Old but Still Relevant: High Resolution Electrophoresis and Immunofixation in Multiple Myeloma

Abstract

Introduction: High resolution electrophoresis (HRE) and immunofixation (IFX) of serum and urine are integral to the diagnostic work-up of multiple myeloma. Unusual electrophoresis patterns are common and may be misinterpreted. Though primarily the responsibility of the hematopathologist, clinicians who are responsible for managing myelomas may benefit from knowledge of these. In this review article we intend to discuss the patterns and importance of electrophoresis in present day scenario.

Methods: Patterns of HRE and IFX seen in our laboratory over the past 15 years were studied.

Results: Monoclonal proteins are seen on HRE as sharply defined bands, sometimes two, lying from γ- to α-globulin regions on a background of normal, increased or decreased polyclonal γ-globulins, showing HRE to be a rapid and dependable method of detecting M-protein in serum or urine. Immunofixation complements HRE and due to its greater sensitivity, is able to pick up small or light chain bands, not apparent on electrophoresis, including biclonal disease even when electrophoresis shows only one M-band. Special features liable to misinterpretation are discussed. Familiarity with the interpretation of the varied patterns seen in health and disease is essential for providing dependable laboratory support in the management of multiple myeloma.

Keywords: High resolution electrophoresis; Immunofixation; Myeloma.

Fig. 1

High resolution electrophoretic patterns on agarose gel (Brilliant Blue R-250 stained gels). Lane 1 Normal human serum. Lane 2 Polyclonal hypergammaglobulinemia. Lane 3 Polyclonal hypergammaglobulinemia with β–γ bridging. Lane 4 Hypogammaglobulinemia. Lane 5 Thick M-band in mid γ-globulin region on reduced polyclonal γ-globulin background. Lane 6 Thick M-band in mid-γ globulin region on increased polyclonal γ globulin background. Lane 7 Thick M-band in fast-γ globulin region on normal polyclonal γ globulin background. Lane 8 Sharp narrow M-band in fast γ-globulin region (Waldestrom’s macroglobulinemia). Lane 9 Thick M-band in fast-γ globulin region on reduced polyclonal γ-globulin background. Lane 10 M-band in slow γ globulin region at extreme cathodal region. Lane 11 A faintly stained M-band in slow γ globulin region at extreme cathodal region (on treatment). Lane 12 Two bands with different electrophoretic mobilities in γ globulin and β–γ inter-zone (partially). Lane 13 M-band in the β region

Fig. 2

High resolution urine electrophoresis (Brilliant Blue R-250 stained gels). Lane 1 Broad, dense urinary M-band in γ globulin region; albumin and other bands due to proteinuria. Lane 2 Thick M band in γ globulin region; albumin and other bands due to proteinuria

Fig. 3

Immunofixation. First lane in each figure is reference electrophoresis (Brilliant Blue R-250 stained gels). a Serum M-band reacting with γ- and λ-but not with α- or κ-antibodies (arrows). IgG λ myeloma. b Serum (bi) and urine (bii) M bands reacting with λ but not with γ-, α- or k-antibodies (arrows). The diffuse staining in the negative lanes is due to the polyclonal serum or urine antibodies. Ig λ myeloma. c M band in γ globulin reacting with γ- and λ-antibodies (arrows). The slower band has the same mobility as the obvious M band. The more anodal band represents free λ-chain. IgG λ myeloma with free λ-light chains. d Biclonal multiple myeloma (arrows). IgG κ-myeloma with free λ-light chains. e Two M-bands, both IgA κ Myeloma