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Association of MBL2 Polymorphisms with HAM/TSP in HTLV-1 Infection: A Case-Control Study Approach
Cleiton Alves Ramos1, Vanessa Gabryelle da Silva Teixeira1, Matheus Azevedo Bomfim1
1Institute of Biological Sciences, University of Pernambuco, Recife, Brazil.
Background:
Human T-lymphotropic virus type 1 (HTLV-1) infection is usually asymptomatic; however, around 3% of infected individuals develop HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP). Host genetic variants of innate immunity may contribute to this clinical outcome.
Objective:
To investigate the association between MBL2 polymorphisms and HAM/TSP in people living with HTLV-1.
Methods:
This case-control study included 89 individuals with confirmed HTLV-1 infection who were followed at an outpatient clinic for at least three years. Of these, 64 were asymptomatic and 25 developed HAM/TSP. Polymorphisms in the MBL2 promoter regions -550 (H/L; rs.11003125) and -221 (Y/X; rs.7096206), and in exon 1 (A/O; rs.5030737, rs.1800450, and rs.1800451) were genotyped. Combined haplotypes were classified according to previously described genotype-based functional categories related to high/intermediate or low/deficient MBL production. Serum MBL levels were not directly measured.
Results:
The H allele and HH/HL genotypes at -550 were more frequent in asymptomatic individuals than in patients with HAM/TSP. In the combined analysis, low/deficient predicted MBL producers were more frequent in the HAM/TSP group than in the asymptomatic group (48 vs. 23%; OR 3.02, 95% CI 1.01-8.89; p = 0.02).
Conclusion:
MBL2 polymorphisms were associated with HAM/TSP status in this cohort. However, these findings should be interpreted cautiously due to the small sample size, the absence of proviral load data for most participants, and the lack of direct serum MBL measurements. Larger independent studies are needed to confirm these associations.
Insights
Genetic variations in MBL2 may influence the development of HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP). Low MBL production was linked to increased HAM/TSP risk in HTLV-1 infected individuals.
Area of Science:
- Immunogenetics
- Virology
- Neurology
Background:
- Human T-lymphotropic virus type 1 (HTLV-1) infection typically remains asymptomatic.
- A small percentage of HTLV-1 infected individuals develop HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP).
- Host genetic factors, particularly in innate immunity genes, may predispose individuals to HAM/TSP.
Purpose of the Study:
- To investigate the association between MBL2 gene polymorphisms and the development of HAM/TSP in HTLV-1 infected individuals.
- To explore the potential role of MBL2 variants in determining clinical outcomes of HTLV-1 infection.
Main Methods:
- A case-control study involving 89 HTLV-1 infected individuals (64 asymptomatic, 25 HAM/TSP).
- Genotyping of MBL2 polymorphisms in promoter (-550, -221) and exon 1 regions.
- Classification of MBL2 haplotypes into functional categories predicting MBL production levels (high/intermediate vs. low/deficient).
Main Results:
- Specific MBL2 alleles and genotypes (-550 H/HH/HL) were more prevalent in asymptomatic individuals.
- Individuals with predicted low/deficient MBL production showed a significantly higher frequency in the HAM/TSP group (48%) compared to the asymptomatic group (23%).
- An odds ratio of 3.02 indicated an increased risk of HAM/TSP associated with low/deficient MBL production.
Conclusions:
- MBL2 polymorphisms are potentially associated with HAM/TSP development in HTLV-1 infected individuals.
- The findings suggest a possible role for MBL2 genotype in modulating HAM/TSP risk.
- Further research with larger cohorts and direct MBL measurements is warranted to confirm these associations.
