Clinical relapse in systemic lupus erythematosus: correlation with antecedent elevation of urinary free light-chain immunoglobulin.
This paper reports preliminary evidence suggesting that measurements of free light-chain Ig (FLIg) in urine may represent quantitative markers of in vivo polyclonal B-cell activation. Thus, longitudinal levels of urinary FLIg in patients with systemic lupus erythematosus (SLE) may be used to track or monitor the in vivo immunopathologic B-cell activity of SLE and be helpful in predicting a disease relapse. Our findings showed that dramatic rises in urinary FLIg occurred during asymptomatic intervals that preceded by 4-8 weeks the first symptomatic signs of acute SLE relapse. These results suggest that a sizable lead time may exist between the occurrence of immunopathologic B-cell stimulation and the resultant symptoms and tissue damage of immune complex-induced acute inflammation. In these studies the measurement of urinary FLIg was accomplished by an indirect method using ng-sensitive radioimmunoassays (RIAs) that measured isotypic IgG, IgA, IgM, total kappa-Ig, and total lambda-Ig. As a control for the assessment of renal tubular function and the excretion of low molecular weight proteins in SLE patients, longitudinal measurements of beta-2-microglobulin (B2M) and lysozyme were made using a novel solid-phase 3H-biotin RIA technique.
Hopper
J E
JE
Section of Hematology, University of Illinois College of Medicine, Chicago 60680.
Sequeira
W
W
Martellotto
J
J
Papagiannes
E
E
Perna
L
L
Skosey
J L
JL
D000328:Adult; D001402:B-Lymphocytes / Q000378:metabolism; D015415:Biomarkers / Q000652:urine; D005260:Female; D006801:Humans; D007147:Immunoglobulin Light Chains / Q000276:immunology / Q000652:urine*; D007164:Immunosorbents; D008180:Lupus Erythematosus, Systemic / Q000276:immunology*; D008297:Male; D008875:Middle Aged; D009113:Muramidase / Q000652:urine; D011379:Prognosis; D011863:Radioimmunoassay; D013997:Time Factors; D001613:beta 2-Microglobulin / Q000652:urine
D015415:Biomarkers; D007147:Immunoglobulin Light Chains; D007164:Immunosorbents; D001613:beta 2-Microglobulin; D009113:Muramidase