Objectives
To evaluate the association of mannose-binding lectin (MBL) deficiency with susceptibility and clinical features of group B Streptococcus (GBS) causing meningitis in Chinese infants.

Methods
During 2014–2017, 33 infants with laboratory-confirmed GBS meningitis were included. Six polymorphisms (H/L, Y/X, P/Q, A/D, A/B and A/C) of MBL were sought for in these patients and in 330 healthy controls by PCR-based sequencing. Serum MBL concentration was determined.

Results
Significantly higher frequency of MBL variant genotype A/B was found in patients than controls (15/33, 45%, vs. 79/330, 24%, p=0.011). Patients with variant genotype A/B had significantly lower serum MBL than those with wild-type genotype A/A (median, 482.87 vs. 1455.13 ng/mL, p=0.002). Moreover, patients with genotype A/B had significantly higher level of C-reactive protein (median, 146 vs. 41 mg/L, p=0.007), neutrophil (median, 58.1% vs. 45.7%, p=0.033) and neutrophil-to-lymphocyte ratio in blood (median, 2.32 vs. 1.03, p=0.018) compared to those with genotype A/A. No significant differences were observed in clinical features of patients with different genotypes.

Conclusions
Our result suggested that infants with MBL deficiency are at higher risk of meningitis caused by GBS. Further studies in different populations with larger number of subjects are needed.