Effect of epigenetics on rheumatoid arthritis. / Efecto de la epigenética en la artritis reumatoide.

Rheumatoid arthritis is an autoimmune and inflammatory disease that predominantly affects the diarthrodial joints. In this pathology, environmental or behavioral factors can act in synergy with genetic predisposition, accelerating the onset and severity of the disease. This link between the environment and the genome is mediated by epigenetic marks on deoxyribonucleic acid, including its methylation, histone modification, and noncoding ribonucleic acid-mediated regulation. Epigenetics can generate heritable phenotypic changes, which are not determined by modifications in the deoxyribonucleic acid sequence and are therefore reversible. Therefore, diet, medications and other environmental factors would have the ability to modulate them. The identification of a specific epigenetic dysregulation can offer a better understanding of the pathophysiology of the disease and positively influence the prevention, diagnosis and development of new therapeutic targets.

La artritis reumatoide es una enfermedad autoinmune e inflamatoria que afecta de manera predominante a las articulaciones diartrodiales. En esta patología los factores ambientales o conductuales pueden actuar en sinergia con la predisposición genética, acelerando el inicio y la gravedad de la enfermedad. Este vínculo entre el medio ambiente y el genoma está mediado por marcas epigenéticas en el ácido desoxirribonucleico, incluyendo su metilación, la modificación de histonas y la regulación mediada por ácido ribonucleico no codificante. La epigenética puede generar cambios fenotípicos hereditarios, que no están determinados por modificaciones en la secuencia del ácido desoxirribonucleico y, en consecuencia, son reversibles. Por lo tanto la dieta, los medicamentos y otros factores ambientales, tendrían la capacidad de modularlos. La identificación de una desregulación epigenética específica, puede ofrecer una mayor comprensión de la fisiopatología de la enfermedad e influenciar positivamente en la prevención, diagnóstico y desarrollo de nuevas dianas terapéuticas.

Efecto de la epigenética en la artritis reumatoide / Effect of epigenetics on rheumatoid arthritis

La artritis reumatoide es una enfermedad autoinmune e inflamatoria que afecta de manera predominante a las articulaciones diartrodiales. En esta patología los factores ambientales o conductuales pueden actuar en sinergia con la predisposición genética, acelerando el inicio y la gravedad de la enfermedad. Este vínculo entre el medio ambiente y el genoma está mediado por marcas epigenéticas en el ácido desoxirribonucleico, incluyendo su metilación, la modificación de histonas y la regulación mediada por ácido ribonucleico no codificante. La epigenética puede generar cambios fenotípicos hereditarios, que no están determinados por modificaciones en la secuencia del ácido desoxirribonucleico y, en consecuencia, son reversibles. Por lo tanto la dieta, los medicamentos y otros factores ambientales, tendrían la capacidad de modularlos. La identificación de una desregulación epigenética específica, puede ofrecer una mayor comprensión de la fisiopatología de la enfermedad e influenciar positivamente en la prevención, diagnóstico y desarrollo de nuevas dianas terapéuticas.

Rheumatoid arthritis is an autoimmune and inflammatory disease that predominantly affects the diarthrodial joints. In this pathology, environmental or behavioral factors can act in synergy with genetic predisposition, accelerating the onset and severity of the disease. This link between the environment and the genome is mediated by epigenetic marks on deoxyribonucleic acid, including its methylation, histone modification, and noncoding ribonucleic acid-mediated regulation. Epigenetics can generate heritable phenotypic changes, which are not determined by modifications in the deoxyribonucleic acid sequence and are therefore reversible. Therefore, diet, medications and other environmental factors would have the ability to modulate them. The identification of a specific epigenetic dysregulation can offer a better understanding of the pathophysiology of the disease and positively influence the prevention, diagnosis and development of new therapeutic targets.

Evaluación del polimorfismo TLR2 Arg753Gln como posible marcador de riesgo para el desarrollo de sepsis

Objetivo: Evaluar el polimorfismo TLR2 Arg753Gln como posible marcador de riesgo para el desarrollo de sepsis Materiales y métodos: Estudio de asociación, el cual incluyó 183 individuos venezolanos no relacionados, agrupados en individuos sépticos (n=50), hospitalizados en el área de emergencia del Hospital Central del Instituto Venezolano de los Seguros Sociales -Dr. Miguel Pérez Carreño-, e individuos aparentemente sanos (n=133). El polimorfismo TLR2 Arg753Gln se determinó utilizando la técnica reacción en cadena de la polimerasa con iniciadores de secuencias específicas. Resultados: Se observó en el grupo de pacientes con escala SOFA en el rango entre 6-9 una mayor frecuencia de fallecimientos con respecto al grupo de pacientes con escala SOFA en el rango entre 0-5 (OR: 8.5; IC 95%: 2.33-30.90, p= 0,000357). El polimorfismo Arg753Gln del gen TLR2 está ausente en los pacientes con diagnóstico de sepsis. Conclusión: Se verificó que la escala SOFA es un sistema que permite predecir la mortalidad. La ausencia del polimorfismo Arg753Gln del gen TLR2 en el grupo de pacientes sépticos y una baja frecuencia del mismo en los individuos aparentemente sanos, sugiere la rareza de este polimorfismo en la población venezolana. Consecuentemente, se requiere incrementar el tamaño de la muestra para poder comprobar si es un marcador de riesgo para el desarrollo de sepsis en nuestra población.

Objective: To evaluate the TLR2 Arg753Gln polymorphism as a possible risk marker for sepsis development. Materials and Methods: Association study which included 183 unrelated Venezuelan individuals, divided into two groups: patients with sepsis (n = 50), hospitalized in the emergency area of the Central Hospital of the Venezuelan Institute of Social Security "Dr. Miguel Pérez Carreño", and apparently healthy individuals (n = 133). The TLR2 Arg753Gln polymorphism was determined using the polymerase chain reaction technique with specific sequence primers. Results: A higher death rate was observed among the group of patients with the SOFA scale range between 6-9, compared to the group of patients with the SOFA scale range between 0-5 (OR: 8.5; 95% CI: 2.33-30.90, p = 0.000357). The Arg753Gln polymorphism of the TLR2 gene is absent in patients diagnosed with sepsis. Conclusion: It was verified that the SOFA scale is a useful system to predict the mortality rate associated with sepsis. The absence of the Arg753Gln polymorphism of the TLR2 gene among the group of patients with sepsis diagnosis and its low frequency in apparently healthy individuals suggests the rarity of this polymorphism in the Venezuelan population. Consequently, it is necessary to increase the size of the sample to be able to evaluate whether it can be considered as a risk marker for sepsis development in our population.

Polymorphisms of the TLR4 gene: Risk factor for chronicity and severity in oral vectorial Chagas disease.

Chagas disease is one of the parasitic infections with the greatest socio-economic impact in Latin America. In Venezuela, epidemiological data has shown different sources of infection, such as the vectorial route by oral transmission. Given the importance of the TLR4 gene in the innate immune response triggered by infection with Trypanosoma cruzi, this work analyses the role of TLR4 polymorphisms and its possible effect on cytokine expression. Genomic DNA was extracted from the peripheral blood of patients from the main outbreak of oral Chagas disease in Venezuela (n = 90), as well as from a group of healthy individuals (n = 183). Subsequently, peripheral blood was also extracted from individuals with different TLR4 haplotypes and then stimulated with LPS to determine the cytokine concentration by ELISA. The internalization of TLR4 was evaluated by flow cytometry. In comparison to healthy individuals, the analysis showed a significantly increased frequency of the Asp/Gly genotype in symptomatic patients. Also, observed a correlation of the 299/399 haplotype with a significant decrease in cytokine concentration and disease severity. Finally, the parasites' trypomastigotes cause the internalization or negative regulation of TLR4. The variants of TLR4 associated with low production of cytokines may be a risk factor for chronicity and severity (cardiac involvement) in oral vectorial Chagas disease.

Polimorfismo de genes de citocinas: ¿factores de riesgo cardiovascular en la población venezolana? / Polymorphism of cytokine genes: cardiovascular risk factors in the Venezuelan population?

Resumen Objetivo: Examinar si los polimorfismos de los genes IL6, TNFA e IL10 representan un marcador de riesgo de infarto agudo de miocardio (IAM) y analizar su correlación con los factores de riesgo, la edad de ocurrencia y el tipo de IAM. Método: Estudio de asociación que incluyó 310 individuos venezolanos, no relacionados, agrupados en 190 pacientes con IAM y 120 controles con o sin factores de riesgo cardiovascular. Los polimorfismos IL6-174 G/C (rs1800795), TNFA-308 G/A (rs1800629) e IL10-1082 A/G (rs1800896), -819 C/T (rs1800871) y -592 C/A (rs1800872) se determinaron utilizando la técnica reacción en cadena de la polimerasa con iniciadores de secuencias específicas. Resultados: La comparación de frecuencias genotípicas y alélicas, mediante el análisis de regresión logística ajustado para los factores de riesgo, mostró una frecuencia significativamente incrementada de la combinación de genotipos G/G-A/A de la variante TNFA-308 G/A (odds ratio [OR]: 3.8; p = 0.00007), GG/-C/C de la variante IL6-174 G/C (OR: 2.3; p = 0.009), A/G-G/G de la variante IL10-1082 A/G (OR: 3.8; p = 0.00001) y del haplotipo GCC de IL10 (OR: 3.71; p = 0.0053) en los pacientes con IAM con respecto a los controles. Se observaron interacciones entre los polimorfismos IL10-1082 A/G y TNFA-308 G/A e hipertensión. Conclusiones: La asociación de las variantes de los genes TNFA, IL6 e IL10 con IAM sugiere que el desbalance en la producción de citocinas promueve un proceso inflamatorio exacerbado, apoyando el papel fundamental de la inflamación en todas las etapas del proceso aterosclerótico.

Abstract Objective: To examine whether the polymorphisms of the IL6, TNFA and IL10 genes represent a risk marker for acute myocardial infarction (AMI) and to analyze their correlation with risk factors, age of occurrence and type of AMI. Method: Association study that included 310 unrelated Venezuelan individuals, grouped in 190 patients with AMI and 120 controls with or without cardiovascular risk factors. The IL6-174 G/C (rs1800795), TNFA -308 G/A (rs1800629), and IL10-1082 A/G (rs1800896), -819 C/T (rs1800871) and -592 C/A (rs1800872) polymorphisms were determined using the polymerase chain reaction technique with sequence-specific primers. Results: Comparison of genotypic and allelic frequencies, using adjusted logistic regression analysis for risk factors, showed a significantly increased frequency of the genotype combination G/G-A/A of TNFA-308 G/A (odds ratio [OR]: 3.8; p = 0.00007), GG/-C/C of IL6-174 G/C (OR: 2.3; p = 0.009), A/G-G/G of IL10-1082 A/G (OR: 3.8; p = 0.00001) and the GCC haplotype of IL10 (OR: 3.71; p = 0.0053) in infarcted patients compared to controls. Interactions between the IL10-1082 A/G and TNFA-308 G/A polymorphisms and hypertension were observed. Conclusions: The association of the variants of the TNFA, IL6 and IL10 genes with AMI suggest that the imbalance in the production of cytokines promotes an exacerbated inflammatory process, supporting the fundamental role of inflammation in all stages of the atherosclerotic process.

Polimorfismo de genes de citocinas: ¿factores de riesgo cardiovascular en la población venezolana? / Polymorphism of cytokine genes: cardiovascular risk factors in the Venezuelan population?

Objective: To examine whether the polymorphisms of the IL6, TNFA and IL10 genes represent a risk marker for acute myocardial infarction (AMI) and to analyze their correlation with risk factors, age of occurrence and type of AMI. Method: Association study that included 310 unrelated Venezuelan individuals, grouped in 190 patients with AMI and 120 controls with or without cardiovascular risk factors. The IL6-174 G/C (rs1800795), TNFA -308 G/A (rs1800629), and IL10-1082 A/G (rs1800896), -819 C/T (rs1800871) and -592 C/A (rs1800872) polymorphisms were determined using the polymerase chain reaction technique with sequence-specific primers. Results: Comparison of genotypic and allelic frequencies, using adjusted logistic regression analysis for risk factors, showed a significantly increased frequency of the genotype combination G/G-A/A of TNFA-308 G/A (odds ratio [OR]: 3.8; p = 0.00007), GG/-C/C of IL6-174 G/C (OR: 2.3; p = 0.009), A/G-G/G of IL10-1082 A/G (OR: 3.8; p = 0.00001) and the GCC haplotype of IL10 (OR: 3.71; p = 0.0053) in infarcted patients compared to controls. Interactions between the IL10-1082 A/G and TNFA-308 G/A polymorphisms and hypertension were observed. Conclusions: The association of the variants of the TNFA, IL6 and IL10 genes with AMI suggest that the imbalance in the production of cytokines promotes an exacerbated inflammatory process, supporting the fundamental role of inflammation in all stages of the atherosclerotic process.

Objetivo: Examinar si los polimorfismos de los genes IL6, TNFA e IL10 representan un marcador de riesgo de infarto agudo de miocardio (IAM) y analizar su correlación con los factores de riesgo, la edad de ocurrencia y el tipo de IAM. Método: Estudio de asociación que incluyó 310 individuos venezolanos, no relacionados, agrupados en 190 pacientes con IAM y 120 controles con o sin factores de riesgo cardiovascular. Los polimorfismos IL6-174 G/C (rs1800795), TNFA-308 G/A (rs1800629) e IL10-1082 A/G (rs1800896), -819 C/T (rs1800871) y -592 C/A (rs1800872) se determinaron utilizando la técnica reacción en cadena de la polimerasa con iniciadores de secuencias específicas. Resultados: La comparación de frecuencias genotípicas y alélicas, mediante el análisis de regresión logística ajustado para los factores de riesgo, mostró una frecuencia significativamente incrementada de la combinación de genotipos G/G-A/A de la variante TNFA-308 G/A (odds ratio [OR]: 3.8; p = 0.00007), GG/-C/C de la variante IL6-174 G/C (OR: 2.3; p = 0.009), A/G-G/G de la variante IL10-1082 A/G (OR: 3.8; p = 0.00001) y del haplotipo GCC de IL10 (OR: 3.71; p = 0.0053) en los pacientes con IAM con respecto a los controles. Se observaron interacciones entre los polimorfismos IL10-1082 A/G y TNFA-308 G/A e hipertensión. Conclusiones: La asociación de las variantes de los genes TNFA, IL6 e IL10 con IAM sugiere que el desbalance en la producción de citocinas promueve un proceso inflamatorio exacerbado, apoyando el papel fundamental de la inflamación en todas las etapas del proceso aterosclerótico.

Genetic variability of molecules involved in the disease pathogenesis in Leishmania infection.

Macrophages are the primary host cell for Leishmania parasites, by Toll like receptors (TLR-MyD88) that are central components of the innate and adaptive immunity against leishmania infection. The CD40/CD40L interaction has also been shown to be important in resistance to various protozoa. In this context, one of the most important properties of suppressors of cytokine signalling (SOCS) proteins, especially SOCS1 and SOCS3, is the regulation of macrophages cell for Leishmania parasites. In the present study we evaluated variants of molecules involved in activation and modulation of leishmanicidal signaling cascades and the possible associations between polymorphisms present in the TLR2, TLR4, MyD88, CD40, SOCS1, SOCS3 genes with susceptibility/resistent to Leishmania. The results suggest the absence of any association between TLR2 and TLR4 variants and susceptibility to Leishmaniasis. Analysis of the nucleotide sequence encoding the TIR recognition domain of the MyD88 molecule showed that it is highly conserved when compared to the reference sequences. In contrast, heterozygous rs 12953258, which reflects a decrease in the expression of SOCS3, suggesting that it may be involved in the leishmaniasis susceptibility. This study is a first advance in the analysis of polymorphisms of genes involved in the signaling pathway of the macrophage and their relationship with leishmaniases infection and disease progression.

Relevancia del polimorfismo de eliminación del gen gstm1 y gstt1 en pacientes con nefritis lupica / Relevance of the elimination polymorphism of the gstm1 and gstt1 gene in patients with lupic nephritis

Objective: To identify if the absence of the GSTM1 and / or GSTT1 genes is correlated with the response to cyclophosphamide and the presence of anti DNA in a patient with SLE. Methodology: An correlational cross study that included 46 patients with a diagnosis of systemic lupus erythematosus. (LES), who attended the rheumatology clinic of the Venezuelan Institute of Social Security- Central Hospital "Dr. Miguel Pérez Carreño ", during the period June 2016 - June 2017. Patients with SLE were classified according to the presence or absence of renal involvement (lupus nephritis). Each individual was extracted 5 mL of peripheral blood, from which the genomic DNA was extracted. The presence or absence of the GSTM1 and GSTT1 genes was determined using the multiplex polymerase chain reaction method with specific primers. Results: In the studied population (n = 46), 95.7% were women and only 4.3% men. The average age was 31 years, being mostly young women of childbearing age. The treatment of patients included the use of chloroquine (78%), mycophenolate (69.6%) and corticoids (38.7%). The GST genes were present, the GSTM1 gene with a frequency.

Objetivo: Identificar si la ausencia de los genes GSTM1 y/o GSTT1 está correlacionada con la respuesta a ciclofosfamida y con la presencia de anti DNA en paciente con LES. Metodología: Estudio transversal correlacional, que incluyó 46 pacientes con diagnóstico de lupus eritematoso sistémico (LES), que acudieron a la consulta de reumatología del Instituto Venezolano del Seguro Sociales- Hospital Central "Dr. Miguel Pérez Carreño", durante el período septiembre 2016 ­ junio de 2017. Los pacientes con LES se clasificaron de acuerdo a la presencia o no de afectación renal (nefritis lúpica). A cada individuo se le extrajo 5 mL de sangre periférica, a partir de la cual se extrajo el ADN genómico. La presencia o ausencia de los genes GSTM1 y GSTT1 se determinó utilizando el método de reacción en cadena de la polimerasa múltiplex con iniciadores específicos. Resultados: En la población estudiada (n= 46), 95,7% eran mujeres y sólo 4,3% hombres. La edad media fue de 31 años, siendo en su mayoría mujeres jóvenes en edad fértil. El tratamiento de los pacientes, comprendió el uso de cloroquina (78%), micofenolato (69,6 %) y corticoides (38,7%). Los genes GST estuvieron presentes, el gen GSTM1 con una frecuencia del 100 % y GSTT1 del 93,5%. Solo un 6,5% de los pacientes no presentaron el gen GSTT1. Conclusión: No se observó una correlación entre la presencia y/o ausencia de los genes GSTM1 y GSTT1 con la respuesta al tratamiento con Ciclofosfamida ni a la presencia de anti-DNA

[Study of the association between the polymorphism of the TNF-α gene and prostate cáncer]. / Estudio de la asociación entre el polimorfismo del gen TNFα y el cáncer de próstata.

BACKGROUND: Prostate cancer is the third cause of cancer death in men in the Western hemisphere and the second cause of cancer death in Zulian men from Venezuela. OBJECTIVE: To determine whether polymorphisms 308 and 238 of the tumor necrosis factor alpha (TNF-α) gene are associated with prostate cancer. METHODS: The DNA that was extracted from the peripheral blood of 40 patients with prostatic specific antigen and 40 controls was amplified by PCR plus digestion with enzymes NcoI and MspI. RESULTS: In the patients, genotypes of the TNF-α-238 polymorphism were observed in 90% GG and 10% GA; in controls, in 97.5% GG and 2.5% GA, odds ratio (OR) = 4,000 for GA. In the patients, genotypes of TNF-α-308 polymorphism were identified in 85% GG and 15% GA, and in controls in 72.5% GG and 27.5% GA, OR = 0.545 for GA and 1.172 for GG. The allelic frequencies for TNF-α-238 in patients were 95% for G and 5% for A; in controls, 98.75% for G and 1.25% for A, with OR = 4,000 for A. The allelic frequencies for TNF-α-308 in the patients were 92.5% for G and 7.5% for A. CONCLUSIONS: There weren't any statistically significant associations. The allele A of the TNF-α-238 polymorphism resulted in a considerable risk factor for prostate cancer.

Antecedentes: El cáncer de próstata es la tercera causa de muerte por cáncer en hombres del hemisferio occidental y la segunda en zulianos de Venezuela. Objetivo: Determinar si los polimorfismos 308 y 238 del gen TNFα están asociados con cáncer de próstata. Métodos: El ADN extraído de sangre periférica de 40 pacientes con antígeno prostático específico y 40 controles fue amplificado por reacción en cadena de la polimerasa más digestión con enzimas NcoI y MspI. Resultados: Respecto al polimorfismo 238 del gen TNFα, en los pacientes se observó 90 % de genotipo GG y 10 % de GA; en los controles, 97.5 % de GG y 2.5 % de GA, razón de momios (RM) = 4.000 para GA. En cuanto al polimorfismo 308, en los pacientes se identificó 85 % de genotipo GG y 15 % de GA; y en los controles, 72.5 % de GG y 27.5 % de GA, RM = 0.545 para GA y 1.172 para GG. Las frecuencias alélicas de TNFα-238 en los pacientes fue de 95 % de G y 5 % de A; en los controles, 98.75 % de G y 1.25 % de A, con RM = 4.000 para A. Las frecuencias alélicas para TNFα-308 en los pacientes fueron 92.5 % de G y 7.5 % de A. Conclusiones: No existieron asociaciones estadísticamente significativas. El alelo A del polimorfismo 238 del gen TNF-α resultó de riesgo para cáncer de próstata.

Postprandial Hypertriglyceridemia Is Associated with the Variant 54 Threonine FABP2 Gene.

Purpose: Fasting or postprandial hypertriglyceridemia is considered an independent cardiovascular disease (CVD) risk factor. The intestinal fatty acid binding protein (FABP2) is involved in the intracellular transport and metabolism of fatty acids. The presence of the Ala54Thr polymorphism of the FABP2 gene appears to be involved in postprandial hypertriglyceridemia. We explored the possible association of the Ala54Thr polymorphism with fat intolerance in apparently healthy, fasting, normolipidemic subjects with normal body-mass index and without diabetes. Methodology: A total of 158 apparently healthy individuals were classified as fat tolerant (n = 123) or intolerant (n = 35) according to their response (plasma triglycerides) to an oral abbreviated tolerance test with blood samples taken at 0, 2 and 4 h. At 0 h, all subjects ingested 26.3 g of fats. Presence of the Ala54Thr polymorphism of the FABP2 gene was evaluated by polymerase chain reaction⁻restriction fragment length (PCR⁻RFLP). Results: The group with fat intolerance (postprandial hypertriglyceridemia group) showed an increased frequency of the Thr54Thr genotype when compared with the group with normal fat tolerance (control group) (23% vs. 4%, respectively, OR: 16.53, 95% CI: 4.09⁻66.82, p: 0.0001, pc: 0.0003). Carriers of at least one Thr54 allele were up to six times more prevalent in the fat intolerant group than in the non-carriers. (OR: 6.35; 95% CI: 1.86⁻21.59, p: 0.0003, pc: 0.0009). The levels of plasma triglycerides (Tg) at 4 h after the test meal were higher in carriers of at least one 54Thr allele than in carriers of the Ala54 allele (p < 0.05). Conclusions: There is a significant association between postprandial hypertriglyceridemia and the presence of at least one 54Thr allele of the FABP2 gene. In addition, subjects with this genotype showed an increased ratio of Tg/HDL-cholesterol. This parameter is a marker of increased CVD risk and insulin resistance.

Papel de los genes TNFA e IL10 en el desarrollo y manifestaciones clínicas de la artritis psoriásica / Role of TNF-Alpha and IL10 genes in the development and clinical manifestations of psoriatic arthritis

RESUMEN Objetivo: Evaluar el impacto de los polimorfismos de los genes TNFA e IL10 y su asociación con el fenotipo clínico de la artritis psoriásica (APs). Materiales y métodos: Se incluyó a 104 individuos venezolanos, no relacionados, agrupados en 52 pacientes con APs, que reunieron los criterios CASPAR, y 52 individuos sanos, sin antecedentes familiares de psoriasis. Los polimorfismos de los genes TNFA e IL10 se determinaron por PCR-SSP. Resultados: El genotipo GA y alelo A del polimorfismo TNFA-238G/A parecen conferir protección contra el desarrollo de APs (OR: 0,31, IC del 95%: 0,92 -1,05, p: 0,02). El genotipo GA del polimorfismo TNFA-308G/A está asociado con una edad de inicio de APs tardía (GA = 60 ± 13,17 arios vs. GG = 43,55 ± 14,29 años; p = 0,002) y el genotipo GG del polimorfismo IL10-1082A/G con un intervalo mayor entre el inicio de la psoriasis y el desarrollo de la APs (GG = 27,4 ± 24,11 años, GA = 5,47 ± 7,23 años, AA = 7,86 ± 8,51 años, p = 0,001). Los genotipos CC de IL10-819 C/T e IL10-592 C/A confieren riesgo de daño a las articulaciones interfalángicas distales (OR: 4,79, p=0,026). Conclusiones: El polimorfismo TNFA-238G/A desempeña un papel importante en el desarrollo de la APs en mestizos venezolanos. Asimismo, los polimorfismos TNFA-308G/A, IL10-1082A/G, -819C/T y -592C/A pueden modificar la expresión clínica de la APs.

ABSTRACT Objective: To evaluate the impact of polymorphisms of TNF-alpha (TNFA) and IL10 genes and their association with clinical phenotypes of psoriatic arthritis (PsA). Materials and methods: The study included 104 unrelated Venezuelan individuals, grouped into 52 patients with PsA, who fulfilled the CASPAR criteria, and 52 healthy individuals with no family history of psoriasis. The polymorphisms of the TNFA and IL10 genes were determined by Single Specific Primer-Polymerase Chain Reaction (SSP-PCR). Results: The GA genotype and A allele of the TNFA-238G/A polymorphism appears to confer protection against the development of PsA (OR: 0.31, 95% CI: 0.92 -1.05, P=.02). The GA genotype of the TNFA-308G/A polymorphism is associated with a late onset age of PsA (GA = 60± 13.17 years vs. GG = 43.55 ± 14.29 years, P=.002), and the GG genotype of the IL10 -1082A/G polymorphism with a longer time interval between the onset of psoriasis and the development of PsA (GG = 27.4±24.11 years, GA = 5.47±7.23 years, AA=7.86±8.51 years, P=.001). The CC genotypes of IL10-819 C/T and IL10-592 C/A confers risk of damage to distal interphalangeal joints (OR: 4.79, P=.026) Conclusions: The TNFA-238G/A polymorphism plays an important role in the development of PsA in mixed-race Venezuelans. Likewise, TNFA-308 G/A, IL10 -1082 A/G, -819C/T, -592C/A polymorphisms may modify the clinical expression of PsA.

NRAMP1 and VDR Gene Polymorphisms in Susceptibility to Tuberculosis in Venezuelan Population.

Natural resistance-associated macrophage protein (Nramp1) and the vitamin D receptor (VDR) are central components of the innate and adaptive immunity against Mycobacterium tuberculosis, and associations between susceptibility to tuberculosis and polymorphisms in the genes NRAMP and VDR have been sought in geographically diverse populations. We investigated associations of NRAMP1 and VDR gene polymorphisms with susceptibility to TB in the Venezuelan population. The results suggest the absence of any association between VDR variants FokI, ApaI, and TaqI and susceptibility to tuberculosis. In contrast, the NRAMP1 3'UTR variants were associated with susceptibility to M. tuberculosis infection, as seen in the comparisons between TST+ and TST- controls, and also with progression to TB disease, as shown in the comparisons between TB patients and TST+ controls. This study confirms the previously described association of the NRAMP1 3'UTR polymorphism with M. tuberculosis infection and disease progression.

The role of haptoglobin genotypes in Chagas disease.

Although the number of people infected with T. cruzi is on the rise, host genetic and immune components that are crucial in the development of the Chagas disease have been discovered. We investigated the frequency of polymorphisms in the gene encoding haptoglobin of patients with chronic Chagas disease. The results suggest that while the HP1-1 genotype may confer protection against infection and the development of chronic Chagas disease due to the rapid metabolism of the Hp1-1-Hb complex and its anti-inflammatory activity, the presence of HP2-2 genotype may increase susceptibility towards a chronic condition of the disease due to a slow metabolism of the Hp2-2-Hb complex, lower antioxidant activity, and increased inflammatory reactivity, which lead to cell damage and a deterioration of the cardiac function. Finally, correlations between HP genotypes in different age groups and cardiac manifestations suggest that HP polymorphism could influence the prognosis of this infectious disease. This study shows some of the relevant aspects of the haptoglobin gene polymorphism and its implications in the T. cruzi infection.

HLA Alleles and Dengue Virus Infection in Venezuelan Patients: A Preliminary Study

En áreas endémicas, una pequeña proporción de individuos infectados con el virus dengue desarrollan la fiebre hemorrágica del dengue (FHD),sugiriendo la existencia de factores de resistencia que pudiesen estar jugando un papel importante en el huésped. Este trabajo describe la frecuencia dealelos HLA clase I y II en pacientes con dengue y su relación con las manifestaciones clínicas de la enfermedad. El análisis de la frecuencia de especificidades HLA en los pacientes con dengue mostró frecuencias disminuidas de los alelos B*15, B*49, DRB1*02 y DRB1*03 y frecuencias incrementadas de los alelos B*57 y DRB1*15 comparado con los controles. Cuando lospacientes fueron agrupados y comparados de acuerdo a la severidad de laenfermedad, se observó una susceptibilidad incrementada a la fiebre del dengue clásico (FD) en pacientes con B*57, una susceptibilidad disminuida aldesarrollo de la FHD en pacientes A*03 y una susceptibilidad incrementada al desarrollo de la FHD en pacientes con B*40. Aunque las asociacionesobservadas proceden de un estudio poblacional caso-control relativamentepequeño y que después de la corrección por múltiples comparaciones se mantuvo únicamente la asociación con DRB1*15, los datos confirman que posiblemente los alelos HLA pueden jugar un papel en la susceptibilidad y/oresistencia a la infección por virus dengue y al desarrollo de la FHD (AU)

In endemic areas, a small proportion of individuals infected with dengue virus develop dengue hemorrhagic fever (DHF) suggesting that theremay be host specific resistance factors playing an important role. Thiswork describes the frequency of HLA class I and class II alleles in patientswith dengue and the relationship with the clinical manifestations of thedisease. The analysis of the frequency of HLA specificities in the dengue patients revealed reduced frequencies of B*15, B*49, DRB1*02 andDRB1*03 and increased frequencies of B*57 and DRB1*15 compared withcontrols. When the patients were grouped and compared according todisease severity, an association with enhanced susceptibility to denguefever (DF) in patients with B*57, an association with reduced susceptibility to DHF in patients with A*03, and an association with enhanced susceptibility to DHF in patients with B*40 was observed. Although the associations revealed in this study come from a very small case-control population and that after correction for multiple testing only the associationwith DRB1*15 is maintained, the data suggest that the HLA alleles canpossibly play a role in the susceptibility and/or resistance to dengue virusinfection and development of DHF (AU)

Influence of CTLA-4 gene polymorphism in autoimmune and infectious diseases.

Cell-mediated immunity requires costimulatory activity to initiate or inhibit antigen-specific T-cell responses. CTLA-4 is an inhibitory receptor expressed by activated and regulatory T cells. The single nucleotide polymorphism (SNP) +49 A/G of the CTLA-4 gene alters intracellular distribution of CTLA-4, interleukin-2 production, and, as a consequence, T-cell proliferation. The aim of this study was to analyze the only coding SNP CTLA-4 +49 A/G polymorphism in patients with either infectious (Chagas's, Dengue, and American cutaneous leishmaniasis) or autoimmune diseases (myasthenia gravis, pemphigus, and psoriasis). No statistically significant differences were reported when all patients of each disease group were compared with healthy individuals. However, the +49 G/G genotype was moderately increased in pemphigus and myasthenia gravis. Patients with diffuse cutaneous leishmaniasis (DCL) exhibited an increased frequency of the A/G +49 genotype compared with patients with localized cutaneous leishmaniasis (LCL; p = 0.009; odds ratio [OR] = 4.25; 95% confidence interval [CI] = 1.245-14.501) and intermediate cutaneous leishmaniasis (ICL; p = 0.027; OR = 4.44; 95% CI = 1.273-15.516), indicating that the heterozygous genotype, associated with overactivation of T-cell proliferation, could confer susceptibility to the development of the more severe clinical form of cutaneous leishmaniasis. The A/A +49 genotype was increased in LCL patients compared with DCL patients (p = 0.019; OR = 0.25; 95% CI = 0.067-0.953), indicating that this genotype, which has been associated with normal proliferation of T cells, could confer protection to the development of DCL. The results indicate that the polymorphism of CTLA-4 is an important genetic factor associated with risk or protection for the development of diffuse cutaneous leishmaniasis and has influence in the pathogenesis of autoimmune diseases. However, other closely linked candidate genes in linkage disequilibrium with CTLA4, such as CD28 and ICOS, could be associated with the development of autoimmune and infectious disease.

Genetic contribution of major histocompatibility complex class II region to type 1 autoimmune hepatitis susceptibility in Venezuela.

AIMS: Autoimmune hepatitis (AIH) is a progressive liver disease characterized by the presence of circulating autoantibodies, hypergammaglobulinaemia and a favourable response to immunosuppressive treatment. Although the pathogenesis of type 1 AIH is unknown, disease susceptibility is partially determined by genes linked to the class II region of the major histocompatibility complex. Type 1 AIH has been associated with DRB1*03, DRB1*04 and DRB3 alleles in European and North American Caucasians, with DRB1*0405 in Japanese, with DRB1*0404 in Mexican, and with DRB1*1301 in Argentinean populations. METHODS: To analyse the molecular basis of these associations in Venezuela (mestizo population), we examined the frequency of human leucocyte antigens (HLA)-A -B -C, HLA-DQ and HLA-DR genes by low- and high-resolution oligonucleotide typing in a population of 41 type 1 AIH patients and 111 ethnic- and aged-matched healthy subjects. RESULTS: The frequencies of both DRB1(*)1301 (P<0.0001) and DRB1*0301 (P<0.005) were significantly higher in patients than in controls. In addition, patients showed a strong association with the DRB3 allele (P<0.01). In contrast, the DQB1*04 allele was significantly decreased in the patient group (P<0.01). The frequencies of haplotypes A*01-B*08-DQB1*02-DRB1*03-DRB3, DQB1*05-DRB1*1301, DQB1*06-DRB1*1301 and A*02-DRB1*1301, B*45-DRB3 were significantly increased in type 1 AIH patients compared with the controls (P<0.01). CONCLUSIONS: In conclusion, our data indicate that type 1 AIH predisposition in a Venezuelan mestizo population of different ethnic backgrounds is associated with DRB1*1301 and DRB1*0301 alleles. In addition, our findings suggest that protection against disease might be conferred by the DQB1*04 allele, with distinct ethnic differences from other populations.

Genetic polymorphisms at four STR loci from the HLA region in a Venezuelan population.

POPULATIONS: Whole blood samples from 74 unrelated healthy individuals were collected. The donors' sample included Venezuelan mestizos from various regions of the country, but mostly from the resident population of Caracas City. A Venezuelan mestizo is the offspring of a mating between a native Venezuelan and a person born in Europe, mainly in Spain.

HLA class II and class I polymorphism in Venezuelan patients with myasthenia gravis.

Oligotyping performed among ethnically mixed Venezuelan patients with myasthenia gravis (MG) and controls has revealed positive associations of HLA class I A*31, B*08, B*39, B*40, C*15, C*17, and class II DRB1*09 and negative associations of DQB1*06 and DQA1*02 with the disease. Sequential removal of human leukocyte antigen B (HLA-B) alleles when relative predispositional effects (RPEs) were looked for demonstrated that B*08 is the allele group with the largest contribution in the overall MG patients followed by B*39 and B*40. Several specificities (A*31, B*08, C*17, DRB1*03, DQA1*05, and DQB1*02) indicated increased frequencies among patients with thymic hyperplasia versus patients without hyperplasia or controls. Tests to identify alleles with the strongest association to MG in our patients detected DRB1*13 and B*38 as possible predisposing secondarily associated alleles in patients with hyperplasia. The associations observed disappear after Bonferoni correction of probability values and have been described in patients of Caucasian and/or Oriental ethnic background. Thus, our results reflect the heterogeneity of our population and of the patients tested and suggest a limited influence of several HLA genes in this heterogeneous disease or that these might be only markers of nearby non-HLA genes responsible for the susceptibility or resistance effect.

Synthesis, characterization, DNA binding study and biological activity against Leishmania mexicana of [Cu(dppz)2]BF4.

[Cu(dppz)(2)]BF(4) complex has been synthesized by the reaction of [Cu(CH(3)CN)(4)]BF(4) and dipyrido[3,2-A:2',3'-c]phenazine (dppz) in a molar ratio of 1:2. The compound was characterized by fast atom bombardment mass spectrometry, 1H nuclear magnetic resonance, UV-Vis and IR spectroscopies. Absorption and viscometric studies carried out on the interaction of [Cu(dppz)(2)]BF(4) complex with calf thymus DNA suggested that the complex binds by intercalation. No covalent binding was observed. Additionally, the results obtained from electrophoresis showed nuclease activity. The biological activity of the complex was tested in vitro on Leishmania mexicana promastigote cultures. A leishmanicidal effect (LD(30)) was observed in 48 h at concentration of 41 nM. Preliminary studies of the ultrastructure of L. mexicana treated with a sublethal dose of the complex (IC(7)=4.1 nM) for 48 h showed an induction of cytoplasm disorganization, vacuolization and binucleated cells. These findings suggest that the leishmanicidal activity of the title complex could be associated with its interaction with the parasitic DNA.

Design of copper DNA intercalators with leishmanicidal activity.

The complexes [Cu(dppz)(NO(3))]NO(3) (1), [Cu(dppz)(2)(NO(3))]NO(3) (2), [Cu(dpq)(NO(3))]NO(3) (3), and [Cu(dpq)(2)(NO(3))]NO(3) (4) were synthesized and characterized by elemental analysis, FAB-mass spectrometry, EPR, UV, and IR spectroscopies, and molar conductivity. DNA interaction studies showed that intercalation is an important way of interacting with DNA for these complexes. The biological activity of these copper complexes was evaluated on Leishmania braziliensis promastigotes, and the results showed leishmanicidal activity. Preliminary ultrastructural studies with the most active complex (2) at 1 h revealed parasite swelling and binucleated cells. This finding suggests that the leishmanicidal activity of the copper complexes could be associated with their interaction with the parasitic DNA.