Background: Mannose binding lectin (MBL) is an innate humoral immune effector
and MBL defi ciency has been suggested as a risk factor for the development of certain
viral infections. However, there is no data about the possible association between MBL
defi ciency and CMV, especially after organ transplantation.
Methods: We measured MBL levels in 16 kidney transplant recipients with highrisk
CMV serostatus (D+/R-) who received valganciclovir prophylaxis for 3 months
(Study 1). In addition, MBL levels were retrospectively assayed in 55 recipients from
a previous study of organ transplant recipients managed preemptively (Study 2). In
Study 2, protracted CMV infection was associated with recipient CMV seronegativity,
increasing age, and high viral load during the initial episode. In both studies, MBL
defi ciency was diagnosed if MBL levels were <500 ng/ml.
Results: In Study 1, after a follow-up of 12 months, 7 out of 16 patients developed
CMV disease, 4 patients developed asymptomatic CMV infection, and 5 patients
never developed any sign of CMV replication. Overall, 9/16 patients (56%) had MBL
defi ciency: 5/7 (71%) of patients with CMV disease, 4/4 (100%) of patients with
asymptomatic CMV infection, and 0/5 (0%) of patients without CMV infection (p=0.005,
between CMV infection/disease versus no infection). Median MBL concentrations
were higher in patients without CMV infection than in those with CMV infection
(p<0.005). In Study 2, among 30 patients with CMV infection, 9/25 (36%) patients
without MBL defi ciency had a protracted course, while 4/5 (80%) with MBL defi ciency
did so (p=0.07).
Conclusion: Data from two separate patient populations suggest that MBL defi ciency
may be a signifi cant risk factor for late CMV disease/infection after prophylaxis, and
protracted infection after preemptive treatment. This suggests a role for MBL in the
control of CMV infection after organ transplantation.