Volumetric dried blood microsampling for monitoring imatinib mesylate therapy: Method development and clinical application in patients with chronic myeloid leukemia.

Chronic Myeloid Leukemia (CML) is a hematologic neoplasia, characterized as a proliferative disease of the hematopoietic system. Imatinib mesylate (IM), a selective tyrosine kinase inhibitor, is considered a first-line therapy for CML, indicated for both adult and pediatric patients presenting the Philadelphia chromosome (Ph+). However, patients in treatment with IM may show different responses due to interindividual pharmacokinetic variability. Therapeutic drug monitoring should be routinely performed to identify treatment response profile, adherence to treatment, or possible drug interactions, thus supporting better treatment management. Volumetric absorptive microsampling (VAMS) are innovative devices for blood collection whose advantages include the possibility of home collection by the patient or at the physician's office. The assay was fully validated according to bioanalytical validation guidelines. Estimated plasma concentrations of IM were not statistically different between groups according to adherence (p = 0.15), with median of 789 ng ml-1 in the group with some level of non-adherence versus 1141.9 ng ml-1 in the group with adherence, classified with the Morisky-Green questionnaire. This study included 33 patients with CML in treatment with IM. These patients answered socioeconomic, sociodemographic, and adherence profile (Morisky-Green) questionnaires. Patients also received instructions for home blood collection with VAMS devices. Afterwards, the samples were analyzed by LC-MS/MS. The mean age of the patients was 52 years, 84.8% were ingesting doses of 400 mg/day and the majority were male (69.7%). IM and its metabolite NIM were extracted from VAMS with an aqueous solution with 0.1% formic acid, followed by protein precipitation with acetonitrile. The methodology developed in this study was satisfactory for the determination of IM and NIM in VAMS and can be used in hospital and office routines for the therapeutic monitoring of patients with CML.

A prospective comparison of ACR-TIRADS and EU-TIRADS in thyroid nodule assessment for FNA-US.

OBJECTIVE: Prospective data on the accuracy of ultrasound (US) classification systems in thyroid nodules are still scarce. The aim of this study is to compare the accuracy of the American College of Radiology Thyroid Imaging Reporting and Data System (ACR-TIRADS) and European (EU)-TIRADS classification systems. DESIGN AND PATIENTS: Consecutive patients with one or more thyroid nodule(s) who underwent fine-needle aspiration (FNA) under ultrasonographic guidance (FNA-US) were prospectively evaluated. MEASUREMENTS: Clinical evaluation and US data were collected. The reference standard used for this study was FNA-US cytology and histopathological diagnosis. RESULTS: A total of 186 thyroid nodules in 166 patients were evaluated, resulting in 168 nodules from 149 patients with conclusive benign or malignant results. Sensitivity, specificity, negative predictive value (NPV) and false negative (FN) were 100.0%, 28.7%, 100.0% and 0.0%, respectively, for ACR-TIRADS; and 90.0%, 19.1%, 96.8% and 9.1% (n = 1), respectively, for EU-TIRADS. The number of unnecessary FNA-US indicated by ACR-TIRADS was lower than EU-TIRADS (71.3% vs. 80.9%, p = .017), and the number of possibly avoided FNA-US was higher (26.7% vs. 17.8%). Using the same threshold of ACR-TIRADS to indicate FNA-US in EU-TIRADS 3 nodules (2.5 cm), there was an improvement in specificity (30.6%) and avoided FNA-US (28.6%). The best performance of both systems was demonstrated when FNA-US would be indicated only in highly suspicious nodules and/or in the presence of lymphadenopathy, with 85.7% and 89.3% of possibly avoided FNA-US for ACR-TIRADS and EU-TIRADS, respectively, without increasing FN. CONCLUSION: Both systems presented high sensitivity, but low specificity in selecting nodules for FNA-US. The use of nodular size for FNA-US selection is questioned.

TLR9 2848 G/A Gene Polymorphism in HCV+, HIV+, and HCV+/HIV+ Individuals.

Background: Host genetic factors play a major role with respect to susceptibility to infections. Many polymorphisms of the Toll-like receptors (TLRs), members of the innate immune response, are directly associated with the clinical outcomes following infection. The 2848 G/A variant (rs352140) of the TLR9 gene is associated with increased TLR9 expression. However, the impact of the genotypes of this SNP on HIV+, HCV+, and HCV+/HIV+ individuals is still debated. Materials and Methods: This study investigated the 2848 G/A polymorphism in HCV infection, HIV infection, and HCV/HIV co-infection in a large sample of Brazilians (n = 1,182). Groups were initially compared without considering stratification by ethnicity and subsequently stratifying individuals between whites and non-whites. Results: Considering non-white individuals, a significant difference between the HIV+/HCV+ group and controls was observed with the GG genotype serving as a protective factor (p = 0.023). Additionally, significant allelic differences were observed between the HCV+ group and controls (p = 0.042); between the HIV+/HCV+ group and controls (p = 0.011); and between the HIV+/HCV+ group and HIV+ individuals (p = 0.047). However, all significant results were lost following adjustment for multiple comparisons (p > 0.05). Conclusion: Although our initial results indicated a potential influence of the rs352140 genotype on host altered susceptibility to viral infections, following correction for multiple comparisions the standard (p < 0.05) for statistical association was lost. This may be due to insufficient sample size as we were examining many different associations. Thus, a larger study is warranted to further pursue this topic.

The genetic predisposition to obesity has no influence on waist circumference when screen time and sleep duration are adequate in children and adolescents.

The aim of the present study was to verify whether the amount of sleep duration, screen time, and physical activity moderate the relationship between FTO rs9939609 polymorphism and waist circumference (WC) in children and adolescents. This is a cross-sectional study conducted with 1338 children and adolescents, aged between 6 and 17 years. Lifestyle habits were assessed through self-reported questionnaire. WC was measured on the narrowest part of the trunk between the last rib and the iliac crest. FTO rs9939609 polymorphism was genotyped by real time polymerase chain reaction. The PROCESS macro for the SPSS was used for moderation analyses, through multiple linear regression models. Results indicated significant interactions were found between sleep duration and screen time X FTO rs9939609, showing that these lifestyle behaviours are moderators in the relationship between a genetic predisposition for obesity and higher WC. For physical activity, there was no significant interaction. Therefore, sleeping more than 564 min a day (i.e. 9.4 h) and spending no more than 233 min in front of screen may counteract the genetic predisposition to obesity in children and adolescents.Highlights A healthy lifestyle may counteract the genetic predisposition to central obesity;Children and adolescents should sleep more than approximately 9 h (564 min) per day and spend less than approximately 4 h (233 min) per day in front of screens in order to counteract the genetic predisposition to central obesity conferred by the FTO gene variant.It is fundamental to promote actions for the adoption of a healthy lifestyle, including the importance of presenting adequate sleep habits and low screen time for a better cardiometabolic health and reduction of obesity.

Impact of maternal dietary counseling in the first year of life on DNA methylation in a cohort of children.

Epigenetic modifications established during prenatal and early life, including DNA methylation, have been suggested as potential mediators of the interaction between environmental exposures during the perinatal period and adult metabolic health adverse outcomes, especially cardiometabolic complications and overweight. The effect of a dietary intervention in the first year of life on global methylation levels in leukocyte samples from a cohort of children born between 2001 and 2002 in southern Brazil was examined. Overall methylation measurements were performed using enzyme-linked immunosorbent assays on DNA samples from 237 children at 4 years old. Mean methylation values were higher in the intervention group (mean: 2.20 ± 1.31%) than in the control group (mean: 1.65 ± 1.11%; P = 0.001). It was observed that nutritional counseling in the first year increased breastfeeding duration and stimulated the development of healthier eating habits. Therefore, these factors might have contributed to increase global DNA methylation. The findings of the present study reinforce the notion that performing nutritional interventions in the early stages of life is important and provide further evidence of the interaction between the environment and epigenetic traits.

Investigation of SIRT1 gene variants in HIV-associated lipodystrophy and metabolic syndrome.

HIV-infected individuals on chronic use of highly active antiretroviral therapy (HAART) are more likely to develop adipose tissue and metabolic disorders, such as lipodystrophy (LD) and metabolic syndrome (MetS). The development of these phenotypes is known to be multifactorial. Thus, variants in genes implicated in adipogenesis and lipid metabolism may increase susceptibility to LD and MetS. Sirtuin 1 (SIRT1) may influence the outcome of these disturbances due to its role in the regulation of transcription factors involved in energy regulation. Therefore, we genotyped four polymorphisms located in SIRT1 (rs2273773 T>C, rs12413112 G>A, rs7895833 A>G, rs12049646 T>C) in 832 HIV-infected patients receiving HAART by real-time polymerase chain reaction. The prevalence of LD was 55.8% and MetS was 35.3%. Lipoatrophy was the most prevalent subtype in all samples (38.0%) and showed significant difference between white and non-white individuals (P = 0.002). None of the genetic variants investigated in SIRT1 was associated with LD and MetS. White individuals and those in longer time of HAART use were more likely to develop LD. We concluded that these SIRT1 polymorphisms are not predictive factors to the development of lipodystrophy and metabolic syndrome in HIV-infected individuals from Brazil.

CCR5Δ32 in HCV infection, HCV/HIV co-infection, and HCV-related diseases.

Although a potential involvement of the CCR5Δ32 variant has already been suggested in relation to susceptibility to hepatitis C virus (HCV) infection, data from the literature is still quite controversial. Thus, our study evaluated the influence of the CCR5Δ32 allele variant in HCV infection, HCV/HIV co-infection, and HCV-related diseases in individuals from southern Brazil. A total of 1352 individuals were included in this study, divided into the following groups: Control (n = 274); HCV+ (n = 674); HIV+ (n = 300); HCV+/HIV+ (n = 104). Individuals from the HCV+ group were further stratified according to clinical/histological criteria, as HCV+/control (n = 124); HCV+/fibrosis (n = 268); HCV+/cirrhosis (n = 190); HCV+/hepatocarcinoma (n = 92). Considering all individuals included in this study, the following genotype frequencies were observed: wild-type homozygous (wt/wt), 88.76%; heterozygous (wt/Δ32), 10.72%; variant homozygous (Δ32/Δ32), 0.52%. Genotypic frequencies were very similar between the groups. Of note, the frequency of the Δ32 homozygous was quite similar comparing control uninfected against the HCV+ individuals (p > 0.999). The overall Δ32 allele frequency was estimated at 5.88%. Considering the number of Δ32 allele carriers and non-carriers, no statistically significant differences (p > 0.05) between the groups were observed, suggesting that the CCR5Δ32 variant does not influence the susceptibility to HCV infection, HCV/HIV co-infection, or HCV-related diseases in individuals from southern Brazil.

Adipokine Levels Versus Hepatic Histopathology in Bariatric Surgery Patients.

BACKGROUND: Obesity is a worldwide prevalent disease and is an underlying factor of non-alcoholic fatty liver disease (NAFLD). It has been understood as a chronic inflammatory state, being associated with the production of adipokines. The aim of this study was to analyze the levels of adipokines in the serum, visceral, and subcutaneous fat and to compare them with hepatic histopathology in morbidly obese patients. METHODS: This is a cross-sectional observational study, which analyzed the findings of liver biopsy in patients undergoing bariatric surgery and who had performed analysis of adipokines mRNA expression (adiponectin-ADIPOQ, leptin-LEP, and resistin-RETN) in subcutaneous and visceral adipose tissue and circulating adipokines in serum. Liver biopsies performed were evaluated according to Kleiner criteria. RESULTS: The study analyzed 25 patients undergoing bariatric surgery. The sample was composed exclusively of women. There was a predominance of NAFLD, with 21 patients (84%) with intrahepatic fat accumulation. Twelve patients presented non-alcoholic steatohepatitis (NASH). Glycated hemoglobin levels (HbA1c) were elevated in NASH patients. ADIPOQ levels were directly correlated with high-density lipoprotein (HDL) cholesterol levels and inversely correlated with triglycerides and total cholesterol. LEP levels showed an inverse relationship with the degree of steatosis, and RETN levels showed an inverse relationship with fibrosis stages. CONCLUSION: Serum LEP levels were reduced in the presence of increased levels of intrahepatic fat, and serum levels of RETN were diminished in the presence of NASH. HbA1c levels were higher in the presence of NASH, indirectly reflecting insulin resistance. Moreover, ADIPOQ levels were related to blood lipid profile.

Endosomal toll-like receptor gene polymorphisms and susceptibility to HIV and HCV co-infection - Differential influence in individuals with distinct ethnic background.

The genetic background of human populations can influence the susceptibility and outcome of infection diseases. Toll-like receptors (TLRs) have been previously associated with susceptibility to human immunodeficiency virus (HIV) infection, disease progression and hepatitis C, virus (HCV) co-infection in different populations, although mostly in Europeans. In this study, we investigated the genetic role of endosomal TLRs on susceptibility to HIV infection and HCV co-infection through the analysis of TLR7 rs179008, TLR8 rs3764880, TLR9 rs5743836 and TLR9 rs352140 polymorphisms in 789 Brazilian individuals (374 HIV+ and 415 HIV-), taking into account their ethnic background. Amongst the 357 HIV+ individuals with available data concerning HCV infection, 98 were positive. In European descendants, the TLR9 rs5743836 C carriers displayed a higher susceptibility to HIV infection [dominant, Odds Ratio (OR)=1.53; 95% CI: 1.05-2.23; P=0.027]. In African descendants, TLR9 rs5743836 CT genotype was associated with protection to HIV infection (codominant, OR=0.51; 95% CI: 0.30-0.87; P=0.013). Also, the TLR9 rs352140 AA variant genotype was associated with susceptibility to HIV+/HCV+ co-infection in African descendants (recessive, OR=2.92; 95% CI: 1.22-6.98, P=0.016). These results are discussed in the context of the different ethnic background of the studied individuals highlighting the influence of this genetic/ethnic background on the susceptibility to HIV infection and HIV/HCV co-infection in Brazilian individuals.

First report of imatinib measurement in hair: Method development and preliminary evaluation of the relation between hair and plasma concentrations with therapeutic response in chronic myeloid leukemia.

BACKGROUND: Imatinib (IM) is a first choice drug for treatment of chronic myeloid leukemia (CML), with a widely accepted concentration threshold of 1000ng/ml being used as a target for therapeutic drug monitoring. Once adherence to the pharmacotherapeutic regimen is of paramount importance during the long treatment course of CML, the measurement of hair IM concentrations could be a surrogate of the patient's exposure to the drug. METHODS: IM was extracted from a 5mg hair sample by a liquid-liquid extraction with ethyl acetate, and IM-d8 was used as internal standard (IS). After evaporation, and reconstitution in acetonitrile, the extract was injected into a LC-MS/MS system. Compounds were eluted on a C8 column in isocratic mode. IM and IS were identified in positive electrospray ionization mode using ion transitions of m/z 494.5>394.5 and 503.0>394.3 respectively. The method was applied to 102 paired hair and samples obtained from CML patients. Treatment response was evaluated according to the European LeukemiaNet recommendations. RESULTS: The assay was validated in the concentration range of 0.5-25ng/mg, with intra- and inter-assay imprecisions of <13.1% and <9.3%, respectively. The limits of quantification and detection were 0.5 and 0.15ng/mg, respectively. Median hair IM concentrations are significantly smaller in patients with therapeutic failure when compared with patients with partial or optimal response (4.63 vs. 7.93, p=0.040), the same trend presented by median plasma IM concentrations (629.5 vs. 1084.8, p=0.009). An IM hair concentration below 5.8ng/mg has 83% sensibility and 70% specificity to identify patients with therapeutic failure. CONCLUSIONS: A fast, sensitive, and selective LC-MS/MS method allowing quantification of IM in hair samples was developed and validated. CML patients with therapeutic failure had significantly lower hair IM concentrations when compared with patients with optimal response. These preliminary findings may support the use of hair as a matrix for IM monitoring in clinical settings, with significant logistic advantages over the collection of venous blood, particularly in developing countries.

DBS sampling in imatinib therapeutic drug monitoring: from method development to clinical application.

BACKGROUND: Imatinib (IM) is widely used in treatment of chronic myeloid leukemia with target trough plasma concentrations above 1000 ng ml(-1). DBS can increase access to IM therapeutic drug monitoring. RESULTS: IM was measured in the range 50-4000 ng ml(-1) by UHPLC-MS/MS using one 6 mm DBS in a fully validated method. IM was stable at DBS maintained at 40°C for 36 days. Plasma and DBS concentrations were highly correlated (r > 0.96). The use of a IM concentration target of 765 ng ml(-1) in DBS identified 93% of patients with plasma concentration below 1000 ng ml(-1). CONCLUSION: IM can be measured in DBS using UHPLC-MS/MS with results comparable to those obtained in blood plasma.

Influence of HLA-G polymorphisms in human immunodeficiency virus infection and hepatitis C virus co-infection in Brazilian and Italian individuals.

OBJECTIVE: This study aimed to investigate the role of Human Leukocyte Antigen (HLA)-G in the susceptibility to HIV-1 infection through the analysis of the HLA-G 3' untranslated region (UTR) polymorphisms 14 bp insertion/deletion (rs66554220) and +3142C>G (rs1063320). DESIGN: We analyzed 582 HIV-1 infected patients and 626 uninfected individuals from Brazil and Italy in a case-control study. METHODS: HLA-G polymorphisms were genotyped using PCR, PCR-RFLP assays or direct sequencing. All analyses were stratified by ethnicity. Genotypic, allelic and diplotypic frequencies were compared between HIV-1 infected subjects and controls using Chi-square or Fischer exact tests. Also, haplotypic frequencies were estimated using MLocus software. RESULTS: African-derived HIV-infected individuals presented a higher frequency of the 14 bp insertion allele as compared to non-infected individuals (0.468 versus 0.373, respectively; p(Bonf) = 0.010). A higher frequency of the 14 bp insertion +3142G (insG) haplotype (0.456 versus 0.346, p<0.001) and the insG/insG diplotype (OR=1.88, 95%CI = 1.08-3.23, p=0.021) was observed among African-derived patients as compared to uninfected controls. Also, we observed a higher frequency of the ins/ins genotype among African-derived HIV patients co-infected with HCV (OR=2.78, 95%CI = 1.20-6.49, p = 0.008). CONCLUSIONS: Our data point out to an increased frequency of alleles and genotypes associated with low HLA-G expression among African-derived patients, suggesting a potential role for HLA-G in the susceptibility to HIV-1 infection and HCV co-infection in those individuals.

Polymorphisms in LEPR, PPARG and APM1 genes: associations with energy intake and metabolic traits in young children.

OBJECTIVE: To assess the association of single nucleotide polymorphisms (SNPs) in five genes - leptin, leptin receptor (LEPR), adiponectin (APM1), peroxisome proliferator-activated receptor gamma (PPARG) and uncoupling protein 1 - with anthropometric, metabolic, and dietary parameters in a Southern Brazilian cohort of 325 children followed up from birth to 4 years old. MATERIALS AND METHODS: SNPs were analyzed using polymerase chain reaction-based procedures, and their association with phenotypes was evaluated by t-test, analysis of variance, and general linear models. RESULTS: LEPR223Arg allele (rs1137101) was associated with higher daily energy intake at 4 years of age (P = 0.002; Pcorrected = 0.024). PPARG 12Ala-carriers (rs1801282) presented higher glucose levels than Pro/Pro homozygotes (P = 0.007; Pcorrected = 0.042). CONCLUSIONS: Two of the six studied SNPs presented consistent associations, showing that it is already possible to detect the influences of genetic variants on susceptibility to overweight in 4-year-old children.

Polymorphisms in LEPR, PPARG and APM1 genes: associations with energy intake and metabolic traits in young children / Polimorfismos nos genes LEPR, PPARG e APM1: associações com ingestão energética e parâmetros metabólicos em crianças em idade precoce

OBJECTIVE: To assess the association of single nucleotide polymorphisms (SNPs) in five genes - leptin, leptin receptor (LEPR), adiponectin (APM1), peroxisome proliferator-activated receptor gamma (PPARG) and uncoupling protein 1 - with anthropometric, metabolic, and dietary parameters in a Southern Brazilian cohort of 325 children followed up from birth to 4 years old. MATERIALS AND METHODS: SNPs were analyzed using polymerase chain reaction-based procedures, and their association with phenotypes was evaluated by t-test, analysis of variance, and general linear models. RESULTS: LEPR223Arg allele (rs1137101) was associated with higher daily energy intake at 4 years of age (P = 0.002; Pcorrected = 0.024). PPARG 12Ala-carriers (rs1801282) presented higher glucose levels than Pro/Pro homozygotes (P = 0.007; Pcorrected = 0.042). CONCLUSIONS: Two of the six studied SNPs presented consistent associations, showing that it is already possible to detect the influences of genetic variants on susceptibility to overweight in 4-year-old children.

OBJETIVO: Avaliar a associação de polimorfismos de nucleotídeo único (SNPs) em cinco genes: leptina, receptor da leptina (LEPR), adiponectina (APM1), receptor ativado por proliferadores de peroxissomas gama (PPARG) e proteína desacopladora 1 com parâmetros antropométricos, metabólicos e dietéticos em uma coorte sul-brasileira composta por 325 crianças acompanhadas desde o nascimento até os 4 anos. MATERIAIS E MÉTODOS: Os SNPs foram analisados por meio da reação em cadeia da polimerase e sua associação com os fenótipos foi avaliada utilizando teste T, análise de variância e análise fatorial. RESULTADOS: O alelo LEPR223Arg (rs1137101) foi associado a uma maior ingestão energética diária aos 4 anos (P = 0,002; Pcorrigido = 0,024). Os portadores do alelo PPARG12Ala (rs1801282) apresentaram maior glicemia em relação aos homozigotos Pro/Pro (P = 0,007; Pcorrigido = 0,042). CONCLUSÕES: Dois dos seis SNPs estudados apresentaram associações consistentes, mostrando que aos 4 anos de idade já é possível detectar as influências de variantes genéticas sobre a suscetibilidade ao excesso de peso.

Association between a frequent variant of the FTO gene and anthropometric phenotypes in Brazilian children.

BACKGROUND: Our goal was to analyze the association of the fat mass and obesity- associated (FTO) gene rs9939609 variant (T/A) with the anthropometric and dietary intake phenotypes related to obesity in Brazilian children. METHODS: We analyzed the association of this single nucleotide polymorphism (SNP) with phenotypes related to the accumulation of body mass in a cohort of 348 children followed from the time of birth until 8 years old and then replicated the main findings in an independent schoolchildren sample (n = 615). RESULTS: At the age of 4, we observed a significant association between the A/A genotype and a higher mean BMI Z-score (P = 0.036). At the age of 8, the A/A individuals still presented with a higher BMI Z-score (P = 0.011) and with marginal differences in the volume of subcutaneous fat (P = 0.048). We replicated these findings in the schoolchildren sample, which showed that those with at least one copy of the A allele presented with a higher BMI Z-score (P = 0.029) and volume of subcutaneous fat (P = 0.016). CONCLUSION: Our results indicate that this FTO variant is associated with increased body mass and subcutaneous fat in Brazilian children beginning at the age of 4.

Are polymorphisms in oestrogen receptors genes associated with lipid levels in response to hormone therapy?

BACKGROUND: Polymorphisms in the oestrogen receptor 1 (ESR1) and oestrogen receptor 2 (ESR2) genes are associated with intermediate or endpoint markers of cardiovascular disease and with the efficacy of postmenopausal hormone therapy (HT). Contradictory findings have been described in the past and the role of these genetics variants remains unclear. METHODS: A cross-sectional study was carried out with 266 postmenopausal women, of whom 115 received oral HT (HT+) and 151 did not receive any HT (HT-). We analysed three single-nucleotide polymorphisms (SNPs) in ESR1 (rs1801132, rs7757956 and rs2813544) and two in ESR2 (rs3020450 and rs7154455) and derived haplotypes with three additional polymorphisms that had been previously investigated by our group (ESR1 rs2234693 and ESR2 rs1256049 and rs4986938). RESULTS: The ESR1 rs2813544 polymorphism was associated with low-density lipoprotein cholesterol (LDL-C) in HT+ postmenopausal women (p = 0.044; pC = 0.388), while one ESR2 gene haplotype was associated with total cholesterol (T-chol) (p = 0.015; pC = 0.090) and LDL-C in HT+ postmenopausal women (p = 0.021; pC = 0.126). CONCLUSION: Our findings suggest that, in HT+ postmenopausal women, the rs2813544 polymorphism may influence LDL-C levels and, as previously described, ESR2 rs1256049 is associated with T-chol and LDL-C. No previous study has investigated the association of this SNP set with lipoprotein levels in women while taking into account the hormonal status of the patients.

The role of mannose-binding lectin gene polymorphisms in susceptibility to HIV-1 infection in Southern Brazilian patients.

OBJECTIVE: This study investigates the role of mannose-binding lectin (MBL) in the susceptibility to HIV-1 infection analyzing polymorphisms located at the MBL2 promoter and exon 1 regions. MATERIALS AND METHODS: The prevalence of MBL2 variant alleles was investigated in 410 HIV-1-infected patients from the South Brazilian HIV cohort and in 345 unexposed uninfected healthy individuals. The promoter variants were genotyped using polymerase chain reaction with sequence-specific primers (PCR-SSP) and exon 1 variants were analyzed by real-time PCR using a melting temperature assay and were confirmed by PCR-restriction fragment length polymorphism (RFLP). MBL2 genotypic and allelic frequencies were compared between HIV-1-infected patients and controls using the chi-squared tests. RESULTS: The analyses were performed subdividing the individuals according to their ethnic origin. Among Euro-derived individuals a higher frequency of the LX/LX genotype was observed in patients when compared to controls (P < 0.001). The haplotypic analysis also showed a higher frequency of the haplotypes associated with lower MBL levels among HIV-1-infected patients (P = 0.0001). Among Afro-derived individuals the frequencies of LY/LY and HY/HY genotypes were higher in patients when compared to controls (P = 0.009 and P = 0.02). CONCLUSIONS: An increased frequency of MBL2 genotypes associated with low MBL levels was observed in Euro-derived patients, suggesting a potential role for MBL in the susceptibility to HIV-1 infection in Euro-derived individuals.