title: [Study of the clonality of cutaneous and blood lymphocytes during drug-induced hypersensitivity in 6 patients].
abstract: BACKGROUND
  The drug-induced hypersensitivity syndrome or DRESS (drug reaction with eosinophilia and systemic symptoms) is a severe toxiderma because it is accompanied by lethal visceral involvement in 6 to 10% cases. Its physiopathology remains unclear. In order to specify the immunological characteristics of this toxiderma we analyzed, prospectively, the rearrangement of the blood and cutaneous T-cell lymphocyte receptor (TCR) genes of patients exhibiting a drug-induced hypersensitivity syndrome between April 1998 and April 2000.
  
  
  METHODS
  The inclusion criteria were: age over 18 years, occurrence of a drug-induced generalized eruption, existence of associated systemic involvement (lymph node or visceral), and presence of hypereosinophilia greater than 0.5 G/l and/or circulating atypical lymphocytes. Six patients (3 men and 3 women), with a mean age of 54 years were included. The imputable drug was an anti-seizure in 3 cases, allopurinol in 2 and oxazepam in one. Remission occurred within a delay of 10 to 30 days after the acute phase. Two patients presented several flares.
  
  
  RESULTS
  No clonal rearrangement in TCR genes was detected in the cutaneous samples. A clonal rearrangement of TCR genes was initially detected in the blood lymphocytes of 3 out of the 6 patients (allopurinol: n=2 and oxazepam: n=1). The latter remained detectable during the evolution, during the second or third flare of the drug-induced hypersensitivity in 2 patients (allopurinol: n=1 and oxazepam: n=1).
  
  
  CONCLUSIONS
  The presence of circulating T-cell clones detectable for several months after the occurrence of a drug-induced hypersensitivity shows the mono or oligoclonal expansion of activated T-cells, induced by the drug imputed. Their persistence over several months corresponds to a remnant activation of the immune system that can explain the prolonged and/or recurrent evolution of the drug-induced hypersensitivity syndrome in some patients.
authors.affiliation: Laboratoires d'hématologie et d'anatomopathologie, Clinique Dermatologique, CHU Rouen, 76031 Rouen, France.
authors.forename: N
authors.initials: N
authors.lastname: Cordel
authors.forename: B
authors.initials: B
authors.lastname: Lenormand
authors.forename: Ph
authors.initials: P
authors.lastname: Courville
authors.forename: P
authors.initials: P
authors.lastname: Joly
mesh_terms: D000328:Adult; D000368:Aged; D004342:Drug Hypersensitivity / Q000097:blood / Q000276:immunology* / Q000473:pathology; D005260:Female; D015329:Gene Rearrangement, T-Lymphocyte; D006801:Humans; D008214:Lymphocytes / Q000276:immunology*; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D012867:Skin / Q000276:immunology