Growth Hormone Abuse and Biological Passport: Is Mannan-Binding Lectin a Complementary Candidate?

Objective: In the detection of human growth hormone (GH) abuse, the approach based on altered GH-related biomarkers is also being considered with respect to its application within the context of a biological passport. As a potential biomarker, mannan-binding lectin (MBL), which is reported to respond to recombinant GH (rGH) administration, is evaluated here. Design: Randomized and single blind and approved by the Ethical Committee (Comite Etico de Investigacion Clinica-Instituto Municipal de Asistencia Sanitaria). Participants: One group of 12 male subjects (24.2 +/- 2.2 years; 76.1 +/- 6.1 kg) was studied. Interventions: Mannan-binding lectin concentration was measured in 12 healthy individuals after subcutaneous daily doses of 6 IU of rGH administration. Mannan-binding lectin serum concentration increased after rGH administration. Mannan-binding lectin concentration increases were observed 48 hours after the first administration and remained elevated for several days after the final dose. Main Outcome Measures: Mannan-binding lectin concentration increase and elapsed time to recover initial MBL values after the last rGH administration. Results: Absolute values displayed high interindividual variability, and 1 individual did not show any MBL increase (potential MBL deficiency). Mannan-binding lectin protein showed a clear concentration increase after continued rGH administration, despite the high heterogeneity found between individuals. Conclusions: The use of MBL as a complementary GH-related biomarker could be of interest, taking advantage of the high increases (up to 700%) and the relatively slow recovery time.