"In the near future, physicians will be able to test patients' genetic makeup before prescribing medications in order to predict those that are likely to have a severe adverse reaction," Chen said. "The technology is here and there will be more advances to come."

Understanding such genetic interactions might also prove a boon to new drug development, said Chen, noting that some drugs have been eliminated in the clinical trial phase because they produced SJS symptoms in some participants.

In the United States, the condition, which is fatal in 10 percent of cases, occurs in approximately 500 people per year. The condition is four or five times more common in the Chinese population in comparison to the U.S., said Chen. Many more people worldwide are at risk of SJS should they take particular prescription drugs, he added.

Adverse drug reactions stem from two primary causes. In some cases, drug concentrations build to toxic levels due to a person's genetic inability to metabolize the medication. In others, elements of the immune system mobilize and attack the drug, thereby producing the symptoms.

The investigators screened genetic factors known to play a role in drug metabolism and the immune response in three groups:

-- 44 patients with carbamazepine-induced SJS
-- 101 patients that had taken the drug for three months with no adverse reaction
-- 93 healthy individuals not taking the drug.

All patients with SJS carried the genetic variant human leukocyte antigen B* 1502 (HLA-B* 1502), while only 3 percent of those tolerant of the drug carried that version of the HLA gene, the team found.

HLA markers -- perhaps most familiar for their use in determining suitable matches for bone marrow transplantation -- play a critical role in the immune system's recogni
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Contact: Kendall Morgan
kendall.morgan@duke.edu
919-684-4148
Duke University Medical Center
1-Apr-2004