title: Use of patch testing for the diagnosis of abacavir-related hypersensitivity reaction in HIV patients.
abstract: BACKGROUND
  The use of antiretroviral drug abacavir (ABC) has been often associated with cutaneous hypersensitivity reactions, the majority being severe.
  
  
  OBJECTIVE
  The present study discusses the issues of patch testing associated with pharmacogenetic screening in light of the development of abacavir hypersensitivity reactions (HSRs).
  
  
  METHODS
  The present authors classified 100 patients into three groups: 20 patients (group A) had experienced a hypersensitivity reaction when treated with highly active antiretroviral therapy (HAART) including ABC; 60 HIV-positive patients (group B) were receiving HAART scheme including ABC; 20 HIV-negative patients acted as control group (group C). Patients of group A and B were patch tested with ABC as such, then with an ABC extract diluted to 1 and 10% in petrolatum. Group C patients underwent patches with petrolatum only. A biopsy of the lesion was performed in those patients who showed a positive skin reaction. All patients had been tested for HLA-B5701.
  
  
  RESULTS
  A correlation between positive ABC-patch testing and HLA-B5701 was found in 50% of patients enrolled in group A, while in group B and C, all patients tested negative for both genetic marker and ABC-patch testing. Histopathology findings confirmed a vigorous CD4+ and CD8+ cellular response that is compatible with HSR.
  
  
  CONCLUSIONS
  Patch testing is a safe and sensitive method that can be used for to confirm or exclude any correlation between abacavir and hypersensitivity skin reactions in patients who have been previously treated with abacavir during HAART. Correlation between patch test, immunohistochimical, and genetic tests results shows that genetic testing increases the possibility to identify patients with a true reaction.
authors.affiliation: Division of Clinical, Preventive and Oncologic Dermatology - Department of Critical Care Medicine and Surgery, University of Florence, Florence, Italy. simonetta.giorgini@unifi.it
authors.forename: S
authors.initials: S
authors.lastname: Giorgini
authors.forename: C
authors.initials: C
authors.lastname: Martinelli
authors.forename: L
authors.initials: L
authors.lastname: Tognetti
authors.forename: A
authors.initials: A
authors.lastname: Carocci
authors.forename: R
authors.initials: R
authors.lastname: Giuntini
authors.forename: V
authors.initials: V
authors.lastname: Mastronardi
authors.forename: F
authors.initials: F
authors.lastname: Torricelli
authors.forename: F
authors.initials: F
authors.lastname: Leoncini
authors.forename: T
authors.initials: T
authors.lastname: Lotti
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D019380:Anti-HIV Agents / Q000009:adverse effects*; D023241:Antiretroviral Therapy, Highly Active; D001706:Biopsy; D015224:Dideoxynucleosides / Q000009:adverse effects* / Q000138:chemical synthesis*; D004342:Drug Hypersensitivity / Q000175:diagnosis* / Q000209:etiology / Q000235:genetics / Q000276:immunology; D005260:Female; D005819:Genetic Markers; D015658:HIV Infections / Q000188:drug therapy*; D015235:HLA-B Antigens / Q000235:genetics; D006801:Humans; D007558:Italy; D008297:Male; D008875:Middle Aged; D010328:Patch Tests; D011237:Predictive Value of Tests; D018894:Reverse Transcriptase Inhibitors / Q000009:adverse effects*; D000099227:Abacavir
chemical_list: D019380:Anti-HIV Agents; D015224:Dideoxynucleosides; D005819:Genetic Markers; D015235:HLA-B Antigens; D018894:Reverse Transcriptase Inhibitors; D000099227:Abacavir; C484830:HLA-B*57:01 antigen