Utility of the Early Sjögren Antibody Panel as a Diagnostic Marker for Sensory Neuropathy

.: Primary Sjögren syndrome (SS) is a chronic autoimmune disease characterized frequently by sensory neuropathy (SN). Carbonic Anhydrase-6 (CA-6), Parotid Secretory Protein (PSP), and Salivary Protein-1 (SP-1) antibodies (Early Sjögren antibodies [ESA]) are found in 45% of SS patients who lack traditional antibodies (Ro/La). But there is a lack of information regarding whether ESA are associated with SN, and if there are any identifying characteristics associated with ESA in SN. Our goal was to close this knowledge gap.

All SN patients tested for ESA from May 2023-October 2024 were retrospectively analyzed for clinical features such as sicca symptoms, onset acuity, small fiber neuropathy (SFN)-questionnaire scores, and pathological features such as length-dependence/vasculitis on skin biopsies, as well as lip biopsy confirmation of SS. Seropositive/seronegative groups were separated for statistical analysis.

Thirty-three adult patients (73% female) with cryptogenic SN had ESA testing. Eighteen (55%) had abnormal ESA. Twelve (100%) seropositive patients had significant sicca symptoms versus four seronegative patients (29%) (p = 0.0002). There were no significant associations between ESA seropositivity and SFN-questionnaires, pathological nonlength dependence (NLD)/vasculitis, or onset acuity.

ESA may be seen in more than half of cryptogenic SN patients, but whether these patients have confirmed SS is unclear. Seropositive patients more frequently have significant sicca symptoms than seronegative patients, but no other significant identifying characteristics were seen. Further work on a larger population should be done to confirm these findings, but this study suggests the utility of checking ESA in cryptogenic SN patients with significant sicca symptoms.