Arthritis & Rheumatism, Volume 62,
November 2010 Abstract Supplement

Abstracts of the American College of
Rheumatology/Association of Rheumatology Health Professionals
Annual Scientific Meeting
Atlanta, Georgia November 6-11, 2010.


Serum Free Light Chains and Disease Activity in Systemic Lupus Erythematosus.

Jolly1,  Meenakshi, Aggarwal4,  Rohit, Mikolaitis3,  Rachel, Block2,  Joel A., Sequeira1,  Winston

Rush University Medical Center, Chicago, IL
Rush University Medical Center, Chicago, IL
Rush University Medical Center
University of Pittsburgh Medical Center, Pittsburgh, PA

Purpose:

We previously reported the superiority of using Total Free Light Chains (TFLC) as a biomarker of disease activity as compared to high sensitivity DsDNA and IgG in 75 patients with Systemic Lupus Erythematosus (SLE). Herein we report our experience with the use of TFLC in 205 SLE patients as a biomarker for disease activity.

Methods:

211 consecutive consenting SLE patients attending an outpatient Rheumatology clinic at a University Hospital were enrolled. Disease activity was assessed using physician global assessments (PGA) and Selena-SLEDAI. Adjusted SLEDAI (adjSLEDAI= SLEDAI –[C3C4 and Ds-DNA score]) was obtained. Serum FLC (Kappa (k), Lambda (l) and total FLC (k+l)) was measured using nephelometry (Binding site, UK). Additional data on DsDNA (positivity {n=182} and titres {n=171}) and complement (C3 & C4 abnormality {n=171} and titres {109}) were available from the same blood sample. Spearman correlation was used to correlate total FLC, DsDNA positivity, titre, Complement abnormality and titre with PGA, SLEDAI and adjusted SLEDAI. Mann-Whitney or Kruskall Wallis test was used to compare continuous data.

Results:

The mean age was 42±13 yrs. African American 45%, Caucasian 30%, Hispanic 12%, Asian 10% and Others 4%. PGA and SLEDAI were (mean± SD, median) 0.7± 0.8, 0.5 and 4.2 ±4.3, 2 respectively. Fifty six percent were taking prednisone. The TFLC values (mean± SD, median) were 62.5 ± 69.8, 44.3. Correlations are tabulated below.

Table 1. Correlation between markers and disease activity.

 TFLCDsDNA abnormalityDsDNA titreComplement abnormalityC3 titreC4 titre
PGA0.39 (P=0.0001)0.39 (P=0.0001)0.34 (P=0.0001)-0.14 (P=0.07)-0.24 (P=0.01)-0.14 (P=0.16)
SLEDAI0.44 (P=0.0001)0.49 (P=0.0001)0.47 (P=0.0001)-0.13 (P=0.16)-0.41 (P=0.0001)-0.23 (P=0.03)
Adj-SLEDAI0.39 (P=0.0001)0.23 (P=0.03)0.211 (P=0.05)-0.08 (P=0.45)-0.15 (P=0.22)-0.12 (P=0.31)

Conclusions:

TFLC is correlated with disease activity, even after removing DsDNA and complement information from the disease activity score. Its correlation with adjusted SLEDAI is the strongest as compared to DsDNA positivity, titres, complement abnormality or complement titres. These data suggest that TFLC may serve as a potential biomarker for SLE, especially in the patients who lack DsDNA antibodies. Longitudinal studies are now indicated.

To cite this abstract, please use the following information:
Jolly, Meenakshi, Aggarwal, Rohit, Mikolaitis, Rachel, Block, Joel A., Sequeira, Winston; Serum Free Light Chains and Disease Activity in Systemic Lupus Erythematosus. [abstract]. Arthritis Rheum 2010;62 Suppl 10 :1175
DOI: 10.1002/art.28941

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