Rapid onset monoclonal gammopathy in cutaneous lupus erythematosus: interference with complement C3 and C4 measurement.
Accurate nephelometric immunoassay requires both the analyte and the calibration standard to have the same molecular mass. Alteration in the size of the analyte can affect light scatter and yield erroneous results. We report a case where an autoantibody, a monoclonal IgM with immunoconglutinin activity, interfered with the nephelometric quantitation of plasma complement components C3 and C4.
Larking-Pettigrew
M D
MD
Department of Pathology, University of Pittsburgh School of Medicine, Pennsylvania 15213-2582, USA.
Ranich
T P
TP
Kelly
R H
RH
D000328:Adult; D001323:Autoantibodies / Q000097:blood*; D003176:Complement C3 / Q000032:analysis*; D003181:Complement C4 / Q000032:analysis*; D005260:Female; D006801:Humans; D007118:Immunoassay / Q000379:methods; D007075:Immunoglobulin M / Q000097:blood; D008178:Lupus Erythematosus, Cutaneous / Q000276:immunology*; D009391:Nephelometry and Turbidimetry; D010265:Paraproteinemias / Q000276:immunology*
D001323:Autoantibodies; D003176:Complement C3; D003181:Complement C4; D007075:Immunoglobulin M