Task force report on non-criteria manifestations: Nephropathy

A small-vessel vaso-occlusive nephropathy defined as antiphospholipid syndrome-associated nephropathy (APS nephropathy) has been recently recognized. APS nephropathy was first described in primary APS patients, characterized by acute thrombotic lesions in glomeruli and/or arterioles (thrombotic microangiopathy) and chronic vascular lesions, such as fibrous intimal hyperplasia of arterioles and interlobular arteries, organized thrombi with or without recanalization, and fibrous arterial and arteriolar occlusions or focal cortical atrophy. Similar lesions were further detected in systemic lupus erythematosus (SLE)-related APS and SLE/non-APS patients with positive antiphospholipid antibodies (aPLs), independently of lupus nephritis. Hypertension is the predominant clinical manifestation of APS nephropathy, followed by hematuria, proteinuria (from mild-to-nephrotic range), and renal insufficiency. Arterial thromboses (especially stroke), pulmonary embolism, livedo reticularis, anticardiolipin antibodies, and a positive lupus anticoagulant test are strongly associated with histological lesions of APS nephropathy. According to the report of a task force group on non-criteria APS manifestations held in the context of the 13th International Congress on aPL, APS nephropathy occurs almost exclusively among patients with positive aPL (with or without APS) in comparison with those without aPL and it is more frequent in APS patients (primary or SLE related) than in SLE/aPL/non-APS patients. aPLs correlate with both acute and chronic lesions of APS nephropathy. Currently, there is no consensus on the management of APS nephropathy that it may occur or improve despite full-dose anticoagulation. Multicenter studies are needed to examine the full spectrum of clinical and histological characteristics, renal outcome, and treatment approach of this nephropathy.