The aim of this study was to evaluate the clinical relevance of rheumatoid factor (RF) and antibodies against cyclic citrullinated peptides (anti-CCP) in patients with Sjögren syndrome (SS) secondary to rheumatoid arthritis (RA).
The study included 118 individuals, and the subjects were divided into three groups: rheumatoid arthritis (RA; n = 46), RA with secondary Sjögren syndrome (RA/SS; n = 20) and healthy controls (C; n = 52). Clinical and laboratory characteristics, including ocular, oral, and serum markers, anti-CCP, and rheumatoid factor (RF), were compared in addition to biopsy of labial minor salivary glands.
The RA group exhibited unstimulated salivary flow rate, and Schirmer test results were similar to those for C and higher than those for RA/SS (P < .05). Furthermore, the frequency of xerophthalmia and xerostomia was similar among the RA and C groups, and much higher in the RA/SS group (P < .05). Anti-CCP positivity and serum levels were similar in both RA groups, irrespective of SS diagnosis (RA × RA/SS; P > .05). RF presented a similar frequency and serum level between the RA and RA/SS groups (P > .05).
Secondary SS seems to be a cluster of oral and ocular symptoms among patients with RA. Anti-CCP and RF are not relevant to evaluate the presence of SS among these patients.