastric mucosa were detected by immunohistochemical method.IL-10 production and phagocytic function in M2-like cells isolated from patients with H.pylori infection were also examined.(2)Peripheral blood from 76 new-onset gastric cancer patients,35 cases of benign gastric disease and 14 healthy controls was examined for the numbers of circulating M2-like monocytes by flow cytometry.For all the patients participated in the experiments above,clinical,pathological and laboratory indexes were measured.Results:(1)CD64+ M1 and CD163+ M2 macrophage expression were evaluated in H.pylori infected tissues,compared with the uninfected tissues.In correspondence,we found that the numbers of CD14+ CD163-CD64+ M1-like monocytes as well as CD14+ CD163+ CD206+,CD14+CD163+CD209+,and CD14+CD163+IL-10+ M2-like monocytes were significantly increased in H.pylori-infected patients in comparison with the controls,accompanied by higher levels of plasma IL-10.Notably,the triple anti-H.pylori therapy significantly reduced the numbers of CD64+ M1-like,CD206+ and CD209+ M2-like monocyte subsets.(2)In comparison with that in patients with H.pylori-positive nonatrophic or atrophic gastritis,patients suffering from H.pylori-positive peptic ulcers had a greater number of CD14+CD163-CD64+ M1 and CD14+CD163+CD209+ monocytes.The numbers of CD14+ CD163+ CD209+ monocytes positively correlated with the extent of H.pylori infection Furthermore,the H.pylori-infected patients with Cag A-or Vac A-positive strains had a significantly higher number of CD14+CD163+CD206+,CD14+CD163+CD209+,CD14+CD163+IL-10+ M2-like monocytes compared to those with Cag A-or Vac A-negative strains.(3)In vitro,phenotype of CD163 and CD206,and IL-10 level were significantly higher in the stimulated M2-like cells from patients with H.pylori infection compared with controls.However,H.pylori inhibited phagocytosis of M2 polarized macrophages.(4)We observed no significant difference in CD14+CD163+,CD14+CD163+CD206+ M2-like monoctyes between H.pylori negative group and H.pylori positive group in patients with gastric cancer.Additionally,there was no significant difference in clinical,pathological and laboratory indexes between two groups.(5)Compared with benign gastric diseases and health controls,patients with gastric cancer have increased number of circulating CD14+CD163+,CD14+CD163+CD206+ M2-like monocytes.After gastric cancer resection,the CD14+CD163+ and CD14+CD163+CD206+ M2-like cells were significantly lower.What’s more,CD14+CD163+,CD14+CD163+CD206+ M2-like monoctyes were positively associated with tumor infiltration depth,lymph node invasion,distant metastasis and even TNM stage.(6)Area under ROC curve for CD14+CD163+ and CD14+CD163+CD206+ M2-like monocytes level was higher than the panel of CEA and CA199.Of these,only CD14+ CD163+ M2-like monocytes for diagnosis of gastric cancer was greater than the value of CEA and CA199.(7)Kaplan-Meier analysis showed that CD14+CD163+,CD14+CD163+CD206+ M2-like cells,TNM stage,tumor size,differentiation,surgical treatment and H.pylori infection were risk factors of poor prognosis for gastric cancer.After COX multi-factor survival analysis,we found that CD14+CD163+ M2-like monocytes,TNM staging,surgical treatment and H.pylori infection were independent factors of predicting the adverse outcomes for patients with gastric cancer.Conclusion:(1)Human H.pylori infection was characterized by a mixed M1/M2 polarization of monocytes.CD64+ M1,CD209+ and CD206+ M2-like monocyte subsets may participate in H.pylori-related chronic gastritis.(2)CD14+CD163+CD209+ M2-like monocytes may help evaluating the disease severity and bacterial loads.(3)The peripheral CD14+CD163+ M2-like monocytes can be probably used as a potential indicator for evaluating the disease severity and prognosis of gastric cancer. |
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