Pauci-immune ANCA-related glomerulonephritis (GN) is extremely uncommon in patients with underlying Sjögren's syndrome (SS) and its clinical and laboratory characteristics have not been previously explored.
We carried out a thorough literature review in order to establish predisposing factors, clinical and laboratory manifestations, kidney biopsy features, treatment modalities and response to treatment of biopsy proven ANCA-related pauci-immune GN in patients with SS.
From 1967 to 2011, seven patients with a mean age of 63±14.7 years were identified. The average duration of SS prior to development of pauci-immune GN was 50±62 months. A high incidence of extraglandular manifestations was identified: 50% had interstitial lung disease and/or peripheral neuropathy. All patients suffered from proteinuria (average 1397±905 mg per 24 hours) and haematuria at presentation. Almost 70% of patients suffered from severe anaemia (average haemoglobin 6.6±1.9 gr%). ANCA MPO was positive in all six patients, while ANCA PR3 was negative in all. All patients received corticosteroids and 70% received cyclophosphamide. One patient died and one patient developed end stage kidney disease. The rest of the study patients had improved renal function over time.
Our study emphasises that patients with SS can present with atypical kidney pathology as ANCA-related GN. Thus, high clinical awareness is warranted to establish correct diagnoses. Given the powerful impact of kidney pathology on management of these patients and responsiveness to treatment demonstrated in our case series, the significance of timely diagnosis can not be overestimated.