AB0537 Histopathology of Antiphospholipid Nephropathy in Saudis

Background Antiphospholipid syndrome (APS) is characterized by recurrent arterial, venous thrombosis and/or pregnancy losses, in the presence of persistently elevated levels of Antiphospholipid antibodies (APLA). (1)Antiphospholipid nephropathy (APSN) is a renal disease caused by antiphospholipid antibodies (APLA). Two types of APS nephropathy lesions were described previously: Acute lesions described as Thrombotic microangiopathy (TMA) and chronic lesions like Fibrous intimal hyperplasia (FIH), tubular atrophy and Focal cortical atrophy (FCA) (2,3). Objectives Describe renal histological features of patients with APS antibodies in SLE patients. Methods Over a one-year period, we prospectively recruited 77 consecutive SLE patients admitted for renal biopsy for evaluation of altered renal function. Patients were divided in two groups based on APS antibodies positivity. Results Seventy-seven renal biopsies were studied. Thirty APS positive patients [25 (83.3%) females and 5 (16.7%) male], and forty-seven APS negative patients [42 (89.4%) females and 5 (10.6%) males.]. Renal histological features suggestive of APSN were seen in 12/30 (40%) of APS positive patients compared to 4/47 (8.5%) APS negative patients ( p 1). APSN Acute lesions [thrombotic microangiopathy (TMA) in 2 (6.6%) patients], while chronic lesions of APSN namely, FCA and FIH in were found in 6 (20%) ( p =0.142) and 9 (30%) ( p =0.009) of APS patients positive and negative respectively. Redundant and wrinkled segments of basal membrane in 12 (40%) and 5 (10.6%) (p-value 0.004). Glomerular double wall contour was seen in 17 (56.7%) and in 13 (27.7%) of APS patients positive and negative respectively ( p =0.016). Conclusions The results of this study showed significant association between the presence of APS antibodies and the development of APS nephropathy.In addition it emphasizes the importance of the more specific albeit less frequent renal lesions in APS nephropathy (thrombotic microangiopathy redundant and wrinkled segments of basal membrane glomerular double wall contour). References Dusse LM,Silva FD, Freitas LG, Rios DR, Armond SC, Marcolino MS. Antiphospholipid syndrome: a clinical and laboratorial challenge. Rev Assoc Med Bras. 2014; 2(60): 181-6. Gigante A.Gasperini M.L.Cianci R. Barbano B. Giannakakis K. Di Donato D. et al. Antiphospholipid Antibodies and Renal Involvement. Am J Nephrol 2009; 30(5): 405-412. D Cruz Dp. Renal manifestations of the antiphospholipid syndrome. Lupus 2005; 14(1): 45-8. Disclosure of Interest None declared