High frequency of clinically significant infections and cytomegalovirus disease in kidney transplant recipients with serum mannose-binding lectin deficiency.

INTRODUCTION Mannose-binding lectin (MBL) constitutes defense against infections when adaptive immune response is compromised. Elevation in serum MBL levels has been shown in patients with kidney failure. We compared serum MBL levels before and after kidney transplant and evaluated association of MBL deficiency with infectious complications in kidney transplant recipients. MATERIALS AND METHODS This study was performed in 71 kidney transplant recipients and 48 healthy controls. In 36 recipients (group 1), serum MBL levels were tested before and on days 7 and 14 after transplantation. They were followed up for 6 months. In 35 recipients (group 2), serum MBL was measured during their posttransplant follow-up visits. In both groups, frequencies of clinically significant infections and acute rejection were compared between those with low MBL (< 500 ng/mL) and normal/high MBL (> or = 500 ng/mL). RESULTS Serum MBL levels (1744 +/- 905 ng/mL) were not higher in group 1 before transplantation than in controls. One and 2 weeks after transplantation, MBL levels decreased to 1699 +/- 1030 ng/mL and 1562 +/- 1020 ng/mL, respectively. Five patients who had low serum MBL levels experienced more frequent episodes of infections (P = .008) and CMV disease (P < .001). Ten patients in group 2 with low MBL levels had more frequent episodes of CMV disease (P = .01). CONCLUSIONS These findings suggest a potential role for MBL in defense against developing posttransplant CMV disease and that low serum MBL levels in kidney transplant recipients be considered an indicator of the need for CMV prophylaxis.