FRI0371 Clinical characteristics and outcome of isolated lupus nephritis
Authors: K. Bugdayli, V.R. Chowdhary, C.S. Crowson, L. Zand, M.P. Alexander, L.D. Cornell
Journal: Annals of the Rheumatic Diseases (2018)

<h3>Background</h3> Lupus nephritis (LN) is a serious manifestation of systemic lupus erythematosus (SLE) associated with significant mortality and morbidity. At least 50% of patients will develop renal involvement at some point in their disease course. Rarely, patients may present with LN alone and have no extra-renal clinical manifestations of lupus. The clinical course, response to treatment and subsequent development of extra-renal manifestations of lupus is not well known in this subset. <h3>Objectives</h3> To study the treatment response and development of extra-renal manifestations of lupus in patients who present with isolated lupus nephritis. <h3>Methods</h3> Subjects were identified by searching a pathologic renal biopsy database for patients with immune complex glomerulonephritis and lupus nephritis (n=1015). Clinical records were reviewed for exclusion of infectious and secondary causes (e.g. IgA nephropathy, C1q nephropathy, C3 glomerulonephropathy, post-infectious glomerulonephritis etc.). Cases with isolated LN were defined per 2012 SLICC criteria as having biopsy proven LN with positive antinuclear antibody (ANA) and/or anti-dsDNA antibodies and who did not have any extra-renal clinical manifestations at onset. Demographics, biopsy information, clinical and laboratory features at onset, and during follow-up and treatment was recorded on a standardised data collection form. Complete and partial renal response were defined per the Dutch Working Party criteria.<sup>1</sup> <h3>Results</h3> Thirty four patients with isolated LN were identified. The median age at presentation was 41 years and majority were female (71%) Caucasians (77%). Median follow up was 5.4 years. At presentation, mean serum creatinine was 1.7 mg/dl (range 0.7–5.4), and mean proteinuria was 6.8 g/24 hours (range 0.1–62.9). Antinuclear antibodies were positive in 71%, positive dsDNA in 36%. Mean C3 and C4 levels were 78.2 mg/dl (range 26.5–133.0) and 11.0 mg/dl (range 3.0–40.0), respectively. Antibodies to extractable nuclear antigens were checked in 12 patients and positive for anti-SSA,<sup>5</sup> anti-SSB,<sup>2</sup> anti-Sm,<sup>2</sup> anti-RNP;<sup>3</sup> Anticardiolipin were positive in 7/13 and lupus anticoagulant in 4/4. Renal biopsies showed changes of Class III nephritis in 10 patients (29%), Class IV in 13 (38%) and class V in 7 (21%). Induction treatment included Corticosteroids (94%), mycophenolate mofetil (76%), cyclophosphamide (18%) and tacrolimus (3%). Maintenance treatment included corticosteroids (73%), MMF (79%), azathioprine (8%), rituximab (5%), cyclophosphamide (5%), calcineurin inhibitor (2%), chlorambucil (2%). At the last follow up CR was seen in 14 (42%) and partial response in 5 (15%). End-stage renal disease developed in 6 (18%) and 3 patients received renal transplant. Extra-renal manifestations of lupus developed in 8 patients (24%) and included acute cutaneous,<sup>2</sup> chronic cutaneous,<sup>3</sup> arthritis<sup>1</sup> and serositis.<sup>4</sup> <h3>Conclusions</h3> Majority of patients with isolated lupus nephritis respond well to treatment. The development of extra-renal manifestations of lupus after treatment is a rare occurrence. <h3>Reference</h3> [1] Neth J Med. 2012May;70(4):199–207. <h3>Disclosure of Interest</h3> None declared