Reduced ADAMTS13 activity is associated with an ADAMTS13 SNP, fever and microparticles in a malaria-like model

BACKGROUND: Severe falciparum malaria (SM) remains a major cause of death in tropical countries. The reduced activity of ADAMTS13, increasing levels of ultra-large von Willebrand factor (ULVWF) in SM patients, are assumed as factors that intensify disease severity. However, the reason why ADAMTS13 activity is reduced in SM remains unclear. OBJECTIVES: To investigate whether rs4962153, febrile temperature, and microparticles, contribute to reduced ADAMTS13 activity. METHODS: Genotypic association of rs4962153 with ADAMTS13 antigen and activity was examined in 362 healthy Thai participants. The collagen binding assay was used to study the effects of febrile temperature and microparticles on ADAMTS13 activity. RESULTS: ADAMTS13 antigen and activity were decreased in participants with AA genotype, compared to AG and GG (antigen: p-value = 0.014, and < 0.001; activity: p-value = 0.036, and < 0.002, respectively). There was significantly reduced ADAMTS13 antigen in AG compared to GG (p-value = 0.013), but not in ADAMTS13 activity (p-value = 0.082). The number of rs4962153 A alleles correlated with the reduced level of antigen and activity (p-value <0.001 and p-value = 0.001, respectively). MPs showed an inhibitory effect on ADAMTS13 activity (p-value = 0.025). Finally, ADAMTS13 activity was decreased in a temperature and time-dependent manner. The interaction between these two factors was also observed (p-value <0.001). CONCLUSIONS: These findings suggest that the A allele of rs4962153, MPs, and febrile temperature, contribute to reduce ADAMTS13 activity in plasma. These data are useful in malaria or other diseases with reduced ADAMTS13 activity.