HLA-B*5701 clinical testing: early experience in the United States.
HLA-B*5701 testing to provide risk stratification for abacavir hypersensitivity has the potential to reduce incidence of hypersensitivity reactions in susceptible individuals. Early experience with clinical HLA-B*5701 testing of the first 100 specimens, from a large clinical reference laboratory in the United States, is presented. Patient samples were tested using a two-step approach. The first step allowed rapid identification of most HLA-B*5701-negative samples in a high throughput mode. The second step involved resolution of putative positives by DNA sequencing to identify B*5701 specifically as well as other B57 subtypes. Test reporting included a phone call from a genetic counselor to obtain the ethnic background and indication for testing and to provide a patient-specific interpretation. The patients population was comprised of Caucasians, 84%; Hispanics, 13%; and African Americans, 3%. Among the 100 samples tested, 92% were HLA-B*5701-negative and 8% were positive for the HLA-B*5701 allele. All HLA-B*5701 allele positives were identified in Caucasian patients. Where the indication for testing was obtainable (57 patients), pre-abacavir therapy screening was the indication 67% of the time. Clarification of previous suspected history of hypersensitivity was the indication 33% of the time. Among samples tested to help clarify a previous history of hypersensitivity, 16/19 or 84% did not carry the HLA-B*5701 allele whereas 3/19 (16%) were carriers of the HLA-B*5701 allele. Early utilization of HLA-B*5701 testing in community practice was not always consistent with the clinical indications for testing. Post-test communication assisted in providing physician education and interpretation of patient-specific results.
Faruki
Hawazin
H
Center for Molecular Biology and Pathology and HLA Testing, Laboratory Corporation of America, Research Triangle Park, NC 27709, USA. farukih@labcorp.com
Heine
Uwe
U
Brown
Trisha
T
Koester
Ruth
R
Lai-Goldman
Myla
M
D019380:Anti-HIV Agents / Q000494:pharmacology; D015224:Dideoxynucleosides / Q000494:pharmacology; D005006:Ethnicity / Q000235:genetics; D005820:Genetic Testing / Q000706:statistics & numerical data*; D015235:HLA-B Antigens / Q000235:genetics*; D006801:Humans; D014481:United States; D000099227:Abacavir
D019380:Anti-HIV Agents; D015224:Dideoxynucleosides; D015235:HLA-B Antigens; D000099227:Abacavir; C484830:HLA-B*57:01 antigen