Human leukocyte antigen B (HLA-B) 57:01

The HLA-B is a gene that is involved in your immune system.  More than 1000 versions (or variants) exist for the HLA-B gene, and each one is identified by a series of numbers.  One of these variants, HLA-B*57:01 is relatively uncommon, but when a patient with that variant is exposed to the medication abacavir, there is a high risk of developing a skin reaction to abacavir.  This skin reaction is also known as a “hypersensitivity reaction.” 

People are classified into 2 categories based on whether or not they have inherited the HLA-B*57:01 variant.

Priority HLA-B genotype

  • HLA-B*57:01 positive – These patients have inherited at least one HLA-B*57:01 variant.  The HLA-B*57:01 variant occurs in about 6% of individuals of European or Asian descent.
    • Drugs that may need to be avoided or have their doses decreased:
      • Abacavir is an anti-viral medication used in the treatment of HIV infections.  Abacavir should be avoided in patients who are HLA-B*57:01 positive because of the increased risk of developing skin hypersensitivity reactions. 

Routine HLA-B genotype.  Most medicines don’t need to be adjusted based on the following genotypes:

  • HLA-B*57:01 negative – These patients have not inherited one of the HLA-B*57:01 variants.  For these patients, there is no need to avoid any medicines based on HLA-B*57:01 status alone.

More information for healthcare professionals

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