Background: Primary immunodeficiencies (PIDs) are inherited disorders in which one or
several components of the immune system are defective. Immunoglobulin replacement therapy is the
mainstay of treatment for patients with impaired antibody production. However, recurrent infections
would continue to occur in some patients due to the other high frequent concomitant defects, such as
mannose-binding lectin (MBL) deficiency.
Methods: A total of 51 PID patients participated in this cross-sectional study. A detailed questionnaire
was completed by interviewing patients in order to record demographic, clinical and laboratory data.
The levels of MBL were determined in the serums of patients by a sandwich enzyme-linked immunosorbent
assay (ELISA) technique.
Results: MBL deficiency was found in 29.4% of cases; 11.8% patients had mild, 3.9% patients had
moderate and 13.7% patients had severe MBL deficiency. In patients with MBL deficiency, the rate of
meningitis, sepsis, pneumonia, and otitis media was higher than patients with normal MBL levels.
Immunoglobulin replacement therapy reduced the rate of infectious complications in PID patients;
however, these reductions were more apparent in patients with normal MBL levels than patients with
Conclusion: Antibody deficient patients with a concomitant immune defect in MBL production have
higher rates of recurrent infections despite receiving Immunoglobulin replacement therapy.