HLA system in solid organ transplantation part 31

After the numerical designation, further letters are used as follows to designate other characteristics of the HLA alleles:

• N to indicate non-coding sequence or null alleles
• L low expression
• S secreted, soluble but not surface expression
• C cytoplasmic expression only
• Q questionable expression
• A aberrant or doubtful expression

For example, a given allele could be denoted as HLA-A*01:01:111:01A
A complete list of currently identified HLA alleles is piblished in the HLA dictionary and updated regularly.