A cross-sectional observational study of patients with sicca with salivary autoantibodies defines a potential new phenotype of Sjögren’s disease

Diagnosis of Sjögren's disease (SjD) consists of clinical examinations that include invasive studies such as lower lip biopsies and blood collection to identify presence of serum autoantibodies. Salivary glands of patients with SjD are sites where antibody-secreting cells accumulate and secrete immunoglobulins. Many patients with dry manifestations who do not meet classification criteria are grouped as non-Sjögren's sicca (NSS) and are heavily understudied. We undertook this cross-sectional observational study to investigate the role of salivary autoantibodies as a diagnostic tool and determine presence of salivary autoantibodies in patients with NSS. In this cross-sectional observational study, we screened whole unstimulated saliva from 446 subjects by direct enzyme-linked immunosorbent assays and capillary western blotting for anti-Ro60, anti-La, and rheumatoid factor (immunoglobulin (Ig)G and IgA) antibodies. All subjects were classified following the ACR/EULAR classification at the Oklahoma Medical Research Foundation Sjögren's Research Clinic. Patients with SjD were significantly more likely to have salivary antibodies compared with those with NSS and healthy control subjects. In this cohort, there were 88 subjects with NSS with seronegative profiles who had detectable salivary autoantibodies and objective measures of dryness. Of these 88 subjects with NSS, we identified 75 subjects that had positive objective examinations of dryness and could belong to an early-onset SjD group. Alternatively, these 75 subjects with NSS could belong to a distinct phenotype of SjD that will remain seronegative while being saliva positive for anti-Ro60. These data showed a relationship between ocular and oral dryness and the presence of salivary anti-Ro60 antibodies in subjects with NSS.