Clinicopathological analysis of Sjogren's syndrome complicated with ANCA associated vasculitis with renal involvement

Objective To investigate the clinical and pathological features of patients with a combination of Sjogren's syndrome (SS) and antineutrophil cytoplasmic antibody (ANCA) associated vasculitis with renal involvement. Methods By searching the Peking Union Medical College Hospital medical database and literature between January 1990 and June 2017, patients had a combination of SS and ANCA associated vasculitis with renal involvement were included. Data of clinical information, autoimmune antibodies, renal manifestations and renal pathology were retrieved and analyzed. Results Eighteen patients were enrolled: 4 from our hospital and 14 from literature. SS was diagnosed no later than ANCA associated vasculitis in all the patients, among which 83.3%(15/18) of patients had extra-glandular and extra-renal organs involved. All the patients were tested positive for myeloperoxidase (MPO)-ANCA, and only two were protein 3 (PR3)-ANCA positive concurrently. The positivity rates of antinuclear antibody (ANA), rheumatoid factor (RF), anti-SSA antibody, and anti-SSB antibody were 83.3%(15/18), 55.6%(10/18), 77.8%(14/18), and 38.9%(7/18), respectively. The renal manifestations were characterized by renal insufficiency with a median serum creatinine of 174 μmol/L, hematuria, moderate proteinuria with a median 24 hour urine protein of 1.70 g, and necrotizing vasculitis with oligo-immune complex and varying degrees of interstitial damage in pathology. Conclusions A combination of Sjogren's syndrome and ANCA associated vasculitis with renal involvement is rare in clinical setting, and almost all of the patients are MPO-ANCA positive, with high probability of ANA positivity and extra-glandular involvement. Physicians should beware of ANCA associated glomerulonephritis in SS patients with inexplicable renal dysfunction and renal biopsy should be carried out in time.