Genotypic testing for HIV-1 drug resistance using dried blood samples.

In third-world countries, dried blood samples (DBS) are a convenient alternative to plasma for monitoring viral load during HIV-1 therapy. In this study, we evaluated the feasibility of using DBS to perform HIV-1 drug resistance genotyping in a ViroSeq assay in which the protease and reverse transcriptase regions of the pol gene are analyzed. Fifty-seven antiretroviral genotypes from plasma samples were tested, and drug resistance genotypes were determined. Only 38.6% paired DBS samples were sequenced. Failure to amplify DNA from DBS samples generally correlated with plasma viral loads below log(10) 5.1. The majority of the mutations identified in plasma pol sequences were also found in their DBS counterpart, with a concordance in genotype interpretation of 96.4%. Several factors were identified that could potentially improve both the sensitivity and the quality of genotype data, such as sample storage conditions and sequence analysis. Therefore, DBS sampling is useful to determine viral load and drug resistance genotypes in HIV patients.

Use of dried blood samples for monitoring hepatitis B virus infection.

BACKGROUND: Hepatitis B virus (HBV) infection is a problem in several regions of the world with limited resources. Blood samples dried on filter paper (DBS) have been successfully used to diagnose and monitor several infectious diseases. In Mexico there is an urgent need for an affordable and easy sampling method for viral load (VL) testing and monitoring of chronic HBV infection. The purpose of this work was to validate the utility of DBS samples for monitoring HBV infection in patients from Mexico City. METHODS: Matched samples of plasma and DBS on filter paper from 47 HBV infected patients from the Instituto Mexicano del Seguro Social (IMSS), were included. To evaluate the DNA stability and purity from DBS stored at different temperature conditions, samples from ten patients were stored at 4 degree, 25 degree, and 37 degree C for 7 days. After DBS elution and DNA extraction, the purity of these samples was determined measuring the O.D. rate 260/280. The DBS utility for molecular studies was assessed with PCR assays to amplify a 322 bp fragment from the "a" determinant region of the HBV "S" gene. The VL from all samples was determined to evaluate the correlation between plasma and DBS matched samples. RESULTS: The quality of the DNA from DBS specimen is not adversely affected by storage at 4 degree, 25 degree and 37 degree C for up 7 days. Statistical ANOVA analyses did not show any significant difference. The same amplification efficiency was observed between DNA templates from samples stored at different temperatures. The Pearson correlation between the VL from DBS and plasma matched samples was 0.93 (p = 0.01). The SD was 1.48 for DBS vs.1.32 for Plasma, and an average of log10 copies/mL of 5.32 vs. 5.53. ANOVA analysis did not show any statistically significant difference between the analyzed groups (p = 0.92). CONCLUSION: The results provide strong evidence that the isolation and quantification of DNA-HBV from DBS is a viable alternative for patient monitoring, and molecular characterization of the virus variants circulating in Mexico.

[Epidemiologic and situational panorama of hepatitis C in Mexico]. / Panorama epidemiológico y situacional de la hepatitis C en México.

OBJECTIVE: To determine the epidemiological situation of Chronic Hepatitis C (CHC) in our country. BACKGROUND DATA: Chronic Hepatitis C affects 170 million people worldwide, and about 0.7% of Mexican population. There is no enough epidemiological information about CHC in our country, and it is very probable that some cases are not even detected. METHODS: An investigation poll was performed. Age, gender, birthday, weight, race, residence and birth place, routes of transmission, ALT levels, histological, serological and molecular diagnosis, evidence of complications and previous treatments were recorded. A data recollection sheet was dispatched to different country provinces; they had 6 months to answer it, in order to recollect all information. RESULTS: 831 patients were analized (58.6% female and 41.4% male) with the following distribution in our country provinces: Aguascalientes 15, Chihuahua 12, Distrito Federal 495, Durango 10, Jalisco 89, Guanajuato 78, Yucatán 8, Querétaro 11, Sonora 40, Tabasco 15, Baja California 5, Veracruz 13, Tamaulipas 2 and 38 patients of Nuevo León. The highest incidence of CHC was found at fifth and sixth decade of life (28.5% y 26.7% respectively. The weight distribution was 36.2% < 65kg, 34.6% 65-75 kg and 29.2% > 75 kg. 86.5% had chronic hepatitis and 13.2% cirrhosis. The risk factors for HCV infection analysis showed that the main route of transmission was via contaminated blood (64.2%); when we excluded the patients that were exposed before 1995, the incidence was lowered to 4.5%. The higher incidence was showed between 1970 and 1990 (68%). The intravenous drug users were predominantly male and on those patients in the provinces near the north border line of our country. The predominant genotype was gen- 1 no matter the province (72.2%), in the intravenous drug users genotype 3 was found in 25%. The viral load was similar in all the provinces. 75% of the patients had have treatment and 22.5% had have two cycles, 50% of cirrhotic patients had have treatment whereas only 28% of the patients with late complications had have it. The most common treatment was pegylated alpha-2a interferon plus ribavirine. CONCLUSIONS: 1. The main route of transmission was blood transfusion. There is a marked decrease in the incidence of post-transfusional hepatitis since the introduction of anti-VHC antibody screening of blood donors (4.5%). 2. The time between the infection and diagnosis was 23 years for chronic hepatitis and 26 years for cirrhosis. 3. Intravenous drugs use was an important route of transmission in the north of our country. 4. The predominant genotype was gen-1. 5. Almost all the patients with chronic hepatitis received treatment, the most common used was pegylated interferon alpha-2a and ribavirin. 6.50% of the patients with CHC have late complications.

Evolución de los marcadores inmunológicos en la hepatitis viral aguda B. Estudio en 177 pacientes / Evolution of immunologic markers in accute B hepatitis. Study in 177 patients

Se reportan los resultados obtenidos en el estudio de 177 pacientes con diagnóstico de hepatitis viral aguda tipo B; 135 (76 por ciento) hombres y 42 (24 por ciento) mujeres. Se efectuó monitoreo secuencial del HBeAg, HBsAg y sus respectivos anticuerpos hasta obtener negativización o positivización, según correspondiera. No obstante que en general la respuesta inmune fue adecuada, se señala que se determinaron tres clases de respuesta: a) Simultánea: los antígenos desaparecen y sus anticuerpos aparecen al mismo tiempo; 46 por ciento para el antígeno e y 39 por ciento para el s. b) Tardía: la eliminación de los antígenos antecede con tiempo variable a la presentación de los anticuerpos; 37 por ciento en el antígeno e y 34 por ciento en el antígeno s. c) Temprana: aquí, los anticuerpos se anticipan a la negativización de sus antígenos ocasionando que ambos marcadores se detecten en forma simultánea; 17 por ciento para el antígeno e y 27 por ciento para el antígeno s

Hepatitis post transfusión: estudio prospectivo / Post-transfusion hepatitis. A prospective study

El presente estudio prospectivo, se efectuó en 30 pacientes que ameritaron transfusión de sangre y/o derivados. En diez (33.3 por ciento) se estableció el diagnóstico de hepatitis por transfusión, cifra equivalente a 15.75 casos por cada 1 000 U transfundidas. Cuatro pacientes desarrollaron ictericia; los otros seis se mantuvieron asintomáticos. Se estableció el diagnóstico de hepatitis noA noB en nueve pacientes (90 por ciento) y un (10 por ciento) caso correspondió a hepatitis B.Dos pacientes (22.2 por ciento) de hepatitis noA noB evolucionaron a la cronicidad, lo que corroboró por medio de biopsia hepática por punción

La importancia de la tuberculosis en el síndrome de inmunodeficiencia adquirida: aspectos clínicos y terapéuticos / The importance of tuberculosis in AIDS: clinical and therapeutic aspects

Se reportan los resultados obtenidos en el estudio de 50 pacientes con TB y SIDA. El total de pacientes se dividió en dos grupos: grupo I, cuando la TB se consideró la primera manifestación de SIDA; 27 hombres y 2 mujeres. Grupo II, la TB fue antecedida por alguna infección oportunista, algún tipo de cáncer, o por manifestaciones clínicas compatibles con síndrome de desgaste; 20 hombres y 1 mujer. No hubo diferencias por cuanto a los antecedentes epidemiológicos pues en ambos grupos predominó la homo-bisexualidad masculina. Las manifestaciones clínicas secundarias a TB fueron muy semejantes en los dos grupos, predominando fiebre, tos productiva y adenomegalia dolorosa. En la mayoría, la imagen radiológica mostró un patrón de tipo miliar. La localización extrapulmonar, sobre todo en ganglios linfáticos también fue frecuente. Sólo se encontró diferencia significativa entre ambos grupos cuando se analizó la mortalidad: en el grupo I 10 pacientes (34.4 por ciento) vs 16 (76 por ciento) del grupo II (p<0.01). En forma independiente se compara la eficacia del tratamiento con isoniacida más rifampicina (31 casos), contra otro esquema de estos dos mismos fármacos más otro antituberculoso (10 casos). La respuesta ante ambos esquemas de tratamiento, no fue significativamente distinta

Absceso esplénico por Salmonella / Splenic abscess by Salmonella

El absceso esplénico es una entidad clínica poco frecuente, su diagnóstico suele ser difícil y en ocasiones se realiza en el momento de la necropsia. El propósito de este estudio fue analizar las características clínicas de tres casos de absceso esplénico por Salmonella. Las principales manifestaciones clínicas fueron fiebre, dolor en hipocondrio izquierdo, dolor en hombro izquierdo, explenomegalia dolorosa, hipoventilación pulmonar basal izquierda y tos. En el examen radiográfico los datos más importantes foram elevación del hemidiafragma izquierdo, derrame pleural izquierdo y explenomegalia. El diagnóstico se corroboró por medio de gammagrafía, ultrasonografía y laparotomía. En los tres casos se practicó esplenectomía; los cultivos del pus del absceso resultaron positivos para Salmonella; su evolución clínica fue satisfactoria