We performed our GWAS for lymphocyte counts using a modest sample size (462 individuals). As might be expected, we did not find any strong genetic association with the trait. This is consistent with the results of three much larger recent studies (with ∼15 000–20 000 subjects each), which also reported GWAS results in different populations for a number of blood differential counts, including lymphocyte count (37–39). Only the largest study (using almost 20 000 subjects of European ancestry) was able to identify genome-wide significant associations (at two genomic regions on chromosomes 6p and 19p) with lymphocyte count. Neither region was implicated in the analyses presented in our study, yet our study was not well suited to test for replicated association in these genomic regions. Indeed, the region on chromosome 6p is not well represented on the Affymetrix array platform that we used for genotyping (nor are any SNPs in strong LD), and the gene on chromosome 19p does not seem to be expressed in LCLs.
