Lupus Anticoagulant-Like Activity Observed in a Dimeric λ Protein Produced by Myeloma Cells
Division of Hematology, Institute of Clinical Medicine, University of Tsukuba, Ibaraki, Japan.International Journal of Hematology (Impact Factor: 1.92). 07/2001; 73(4):526-31. DOI: 10.1007/BF02994017
We report here a lupus anticoagulant (LA)-like activity observed in a 45-year-old man with Bence-Jones protein (BJP) lambda-type multiple myeloma. This patient showed no clinical symptoms of thrombosis or bleeding diathesis. Laboratory examination on admission showed mild anemia, prolongation of activated partial thromboplastin time (APTT) (APTT, 56.2 seconds; control, 29.1 seconds), normal prothrombin time, normal thrombin time, and massive proteinuria (2.3 g/d). The mix test with normal plasma showed the presence of circulating anticoagulant. Based on the assumption that the lambda-type BJP may have been responsible for the prolongation of APTT, we purified the BJP from the patient's urine using column works. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis and immunoblotting showed that the purified protein was a 48-kd homodimer of immunoglobulin lambda-chains. Addition of the purified dimeric lambda-type BJP to the normal plasma prolonged both APTT and dilute Russell's viper venom time (DRVVT) in a dose-dependent manner, and the negatively charged phospholipid-dependent prothrombinase activity was significantly inhibited in the presence of this protein. Furthermore, both the prolongation of DRVVT and the inhibition of the prothrombinase activity were almost completely abrogated under the condition of high ionic strength. These findings collectively suggest that the dimeric lambda-type BJP showed LA-like activity via the mechanism of ionic charge.
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ABSTRACT: We investigated the rare case of a patient with IgGlambda multiple myeloma for whom both prothrombin time and APTT were significantly prolonged. The IgG inhibited coagulation reactions upstream from prothrombin when coagulation was initiated by mRVVT, but not by FXa, as indicated by a chromogenic substrate for FXa. The mPT and the mAPTT showed inhibition of FXa generation in both the intrinsic and extrinsic pathways. The IgG inhibited both protein C (indicated by APTT) and FX (indicated by RVV) but not amidolysis for either activated protein C or FXa. The addition of excess phospholipid significantly shortened the prolonged RVVT of the patient. It inhibited the coagulation reactions of normal plasma and was dependent on decreasing the PS concentration in the APTT reagent. It was suggested that the IgG showed lupus anticoagulant (LA)-like activity that inhibited phospholipid-dependent coagulation reactions in the intrinsic, extrinsic, and common pathways. However, the IgG did not bind cardiolipin-beta2GPI complex, beta2GPI, or prothrombin in ELISA assays. The IgG did not bind to either PS or phospholipid complexes in the presence or absence of prothrombin, FX, or FXa. Interestingly, the IgG lost its LA like-activity when it was degraded to F(ab')2 and Fc fragments by pepsin. We suspected that the IgG might inhibit the interaction between coagulation factors and acid phospholipid non-immunologically and that this process requires an intact IgG conformation, although the reaction mode is still not clear.
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ABSTRACT: To describe the different types of malignancies associated with antiphospholipid antibodies (aPL). We performed a computer-assisted (MEDLINE, National Library of Medicine, Bethesda, MD) search of the literature from 1966 to 2003 to identify all cases of malignancies having aPL. One hundred twenty patients were found. The mean age was 56+/-17 years (range 5 to 88). Sixty-two (52%) patients were men and 58 (48%) were women. A heterogeneous group of malignancies were found. Regarding hematological malignancies, 10 (8%) patients suffered from B-cell lymphoma, 8 (7%) from spleen lymphoma, 7 (6%) from chronic myeloid leukemia, and 6 (5%) from non-Hodgkin's lymphoma (NHL). Regarding solid tumors, renal cell carcinoma was diagnosed in 7 (6%) patients, primary tumor with unknown origin in 7 (6%), lung adenocarcinoma in 6 (5%), breast carcinoma in 6 (5%), and melanoma in 6 (5%). The main aPL-related manifestations were thrombocytopenia (25%), cerebrovascular accidents (24%), deep vein thrombosis (19%), pulmonary embolism (15%), and heart valve lesions (9%). In 17 cases, catastrophic antiphospholipid syndrome was considered to be triggered by the malignancy. Seventy-one (63%) of 113 patients recovered or are still alive after cancer treatment. Twenty-three (35%) of 65 patients achieved aPL remission after proper treatment of the malignancy. It is important to bear in mind, especially in elderly patients, that thrombotic events associated with aPL can be the first manifestation of malignancy. At the same time, the presence of aPL in patients with malignancies has important implications in their treatment and prognosis.
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