RT Book, Section A1 Wahner-Roedler, Dietlind L. A1 Kyle, Robert A. A2 Kaushansky, Kenneth A2 Prchal, Josef T. A2 Burns, Linda J. A2 Lichtman, Marshall A. A2 Levi, Marcel A2 Linch, David C. SR Print(0) ID 1180466901 T1 Heavy-Chain Disease T2 Williams Hematology, 10e YR 2021 FD 2021 PB McGraw-Hill Education PP New York, NY SN 9781260464122 LK accessmedicine.mhmedical.com/content.aspx?aid=1180466901 RD 2024/03/29 AB SUMMARYThe heavy-chain diseases (HCDs) are B-cell lymphoplasmacytic proliferative disorders in which neoplastic cells produce monoclonal immunoglobulins (Igs) consisting of truncated heavy chains (HCs) without attached light chains. The complex abnormalities of HCD proteins and the usual lack of normal light chains are a result of several distinct gene alterations, including somatic mutations, deletions, and insertions. HCDs involving the three main immunoglobulin classes have been described: α-HCD is the most common and has the most uniform presentation; γ- and μ-HCDs have variable clinical presentations and histopathologic features. (see Table 109–1) The diagnosis is established from immunofixation of serum, urine, or secretory fluids in the case of α-HCD or by immunohistologic analysis of the proliferating lymphoplasmacytic cells in nonsecretory disease. Treatment of α-HCD consists of antibiotics. If there is no response to antibiotics or if aggressive lymphoma is diagnosed, chemotherapy is indicated. Treatment of γ- and μ-HCDs depends on the underlying clinicopathologic features rather than on the presence of the abnormal protein. Table 109–1 summarizes the features of the HCDs.