FRI0247 PROGNOSTIC ROLE OF TUBULO-INTERSTITIAL INFILTRATE IN PATIENTS AFFECTED BY LUPUS NEPHRITIS
Authors: viviana antonella pacucci, Francesca Spinelli, Konsantinos Giannakakis, Simona Truglia, Fulvia Ceccarelli, Francesca Morello, Cristina Garufi, Cristiano Alessandri, Guido Valesini, Fabrizio Conti
Journal: Annals of the Rheumatic Diseases (2019)

<h3>Background:</h3> Lupus nephritis (LN) occurs up to 50% of patients affected by Systemic Lupus Erythematosus (SLE) representing one of the major causes of morbidity and mortality in lupus population (1). Kidney biopsy is a fundamental tool for the diagnosis and management of lupus nephritis. The presence of pathological changes such as inflammatory infiltrate in glomeruli and/or in tubulo-interstitium are relevant in terms of prognosis and response to therapy (2). <h3>Objectives:</h3> The aim of the study was to correlate the clinical and laboratory findings and the response to therapy with presence of glomerular and/or interstitial infiltrate in kidney section of patients with a biopsy-proven LN. <h3>Methods:</h3> Kidney sections of patients with SLE undergoing a renal biopsy for diagnostically purpose were studied; samples were classified according to the 2004 International Society of Nephrology/Renal Pathology Society classification criteria (3). Clinical, laboratory and histological data were collected in a standardized, computerized and electronically filled form, including demographics, past medical history, autoantibody profile, previous and concomitant treatments. We assessed the disease activity by using SLEDAI-2K and remission in response to therapy was defined as the absence of renal impairment and as a score 0 of renal SLEDAI (proteinuria &lt;500mg/24 hours, absence of hematuria and urinary casts) (4). All patients underwent to cyclophosphamide or mycophenolate treatment (5, 6). Two to three micron thick sections from paraffin-embedded blocks routinely stained with hematoxylin-eosin (HE) and Periodic acid-Shiff (PAS) for light microscopy investigation were re-evaluated. Predictive value of the presence of interstitial infiltrate on renal remission was evaluated. The results were expressed as mean±standard deviation (SD) depending on the distribution of the variables. The values of P &lt; 0.05 were considered statistically significant. <h3>Results:</h3> We evaluated 53 kidney samples from patients with LN (F:M = 51:2, mean age at biopsy 35±7.7 years; mean disease duration at date of biopsy 8±8.3 years). Class IV (46%) was the most common class followed by class III (29%), class II (13%), class V (11.5%) and class VI (0,5%). Tubulo-interstitial infiltrate was found in 33 kidney specimens, with germinal centres (GC)-like features in 13 renal samples (Figure 1). During the follow up (6±3.8 years) the tubulo-insterstitial infiltrate, either diffuse or with GC-like feature, was negatively correlated with renal remission (P=0.03). <h3>Conclusion:</h3> Assessment and management of patients with LN are greatly facilitated by information obtained by renal biopsy. In the present study we demonstrate that the presence of tubulo-interstital infiltrate is associated with a worse outcome in response to therapy. Our data highlight the importance of tubulo-interstitium damage, scarcely considered in the current classification criteria, since it represents a key point to predict long-term prognosis. <h3>References:</h3> [1] Schwartz N, et al. Curr Opin Rheumatol. (2014) [2] Giannakakis K, et al. Clinic Rev Allerg Immunol (2011) [3] Weening JJ, et al. J Am Soc Nephrol (2004) [4] Gladman DD, et al. J Rheumatol (2002) [5] Houssiau FA, et al. Arthritis Rheum (2002) [6] Hahn BH, et al. Arthritis Care &amp; Research (2012) <h3>Disclosure of Interests:</h3> None declared