1. B cell–directed therapies for autoimmune disease and correlates of disease response and relapse 
Marc C. Levesque, MD, PhD, E. William St. Clair, MD 
Journal of Allergy and Clinical Immunology 
Volume 121, Issue 1, Pages (January 2008)
DOI: /j.jaci
Copyright © 2008 American Academy of Allergy, Asthma & Immunology Terms and Conditions

2. Fig 1
Human B-cell development. The developmental steps of human B cells are outlined. Initial development of B cells in adults occurs in the bone marrow and includes development of progenitor cells into pro–B-cell and pre–B-cell populations. The bone marrow stages of human B-cell development are characterized by the expression of CD19 by pro-B cells, the subsequent expression of CD20 by pre-B cells, the rearrangement of the heavy-chain and light-chain immunoglobulin loci, and the expression of cell surface IgM. Self-reactive B cells undergo either deletion or immunoglobulin receptor editing to eliminate autoreactive B cells. After exiting the bone marrow, transitional B cells undergo further development in peripheral lymphoid organs and circulate in the blood as naive B cells. Naive B cells encounter antigen and are stimulated via T-dependent and independent pathways in germinal centers and in the marginal zones of lymphoid organs to form memory B cells, plasmablasts, and long-lived plasma cells. The introduction of AID-mediated somatic mutations in germinal center B cells and the subsequent expression of CD27 mark the transition from naive B cells to memory and plasma cell B-cell populations. The asterisk for μ/δ at the germinal center stage indicates that μ and δ immunoglobulin heavy-chains are expressed during the pregerminal stage with subsequent replacement by γ, α, or ɛ or less frequently by continued μ or δ expression at later stages of germinal center development and at the memory B-cell stage. Most terminally differentiated plasma cells are characterized by the absence of CD20 expression and low or negative expression of CD19 and surface immunoglobulin.
Journal of Allergy and Clinical Immunology  , 13-21DOI: ( /j.jaci )
Copyright © 2008 American Academy of Allergy, Asthma & Immunology Terms and Conditions

3. Fig 2
Peripheral blood B-cell subsets on the basis of cell surface expression of CD38 and IgD. Flow-cytometric analysis of CD19+ peripheral blood B cells on the basis of expression of CD38 (x-axis) and IgD (y-axis). The upper right flow cytometry plot displays peripheral blood CD5+CD19+ B cells on the basis of expression of CD38 and IgD. CD5+ peripheral blood B cells from adults have a similar pattern of CD38 and IgD expression compared with CD5− B cells, although CD5+ B cells have somewhat higher percentages of naive CD38modIgD+ B cells. For comparison, a plot of CD5+ transitional B cells (CD38hi, IgM+, IgD+, CD10+) from a cord blood sample is shown in the lower right flow cytometry plot.
Journal of Allergy and Clinical Immunology  , 13-21DOI: ( /j.jaci )
Copyright © 2008 American Academy of Allergy, Asthma & Immunology Terms and Conditions