Six functionally HLA‐D homozygous typing cells were identified by a restricted investigation into the Hungarian inbred population of Ivad. These putative HLA‐D homozygous typing cells were then tested against a highly selected Scandinavian population sample of 60 individuals previously typed by histocompatibility reference reagents. Three different HLA‐D specificities could thus be identified: one closely matching HLA‐Dw5, another resembling the Oslo LDoH specificity, while the last seems to be unique.Only one of the typing cells thus ascertained were HLA‐B homozygous and were selected on the basis of the Ivád family structure and not on the basis of serological