Abacavir hypersensitivity (HLA-B*57:01)

Carrying the HLA-B*57:01 immune type makes a severe allergic reaction to the HIV drug abacavir very likely, so abacavir is avoided in people who screen positive. This marker tags that immune type. It only matters if abacavir is ever considered.

Possible results

HLA-B*57:01 not detected. You don't carry the marker for HLA-B*57:01, so this tag makes the immune type that causes severe abacavir allergy unlikely for you. If abacavir is ever needed, standard guidance applies (a clinic may still confirm with a direct HLA test).

HLA-B*57:01 likely (avoid abacavir). You carry one copy of the marker for HLA-B*57:01, the immune type linked to a severe, sometimes dangerous allergic reaction to the HIV drug abacavir. Guidelines say to avoid abacavir in people who are positive. This only matters if abacavir is ever considered, and a direct HLA-B*57:01 test should confirm it.

HLA-B*57:01 likely (avoid abacavir). You carry two copies of the marker for HLA-B*57:01, strongly suggesting you have this immune type, which makes a severe allergic reaction to the HIV drug abacavir very likely. Abacavir should be avoided, confirmed by a direct HLA-B*57:01 test. It has no effect unless abacavir is being considered.

Evidence & sources

Across global populations, fewer than 1% of people carry two copies of this variant, and about 94% carry none.

CPIC provides dosing guidance for abacavir based on this gene.

Related

Drug acetylation speed (NAT2) · Efavirenz / drug metabolism (CYP2B6*6) · Gilbert syndrome (UGT1A1 gene) · Hepatitis C treatment response (IL28B) · Opioid receptor response (OPRM1 A118G) · Thiopurine metabolism (TPMT and NUDT15 genes) · Warfarin dose sensitivity