Monitoring dendritic cells in clinical practice using a new whole blood single-platform TruCOUNT assay

Dendritic cells (DC) from distinct DC subsets are essential contributors to normal human immune responses. Despite this, reliable assays that enable DC to be counted precisely have been slow to evolve. We have now developed a new single-platform flow cytometric assay based on TruCOUN(TM) beads and the whole blood Lyse/No-Wash protocol that allows precise counting of the CD14(-) blood DC subsets: CD11c(+)CD16(-) DC, CD11c(+)CD16(+) DC, CD123(hi) DC, CD1c(+) DC and BDCA-3(+) DC. This assay requires 50 mul of whole blood; does not rely on a hematology blood analyser for the absolute DC counts; allows DC counting in EDTA samples 24 It after collection; and is suitable for cord blood and peripheral blood. The data is highly reproducible with intra-assay and inter-assay coefficients of variation less than 3% and 11%, respectively. This assay does not produce the DC-T lymphocyte conjugates that result in DC counting abnormalities in conventional gradient-density separation procedures. Using the TruCOUNT assay, we established that absolute blood DC counts reduce with age in healthy individuals. In preliminary studies, we found a significantly lower absolute blood CD11c(+)CD16(+) DC count in stage III/IV versus stage I/II breast carcinoma patients and a lower absolute blood CD123(hi) DC count in multiple myeloma patients, compared to age-matched controls. These data indicate that scientific progress in DC counting technology will lead to the global standardization of DC counting and allow clinically meaningful data to be obtained. (C) 2003 Elsevier B.V. All rights reserved.

Assessing professionalism: theory and practice

Professional attitudes and behaviours have only recently been explicitly recognized by medical educators as legitimate and necessary components of global competence, although the idea of Fitness to Practice has always presupposed acceptable professional behaviour. Medical schools have recently begun to introduce teaching and assessment of professionalism, including attitudes and behaviours. Partly as a result of the difficulty of assessment in this area, selection of students is receiving greater attention, in the pursuit of globally competent graduates. However, selection processes may be overrated for this purpose. Assessing actual attitudes and behaviour during the course is arguably a better way of ensuring that medical graduates are competent in these areas. I argue that judgments about attitudinal and behavioural competence are legitimate, and need be no more arbitrary than those made about scientific or clinical knowledge and skills, but also that these judgments should be restricted to what is agreed to be unacceptable behaviour, rather titan attempting to rate attitudes and behaviour positively. This model introduces students to the way in which their behaviours will be judged in their professional lives by registration authorities. These theoretical positions are illustrated by a recent case of academic failure based on inadequate attitudes and behaviours.