Research On Regulation Mechanism Of H2R/H4R In Anaphylactoid Purpura

Backgraund: Anaphylactoid purpura(Henoch-Schonlein purpura HSP),as one of common allergic diseases in children,cancause multi-organ damage.The typical clinical manifestation includes: skin purpura,joint swelling,abdominal pain,hematochezia,hematuria and proteinuria.The etiology and pathogenesis were not entirely clear yet.Many studies found that the main reason is abnormal immune and inflammatory reaction,increase of serum inflammatory factors level and the IgA immune complex deposition in the small blood vessels.In the process of acute stage in children with HSP,The number of CD4+T cells in peripheral blood decreased,the number of CD8+T cells increased,resulted in the imbalance of Th1/Th2.As the important inflammatory mediators,histamine receptor has been extensively studied,Histamine receptor H2 and H4 involved in the development of various allergic diseases by regulating cytokine expression,antigen presenting cell function.More recently found on H4 R activation of the cell membrane of DC can regulate the differentiation of T helper cells.So the abnormal imbalance of Th1/Th2 caused by the regulation of DC,May be the important pathogenesis of HSP.Therefore we hypothesized that H2R,H4R may be closely associated with allergic purpura.Based on these results,we intended to have research on expression and mechanism of H2R and H4 R in HSP from the clinical features,cytokines and and investigate the regulation function of their antagonists.Our research may be helpful to understand the immunological mechanism of HSP and provide new molecular targets for treatment and intervention strategies.Objective: To study the role of H2R/H4 R in the process of development and its mechanism of children HSP.To explore the role of regulation of H2R/H4 R antagonist in HSP.Methods: 1.To evaluate the clinical characteristics HSP,analyse the inmmulogical datas.Retrospective analysis the patient with HSP in Pediatric department in Changhai hospital from June 2012 to July 2014.2.Accourding to the clinical manifestation,we devided the patients into Skin Group(SK),No Renal Mix Group(NRMG)and Renal Group(RG),H2R and H4 R mRNA were detected in peripheral blood mononuclear cells(PBMC)of the 3 groups,and then further observation were conducted in skin and renal tissue.3.Detect the expression of CXCL16,CCL17 and p-STAT1 in PBMC from patients in active phase and remission phase,and analysis their correlation with H2R and H4 R.4.Detect the expression of CD80 and CD86 in PBMC from patients in activive phase and remission phase;observe the impact of H2R and H4 R antagonist on the expression of p-STAT1 on PBMC;Isolated the peripheral blood from healthy volunteer and generated DC in vitro.To detect the expression of H4 R,p-STAT1,CCL17 and CXCL16 on DC stimulated with histamine or adding H4 R antagonist at the same time.Results:.1.The male to female ratio was 0.91:1.Mean age at onset was9.85±4.73,while the range of age is 2.5~15.Peak morbidity was between 5–10 years old.And the morbidity time consentrated between October and December.About 37.30% cases were associated with infection.Refers to the clinical manifestation,110(87.3%)patients had rash at the beginning,while about 46.03% of first symptom were merely purpura,42.86% were mix minifastetion without renal involvement and 11.11% were found renal involvement at the first stage.But through the whole course of disease,about100% children suffered from purpura,and renal involvement rised from 11.11% to 38.89%.Among the renal involvement cases,there are 17 nephritis/nephriticsyndrome,25 mild proteinurine and 15 heamourine cases.The average time of company syndrome was 7 days.The time of rash was about 3 days while the abnormal renal function was about 10 days.The CD4 T cell in HSP group was lower than those in control group(P=0.00),and CD8 T cell was a little higher than control group(P=0.006).Among the 3 clinical groups,there were no significantly differences.The level of IgA,IgG,IgE of HSP group were higher than control group(P=0.00).But no significant change of IgM and C3 were observed(P=0.707,P=0.842).The level of IgG and IgA in skin group were lower than that in nephritis group(P<0.01,P=0.045).And no significant differences were detected between nephritis and non-nephritis groups.2.The histamine receptor H2R and H4 R of acute phase was significantly higher than that of remission and healthy children(P=0.00).The expretion of H4 R in renal involvement group was significant higher than the other 2 groups(P=0.00,P=0.008).But no significant difference of H2R was observed in the 3 groups.The H4 R presented in the inflammetary cells around skin blood vessel of acute HSP.While no expression of H2R in the remission purpura.In the renal tissue,H4 R can be detacted in the tubles and mesangial cells,and the expression ratio is 84.6%,while expression ratio of control group is 0 %.3.The gene and protein expression of CXCL16,CCL17 from HSP in active period were much higher than the level of remission and healthy control groups(p<0.01),and there was a significantly positive correlation between the expression of CCL17/CXCL16 and H2R/H4 R.The expression of p-STAT1 in active period were much higher than the level of remission and healthy controls groups(p<0.01),and there was also a significantly positive correlation between the expression of p-STAT1 and H2R/H4 R.4.The espression of CD86 of HSP in active and remission period were significatnt higher than healthy control group.While the expression of CD80 of HSP in active group was lower than remission and healthy control group.And there was no statisitis defference between remission and healthy control group.The expression of p-STAT1 on PBMC raised stimulated by histamine,and the level decreased after adding the specificity antangonist of the H2R and H4 R.The effect of H4 R antagonist were more obvious..Induced DC which stimulated by histamine had an increase in expression of p-STAT1 and H4 R and secretion of CXCL17 and CCL17.But rising trend went down after adding H4 R antagonist.Especially the level of CXCL16 decreases as low as control group.Conclusions:1.Infection is the main inducement of HSP.Especially the hiding infection should be payed attention.Renal involvement is always imperceptible.So monitoring the urine and renal function at early stage is very important.The inbalance of T cells plays an important role in the HSP,but no effect was observed in the severity and progress of the disease.No relevance was observed between Ig A level in the peripheral blood and the renal involvement.2.The H2R and H4 R participated in the pathogenesis of HSP.Compared with H2R,H4R played a more important role in the process of skin and renal involvement.3.In the acute phase of HSP,there were increases in the expression of CD86 on APC cells,and the upregulation of p-STAT1,CXCL16 and CCL17 on PBMC can be observed,which have a positive correlation with expression of H2R and H4 R.4.As one of the most important APC,DC also espressed H4 R.And we found that the activated H4 R may upregulate the expression of p-STAT1,promote the production of chemokine,activate the T/B lymphocyte and aggravate the inflammation reaction of HSP.