Measurement of increases in anti‐double‐stranded dna antibody levels as a predictor of disease exacerbation in systemic lupus erythematosus

TLDR

The study evaluates whether changes in anti‑dsDNA antibody levels predict disease exacerbations in systemic lupus erythematosus. In a prospective cohort of 72 SLE patients followed for an average of 18.5 months, plasma samples were collected monthly and analyzed for anti‑dsDNA antibodies using Crithidia luciliae, ELISA, and Farr assays, along with C3 and C4 complement levels, while disease activity was scored quarterly. Twenty‑seven of 33 exacerbations were associated with positive anti‑dsDNA tests, and 24 were preceded by significant antibody rises occurring 8–10 weeks before flare; serial anti‑dsDNA monitoring, particularly with the Farr assay, proved more sensitive and reasonably specific than C3/C4 levels for predicting exacerbations.

Abstract

Abstract To evaluate the predictive power of changes in levels of antibodies to double‐stranded DNA (anti‐dsDNA) as a predictor of disease exacerbations in systemic lupus erythematosus (SLE), we performed a prospective study on 72 unselected patients with SLE (mean duration of study 18.5 months, range 6–35 months). Patients were seen at least once every 3 months, and disease activity was scored according to a specific protocol. Plasma samples were obtained at least once every month and were assessed for anti‐dsDNA antibody (by the Crithidia luciliae assay, an enzymelinked immunosorbent assay [ELISA], and the Farr assay) and for complement components C3 and C4. Twenty‐seven of 33 disease exacerbations observed during the study period were accompanied by a positive test result for anti‐dsDNA antibody (27 by the Farr assay, 19 by the C luciliae assay, and 23 by the ELISA). Twenty‐four of these exacerbations were preceded by a significant increase in anti‐dsDNA antibody levels (23 by the Farr assay, 12 by the C luciliae assay, and 17 by the ELISA). The first observance of a significant increase in anti‐dsDNA antibody levels preceded the exacerbation by 8–10 weeks. Significant increases in anti‐dsDNA antibody levels not followed by an exacerbation were observed in 5 cases by the Farr assay, in 7 cases by the C luciliae assay, and in 3 cases by the ELISA; however, in 3 cases, 2 cases, and 1 case, respectively, these increases were followed by an increase in disease activity that did not fulfill the criteria for an exacerbation. Serial measurement of anti‐dsDNA antibody levels was more sensitive for predicting exacerbations than was measurement of C3 and/or C4 levels ( P < 0.03). Serial assessment of anti‐dsDNA antibody levels, especially by the Farr assay, is a sensitive and reasonably specific method for predicting disease exacerbations in SLE.