Antibodies to HTLV-1–2, HIV-1 and HIV-2 in syphilitic patients

Antibodies to human immunodeficiency virus type 1 (HIV-1) and type 2 (HIV-2) and to human T-cell leukemia virus (HTLV-1) were investigated by ELISA, Western blot and radioimmunoprecipitation (RIPA) assay in 318 sera (191 males and 127 females) obtained from syphilitic patients. The sera from 10% of the males and 3.1% of the females were positive for HIV-1. None of the sera contained antibodies to HIV-2. Antibodies to HTLV-1–2 were present in the sera of 7.1% of the males and 4.8% of the females who were seronegative for HIV. Five out of 24 (20.8%) HIV-1 positive subjects had antibodies to HTLV-1–2 as well.Sera from another group of 58 syphilitic patients (38 males and 20 females in the Anti-Venereal Disease Department), seronegative for HIV-1 and HIV-2, who denied both i.v. drug abuse and blood transfusion, were investigated in the same manner. None of the males had antibodies to HTLV-1–2, while 2 females (10%) were positive.     

HTLV-1, HIV-1, hepatitis B and hepatitis delta in the Pacific and South-East Asia: a serological survey

Blood samples from 13 locations in the Pacific and South-East Asia were tested for evidence of infection with human T-cell lymphotropic virus type-1 (HTLV-1), human immunodeficiency virus (HIV-1), hepatitis B virus (HBV) and hepatitis delta virus (HDV). No samples were positive for antibody to HIV-1. Antibodies to HTLV-1 were found in samples from five locations, the maximum prevalence being 19%, in Vanuatu. Serological markers of HBV infection were found in all locations, the maximal prevalence being 88%, in Majuro, Micronesia. Antibodies to HDV in HBsAg positive sera were found in six locations with a maximum prevalence of 81% in Kiribati.     

HTLV-1 seroprevalence in aids patients and in HIV-1 seropositive and seronegative subjects at risk for aids in Northern Italy

Sera of 1023 subjects belonging to categories at risk for AIDS, positive for HIV-1, were tested for antibodies to human T-cell leukemia virus (HTLV-1) by ELISA, Western blotting, and radioimmunoprecipitation (RIP) assay. Sera of these subjects were positive for antibodies to HTLV-1 in a percentage of 18.54%. Nine out of 18 sera from patients with AIDS had antibodies to HTLV-1 (50%). Sera of 207 intravenous drug abusers and 64 homosexual males, seronegative for HIV-1, were tested for antibodies to HTLV-1 and 6.7% of intravenous drug abusers and 7.8% of homosexual males were found to be HTLV-1 antibody positive, showing that HTLV-1 infection occurred independently of HIV-1 and HIV-2 infections. In fact the same HIV-1 seronegative patients were also tested for the presence of antibodies to HIV-2 and none of them was found to be positive.Corresponding author.     

Phylogenetic and phylodynamic study of Human T-cell lymphotropic virus Type 1 (HTLV-1) in Iran

Human T-lymphotropic virus type-1 (HTLV-1) is a retrovirus that causes the neurological disorder HTLV-1 associated myelopathy/ tropical spastic paraparesis (HAM/TSP) and/or adult T-cell leukemia/lymphoma (ATLL). Iran is one of the endemic regions of the HTLV-1 in the Middle East. To infer the origin of the virus in Iran and to follow the movements of human population and routes of virus spread to this country, phylogenetic and phylodynamic analyses were performed. To this purpose, the long terminal repeat (LTR) region of HTLV-1 was used. New LTR sequences were obtained from 100 blood samples which infected with HTLV-1. Moreover, all Iranian LTR sequences which have been reported so far, were obtained from GenBank database. Sequences were aligned and maximum-likelihood and Bayesian tree topologies were explored. After identification of Iranian specific cluster, molecular-clock and coalescent models were used to estimate time to the most recent common ancestor (tMRCA). Bayesian Skyline Plots (BSP), representing population dynamics HTLV-1 strains back to the MRCA, were estimated using BEAST software. Phylogenetic analysis demonstrated that the Iranian, Kuwaiti, German, Israelite and southern Indian isolates are located within the widespread “transcontinental” subgroup A clade of HTLV-1 Cosmopolitan subtype a. Molecular clock analysis of the Iranian cluster dated back their respective tMRCA to be 1290 AC with a 95% HPD confidence intervals (918, 1517). BSPs indicated a rapid exponential growth rate in the effective number of infections prior the 15th century. Our results support the hypothesis of a multiple introductions of HTLV-1 into Iran with the majority of introductions occurring in prior the 15th century, at the same time the Mongol invasion of Iran. Our results further suggest that HTLV-1 introduction into Iran was facilitated by the commercial/migratory linkage as known as the ancient Silk Road which linked China to Antioch (now in Turkey).     

HTLV-1 infection is associated with a history of active tuberculosis among family members of HTLV-1-infected patients in Peru

The purpose of this study was to assess the association between human T-lymphotropic virus 1 (HTLV-1) and a lifetime history of active tuberculosis (TB) among relatives of HTLV-1-infected patients. We reviewed clinical charts of all relatives of HTLV-1-infected index cases who attended our institute in Lima from 1990-2004. The data of 1233 relatives was analysed; 394 (32.0%) were HTLV-1 positive. Eighty-one subjects (6.6%) had a history of active TB, including 45/394 (11.4%) HTLV-1-positive and 36/839 (4.3%) HTLV-1-negative relatives (P<0.001). On multivariate analysis, three factors were associated with TB history: HTLV-1 infection (adjusted OR 2.5, 95% CI 1.6-3.9), age (adjusted OR 1.3, 95% CI 1.1-1.5 per 10-year age increase) and relation to the index case (adjusted OR 2.6, 95% CI 1.3-5.1, for siblings vs. spouses of index cases). In conclusion, HTLV-1 infection may increase the susceptibility to active TB. In populations where both infections are frequent, such an association could affect the dynamics of TB.     

Insights into origins of Human T-cell Lymphotropic Virus Type 1 based on new strains from aboriginal people of Canada

The causes of the worldwide distribution of Human T-cell Lymphotropic Virus Type 1 (HTLV-1) remain incompletely understood, with competing hypotheses regarding the number and timing of events leading to intercontinental spread on historical and prehistoric timescales. Ongoing discovery of this virus in aboriginal populations of Asia and the Americas has been the main source of evidence for the latter. We conducted molecular phylogenetic and dating analyses for 13 newly reported HTLV-1 strains from Canada. We analyzed two full-length proviral genomes from aboriginal residents of Nunavut (an autonomous territory in Northern Canada including most of the Canadian Arctic), 11 long-terminal-repeat (LTR) sequences from aboriginal residents of British Columbia’s Pacific coast, and 2 LTR sequences from non-aboriginal Canadians. Phylogenetic analysis demonstrated a well-supported affinity between the two Nunavut strains and two East Asian strains, suggesting the presence of an Asian–American sublineage within the widespread “transcontinental” subgroup A clade of HTLV-1 Cosmopolitan subtype a. This putative sublineage was estimated to be 5400–11,900 years in age, consistent with a long-term presence of HTLV-1 in aboriginal populations of the Canadian Arctic. Phylogenetic affinities of the other 11 Canadian HTLV-1 aboriginal strains were diverse, strengthening earlier evidence for multiple incursions of this virus into coastal aboriginal populations of British Columbia. Our results are consistent with the hypothesis of ancient presence of HTLV-1 in aboriginal populations of North America.     

Epidemiology of Human T-cell Lymphotropic Virus Type 1 Infection in Blood Donors, Israel

The prevalence of infection with human T-cell lymphotropic virus type 1 (HTLV-1) in blood donors from Israel is 1 infection/100,000 persons. In donors originating from Eastern Europe, the Middle East, and Latin America, prevalences are 7.7, 14.6, and 20.4, respectively. HTLV-1 prevalence may be high outside areas where HTLV-1 previously was known to be endemic.     

Human T-Lymphotropic virus type 1 infection in absence of tax gene: A challenge for molecular diagnosis

This is the first report of HTLV-1 infection without detectable tax gene. Even though the tax gene of HTLV-1 presents high genetic stability, in the case presented here no sequence of tax was detected by three different and widely used molecular assays targeting several sequences of the gene. Nevertheless, HTLV-1 pol and env genes and LTR region were properly detectable. Several PCRs targeting tax sequences have been developed and largely used for molecular diagnosis of HTLV infection since the tax gene of HTLV-1 is known to be well preserved and intolerant to changes or mutations. In the case reported here, molecular detection of the virus was challenging. HTLV prevalence is complex and in many regions remains unknown. The identification of HTLV-infected individuals is important to determine its actual prevalence and design strategies to reduce viral spread. The finding and communication of HTLV-1 defective-provirus strains is important and necessary to guide the selection of representative target sequences on HTLV genome to design molecular assays, highlighting that different sequences should be combined to ensure adequate diagnosis. The latter is especially relevant in cases when discordant results between serological and molecular assays. This report contributes to the knowledge of the overall molecular epidemiology of HTLV-1 and encourages the need of surveillance of HTLV-1 “missed tax gene profiles” and the evaluation of the impact of these defective viral variants on molecular diagnosis and human health.     

Antenatal survey for the seroprevalence of HTLV-1 infections in the West Midlands, England.

The sera of 3522 women who attended an antenatal clinic in Birmingham, England were tested anonymously for antibodies against HTLV-1. Samples from 5 women (0.14%) were positive, one serum showed indeterminate reactivity. Two of the women (0.06%) were born in the West Indies (of Afro-Caribbean ethnic origin), one (0.03%) in Africa (of African ethnic origin), and three (0.09%) were white Caucasian women born in the UK. Thus, HTLV-1 infection in pregnant women in the UK, though comparatively rare, is not negligible. As transmission of HTLV-1 to the newborn via breast milk has been observed and as seropositive mothers can be advised to refrain from breastfeeding or to treat their milk, the question of routine screening for HTLV-1 infection during antenatal care is discussed.     

Evaluation of commercial HTLV-1 test kits by a standard HTLV-1 serum panel.

To evaluate the performance of currently available test kits for human T-cell lymphotropic virus type 1 (HTLV-1), we examined two particle agglutination (PA) tests and nine enzyme immunoassays (EIA) using a standard serum panel consisting of HTLV-1-positive and HTLV-1-negative sera that had been characterized by immunofluorescence and the polymerase chain reaction (PCR). The PA kits exhibited 94.0-100.0% sensitivity and 99.5-100.0% specificity; the sensitivity range was ascribed to the quality of the HTLV-1 antigens coated on the particles. The EIA kits had 99.5-100% sensitivity and 98.5-100% specificity; the 98.5%-99.5% specificity exhibited by five of the EIA kits could have been due to nonspecific reactions that were detected through use of an inadequate cut-off value and the use of recombinant proteins. It can be concluded that the sensitivity of the currently available PA and EIA kits is sufficient to permit their use for screening purposes; however, the specificity of some EIA kits should be optimized.     

A seroepidemiological survey of HTLV-1 in the Philippines

The prevalence of human T-lymphotropic retrovirus type-1 (HTLV-1) was examined in the Asian Pacific area to search for endemic foci outside Japan. A total of 1323 sera from healthy subjects in the Philippines including Filipino lowlanders, Mongoloid slash-and-burn agriculturalists and the Mongoloid aboriginal hunter-gatherers (Aeta group and Mamanwa group) were examined for the presence of antibodies to HTLV-1 by the indirect immunofluorescence test and by the Western blot technique using HTLV-1 carrying cells. Nineteen out of 20 HTLV-1 antibody carriers found in the present study are clustered in the Aeta group of Mongoloid aboriginal hunter-gatherers who have until recently been isolated in the remote mountainous areas of Luzon Island since their arrival in the Philippines during the last glacial era (12,000-15,000 years ago). This finding supports the theory that HTLV-1 originated in Mongoloid racial groups during prehistoric times.     

A ten year serological survey of hepatitis A, B and C viruses infections in Nepal

BACKGROUND: In 1987, we reported that the prevalence of hepatitis B virus (HBV) and hepatitis C virus (HCV) infection in Nepal was low, as compared to hepatitis A virus (HAV) infection, and that no human T-lymphotropic type-1 (HTLV-1) infection was found in Nepal. OBJECTIVES: To determine changes in the prevalence of HAV, HBV, and HCV infections between 1987 and 1996 in inhabitants of Bhadrakali (suburban) and Kotyang (rural) villages in Nepal. STUDY DESIGN: We did a cross-sectional survey of 458 inhabitants of two Nepalese villages, to assess the prevalence of antibody to HAV (anti-HAV), antibody to hepatitis B core antigen (anti-HBc), hepatitis B surface antigen (HBsAg), antibody to HCV (anti-HCV), and antibody to HTLV-I (anti-HTLV-I). RESULTS: Anti-HAV was detected in 454 (99.1%), HBsAg in 5 (1.1%), anti-HBc in 33 (7.2%) and anti-HCV in 8 (1.7%) of serum samples tested in 1996. Statistically significant differences by gender or age group were nil. The prevalence of HCV infection was significantly higher in 1996 than in 1987 after adjusting for age of subjects living in the two villages (p < 0.01). The prevalence of HBsAg was significantly higher in 1996 than 1987 in Bhadrakali after adjusting for the factor of age (p < 0.05). Between 1987 and 1996, evidence for HTLV-1 positive residents was nil. CONCLUSION: These results suggest that HAV has been endemic in Nepal for long time while not of HBV, and that HCV infection tends to be increased recently.     

Human infections with non-O157 Shiga toxin-producing Escherichia coli, Switzerland, 2000-2009

We characterized 97 non-O157 Shiga toxin (stx)-producing Escherichia coli strains isolated from human patients during 2000-2009 from the national reference laboratory in Switzerland. These strains belonged to 40 O:H serotypes; 4 serotypes (O26:H11/H-, O103:H2, O121:H19, and O145:H28/H-) accounted for 46.4% of the strains. Nonbloody diarrhea was reported by 23.2% of the patients, bloody diarrhea by 56.8%. Hemolytic uremic syndrome developed in 40.0% of patients; serotype O26:H11/H- was most often associated with this syndrome. Forty-five (46.4%) strains carried stx2 genes only, 36 strains (37.1%) carried stx1, and 16 (16.5%) strains carried stx1 and stx2. Genes encoding enterohemolysin and intimin were detected in 75.3% and 70.1% of the strains, respectively. Resistance to ≥1 antimicrobial agent was present in 25 isolates. High genetic diversity within strains indicates that non-O157 stx-producing E. coli infections in Switzerland most often occurred as single cases.     

Impact of depression on quality of life in people living with human T cell lymphotropic virus type 1 (HTLV-1) in Salvador, Brazil

Purpose

A previous study found the prevalence of depression in HTLV-1-infected patients to be approximately 30%, but few studies have attempted to correlate depression with quality of life (QOL) in these patients. The present study investigates the association between depression and QOL in people living with HTLV-1.

Methods

A clinical-epidemiological questionnaire, the Mini International Neuropsychiatric Interview and the WHOQOL-Bref were applied to 88 HTLV-1-infected patients (32 with TSP/HAM) at the HTLV Center of the Bahiana School of Medicine and Public Health, Salvador, Brazil.

Results

The prevalence of depression among people living with HTLV-1 was 34.1%. Depression was significantly associated with a poor QOL in the physical, psychological, social relationship and environment domains, when controlling for other variables, such as gender, age, time of knowledge of serological diagnosis and presence of tropical spastic paraparesis/HTLV-1associated myelopathy (TSP/HAM). Moreover, patients with TSP/HAM experienced a reduction in their QOL in the physical, psychological and environment domains.

Conclusion

Our results showed that depression negatively affects the quality of life of people living with HTLV-1, regardless of the presence of TSP/HAM. Since it is possible to improve a patient??s QOL by treating depression, psychological evaluations are strongly recommended as a measure to integrate the treatment protocols of HTLV-1 intervention programs.     

Analysis of the complete genome sequences of one swine and two human hepatitis E virus genotype 4 strains isolated in Beijing,China

Full-length sequences were determined and analyzed for two human (MO and W3) and one swine (W2–5) hepatitis E virus (HEV) isolates from Beijing, China. The genomes of the three strains were composed of 7242, 7239, 7239 nucleotides, respectively, excluding the poly (A) tails, and were 84% identical to each other. All were classified into genotype 4. Sequence analysis shows that the 2 human isolates have up to 91–94% nucleotide identity in full length genome with swine strains isolated in China, while the swine isolate share 92% identity with the human strain T1 from Beijing. At the amino acid level, the three strains share 94%, 97% and 89–92% identity in the ORF1, ORF2 and ORF3, proteins respectively. The human strains MO and W3 have the highest identity, 97%, 98–99% and 96–98% in ORFs 1–3, respectively, to swine strains CHN-XJ-SW13 and CHN-XJ-SW33 from Xinjiang, China, while swine strain W2–5 has highest identity with the human strain HE-JA2, 96%, 99% and 91% in ORFs 1–3, respectively. Genotype specific amino acid substitutions were found at a single site in all three ORFs by sequences alignment, and genotype specific short sequences (5–10aa in length) were found in ORF1 and the C-terminus of ORF3. However, no difference was found at any amino acid position that discriminates between human and swine HEVs within genotype 4 for any of the three ORFs. These results indicated that the genotype 4 HEV strains from humans and pigs in China may evolve from the common ancestor.     

Circulating miR-29c,miR-30c,miR-193a-5p and miR-885-5p: Novel potential biomarkers for HTLV-1 infection diagnosis

Human T-cell leukemia virus type 1 (HTLV-1) is an oncoretrovirus that infects 5–10 million people worldwide. Currently, different methods are used to test HTLV-1 infection. However, a biomarker that could enable an early and accurate diagnosis of HTLV-1 infection is still lacking. Here, we compared the serum miRNA expression profile in HTLV-1 infected patients versus healthy individuals to identify a potential biomarker for diagnosis of HTLV-1 infection.TaqMan miRNA microarray (TLDA) was carried out to compare the miRNA expression profile in infected versus healthy individuals. Quantitative real-time RT-PCR (qRT-PCR) was applied to validate TLDA results. Receiver-operator characteristic (ROC) curve analysis was performed to determine the diagnostic accuracy of the most highly and significantly identified deregulated miRNA(s) as potential biomarker(s). We identified deregulated expression for ten miRNAs with miR-127, miR-136, miR-142-3p, miR-221, and miR-423-5p being down-regulated whilst let-7b, miR-29c, miR-30c, miR-193a-5p, and miR-885-5p being up-regulated in infected individuals. ROC curve analyses showed an AUC (Areas Under the ROC Curve) of 0.875 (95% CI: 0.7819–0.9581; P = .0021), 0.861 (95% CI: 0.7596–0.9754; P = .003), 0.856 (95% CI: 0.689–0.895; P = .011), and 0.849 (95% CI: 0.678–0.855; P = .017) for miR-29c, miR-30c, miR-193a-5p, and miR-885-5p respectively. Combined ROC analyses using these 4 miRNAs showed a greater AUC of 0.907 (95% CI: 0.809–1; P = .000001) indicating a robust diagnostic value of these 4 miRNAs. Our findings highlight serum miR-29c, miR-30c, miR-193a-5p and miR-885-5p as novel potential biomarkers important for HTLV-1 diagnosis.     

In vivo and in vitro immunogenicity of novel MHC class I presented epitopes to confer protective immunity against chronic HTLV-1 infection

Human T-cell leukemia virus type 1 (HTLV-1) has infected as many as 10 million people worldwide. While 90% are asymptomatic, 5% develop severe diseases including adult T-cell leukemia/lymphoka (ATLL) and HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP). No vaccine against HTLV-1 exists, and screening programs are not universal. However, patients with chronic HTLV-1 infection have high frequencies of HTLV-1-activated CD8+ T cells, and the two main HLA alleles (A2, A24) are present in 88% of infected individuals. We thus utilized an immunoproteomics approach to characterize MHC-I restricted epitopes presented by HLA-A2+, A24+ MT-2 and SLB-1 cell lines. Unlike traditional motif prediction algorithms, this approach identifies epitopes associated with cytotoxic T-cell responses in their naturally processed forms, minimizing differences in antigen processing and protein expression levels. Out of nine identified peptides, we confirmed six novel MHC-I restricted epitopes that were capable of binding HLA-A2 and HLA-A24 alleles and used in vitro and in vivo methods to generate CD8+ T cells specific for each of these peptides. MagPix MILLIPLEX data showed that in vitro generated epitope-specific CD8+ T cells secreted IFN-ɣ, granzyme B, MIP-1α, TNF-α, perforin and IL-10 when cultured in the presence of MT-2 cell line. Degranulation assay confirmed cytotoxic response through surface expression of CD107 on CD8+ T cells when cultured with MT-2 cells. A CD8+ T-cell killing assay indicated significant antiviral activity of CD8+ T cells specific against all identified peptides. In vivo generated CD8+ T cells similarly demonstrated immunogenicity on ELISpot, CD107 degranulation assay, and MagPix MILLIPLEX analysis. These epitopes are thus candidates for a therapeutic peptide-based vaccine against HTLV-1, and our results provide preclinical data for the advancement of such a vaccine.     

Analyses of HTLV-1 sequences suggest interaction between ORF-I mutations and HAM/TSP outcome

The region known as pX in the 3′ end of the human T-cell lymphotropic virus type 1 (HTLV-1) genome contains four overlapping open reading frames (ORF) that encode regulatory proteins. HTLV-1 ORF-I produces the protein p12 and its cleavage product p8. The functions of these proteins have been linked to immune evasion and viral infectivity and persistence. It is known that the HTLV-1 infection does not necessarily imply the development of pathological processes and here we evaluated whether natural mutations in HTLV-1 ORF-I can influence the proviral load and clinical manifestation of HTLV-I-associated myelopathy/tropical spastic paraparesis (HAM/TSP). For that, we performed molecular characterization, datamining and phylogenetic analysis with HTLV-1 ORF-I sequences from 156 patients with negative or positive diagnosis for HAM/TSP. Our analyses demonstrated that some mutations may be associated with the outcome of HAM/TSP (C39R, L40F, P45L, S69G and R88K) or with proviral load (P34L and F61L). We further examined the presence of mutations in motifs of HBZ and observed that P45L mutation is located within the HBZ nuclear localization signal and was found more frequently between patients with HAM/TSP and high proviral load. These results indicate that some natural mutations are located in functional domains of ORF-I and suggests a potential association between these mutations and the proviral loads and development of HAM/TSP. Therefore it is necessary to conduct functional studies aimed at evaluating the impact of these mutations on the virus persistence and immune evasion.     

Patient research priority setting partnership in human T-cell lymphotropic virus type I

Introduction

Human T-cell lymphotropic virus type 1 (HTLV-1) is a chronic infection affecting 5–10 million people worldwide. Ten percent develop HTLV-1-associated diseases, and 3%–5% develop HTLV-1-associated myelopathy (HAM)/tropical spastic paraparesis. Low health-related quality of life (HRQoL) is a significant concern for those with HTLV-1, and little is known about how it impacts daily life or what patients need from healthcare services. To address this, we report on patient involvement workshops aimed at identifying research priorities for HTLV-1 health service provision.

Methods

Participants recruited through HTLV-1 clinics in England attended six 90-min virtual workshops over 10 months, and two 60-min consolidation workshops. Content developed iteratively from topic focussed group discussions. All workshops were video-recorded with consent, transcribed verbatim and thematically analysed. Using consensus voting rounds, participants individually ranked their top six and then collectively their top three research priorities from the themes inferred from the analysis. A final feedback session explored the experiences of participating in the workshops.

Findings

Twenty-seven people with HTLV-1 engaged with the workshops with up to 22 participants attending each meeting. The majority were diagnosed with HAM (n = 22). The top three research priorities were identified as understanding disease progression, psychosocial wellbeing, and information and knowledge. Participants valued being asked to set research priorities that directly addressed their needs and enjoyed the workshops. They stressed the importance of patient advocates for promoting research that positively impacts everyday life.

Conclusion

This is the first of this type of research engagement with people with HTLV-1 in the United Kingdom. Participants identified several avenues of investigation that could lead to improvements in healthcare services and HRQoL. Participants believed the workshops signified the start of a conversation to progress person-centred and meaningful research in HTLV-1.

Patient or Public Contribution

People living with HTLV-1 were involved in the iterative design, conduct, analysis, writing and dissemination of this project through the patient involvement workshops. As a result of this engagement, a patient led advisory group has been set up to assist with the dissemination of the findings.     

Association between -221 X/Y polymorphism of mannose-binding lectin (MBL) gene and susceptibility to HTLV-1 infection among people from an endemic region in the Northeast of Iran

BackgroundThe role of (MBL) gene single nucleotide polymorphisms (SNPs) has been well documented in susceptibility to several infectious diseases. This study aimed to investigate the association between two MBL promoter variants, -550 H/L and -221 X/Y, and susceptibility to HTLV-1 infection.MethodsA total of 153 subjects infected with HTLV-1 and 169 healthy controls were recruited. SSP-PCR method was applied to genotype -550 H/L and -221 X/Y polymorphisms. Associations between genotypes or alleles and susceptibility to HTLV-1 infection were analyzed by Pearson's Chi-Square. p ≤ .05 was considered statistically significant.ResultsStatistical analysis revealed significant differences between the two groups in the -221 position (χ2 = 19.709; p = .000). The MBL YX genotype was significantly associated with increased susceptibility to HTLV-1 (OR = 2.73, %95 CI = 1.74–4.30). Combined genotype of the two loci showed that the HYHX genotype (OR = 2.20, 95% CI = 1.95–2.48) and LYLX (OR = 1.97, 95% CI = 1.13–3.45) were associated with an increased risk of HTLV-1 infection.ConclusionOur results represent the importance of -221 X > Y variants in acquisition of HTLV-1 as this is the case for several other viral and bacterial infections.