LAUSR

Background 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. Objectives To study the treatment response and development of extra-renal manifestations of lupus in patients who present with isolated lupus nephritis. Methods 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.1 Results 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,5 anti-SSB,2 anti-Sm,2 anti-RNP;3 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,2 chronic cutaneous,3 arthritis1 and serositis.4 Conclusions 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. Reference [1] Neth J Med. 2012May;70(4):199–207. Disclosure of Interest None declared