Elevated serum IgG4 levels in diagnosis and treatment response in patients with idiopathic retroperitoneal fibrosis

• Published in: Clinical rheumatology 2017-04, Vol.36 (4), p.903-912
• Main Authors: Pelkmans, L.G., Hendriksz, T.R., Westenend, P.J., Vermeer, H.J., van Bommel, E.F.H.
• Format: Article
• Language: English
• Subjects: Adrenal Cortex Hormones - therapeutic use; Adult; Aged; Female; Humans; Immunoglobulin G - blood; Logistic Models; Male; Medicine; Medicine & Public Health; Middle Aged; Multivariate Analysis; Netherlands; Original Article; Prognosis; Prospective Studies; Retroperitoneal Fibrosis - blood; Retroperitoneal Fibrosis - diagnostic imaging; Retroperitoneal Fibrosis - drug therapy; Rheumatology; ROC Curve; Tamoxifen - therapeutic use; Tomography, X-Ray Computed; Treatment Failure
• ISSN: 0770-3198; 1434-9949
• DOI: 10.1007/s10067-017-3542-8

Idiopathic retroperitoneal fibrosis (iRPF) may be a manifestation of IgG4-related disease. Measuring serum IgG4 (sIgG4) may be of value in monitoring iRPF, but this has scarcely been evaluated. It is unknown if tamoxifen (TMX) affects sIgG4 levels. We performed a prospective inception cohort study of 59 patients with untreated (re)active iRPF stratified by elevated (>1.4 g/L) or normal sIgG4 level. Changes in sIgG4 levels following TMX initiation and, if treatment failed, during subsequent corticosteroid (CS) treatment were analyzed. The median sIgG4 level was 1.1 g/L (interquartile range (IQR) 0.4–2.2); 24 patients (40%) had elevated sIgG4 level. Patients with elevated sIgG4 tended to present with higher ESR (46 vs. 34 mm/h; P  = 0.08) and more frequent locoregional lymphadenopathy adjacent to the mass (41.7 vs. 20.0%; P  = 0.08). sIgG4 also correlated with ESR ( ρ  = 0.26; P  = 0.05) and serum creatinine (SC) ( ρ  = 0.26; P  = 0.04). Following TMX initiation, sIgG4 level decreased, particularly when achieving treatment success ( P