Antibody reactivities to skeletal muscle proteins in a patient with lambdalight chain secreting multiple myeloma, generalised amyloidosis and rhabdomyolysis

Rhabdomyolysis is a rare complication in haematological malignancies, and a diverse range of factors has been implicated in the etiology of the syndro me. In the present study we analysed muscle morphology and antibody reactiv ities to skeletal muscle proteins in a patient diagnosed with lambda (lambd a) light chain-secreting multiple myeloma (MM) and amyloidosis, who develop ed a progressive rhabdomyolysis. The muscle tissue analysis showed focal am yloid depositions and a low degree of atrophy and inflammation. Antibody re activities against muscle proteins of approximately 42, 51 and 66 kD, respe ctively, were present in the patient's serum. The antibody specificities we re revealed by lambda light chain- or IgM-specific antibodies. The results indicate a possible etiologic link between antibody reactivities towards mu scle proteins and muscle tissue disorder in a patient with the unique combi nation of rhabdomyolysis, amyloidosis and MM of the light chain type.