Impact of Exon 1 Polymorphism in the MBL2 Gene on MBL Serum Levels and Infection Susceptibility in Acute Lymphoid Leukemia 

Abstract Polymorphisms in the MBL2 gene exon 1 can decrease serum levels of mannose-binding lectin (MBL), increasing the risk of infection in immunocompromised individuals. This study evaluated the association between the polymorphism in exon 1 of the MBL2 gene, genotypes, serum MBL levels, and infection in 122 patients with acute lymphoid leukemia (ALL). The MBL*A allele exhibited the highest frequency (0.37) within the study population. The MBL*D (0.32) was the predominant variant. The combined frequency of O polymorphic alleles (either B or D) was 0.63. The frequencies of the A/A, A/O and O/O genotypes were 0.13, 0.49 and 0.38, respectively. All patients exhibited consistently low levels of serum MBL, irrespective of their exon 1 genotype. Parasitic infections (n = 103), bacterial (n = 69) and viral (n = 48). A/O genotype (0.49) had higher infection rates, A/A (0.13) had lower rates, and O/O showed increased viral susceptibility (OR: 0.37; 95% CI 0.13–1.06; p = 0.05). Our findings demonstrated that the study population were MBL-deficient, regardless of their MLB2 genotype. Individuals with the A/O genotype had more infections, while those with the O/O genotype appeared more susceptible to viral infections. These findings highlight the impact of MBL levels and genetic variants on infection susceptibility in ALL patients.