Heavy chain disease

Heavy chain disease refers to a group of rare monoclonal gammopathies characterised by elevated levels in the serum and urine of a specific heavy chain.

Three variants are recognised:

• alpha chain disease - the most common HCD, seen especially in the Mediterranean. Associated with massive infiltration of the lamina propria of the intestine and abdominal lymph nodes by lymphocytes, plasma cell and histiocytes causing villous atrophy and malabsorption. There is an increased risk of gastrointestinal lymphoma.
  
  
• gamma chain disease - seen most frequently in the elderly. The clinical presentation resembles a malignant lymphoma more than a multiple myeloma. Principle features are lymphadenopathy, anaemia, and fever; often, splenomegaly or hepatomegaly
  
  
• mu chain disease - the least common HCD, seen usually in chronic lymphocytic leukaemia. Splenomegaly and hepatomegaly are common; lymphadenopathy is rare.