Allele frequencies of candidate immune genes were calculated for 62 SNPs on 17 human chromosomes for their possible involvement in clearance of drug-resistant parasites with the triple mutations of pfcrt76T , pfmdr86Y , and pfmdr1246Y ( TY ) and pfdhfr51I , pfdhfr59R , pfdhfr108N , and pfdhps437G ( IRNG ) which were determined by dotblot or PCR-restriction analysis .