The authors wish to thank the laboratory, clinical, and nursing staff of HDP, whose high quality of service and cooperation have made this study possible. Financial support was provided by the Fundacao para a Ciencia e a Tecnologia (FCT) Portugal [PTDC/SAU-EPI/122400/2010], part of the EDCTP2 program supported by the European Union. JP was supported by a post doc fellowship from project [PTDC/SAU-EPI/122400/201...