Genetic predisposition for the development of lamotrigine-induced Stevens-Johnson syndrome/toxic epidermal necrolysis: a systematic review and meta-analysis.

Studies report an association between the expression of HLA alleles and lamotrigine (LTG)-induced Stevens-Johnson syndrome (SJS). This systematic review and meta-analysis evaluates the association between HLA alleles and LTG-induced SJS in different populations. Two alleles, HLA-B*0702 and HLA-C*0702, were deemed to be protective; five alleles, HLA-B*1502, HLA-B*4403, HLA-A*2402, CYP2C19*2 and HLA-B*38, may play a role in LTG-induced SJS, for which only data studying HLA-B*1502 could be extracted. The pooled odds ratio of 2.88, 95% CI of 1.60-5.17 and p-value of 0.0004 establish the presence of HLA-B*1502 as a major risk factor for the development of LTG-induced SJS/toxic epidermal necrolysis (TEN). Although multiple alleles that may play a role in the development of LTG-induced SJS/TEN were identified, the expression of the risk alleles may be ancestry-specific, and genetic screening is warranted for preventing this life-threatening adverse drug reaction.

A study of the free radical scavenging effects of Piper betle leaf extract in patients with vitiligo.

BACKGROUND: Vitiligo is an idiopathic skin disease manifested by depigmented macules. It is characterised by melanocyte destruction, and redox imbalance is proposed to play a contributory role. AIM: The aim of this study was to analyze the effects of an ethanolic extract of Piper betle leaves on the generation of reactive oxygen species in erythrocytes sourced from vitiligo patients. METHODS: The effect of Piper betle on the generation of reactive oxygen species in erythrocytes was measured by flow cytometry in patients with active and stable vitiligo versus healthy controls, using 5-(and-6)-chloromethyl-2'-7'-dichlorodihydrofluorescein diacetate. RESULTS: The generation of reactive oxygen species in erythrocytes was higher in patients with vitiligo (n = 23) compared to healthy controls (n = 18). The geometrical mean fluorescence channel was 23.05 ± 2.11 in patients versus 17.77 ± 1.79 in controls, P = 0.039. The levels of reactive oxygen species were higher in patients with active vitiligo. Treatment of erythrocytes with Piper betle in concentrations of 0.5 and 1.0 µg/ml significantly decreased the baseline levels of reactive oxygen species by 31.7% in healthy controls, and 47.6% and 44.3% in patients with active vitiligo, respectively. Piper betle effectively scavenged hydrogen peroxide, which was evident by a decrease in the geometrical mean fluorescence channel by 52.4% and 62.9% in healthy controls, and 45.0% and 57.0% in patients with active vitiligo. LIMITATIONS: The study had a small sample size. Future studies should focus on evaluation of the antioxidant role of Piper betle at the lesional site. CONCLUSION: This pilot study indicates that patients with active vitiligo demonstrate enhanced generation of reactive oxygen species in erythrocytes, which was significantly reduced following ex vivo treatment with Piper betle.