Circulating
lupus anticoagulant (LA) is associated with
thrombosis in large and small vessels. To determine how often the presence of LA is associated with
thrombosis within the renal microcirculation, 33 patients with
systemic lupus erythematosus (SLE), renal dysfunction, and LA were identified over a 25-year period (LA group) and 32 patients with renal SLE but with normal gross coagulation screen were matched for age, sex, and biopsy timing (C group). Prevalences of
serositis, neuropsychiatric illness,
leukopenia,
thrombocytopenia,
hemolysis, anti-
DS-DNA elevation, and
complement reduction were similar.
Arthritis was less and
biologic false-positive (
BFP)
syphilis serology more common in LA. More LA patients had thrombotic events (LA 39% v C 13%; P = 0.014);
bleeding episodes, including postbiopsy, were similar. At biopsy,
hypertension (LA 55%, C 41%), serum
creatinine (mean +/- SD: LA 186 +/- 168 mumol/L [2.1 +/- 1.9 mg/dL] v C 150 +/- 168 mumol/L [1.7 +/- 1.9 mg/dL]) and
proteinuria (LA 2.6 +/- 3.1 g/24 h v C 3.1 +/- 2.7) were similar. Lesions by World Health Organization (WHO) class, activity, and chronicity indices, as well as immunofluorescence (IF) and electron microscopy (EM) findings, were not significantly different. Occlusive glomerular, arteriolar, and arterial
fibrin thrombi, along with varying degrees of renal
thrombotic microangiopathy, were seen in five of 33 patients with LA, but zero of 32 C patients (P = 0.053); three of these five patients died soon after biopsy. Overall, mortality was not different between LA and C. We conclude that the majority of patients with SLE, renal dysfunction, and LA exhibit renal morphologic findings indistinguishable from patients without LA. However, a significant minority of LA patients have
thrombotic microangiopathy in their biopsy, which is accompanied by a worse prognosis.