title: Clinical features and major histocompatibility complex genes as potential susceptibility factors in pediatric immune thrombocytopenia.
abstract: OBJECTIVE
  Immune thrombocytopenia (ITP) is a heterogeneous autoimmune disorder with diverse response rates to treatments that include corticosteroids, intravenous immunoglobulins (IVIG), and splenectomy. The predisposing causes of this autoimmune disorder, one of which is immunogenetic susceptibility, have not been fully determined. We investigated whether clinical features and human leukocyte antigen (HLA) genotypes influence the occurrence, treatment response, and disease duration of childhood ITP in Taiwan.
  
  
  METHODS
  We performed HLA genotyping of 70 Taiwanese children with ITP and of 70 healthy controls and compared the data. Demographic data were also collected and evaluated.
  
  
  RESULTS
  The frequencies of heterozygous HLA-A11 and the HLA-Cw1 allele were both significantly decreased in the ITP group (p = 0.0160 and p = 0.0089, respectively), whereas the frequency of heterozygous HLA-DQ5 was significantly increased in the ITP group (p = 0.0057). Patients with HLA-DRB1*11 or -DRB1*15 were more likely to respond poorly to corticosteroids than IVIG (p = 0.0446 and p = 0.0008, respectively). In addition, we observed a positive association between HLA-A11 homozygosity and the development of persistent or chronic ITP [odds ratio (OR) = 6.3165, p = 0.0479]. The presence of HLA-DRB1*08 was, however, negatively correlated with the development of persistent or chronic ITP (OR = 0.1729, p = 0.0657). Children with antecedent of preceding illness (API) and with a younger age of onset were more likely to experience a better treatment response and shorter course of ITP.
  
  
  CONCLUSIONS
  We suggest that API, age of onset, and particular HLA class I and class II alleles, may be involved in and influence the occurrence and disease duration of childhood ITP, as well as responses to different therapeutic approaches.
authors: Department of Pediatrics, Shin Kong Wu Ho-Su Memorial Hospital, Taipei, Taiwan.
authors: Wan-Ling
authors: WL
authors: Ho
authors: Meng-Yao
authors: MY
authors: Lu
authors: Fu-Chang
authors: FC
authors: Hu
authors: Chin-Cheng
authors: CC
authors: Lee
authors: Li-Min
authors: LM
authors: Huang
authors: Shiann-Tarng
authors: ST
authors: Jou
authors: Dong-Tsamn
authors: DT
authors: Lin
authors: Kai-Hsin
authors: KH
authors: Lin
mesh_terms: D000483:Alleles; D016022:Case-Control Studies; D002648:Child; D002675:Child, Preschool; D005260:Female; D005787:Gene Frequency / Q000235:genetics; D020022:Genetic Predisposition to Disease / Q000235:genetics*; D060005:Genotyping Techniques; D006680:HLA Antigens / Q000235:genetics; D006579:Heterozygote; D006720:Homozygote; D006801:Humans; D008285:Major Histocompatibility Complex / Q000235:genetics*; D008297:Male; D016553:Purpura, Thrombocytopenic, Idiopathic / Q000235:genetics*; D013624:Taiwan / Q000453:epidemiology
chemical_list: D006680:HLA Antigens