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Chapter 106. Plasma Cell Disorders (Part 10)

Heavy Chain Diseases The heavy chain diseases are rare lymphoplasmacytic malignancies. Their clinical manifestations vary with the heavy chain isotype. Patients secrete a defective heavy chain that usually has an intact Fc fragment and a deletion in the Fd region. Gamma, alpha, and mu heavy chain diseases have been described, but no reports of delta or epsilon heavy chain diseases have appeared. Molecular biologic analysis of these tumors has revealed structural genetic defects that may account for the aberrant chain secreted. Gamma Heavy Chain Disease (Franklin's Disease) This disease affects individuals of widely different age groups and countries of origin. It. | Chapter 106. Plasma Cell Disorders Part 10 Heavy Chain Diseases The heavy chain diseases are rare lymphoplasmacytic malignancies. Their clinical manifestations vary with the heavy chain isotype. Patients secrete a defective heavy chain that usually has an intact Fc fragment and a deletion in the Fd region. Gamma alpha and mu heavy chain diseases have been described but no reports of delta or epsilon heavy chain diseases have appeared. Molecular biologic analysis of these tumors has revealed structural genetic defects that may account for the aberrant chain secreted. Gamma Heavy Chain Disease Franklin s Disease This disease affects individuals of widely different age groups and countries of origin. It is characterized by lymphadenopathy fever anemia malaise hepatosplenomegaly and weakness. Its most distinctive symptom is palatal edema resulting from involvement of nodes in Waldeyer s ring and this may progress to produce respiratory compromise. The diagnosis depends on the demonstration of an anomalous serum M component often 20 g L 2 g dL that reacts with anti-IgG but not anti-light chain reagents. The M component is typically present in both serum and urine. Most of the paraproteins have been of the gammai subclass but other subclasses have been seen. The patients may have thrombocytopenia eosinophilia and nondiagnostic bone marrow. Patients usually have a rapid downhill course and die of infection however some patients have survived 5 years with chemotherapy. Alpha Heavy Chain Disease Seligmann s Disease This is the most common of the heavy chain diseases. It is closely related to a malignancy known as Mediterranean lymphoma a disease that affects young persons in parts of the world where intestinal parasites are common such as the Mediterranean Asia and South America. The disease is characterized by an infiltration of the lamina propria of the small intestine with lymphoplasmacytoid cells that secrete truncated alpha chains. Demonstrating alpha heavy chains is .