Rapid detection of HLA-A☆31:01 allele in DNA and blood samples using loop-mediated isothermal amplification

Background The human leucocyte antigen (HLA) allele, HLA-A*31:01, is a biomarker for adverse cutaneous reactions to carbamazepine, a first-line antiepileptic drug. Objectives To develop a platform that can rapidly detect the HLA-A*31: 01 allele in blood samples to facilitate pretreatment screening. Methods A novel protocol based on loop-mediated isothermal amplification (LAMP) was designed and optimized. It was applied to purified genomic DNA samples derived from B-cell lines with known HLA genotypes, and to DNA and whole blood samples collected from patients with epilepsy, in whom HLA-A genotypes were determined by sequence-based typing. Results The turnaround time for the LAMP-based protocol was <45 min. In the DNA samples derived from B-cell lines (n = 66), the sensitivity, specificity, positive predictive value and negative predictive value of the LAMP-based protocol for detecting HLA-A*31: 01 were 1.00 [95% confidence interval (CI) 0.88-1.00], 0.95 (95% CI 0.82-0.99), 0.94 and 1.00, respectively. The LAMP-based protocol produced the same results in the DNA and whole blood samples collected from patients (n = 34). Its sensitivity, specificity, positive predictive value and negative predictive value in detecting HLA-A*31: 01 in the patient samples were 1.00 (95% CI 0.57-1.00), 0.97 (95% CI 0.83-0.99), 0.83 and 1.00, respectively. Conclusions The findings demonstrated the feasibility of accurately detecting HLA-A*31: 01 in DNA and whole blood samples using a LAMP-based protocol. Given its rapid turnaround time, this novel platform has the potential to be adapted into a point-of-care screening test.