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International audience; The 3' regulatory region (3'RR) located downstream of the IgH gene is the master element that controls class switch recombination and sustains high-level transcription at the plasma-cell stage. This latter role suggests that the 3'RR may be involved in oncogene deregulation during the frequent IgH translocation events associated with B-cell malignancies. A convincing demonstration of the essential contribution of 3'RR in lymphomagenesis has been provided by transgenic animal models. The mouse 3'RR shares a strong structural homology with the regulatory regions located downstream of each human Cα gene. Mouse models exploring the role of the 3'RR in B-cell physiology and in malignancies should provide useful indications about the pathophysiology of human cell lymphocyte proliferation.

International audience

International audience; Electronic white blood cell (WBC) differential by standard cytology (hematology analyzer and visual inspection of blood smears) is limited to five types and identification of abnormal cells is only qualitative, often problematic, poorly reproducible, and labour costing. We present our results on WBC differential by flow cytometry (FCM) with a 6 markers, 5 colors CD36-FITC/CD2-PE+CRTH2-PE/CD19-ECD/CD16-Cy5/CD45-Cy7 combination, on 379 subjects, with detection of 12 different circulating cell types, among them 11 were quantified. Detection of quantitative abnormalities of whole leucocytes, neutrophils, eosinophils, basophils, monocytes, or lymphocytes was comparable by FCM and by standard cytology in terms of sensitivity and specificity. FCM was better than standard cytology in detection and quantification of circulating blast cells or immature granulocytes, with a first lineage orientation in the former case. All cases of lymphocytosis, with lineage assignment, were detected by FCM. FCM identified a group of patients with excess of CD16pos monocytes as those having an inflammatory syndrome. WBC differential by FCM is at least as reliable as by standard cytology. FCM superiority consists in identification and systematic quantification of parameters that cannot be assessed by standard cytology such as lineage orientation of blast cells or lymphocytes, and expression of markers of interest such as CD16 on inflammatory monocytes.

Yves Denizot*, Bernard Descottes, Veronique Truffinet, Denis Valleix, Francois Labrousse and Muriel Mathonnet UMR CNRS 6101, Laboratoire d’Immunologie, Faculte de Medecine, Limoges, France Service de Chirurgie Viscerale et Transplantations, CHU Dupuytren, Limoges, France Service d’Anatomo-Pathologie, CHU Dupuytren, Limoges, France Chirurgie Digestive, Endocrinienne et Generale, CHU Dupuytren, Limoges, France