Background and aims TNF-like WEAK inducer of apoptosis (TWEAK), a TNF ligand superfamily is mainly produced by monocytes/macrophages, and is widely expressed at the RNA level in tissues including kidneys. The usefulness of urinary TWEAK (uTWEAK) to identify renal involvement in Mestizo and African-Latin American (ALA) SLE patients has not been examined yet.

Methods Patients meeting the revised ACR criteria for SLE were recruited from 2 different centres at Medellín and Baranquilla, Colombia. uTWEAK were measured using an ELISA kit (R and D system, USA)

Results 158 SLE patients were recruited (89% female) with median age of 32.8±12.1 years and median disease duration of 7.27±6.6 years. Mestizo (77%) and ALA (20%) were majority. 64% of patients had lupus nephritis (LN). 50 out of 71 biopsy proven LN had proliferative forms. Mean SLEDAI score was 8.5±8.7. LN patients (2803±6086 vs 672±1042, p=0.013) (Fig 1A) and ALA patients (3995±9656 vs 1618±2653, p=0.002) had significant higher levels of uTWEAK. uTWEAK levels were higher in patients with active LN and in Class V LN (Fig. 1B). uTWEAK levels were significantly correlated with 24 hours proteinuria, SLEDAI (Fig. 1C) and serum anti-C1q titers. An ROC curve constructed showed a good level of sensitivity and specificity (Fig. 1D)

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Abstract 273 Figure 1

Conclusions In our cohort of Colombian SLE patients, uTWEAK levels were 4 and 2 times higher in LN patients and ALA respectively. uTWEAK were significantly higher in active LN and were correlated with disease activity, proteinuria and anti-C1q antibodies.