HLAtools, Searching Shared HLA Amino Acid Residue Prevalence, and the Global Frequency Browsers: New Computational...

The highly polymorphic HLA genes inform susceptibility and resistance to infectious and autoimmune diseases and cancers and are key for successful solid-organ and stem-cell transplantation therapies. Over 41,000 HLA alleles are known and are unevenly distributed across the human population. Here, we describe HLAtools, Searching Shared HLA Amino-Acid Residue Prevalence (SSHAARP) and the Global Frequency Browser (GFB), new informatic tools developed to facilitate working with HLA data and visualizing the global distribution of HLA variants in human populations. HLAtools is an R package that consumes static resources for HLA alleles and sequences and makes these data locally computable alongside data-query, data-customization and data-analysis functions. The package further includes new reference datasets that dissect and catalogue HLA regions and HLA gene structures and provide insight into the organization of HLA pseudogenes and gene fragments. SSHAARP is an R package that describes the frequency distributions of individual HLA haplotypes, alleles and amino-acid motifs as global heatmaps. Allele frequency maps for more than 800 HLA alleles can be browsed using the GFB web and mobile applications. HLAtools and SSHAARP are available from the Comprehensive R Archive Network, and the GFB apps are available on GitHub.