RESUMO
BACKGROUND: The risk for tuberculosis (TB) reactivation in hemodialysis (HD) patients is increased, and screening for latent TB is recommended. The tuberculin skin test (TST) is inaccurate because of the high incidence of anergy in skin testing in HD patients and its inability to differentiate latent from eradicated TB infection. In this study, use of serum antilipoarabinomannan (anti-LAM) antibody detection for the diagnosis of latent TB in a dialysis population was evaluated. METHODS: Seventy-four HD patients never treated for TB composed the first group. Forty-eight healthy volunteers never treated for TB served as controls. Twenty-one TST-positive renal transplant candidates on dialysis therapy who had completed preventive anti-TB treatment formed a third group. The TST (using the Mantoux method) and anti-LAM test (using an immunochromatographic assay) were performed in all subjects participating in the study. RESULTS: In the first group, a strong association was detected between results of the TST and anti-LAM test (P < 0.0001, chi-square test). A similar association was found in the second group. In the group of HD patients treated for TB, a positive TST result and negative anti-LAM test result was a constant finding. CONCLUSION: The association between the TST and anti-LAM test in HD patients suggests that the anti-LAM test could be a useful tool for diagnosing latent TB. The absence of anti-LAM antibodies in anti-TB-treated HD patients suggests that immune response to lipoarabinomannan lacks long-lasting memory. A negative anti-LAM test result might reflect the absence of latent TB, even in patients with a positive TST result.