HLA-DR generic typing by AFLP.

We have described a practical and inexpensive method whereby any individual can be typed and assigned to any of the 14 generic HLA-DR types: DR1, DRw15, DRw16, DRw17, DRw18, DR4, DRw11, DRw12, DRw13, DRw14, DR7, DRw8, DR9 and DRw10. Previous methods to type these specificities include - among others - serology, conventional RFLP, PCR-oligonucleotide typing, and a PCR-RFLP method useful for typing homozygous individuals. In the method reported here, DNA is amplified with a set of group-specific primers and then restricted with a number of endonucleases. Six group-specific pairs of primers have been chosen to avoid cross-amplification with other DRB alleles, including DRB3, DRB4 and DRB5 alleles, and to anneal at uniform temperature: 61 degrees C. Endonucleases were chosen to generate unique patterns of easily recognizable bands that led to unequivocal assignments of HLA-DR generic types in heterozygous as well as homozygous individuals. This technique involves two steps: 1) Amplification of DNA with six different pairs of primers where DR1, DR4 and DRw10 types can be assigned at once, and 2) Endonuclease digests of amplified DNA to assign DR7, DRw8, DR9, DRw11, DRw12, DRw13, DRw14, DRw15, DRw16, DRw17 and DRw18 types. Individuals carrying any combination of all alleles published so far can be typed by this method. The ease, low cost and reliability of this method are discussed.