Immunofixation electrophoresis of serum in the most common type of multiple myeloma typically shows which pattern?

• A. Monoclonal bands of the IgG type
• B. Oligoclonal bands
• C. β-γ bridging
• D. Monoclonal bands of the IgM type

Answer: (A)

In this disease, a single malignant plasma-cell clone secretes one type of immunoglobulin, producing a monoclonal protein detectable by immunofixation. The most common form of the disease makes IgG, so you typically see a monoclonal band corresponding to IgG (with a specific light chain, either kappa or lambda). This sharp, discrete band reflects the single clone’s immunoglobulin, distinguishing it from polyclonal patterns seen with other conditions. Oligoclonal bands, β-γ bridging, or an IgM monoclonal pattern would point to different processes: polyclonal responses, chronic inflammatory states, or a different plasma-cell/lymphoplasmacytic disorder like Waldenström’s macroglobulinemia, respectively.