MBL2 and systemic lupus erythematosus: When functional MBL activity with respect to the severity of infections was analysed, no significant differences were found between median values of functional MBL serum level, C4 deposition, and MBL pathway activity in three subgroups of patients: SLE patients with one or more major infections, patients with SLE who experienced minor infections only, and SLE patients without any infections (Figure 2).