NODULAR PULMONARY IMMUNOGLOBULIN LIGHT-CHAIN DEPOSITS WITH COEXISTENTAMYLOID AND NONAMYLOID FEATURES IN AN HIV-INFECTED PATIENT

Isolated nodular pulmonary amyloidosis is a rare condition characteriz ed by localized deposits of immunoglobulin (Ig) Light chain amyloid. N onamyloid nodular light chain deposits in lungs can occur in systemic light chain deposition disease. Both amyloid and nonamyloid light chai n deposits have been described at separate sites in the same or differ ent organs but rarely in lungs. We report the clinical, radiologic, an d pathologic findings in a drug user infected with the human immunodef iciency virus who had multinodular pulmonary Ig light chain deposits c onsisting of both amyloid and nonamyloid granular morphologic features . The deposits, closely associated with numerous plasma cells, had a u nique histochemical and ultrastructural profile, with intermixed Congo red-positive fibrillar amyloid and Congo red-negative granular nonamy loid components. Immunohistochemical and immunoelectron microscopic st udies showed reactivity of both the fibrillar and granular deposits fo r kappa and lambda light chains but not heavy chains, There was no evi dence of restricted clonality of local or bone marrow plasma cells, se rum or urine monoclonal protein, or secondary causes of amyloidosis. T he amyloid deposits (but not the nonamyloid deposits) were reactive wi th antibody to amyloid P component. There was no staining for other ty pes of amyloid, i.e., amyloid A or transthyretin, The relationship bet ween pulmonary amyloidosis, infection with the human immunodeficiency virus, and illicit drug use is unknown. We conclude that the nodular p ulmonary light chain deposits with both amyloid and nonamyloid morphol ogic features are related to local plasma cell proliferation and that the fibrillar and nonfibrillar components most likely result from diff erent conformations of the Ig light chains.