PMC6954170_01
An M-peak was noted on serum electrophoresis (A). This M-protein was revealed to be monoclonal IgG lacking the light chain by immunofixation (B).
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The serum concentration of IgG was increased to 3,525 mg/dL (normally 870 to 1,700 mg/dL) and an M peak was observed on serum electrophoresis (Figure 1A), revealed to be monoclonal IgG lacking the light chain by serum immunofixation (Figure 1B), indicating gamma-HCD. gamma-HCD was further confirmed by rocket immunoselection assay (Figure 2).
Rocket immunoselection assay. A precipitation line representing a reaction with the anti-gamma-antibody was observed (arrow) even after immuno-precipitation of whole immunoglobulins with anti-kappa and -lambda antibodies (lane 4).
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The serum concentration of IgG was increased to 3,525 mg/dL (normally 870 to 1,700 mg/dL) and an M peak was observed on serum electrophoresis (Figure 1A), revealed to be monoclonal IgG lacking the light chain by serum immunofixation (Figure 1B), indicating gamma-HCD. gamma-HCD was further confirmed by rocket immunoselection assay (Figure 2).
Cytospin preparation of ascites. Many large abnormal lymphoid cells were observed. Their nuclear chromatin was fine and some of these abnormal cells were morphologically plasma cell-like (arrows).
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Furthermore, many immature abnormal lymphocytes were observed in the ascites (Figure 3). FCM analysis of these cells yielded identical results to those of the peripheral blood, although cytoplasmic immunoglobulin heavy and light chains were not examined.
Immunopathological examination of necropsied bone marrow. A: many immature large lymphoid cells can be seen (arrows) (HE staining, x400). B: These abnormal cells were positive for IgG (immunostaining with polyclonal anti-IgG, x400). C and D: Few cells were positive for kappa- and lambda- light chains (immunostaining with anti-kappa and -lambda antibodies, respectively, x200). E: These abnormal cells were positive for EBV-encoded small RNA (EBER) (x200).
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Immunohistological examination of necropsy specimens from the spleen and bone marrow revealed many abnormal lymphocytes positive for IgG, but not for kappa and lambda light chains (Figure 4) These abnormal lymphocytes were positive for EBV-encoded small RNA (EBER) (Figure 4) but negative for CD20, CD79a, CD138, and Pax5 (data not shown).