We report a case of light chain deposition disease in a 59-yr-old female showing deposition of monoclonal light chain in the kidney and bone marrow accompanied with a schistocytosis, the morphologic finding of microangiopathic hemolytic anemia. The immunofluorescence examination of the kidney revealed strongly stained kappa-light chain deposits on the glomerular mesangium and capillary wall, tubules, and vessel wall. The electron microscopy demonstrated electron-dense deposits on the glomerular basement membrane and mesangium. Anemia was observed with schistocytosis and Howell-Jolly body in the peripheral blood smears. The immunohistochemical examination of the bone marrow showed the presence of kappa-light chain deposits in scattered plasma cells and thickened vessel wall in the absence of a prominent plasma cell proliferation. Although an immunofixation electrophoresis failed to detect a monoclonal gammopathy, the presence of monoclonal protein could be identified by an abnormal kappa/lambda ratio on the serum free light chain analysis.
Anemia, Hemolytic/complications/*diagnosis ; Bone Marrow/*pathology ; Female ; Glomerulonephritis/complications/*diagnosis/pathology ; Humans ; Immunoglobulin Light Chains/*analysis ; Kidney Glomerulus/*pathology/ultrastructure ; Middle Aged ; Paraproteinemias/complications/*diagnosis/immunology

BACKGROUND: Korea is an endemic area of scrub typhus and it is a common seasonal febrile illness. Although, various humoral immune responses to scrub typhus have been documented, no association between gammopathy and scrub typhus has ever been reported. We analyzed the incidences and types of monoclonal and biclonal gammopathies in scrub typhus for better coping with those gammopathies in scrub typhus. METHODS: Anti-Orientia tsutsugamushi antibody-positive sera identified by indirect immunofluorescence assay were acquired from 40 patients with confirmed scrub typhus. Monoclonal and biclonal gammopathies were screened by protein electrophoresis and were confirmed using immunofixation electrophoresis (IFE). Laboratory findings on admission of the patients with monoclonal or biclonal gammopathy were investigated retrospectively to characterize the gammopathies. RESULTS: Monoclonal or biclonal gammopathies were detected in 30% (12/40) of patients with scrub typhus (IgG-lambda, 40%; IgG-kappa, 30%; IgM-kappa, 10%; IgM-lambda, 10%; IgA-kappa, 5%; IgA-lambda, 5%). Concentrations of clonal immunoglobulin were less than 3 g/dL in all gammopathies, and hypercalcemia was not detected in any of the patients. CONCLUSIONS: Our results suggest possible association between gammopathies and scrub typhus. Further studies in larger series will be needed for exact incidence and clinical course of gammopathies in scrub typhus.
Adult ; Aged ; Humans ; Immunoglobulin A/blood ; Immunoglobulin G/blood ; Immunoglobulin Heavy Chains/blood ; Immunoglobulin Light Chains/blood ; Immunoglobulin M/blood ; Incidence ; Middle Aged ; Orientia tsutsugamushi/immunology ; Paraproteinemias/complications/*diagnosis/epidemiology/immunology ; Retrospective Studies ; Scrub Typhus/complications/*diagnosis/immunology