Little is known about the differences in the immunopathogenesis between elderly-onset rheumatoid arthritis (EORA) and younger-onset RA (YORA) and the factors responsible for their clinical characteristics.
It was the aim of this study to investigate proinflammatory cytokines of EORA patients and compare them with those of YORA patients.
Serum levels of interleukin (IL)-1beta, IL-6, IL-8, tumor necrosis factor (TNF)-alpha and interferon (IFN)-gamma were determined by cytometric bead array in 86 patients with active EORA, in 76 patients with active YORA and in 30 healthy controls. Disease activity of RA was assessed using the 28-joint disease activity score. Erosion scores were recorded using a modified version of the Sharp method. Levels of anti-cyclic citrullinated peptide antibodies were determined by ELISA, and levels of rheumatoid factor-IgM and C-reactive protein were measured by nephelometry.
A higher proportion of men and a higher frequency of acute onset with constitutional symptoms and comorbidities were observed in EORA compared with YORA patients. Increased levels of serum IL-1beta, IL-6, TNF-alpha, IFN-gamma and IL-8 were positively correlated with the 28-joint disease activity score, and elevated levels of IL-1beta and TNF-alpha were positively correlated with erosion scores for both groups of RA patients. Significantly higher IL-6 levels and lower TNF-alpha levels were found in EORA compared with YORA patients. Higher levels of serum IL-6 were found in EORA patients with polymyalgia rheumatica-like symptoms than in those without and were also noted in male patients with EORA compared with female patients. Multivariate analysis showed that high levels of TNF-alpha were associated with the occurrence of constitutional symptoms, and high levels of IL-1beta were associated with the presence of anti-cyclic citrullinated peptide antibodies in EORA patients.
EORA patients appear to have differences in clinical characteristics and the patterns of proinflammatory cytokines when compared with YORA patients.