Introduction: Hypersensitivity reaction to abacavir (a powerful inverse transcriptase inhibitor) is a serious adverse effect that limits its use in antiretroviral treatment and requires a high level of clinical surveillance. Certain haplotypes of the primary histocompatibility complex proteins (HLA-B*5701) are very significant predictors of the risk of hypersensitivity to this drug. The purpose of this study is to identify the cases where a probable hypersensitivity reaction to abacavir presented the HLA-B*5701 allele.
Method: A retrospective study was conducted in all HIV-1 positive adult patients infected treated with abacavir between January 2000 and December 2007, in Department 6 of the Agencia Valenciana de Salud (Valencia Health Agency). The adverse effects developed by the patients were collected to determine which cases presented a probable clinically diagnosed hypersensitivity reaction. Finally, these 39 patients were screened for HLA-B*5701.
Results: In total, 323 patients were treated with abacavir between 2000 and 2007. The treatment was discontinued in 12.1 % (n = 39 patients) presenting a hypersensitivity reaction. Nine (23.1 %) of these were HLA-B*5701 positive. Eight patients presented skin rash and positivity was observed in only single patient with gastrointestinal symptoms and fever.
Conclusions: The administration of the HLA-B*5701 gene test may be of benefit in clinical practice, because it prevents diagnostic errors of the hypersensitivity reaction and enables more accurate interpretation of the symptoms.