Schematic portrait of the human CD38 molecule and gene. Full details may be found in the pertinent sections of the paper. The yellow rectangles identify the single exons; the green oval, the CpG island; the red circles, specific responsive elements in the regulatory region of the gene; the red pentagons, regulatory interleukins for which no responsive element has been identified (the small arrows indicate whether they exert upmodulatory or downmodulatory effects); the red diamond, the polymorphic site; ER, estrogen-responsive element; IRF, interferon-responsive element; RARE, retinoic acid–responsive element; TSSs, transcription start sites (indicated by the big arrows); E2, estrogen; SNP, single-nucleotide polymorphism; and RAR, retinoic acid receptor. The modulatory role of TNFα on CD38 expression is unpublished (Mone Zaidi, personal communications, January 2006).