Figure 3.

Increase in the IgM PC compartment in bone marrow from Myd88^L252P transgenic mice. (A) Example of bi and triple parametric flow cytometry histograms gated on mature B or plasma cells for expression of IgM, B220 and CD138 for Cd19^Cre and Myd88^L252P mice (left and right panels respectively). Upper panels: IgM^{low or neg} CD138^neg, IgM^high CD138^low, IgM^high CD138^high and IgM^low CD138^high cells are colored in blue, orange, red and purple respectively using a hinged quadstat of the Kaluza software and an IgM/CD138 2-dimensional plot. The hinged quadstat was set-up for one Cd19^Cre mouse. Lower panels: triple parametric histograms using the radar function of the Kaluza software. Note the CD138 expression continuum on Myd88^L252P bone marrow B-cells that correlated with a progressive decrease in B220 expression. This CD138 expression continuum was virtually absent in Cd19^Cre mice. (B) Percentages of total IgM^pos B cells and IgM^high CD138^low pre PCs and B220^low CD138^high PCs in bone marrow from 16-24 week-old Cd19^Cre (n =6) and Myd88^L252P mice with normal SPE or hyper Ig (n = 6 and n = 3 respectively). Results are shown as the mean ± SEM. Mann Whitney test p-value < 0.05 is symbolized by *. (C) Percentages of IgM^pos CD138^high PCs among total PCs in bone marrow from 16-31 week-old Cd19^Cre (n =6) and Myd88^L252P mice with normal SPE or hyper Ig (n = 6 and n = 3 respectively). Results are shown as the mean ± SEM. Mann Whitney test p-value < 0.05 and < 0.01 are symbolized by * and ** respectively.