HLA-B* 1502 allele and cutaneous adverse drug reactions by antiepileptic drugs [e. gr. carbamazepine (CBZ) and lamotrigine (LTG)]

Cutaneous adverse drug reactions (cADRs) caused by most of the antiepileptic drugs are delayed type of hypersensitivity ranging from mild maculopapular eruption (MPE), with increasing severity of hypersensitivity syndrome (HSS), severe and life-threatening Stevens-Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN).

Antiepileptic drugs, especially drugs with aromatic structure such as carbamazepine (CBZ) and lamotrigine (LTG), are among the most common causes of severe cADRs.

Lamotrigine (LTG) is a common used antiepileptic drug. However, the use of LTG is limited because of its cutaneous adverse drug reactions (cADRs).

Pharmacogenetic studies have identified a genetic association between HLA-B* 1502 allele and carbamazepine-induced SJS (Stevens-Johnson) and TEN (toxic epidermal necrolysis) in Han Chinese and Thai populations but not in caucasians and Japanese.

The relationships between the HLA-B* 1502 allele and the cutaneous adverse drug reactions (cADRs) have been studied in several patient groups. In this sense, the presence of HLA-B* 1502 allele has been found in 100% CBZ-SJS (carbamazepine/Stevens-Johnson) patients but in only 3% of CBZ-drug tolerant patients and in 9% of the control population. HLA-B* 1502 was found to be strongly associated with CBZ/SJS/TEN (carbamazepine/Stevens-Johnson/toxic epidermal necrolysis), but not with MPE (maculopapular eruption) or HSS (hypersensitivity syndrome).

Tests performed in IVAMI: in IVAMI we perform the detection of HLA-B* 1502 allele, by means of the PCR amplification of the allele and its subsequent sequencing.

Recommended samples: non-coagulated blood obtained with EDTA for separation of blood leucocytes, or a card with a dried blood sample (IVAMI can mail the card to deposit the blood sample).