Analysis On The Relationdhip Beteeen Primarry Immune Thrombocytopenia In Chidren And Genetic Polymorphisms Of Human Platelet Antigen Systems

Objective:This study was aimed to investigate the distribution of allele frequencies of human platelet antigen HPA-1～6,15 systems among Guangxi pediatric patients with immune thrombocytopenia (ITP), and to study the potential correlation between ITP and HPA-1～6,15 systems genetic polymorphisms.Methods:(1)The clinical and laboratory data of 46 children diagnosed with acute ITP and 46 children diagnosed with chronic ITP between January 2007 and December 2014 were collected and divided into acute ITP group and chronic ITP group. As well as 48 normol healthy children for health examinationd were selected as control group. (2) Genotyping of HPA-1～6,15 in 92 ITP patients and 48 healthy controls was performed by using polymerase chain reaction (PCR) combined with direct sequencing.Results:The allele frequencies of HPA-2 and HPA-15 systems were significantly different among the three groups, the P value was 0.026、0.020, respectively. The allele frequency of HPA-2a of the three groups was 93.5%,95.7% and 100%, as well as the allele frequency of HPA-2b of the three groups was 6.5%,4.3% and 0.0%, respectively. The allele frequency of HPA-15a of the three groups was 41.3%,48.9% and 61.5%,and the allele frequency of HPA-15b was 58.7%,51.1% and 38.5%,respectively.The same time,compared respectively, the allele frequencies of HPA-2,15 were significantly different between the chronic ITP group and the control group (P<0.0167), while there was no statistically significant difference between the acute and chronic ITP groups as well as between the acute ITP and the control group (P>0.0167). There were 4 patients found to be HPA-2a/2b heterozygous among the actue ITP group which was equal to the chronic ITP group, and one homozygote HPA-2b/2b was found in chronic ITP group.The allele frequency of the HPA-2b heterozygous in the chronic ITP group and the actue ITP group is 6.5% and 4.3%, respectively,while there was no heterozygou of HPA-2a/2b as well as HPA-2b allele found in control group. There were no significant statistical differences among the frequencies of other alleles (P>0.05)Conclusions (1) There was a possible association between the HPA-2,15 antigens and chronic ITP in children.The HPA-2b,15b may be a risk factor for with in children chronic ITP,while HPA-2a,15a may be a favorable factor for children with chronic ITP. (2) The HPA-2,15 antigen system polymorphisms have nothing to do with acute ITP in children. (3) There was no association between the HPA-1,3-6 alleles and ITP in children. (4) The allele HPA-2b can be found in chronic ITP group and the acute group,there is no HPA-2b allele found in control group.So there was a possible association between the HPA-2b allele and ITP in children.