What is your treatment approach for MAG antibody-associated polyneuropathy?

When patients have a classic Distal acquired demyelinating sensory (DADS) Neuropathy phenotype (by clinical +/- EDX criteria), typically an SPEP/IFE is checked first, and if an IgM monoclonal gammopathy is observed, then I typically check MAG antibodies at that point (if clinical and EDX features are strongly present, I may check the MAG level despite SPEP findings). Also, here we are presuming there are no clinical features concerning myeloma, Waldenstrom's macroglobulinemia, or amyloidosis, which would entail co-management with our hematology colleagues (I like this flow chart from Continuum [1]).

As in your question, where the Anti-MAG DADS neuropathy is confirmed, then I have a detailed risks/benefits discussion with the patient regardin...

When managing Anti-MAG antibody-associated polyneuropathy, my treatment strategy is dictated by the degree of functional impairment, disease trajectory, and a transparent risk-benefit discussion regarding B-cell depletion therapy. In patients presenting with the classic distal acquired demyelinating symmetric (DADS) phenotype, I first obtain a serum protein electrophoresis with immunofixation (SPEP/IFE); if an IgM monoclonal gammopathy is identified - or if clinical and electrodiagnostic (EDX) features are exceptionally compelling regardless of SPEP findings - I test for anti-MAG antibody titers, while co-managing with hematology to exclude underlying Waldenström’s macroglobulinemia, systemic AL amyloidosis, or multiple myeloma. Because thi...