The single-dose pharmacokinetics of alitretinoin and its metabolites are not significantly altered in patients with cirrhosis.

BACKGROUND: Alitretinoin (9-cis-retinoic acid, Toctino(®) ) has been marketed recently for oral therapy for chronic hyperkeratotic hand eczema. As alitretinoin is highly lipophilic and metabolized mainly in the liver, it is currently considered to be contraindicated in patients with liver disease. However, the pharmacokinetics and metabolism of alitretinoin have not been studied in these patients. OBJECTIVES: To study the single-dose pharmacokinetics and metabolism of alitretinoin and its metabolites in patients with cirrhosis following oral administration. METHODS: Eight patients with cirrhosis and eight matched volunteer healthy controls were given a single 30-mg oral dose of alitretinoin. Blood and urine samples were collected during the following 24-h study period. Samples were analysed for alitretinoin and for known metabolites using reverse-phase high-performance liquid chromatography. The pharmacokinetics were then evaluated using standard noncompartmental models. RESULTS: No significant differences were found between healthy controls and patients with cirrhosis when analysing the pharmacokinetic parameters of alitretinoin and its metabolites. Thus, the mean half-lives of alitretinoin were 5·3 and 5·6 h (P = 0.733) and the oral clearances were 1·92 and 1·39 L h(-1) kg(-1) (P = 0·243) in the patient group and the healthy control group, respectively. CONCLUSIONS: The metabolism and pharmacokinetics of alitretinoin following oral administration of the recommended dose of 30 mg for the treatment of severe hand eczema were similar in patients with cirrhosis and in healthy controls. If indicated, alitretinoin can be used in these patients with careful and close monitoring.

Are desmoglein autoantibodies essential for the immunopathogenesis of pemphigus vulgaris, or just "witnesses of disease"?

Pemphigus vulgaris (PV) is fascinating to dermatologists, epithelial biologists and immunologists alike, as its pathogenesis has been clarified to a much greater extent than that of most other organ-specific autoimmune diseases, and as it has provided abundant novel insights into desmoglein biology and pathology along the way. Historically, the most influential PV pathogenesis concept is that of Stanley and Amagai. This concept holds that autoantibodies against desmogleins are both essential and sufficient for epidermal blister formation (acantholysis) by impeding the normal functioning of these major adhesion proteins. However, as with most good theories, this landmark concept has left a number of intriguing and important questions open (or at least has not managed to answer these to everyone's satisfaction). Moreover, selected dissenting voices in the literature have increasingly called attention to what may or may not be construed as inconsistencies in this dominant PV pathogenesis paradigm of the recent past. The present debate feature therefore bravely rises to the challenge of re-examining the entire currently available evidence, as rationally and as undogmatically as possible, by provocatively asking a carefully selected congregation of experts (who have never before jointly published on this controversial topic!) to discuss how essential anti-desmoglein autoantibodies really are in the immunopathogenesis of PV. Not surprisingly, some of our expert "witnesses" in this animated debate propose diametrically opposed answers to this question. While doing so, incisive additional questions are raised that relate to the central one posed, and our attention is called to facts that may deserve more careful consideration than they have received so far. Together with the intriguing (often still very speculative) complementary or alternative pathogenesis scenarios proposed in the following pages, this offers welcome "food for thought" as well as very specific suggestions for important future research directions--within and beyond the camp of PV aficionados. The editors trust that this attempt at a rational public debate of the full evidence that is currently at hand will constructively contribute to further dissecting the exciting--and clinically very relevant!--immunopathogenesis of PV in all its complexity.