THU0318 ANCA-ASSOCIATED GLOMERULONEPHRITIS WITHOUT CRESCENT FORMATION HAS ATYPICAL CLINICOPATHOLOGICAL FEATURES; A MULTICENTER RETROSPECTIVE STUDY
Authors: Kazuyuki Suzuki, Takeshi Zoshima, Hajime Sanada, Fae Suzuki, Satoshi Hara, Mitsuhiro Kawano
Journal: Annals of the Rheumatic Diseases (2019)

<h3>Background:</h3> The most typical histopathological feature of ANCA-associated glomerulonephritis (ANCA-GN) is crescentic GN. However, ANCA-GN is also complicated by other renal lesions, including vascular ones (arteritis and arteriolitis) and tubulointerstitial ones (tubulitis and peritubular capillaritis) [Reference 1], and tubulointerstitial or vascular-dominant inflammation without glomerulopathy sometimes exists. Few reports have focused on ANCA-GN without crescent formation in a large multicenter study. <h3>Objectives:</h3> To identify the clinicopathological features of ANCA-GN without crescent formation. <h3>Methods:</h3> We enrolled 122 Japanese ANCA-GN patients who were subjected to renal biopsy in 16 hospitals from 2001 to 2018. We measured various clinical parameters at the time of renal biopsy, including creatinine (Cr), estimated glomerular filtration rate (eGFR), C-reactive protein (CRP), MPO-ANCA, PR3-ANCA in the sera, urinalysis findings, and presence of comorbidities (hypertension, hyperlipidemia, diabetes mellitus, and hyperuricemia). Renal biopsy findings were evaluated by light microscopy. We also measured serum Cr and eGFR at the last patient visit, and recorded medications prescribed for ANCA-GN. We retrospectively compared these clinical and histological findings between those with crescent (C+ group) and without crescent (C- group). The primary endpoint was the cumulative percentage of patients who died from any cause. <h3>Results:</h3> Of 122 patients (63 females; mean age 69.5 years; observational period 37.1±41.8 years), C- group included 20 (16.4%). Although C- group had higher CRP levels (11.2±8.5 vs 6.6±6.2 mg/dl, p=0.01), they had less proteinuria (0.8±0.9 vs 1.6±1.7 g/gCr, p=0.04) and better renal function (eGFR; 52.1±29.5 vs 32.0±25.4 ml/min/1.73m2, p&lt;0.01) than C+ group. There were no significant differences in any other clinical findings including ANCA serology. In histological findings, C- group had a higher frequency of arteritis (40.0% vs 16.8%, p=0.03), while other histological findings such as arteriolitis, tubulitis and peritubular capillaritis did not differ. There were no significant differences in medications or observational period. C- group had better latest renal function (eGFR; 57.3±27.8 vs 39.0±23.6 ml/min/1.73m2, p=0.02) than C+ group. However, overall survival rate did not differ (68.4% vs 78.7%, p=0.37). <h3>Conclusion:</h3> ANCA-GN without crescent formation had specific clinicopathological features including higher systemic inflammation and frequency of renal arteritis than ANCA-GN with crescent formation. Though renal function throughout the clinical course was better in ANCA-GN without crescent formation, overall survival rate was similar with ANCA-GN with crescent formation. <h3>Reference:</h3> [1] J. C. Jennette and H. K. Singh. Pauci-Immune and Antineutrophil Cytoplasmic Autoantibody-Mediated Crescentic Glomerulonephritis and Vasculitis. In: J. C. Jennette, J. L. Olson, F. G. Silvia, V. D. D'Agati editors. The Heptinstall's Pathology of the Kidney. SEVENTH EDITION. Wolters Kluwer; 2015. p. 685-713. <h3>Disclosure of Interests:</h3> None declared