Urinary monocyte chemotactic protein-1 (MCP-1) in leprosy patients: increased risk for kidney damage.

BACKGROUND: We aimed to evaluate urinary MCP-1 and oxidative stress through urinary malondialdehyde (MDA) in leprosy and correlate them with traditional, but less sensitive markers of renal disease.

METHODS: This is a cross-sectional study of 44 patients with diagnosis of leprosy and no previous treatment. Skin smear was assessed through a bacteriological index - from 0 to 6+. Glomerular filtration rate (GFR), protein excretion rate, microalbuminuria, urinary oxidative stress, malondialdehyde (MDA) and urinary MCP-1 were measured. Also, high- sensitivity C-reactive protein (hs-CRP) was measured in the blood. Fifteen healthy subjects composed a control group.

RESULTS: Age and gender were similar between leprosy patients and control groups. No patient had a GFR < 60 mL/min/1.73 m2 or albumin excretion rate greater than 30 mg/g-Cr. Leprosy patients had higher urinary protein excretion (97.6 +/- 69.2 vs. 6.5 +/- 4.3 mg/g-Cr, p < 0.001), urinary MCP-1 (101.0 +/- 79.8 vs. 34.5 +/- 14.9 mg/g-Cr, p = 0.006) and urinary MDA levels (1.77 +/- 1.31 vs. 1.27 +/- 0.66 mmol/g-Cr, p = 0.0372) than healthy controls. There was a positive correlation between urinary MCP-1 and bacteriological index in skin smears (r = 0.322, p = 0.035), urinary protein excretion (r = 0.547, p < 0.001), albumin excretion rate (r = 0.414, p = 0.006) and urinary MDA (r = 0.453, p = 0.002). After adjusting for hs-CRP, urinary MCP-1 remained correlated with albumin excretion rate (rpartial = 0.483, p = 0.007) and MDA levels (rpartial = 0.555, p = 0.001).

CONCLUSION: Leprosy patients with no clinical kidney disease have increased urinary MCP-1 mainly in lepromatous polar form. Inflammatory (MCP-1) and oxidative stress markers suggest leprosy patients are at high risk of developing kidney disease.