DETERMINATION OF INTERFERON-ALPHA-2 ALLELE COMPOSITION IN THE GENOMICDNA FROM HEALTHY-VOLUNTEERS AND LEUKEMIC PATIENTS IN JAPAN

The three interferon-alpha 2 (IFN-alpha 2) sequences identified to dat e differ from each other in just two nucleotide positions, both of whi ch result in changes in amino acids. Thus, the mature IFN-alpha 2a pro tein product is characterized by a lysine residue at position 23 (AAA) and a histidine at position 34 (CAA), IFN-alpha 2b has an arginine at position 23 (AGA) and histidine at position 34 (CAT), and IFN-alpha 2 c has arginine residues at both positions 23 (AGA) and 34 (CGT). These nucleotide variations in the DNA sequence can be distinguished by sel ective restriction enzyme analysis. We studied the distributions of th e three IFN-alpha 2 variants by analyzing chromosomal DNA from 103 Jap anese volunteers and 33 patients with hematologic disorders. Fragments of 238 bp and 617 bp of the IFN-alpha 2 gene containing codons 23 and 34 were amplified by PCR using specific primers, and the PCR products were analyzed with specific restriction nucleases to identify the IFN -alpha 2 variant sequences. Only IFN-alpha 2b gene was detected in nor mal volunteers, and no IFN-alpha 2a gene was detected in Japanese subj ects. However, IFN-alpha 2c was detected in 4 of 33 (12.1%) patients w ith leukemia.