6.7-kb deletion genotyping
LILRA3 presence-absence variation was detected by polymerase chain reaction (PCR) using the two sets of primers listed in Supplementary Table 2. With LILRA3 deletion, primer 1 (flanking the deletion) amplified a fragment of 166 bp. When LILRA3 was present, primer 2 (designed within the 6.7-kb region) amplified a fragment of 250 bp. Each DNA sample was tested using the two sets of primers in separate reactions. The amplified products were analyzed on a 1.5% agarose gel. The results of gel electrophoresis are shown in Supplementary Figure 1.