Research On The Effect And Mechanism Of Immunoglobulins On Infantile Hemangioma

Background:Infantile hemangioma(IH)is the most common congenital benign tumor in infants,about 60%of which develops in head and neck region.It usually emerges within several days after birth,and generally,its rapid proliferation phase is 4 weeks or 4-5 months after birth.The involution phase usually appears after 1-year-old,which could lasts for 3-8 years or even longer.Most of the lesions are incomplete involution.The pathogenesis of IH is still not very clear.Recent studies often focused on Hemangioma Endothelial Cells(HemECs),which were the major component of IH and determined various biological characteristics of IH.The cells could secrete the Vascular Endothelial Growth Factor(VEGF)to act on the receptors on themselves or surrounding cells.And then,the downstream pathway was activated to promote angiogenesis and lead to the proliferation of IH.It is an international consensus that IH should be treated earlier to reduce complications.However,there are more or less insufficiencies of all the present therapeutic methods.Therefore,it is essential to make further exploration on the pathogenesis of IH and find out more safe and effective therapeutic methods.Humoral immunity plays an important role in tumor immunity.Tumor antigens could stimulate the production of antibodies,which are immunoglobulin,for responding to tumor cells.Immunoglobulins could activate the Complement system and form Complement Membrane Attack Complex(MAC),which is mainly C5b-9 in tumor immunity.Then,the MAC lyses the tumor cells by Complement-dependent Cytotoxicity(CDC).Studies of pediatric immunology elucidated that the level of immunoglobulin and complement system revealed temporal correlation with the proliferation and involution of IH.Moreover,Intravenous Immunoglobulin(IVIg),a kind of common drug in clinical,could inhibit the proliferation of normal endothelial cells like Human Umbilical Vein Endothelial Cells.The main component of IVIg is IgG,with some maltose as accessory.The mechanism of the anti-proliferation effect is that IVIg could inhibit the expression or function of VEGF via several approaches.Little studies explored the relationship between humoral immunity and IH.It was unclear that whether immunoglobulin played a role in the development of IH.Herein,our study sought to explore the pathogenesis of IH from the perspective of immunology through pathological section staining,cell culture and drug intervention,to provide a primary theoretical basis for the immunotherapy of IH.Objectives:1.To detect the expression and localization of Antibodies and Complements Membrane Attack Complex(MAC)in different periods of IH.2.To observe the proliferation and the secretion of VEGF of HemECs after treated by IVIg.3.To explore the relationship between the Antigen-Complement system and IH and primary experimental evidences for novel therapeutic method of IH.Methods:1.The type of immune cells was detected by HE staining.The co-expression of IgG and C5b-9 in different phases of IH was detected by Immunofluorescent staining.2.HemECs were isolated from the fresh proliferating IH specimen,purified by CD31+ immunomagnetic beads and identified by immunocytochemistry and flow cytometry.3.The experimental groups were intervened by IVIg at different concentration,while the control group was treated by 25mg/mL maltose.Thereafter,the proliferation of HemECs was detected by CCK-8 assay,with the secretion of VEGF detected by ELISA.Results:1.In the early proliferation phase,both IgG and C5b-9 were not significantly expressed.In the later proliferation phase,IgG was observed on the endothelium within the tumor,while C5b-9 expression was unapparent.In the involution phase,IgG and C5b-9 were mainly observed in the margin of the tumor,with local co-deposition band.2.HemECs were isolated from the fresh proliferating IH specimen.The cells were purified by CD31+ immunomagnetic beads and showed CD31 and vWF-positive,with the purity reaching 99%.3.CCK-8 assay displayed that IVIg at the concentration of no less than 10mg/mL could lead to the decrease of OD value.ELISA showed that IVIg at the concentration of 5mg/mL could increase the secretion of VEGF.While the concentration of IVIg exceeded 10mg/mL,the secretion of VEGF was decreased.Conclusions:1.The co-deposition of IgG-C6b-9 is relevant to the involution of IH.2.IVIg at a certain concentration could inhibit the proliferation in vitro,which potentially resulted from the drug decreasing the secretion of VEGF.3.Antigen-Complement system may affect the development process of IH.It could be a candidate of novel target for the treatment of IH.