PMC6425334_01
Changes in hemoglobin and IgA levels. BDR: bortezomib, dexamethasone, and rituximab combination therapy. CAD: cold agglutinin disease.
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fig1
The further development in Hb and IgA levels is shown in Figure 1.
Bone marrow trephine biopsies from 2012 (a-d) and 2018 (e-h), respectively. The nodular lymphoid infiltrates (a) are CD20 positive (b) and surrounded by kappa positive plasma cells (c), typical for CAD. In other areas, there are small focal aggregates of lambda positive plasma cells (d), consistent with MGUS. In the 2018 biopsy, there is extensive plasma cell infiltration (e), consistent with MM. CD20 staining (f) shows remaining CD20 positive CAD infiltrates. The MM is IgA positive (g), whereas the CAD infiltrates are IgM positive (h).
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fig2
IgAlambda positive plasma cell population that has expanded, but IgMkappa positive B-cell infiltrates can still be seen. In retrospect, therefore, all three biopsies show two clones; and in the 2018 sample, the CAD-associated IgMkappa plasma cell population seems "hidden" among the expanding, myeloma-associated IgAlambda plasma cells (Figure 2).