To define the in vivo significance of R77H we elected to study the risk allele in heterozygosity as this is the genotype of the vast majority of SLE patients [9]–[11] and to assess several CR3-mediated activities in the major human CR3 expressing cell types: monocytes, macrophages, neutrophils and DCs. Here, CRIPTO3 is linked to systemic lupus erythematosus.