Screening of anti HLA-DR sera was obtained without absorptions of sera on platelets. In the first place, all our sera were tested by a lymphocytotoxicity technic on 20 T lymphocytes varieties, containing all the known HLA-A, B, C antigens. Anti HLA-A, B, C antibodies are isolated and excluded. Other sera are tested on 20 B lymphocytes varieties and positive sera are harvested, which often contains anti HLA-DR antibodies. HLA-DR typing were performed on 100 healthy not related individuals. The sera were, some from different laboratories (France-Transplant, Lyon), others from Montpellier (37 local sera). A lymphocytes were isolated by adhesivity on nylon wool column. A one stage lymphocytotoxicity technic was used for typing. Anti HLA-DR sera often are polyspecific and often contain antibodies with unknown specificity. The frequency of seven classical antigens, from DRw1 to DRw7 was established in the Languedoc populations. The antigens distribution is close to that observed in Europe, except for DRw1 which is more frequent. Several cross reactions between HLA-DR antigens were noticed.