Alpha tryptase allele of Tryptase 1 (TPSAB1) gene associated with Dengue Hemorrhagic Fever (DHF) and Dengue Shock Syndrome (DSS) in Vietnam and Philippines.

We previously reported, significantly higher levels of Chymase and Tryptase in early stage plasma of DSS patients prior to the occurrence of shock suggesting a possible role of mast cells in dengue pathogenesis. To further investigate, we analyzed CMA1 promoter SNP (rs1800875) and TPSAB1 gene alleles, which encode the Human Chymase and α- and β- tryptase 1 enzymes respectively, for susceptibility to Dengue Hemorrhagic Fever (DHF) and Dengue Shock Syndrome (DSS) in patients from hospitals in Vietnam (Ho Chi Minh City and Vinh Long) and the Philippines. While the CMA1 promoter SNP (rs1800875) was not associated with DHF/DSS, the homozygous form of α-tryptase allele was associated with DSS patients in Vinh Long and the Philippines (OR=3.52, p<0.0001; OR=3.37, p<0.0001, respectively) and with DHF in Ho Chi Minh City (OR=2.54, p=0.0084). Also, a statistically significant association was observed when DHF and DSS were combined in Vinh Long (OR=1.5, p=0.034) and the Philippines (OR=2.36, p=0.0004); in Ho Chi Minh City when DHF and DSS were combine an association was observed, but it was not statistically significant (OR=1.5, p=0.0505). Therefore, the α-tryptase might have a possible effect on the susceptibility to severe form of Dengue infection.