Male patients with primary Sjogren's syndrome: A distinct clinical subgroup?

Aim Because the clinical and immunologic phenotypes of male primary Sjogren's syndrome (pSS) patients have not been fully elucidated, we aimed to investigate the clinical characteristics of male patients with pSS in Korea. Methods We retrospectively evaluated the medical records of male patients with pSS, who visited Seoul St. Mary's Hospital, a tertiary referral center in Korea, between January, 2015 and December, 2019. Of a total of 1107 patients with pSS, 33 were male, which is a prevalence of 2.9%. These 33 were compared with 353 female patients as a control group, whose records were extracted from the database of the Korean Initiative of Primary Sjogren's Syndrome, our nationwide pSS database. Various clinical aspects were assessed, including secretory functions, extra-glandular manifestations (EGM), disease activity-measuring indices, and hematological and serological variables. Results Male patients were less likely to complain of xerophthalmia and xerostomia and presented with fewer patient-reported disease outcomes and glandular dysfunctions as compared with female patients. White blood cell and neutrophil counts and the seropositivity of anti-ribonucleoprotein antibody were higher in male patients than in their female counterparts, whereas anti-Ro/SSA antibody and rheumatoid factor were less concentrated in sera from male patients. Pulmonary involvement and lymphoma were seen more frequently in male patients. Among other EGMs, female patients had a higher prevalence of autoimmune thyroid diseases. Conclusions Male patients with pSS present less severe glandular dysfunctions, better patient-reported disease outcomes, and a higher prevalence of pulmonary involvement and lymphoma compared to females, suggesting distinct clinical phenotypes of pSS.