Serum Markers Associated With Disease Activity in Giant Cell Arteritis and Polymyalgia Rheumatica

Kornelis S. M. van der Geest; Wayel H. Abdulahad; Abraham Rutgers; Gerda Horst; Johan Bijzet; Suzanne Arends; Mirjam P. Roffel; Annemieke M. H. Boots; Elisabeth Brouwer

Disclosures

Rheumatology. 2015;54(8):1397-1402. 

In This Article

Abstract and Introduction

Abstract

Objective. To compare multiple serum markers for their ability to detect active disease in patients with GCA and in those with PMR.

Methods. Twenty-six markers related to immune cells that may be involved in GCA and PMR were determined by ELISA and multiplex assay in the serum of 24 newly diagnosed, untreated GCA/PMR patients, 14 corticosteroid (CS)-treated GCA/PMR patients in remission and 13 healthy controls. Receiver operating characteristic analysis with area under the curve and Spearman's correlation coefficients were performed.

Results. Serum B-cell activating factor (BAFF), CXCL9 and IL-6 were increased in newly diagnosed GCA and PMR patients. Serum CCL2, CCL11, IL-10 and sIL-2R were modulated in GCA patients only and CXCL10 in PMR patients only. BAFF, CXCL9 and IL-6 accurately distinguished newly diagnosed GCA and PMR patients from healthy controls, as shown by area under the curve > 0.80. Upon CS-induced remission, serum BAFF and IL-6 decreased significantly in both GCA and PMR patients, whereas CXCL9 remained high. Serum BAFF and IL-6 correlated strongly with ESR and CRP in GCA and PMR patients.

Conclusion. Among the serum markers tested, BAFF and IL-6 showed the strongest association with disease activity in both GCA and PMR patients. The diagnostic value of these markers should be evaluated in larger, longitudinal studies with GCA and PMR patients, and in patients with infections or other inflammatory conditions.

Introduction

GCA and PMR are closely related inflammatory diseases that frequently co-occur.[1] GCA involves inflammation of large- and medium-sized arteries and gives rise to classic symptoms such as headache, blindness and stroke. PMR is a rheumatic disease characterized by pain and stiffness of shoulders and hips.

Besides careful examination of clinical signs and symptoms, the assessment of GCA and PMR patients typically relies on measurement of the ESR and serum levels of CRP. The ESR has been considered the gold standard inflammation marker in GCA and PMR for many years, and is also part of the classification criteria for GCA and PMR.[1] Although the ESR and CRP are increased in the majority of GCA and PMR patients with active disease,[2,3] these inflammatory markers remain normal in a subpopulation of patients.[2,3] As objective measures for disease activity are important not only for daily clinical practice, but also for evaluating treatment outcomes in clinical trials, novel markers for active GCA and PMR are needed.[4,5]

As a first step towards identifying alternative markers for active GCA and PMR, we performed a comprehensive analysis of 26 serum markers in well-defined cohorts of GCA and PMR patients. These markers, which were related to immune cells that may be involved in the immunopathology of GCA and PMR,[6,7] were studied both before and after initiation of CS treatment. In essence, we searched for markers that not only discriminated newly diagnosed GCA and PMR from healthy controls, but also modulated with disease activity upon CS-induced remission.

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