title: Incidence of antiphospholipid antibodies in patients with monoclonal gammopathy of undetermined significance.
abstract: The incidence of antiphospholipid antibodies in patients with monoclonal gammopathy of undetermined significance (MGUS) was studied. Antiphospholipid antibodies were measured in the sera of 93 patients (49 women, 44 men; mean age 70 [+/- 21] years) with MGUS by using an enzyme-linked immunosorbent assay (ELISA). The phospholipids tested were cardiolipin (CL), phosphatidylserine (PS), phosphatidylinositol (PI), phosphatidylglycerol (PG), phosphatidic acid (PA), phosphatidylcholine (PC), and phosphatidylethanolamine (PE). Positive results were defined as a value higher than the number of multiples of the mean per phospholipid, which included 76 of 80 (95%; 20 age-matched) control individuals. The immunoglobulin-G (IgG) or IgM antiphospholipid antibodies isotype varied among the patients, as did the phospholipid specificity. For IgG, PI was found elevated in 32% of the MGUS samples, whereas the other phospholipid antigens ranged from 9% to 15%. The percentage of patients with IgM antiphospholipid antibodies was higher. The authors observed PS, PI, PA, and PC as positive in 45%, 35%, 25%, and 25% of patients, respectively. Of the 12 sera studied for IgA isotype, three (25%) were positive for PS, six (50%) for CL, and none for PE. Patients with MGUS manifested a significantly higher (P < .01) incidence of antiphospholipid antibodies in their blood than did the control persons. No difference in the incidence of antiphospholipid antibodies was seen between younger and older (age-matched) control patients. No correlation was found between serum levels of immunoglobulins and optical density reading of the blank plates used as ELISA controls.
authors.affiliation: Center for Reproduction and Transplantation Immunology, Methodist Hospital of Indiana, Indianapolis 46202.
authors.forename: J J
authors.initials: JJ
authors.lastname: Stern
authors.forename: R H
authors.initials: RH
authors.lastname: Ng
authors.forename: D A
authors.initials: DA
authors.lastname: Triplett
authors.forename: J A
authors.initials: JA
authors.lastname: McIntyre
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D017152:Antibodies, Antiphospholipid / Q000097:blood*; D005260:Female; D006801:Humans; D007070:Immunoglobulin A / Q000097:blood*; D007074:Immunoglobulin G / Q000097:blood*; D007075:Immunoglobulin M / Q000097:blood*; D008297:Male; D008875:Middle Aged; D008998:Monoclonal Gammopathy of Undetermined Significance / Q000097:blood / Q000276:immunology*
chemical_list: D017152:Antibodies, Antiphospholipid; D007070:Immunoglobulin A; D007074:Immunoglobulin G; D007075:Immunoglobulin M