The autoimmune dermatologic disease pemphigus vulgaris (PV) is associated with the serotypes HLA-DR4and HLA-DRw6. Based on nucleotide sequence and oligonucleotide probe analysis of enzymatically amplified DNA encoding HLA-DR P chain (HLA-DRB) and HLA-DQ (3 chain (HLA-DQB; henceforth HLA is omitted from designations), we showed previously that the DR4 susceptibility was associated with the DwlO DRBI allele [encoding the mixed lymphocyte culture (MLC)-defined DwlO specificity]. The DRw6 suscep-