ABC of clinical haematology: Multiple myeloma and related conditionsBMJ 1997; 314 doi: https://doi.org/10.1136/bmj.314.7085.960 (Published 29 March 1997) Cite this as: BMJ 1997;314:960
- Charles R J Singer
The plasma cell dyscrasias represent a heterogeneous group of conditions characterised by disordered proliferation of monoclonal plasma cells, most of which produce monoclonal immunoglobulin (M protein or paraprotein) in the serum or urine. The clinical phenotype is determined by the rate of accumulation and the biological properties of the abnormal cells and the monoclonal protein.
Conditions associated with M proteins
Monoclonal gammopathy of undetermined significance
Smouldering multiple myeloma
Multiple myeloma (IgG, IgA, free light chains, IgD, IgE)
Plasma cell leukaemia
Solitary plasmacytoma of bone
WaldenstrÖm's macroglobulinaemia (IgM)
Chronic lymphocytic leukaemia
Heavy chain disease
Clinical features of myeloma
Bone pain and pathological fractures
Anaemia and bone marrow failure
Infection due to immuneparesis and neutropenia
The incidence of myeloma is about 4 per 100 000 in Britain. It is more than twice as high in African Americans as in white Americans and Europeans, although it is much lower among Chinese and Japanese Asians. Myeloma is extremely rare in people aged under 40 years, but its incidence increases to over 30 per 100 000 in those aged over 80. The median age at diagnosis is 69 years, with slight male predominance.
Pathogenesis and clinical features
Myeloma is due to unregulated, progressive proliferation of neoplastic monoclonal plasma cells that accumulate in the marrow, leading to anaemia and marrow failure. The cell of origin is probably a memory B lymphocyte, and neoplastic cells home to the bone marrow, where the environment rich in interleukin 6 stimulates proliferation of plasma cells.
Myeloma cells produce and secrete a monoclonal protein, usually intact immunoglobulin. IgG paraprotein is present in 60% of cases and IgA in 20-25%, and in 15-20% of cases free immunoglobulin light chains alone are produced. Myelomas whose cells secrete IgD, two clonal proteins, IgM, or no protein are rare. Free light chains are …