Case Report: A refractory unusual tetrad of overlap syndrome involving rheumatoid arthritis, Sjögren's syndrome, autoimmune hepatitis, and type 1 renal tubular acidosis, successfully treated with a BLyS/APRIL dual inhibitor

Abstract

Introduction: Rheumatoid arthritis (RA) and Sjögren's syndrome (SS) are systemic autoimmune conditions. SS frequently occurs associated with RA. In patients with RA, those with SS exhibit a higher disease burden, increased disease activity, and more complex comorbidities compared with those without SS.

Case report: We report a 54-year-old female patient who was previously diagnosed with early-stage RA less than 1 year ago. She was subsequently confirmed to have SS associated with RA. Additionally, she developed multiple autoimmune comorbidities, including autoimmune hepatitis and type 1 renal tubular acidosis. The patient resisted various treatments, including immunosuppressive drugs, disease-modifying antirheumatic drugs, and anti-inflammatory small-molecule drugs. This was evidenced by poor DA28 responses, persistent laboratory abnormalities, and ongoing symptoms and signs. Finally, she responded well to Telitacicept, a BLyS/APRIL dual inhibitor.

Discussion: Even in the early stage, multiple autoimmune comorbidities can exhibit high levels of disease activity and may not respond to conventional therapies. Telitacicept, the first dual inhibitor of BLyS/APRIL, has the potential to provide significant efficacy and safety for RA patients who also have overlapping SS and other autoimmune diseases that do not respond to standard treatments. The limitations included the absence of a liver biopsy and the short follow-up period.

Keywords: BLyS/APRIL dual inhibitor; Sjögren’s syndrome; Telitacicept; autoimmune hepatitis; rheumatoid arthritis; type 1 renal tubular acidosis.

Figure 1

(A) DR image of the left wrist joint showed no signs of RA. The arrow indicates the left radiocarpal joint, where signs were observed on the Doppler scan. (B) Grayscale Doppler sagittal image of the left radiocarpal joint: The arrow (a) indicates synovial hypertrophy. (C) Color Doppler image of the left radiocarpal joint: The arrow (b) indicates hypervascularity.

Figure 2

The microphotograph of the LGS biopsy, stained with hematoxylin and eosin, showed one focus within the whole glandular area containing more than 50 lymphocytes and plasmacytes. Original magnification: (A) ×2, (B) ×4, (C) ×10, (D) ×20.

Figure 3

Comprehensive events: (A) related to the Patient Journey; (B, C) focused on Treatment Outcomes. PIP, proximal interphalangeal joint; RF, rheumatoid factor; ACCPA, anti-cyclic citrullinated peptide antibody; AMCVA, anti-mutated citrullinated vimentin antibody; ASMA, anti-smooth muscle antibody; CRP, C-reaction protein; ESR, erythrocyte sedimentation rate; ANA, antinuclear antibody; Anti-SSA/Ro, anti-Sjögren’s-syndrome type A antibodies; Anti-SSB/La, anti-Sjögren’s syndrome type B antibodies; ASMA, anti-smooth muscle antibody; HCO₃ ⁻, bicarbonate; ALT, serum alanine transaminase; AST, serum aspartate transaminase; DS28(ESR), disease activity score in RA by assessing joints and ESR; DS28(CRP), disease activity score in RA by assessing joints and CRP; HCQ, hydroxychloroquine; TGP, total glucosides of paeony. ^†The detections were performed using indirect immunofluorescence. ^§ANA was quantified using chemiluminescent immunoassay.