In vivo emergence of drug-resistant mutations at less than 50 HIV-1 RNA copies/mL that are maintained at viral rebound in longitudinal plasma samples from human immunodeficiency virus type-1-infected patients on highly active antiretroviral therapy.

OBJECTIVE: Emergence of human immunodeficiency virus type-1 (HIV-1) genotypic drug resistance is generally attributed to noncompliance, poorly absorbed drugs, or drug-to-drug interaction. Attempts to determine emerging genotypic drug resistance from study subjects on highly active antiretroviral therapy (HAART) relied on insensitive polymerase chain reaction (PCR) techniques, revealing wild type HIV-1 or precursor resistant genotypes from few plasma samples successfully amplified with <50 copies/mL. STUDY DESIGN/METHODS: In this analysis, using Applied Biosystems' ViroSeq HIV-1 Genotyping Systems, Version 2.0 (Applied Biosystems, Foster City, CA, USA) and the supplemental, for research use only, nested PCR primers, genotypic drug resistance was determined in longitudinal plasma samples from 11 study subjects on HAART. RESULTS: In 4 of 11 study subjects, newly emerging genotypic primary resistant mutations were detected in plasma samples with <50 copies/mL. Most of these primary drug-resistant mutations were detected in subsequent longitudinal samples with detectable viral load (viral breakthrough). CONCLUSIONS: This analysis suggests sufficient viral replication <50 copies/mL to generate genotypic drug resistance in study subjects on suppressive HAART.

Hepatitis B seroprevalence in Latin America.

The seroprevalence of hepatitis B was investigated in over 12,000 subjects in six countries of Latin America: Argentina, Brazil, Chile, the Dominican Republic, Mexico, and Venezuela. Each study population was stratified according to age, gender, and socioeconomic status. Antibodies against hepatitis B core antigen (anti-HBc) were measured in order to determine hepatitis B infection. The highest overall seroprevalence was found in the Dominican Republic (21.4%), followed by Brazil (7.9%), Venezuela (3.2%), Argentina (2.1%), Mexico (1.4%), and Chile (0.6%). In all the countries an increase in seroprevalence was found among persons 16 years old and older, suggesting sexual transmission as the major route of infection. In addition, comparatively high seroprevalence levels were seen at an early age in the Dominican Republic and Brazil, implicating a vertical route of transmission.

Hepatitis B in Latin America: epidemiological patterns and eradication strategy. The Latin American Regional Study Group.

A comprehensive epidemiological analysis of hepatitis B virus (HBV) endemicity and transmission in Latin America was carried out to suggest policies and strategies for the use of hepatitis B vaccine in the region. The pattern of HBV endemicity based on available data from blood bank screening programmes and clinical and epidemiological studies varied widely: it was low in temperate South America, Mexico and some Caribbean islands; moderate in Brazil, Andean countries, part of central America and the Caribbean; and high in Hispaniola, St. Kitts/Nevis and in the Amazon basin (parts of Brazil, Peru, Venezuela, Colombia). Statistical estimates of HBV-related morbidity showed that greater than 150,000 acute HBV cases occur per year. As the endemicity of HBV varies considerably, different prevention strategies should be applied in this area. The highest priority should be the prevention of perinatal and early childhood transmission, but vaccination of adults belonging to high-risk groups should also be recommended.

HBeAg/anti-HBe seroconversion during and after protracted immunosuppressive treatment in type B chronic hepatitis.

Seventy-seven consecutive HBeAg-positive chronic hepatitis patients were studied from 1971 to 1983 to establish the seroconversion rate in the e system. Patients with less than a year of follow-up were not included in the study. Fifty-six patients with chronic active hepatitis (CAH) received immunosuppressive treatment (corticosteroids combined with azathioprine). The remaining twenty-one patients received no treatment, nine of them with chronic persistent hepatitis (CPH) and 12 with CAH. A retrospective study was performed with stored sera samples: HBeAg and anti-HBe were determined by RIA, and results were correlated with alanine aminotransferase (ALAT) levels in the same samples. The linearized seroconversion rate from HBeAg to anti-HBe was expressed as percent per patient-year. It was 9.6% in CPH patients and 8.8% in CAH patients without treatment. In CAH patients under immunosuppressive drugs it was as low as 1.1% and increased to 28.7% when treatment was withdrawn. ALAT levels were significantly lower in total seroconverted patients when compared with nonseroconverted (NS) patients, but no difference was found between partial seroconverted (PS) and NS patients. The results suggest that although immunosuppressive drug withdrawal may enhance seroconversion rate in type B CAH, delayed seroconversion and reported side effects during treatment stand against protracted usage of these drugs.

Biphasic form of hepatitis A virus infection: a frequent variant in Argentina.

In a retrospective study, we review here the clinical presentation of patients with the biphasic form of hepatitis A, a variant of viral hepatitis characterised by an increase in ALAT levels after an initial recovery in clinical condition and laboratory tests. Twenty-one patients were diagnosed as having a biphasic form; they represent about 10% of a selected population of hepatitis A cases. Six patients were asymptomatic. Eleven patients were jaundiced, nine of them showing a "cholestatic" pattern. The second phase of the disease had a more protracted course and displayed higher ALAT levels than the first phase. The total duration of the disease was 120 +/- 28 (mean +/- SD) days, and its course was benign.

HBV and HAV infection in chronic hepatitis in Argentina.

Sera of 155 chronic hepatitis (CH) patients in Argentina were tested for the presence of HBsAg, anti-HBs, anti-HBc, and anti-HAV. Our purpose was to define the role that both virus A and B might play in the etiology and pathogenesis of this condition. The patients were divided into two groups: group I (57) HBsAg-negative; group II (98) HBsAg-positive. The control group consisted of 1,209 healthy blood donors from Banco Central de Sangre de Rosario; 286/1,209 (24%) had viral markers for HBV. In group I, 38/57 (67%) had anti-HBs and/or anti-HBc, but none had anti-HBs alone. Group II showed a higher percentage of males (P less than 0.05). We found similar incidence of anti-HAV among group I, group II, and the control group.

Prevalencia de los anticuerpos contra el virus A de la hepatitis (VAH) en donantes de sangre de 13 paises y territorios del Hemisferio Occidental. / Prevalence of antibodies to hepatitis A virus (HAV) in blood donors of 13 countries and territories of the Western-Hemisphere

Los resultados de una encuesta con 7,342 muestras de sangur de 13 paises y territorios de las Americas indican una elevada prevalencia de los anticuerpos contra el virus A de la hepatitis en esa Region. Los resultados senalan tambien una correlacion significativa entre la ausencia de dichos anticuerpos y la ausencia de marcadores indicativos de infeccion por el virus B de la hepatitis

Similarities of two hepatitis A virus strains.

In outbreaks of type A hepatitis in Los Angeles, USA, and Rosario, Argentina, virus particles were isolated from faeces. The geographically diverse strains were identical in appearance and serological reactivity. They differed only in buoyant density, but other workers have also obtained inconsistent results in estimating this. We conclude that the virus strains in the two epidemics were identical.

[The frequency of the e-antigen in acute and chronic hepatitis (author's transl)]. / Das e-Antigen bei akuter und chronischer Hepatitis

Five groups of patients were studied: (a) 88 HBsAg-positive cases of acute viral hepatitis (AVH) who completely cured within 90 days; (b) 75 cases of acute HBsAg-negative hepatitis with early resolution; (c) 15 AVH patients who became chronic; (d) 94 HBsAg-positive cases of chronic hepatitis (CH) and liver cirrhosis; (e) HBsAg-negative cases with CH. The e-antigen was investigated in every patient and was found in 9 of the AVH cases with favorable evolution, and in 8 of the AVH patients evolving to chronicity. Amont the CH and cirrhosis group, 48 of the HBsAg carriers were positive while e-antigen could not be detected in any of the HBsAg-negative ones. The high incidence of e-antigen carriers among patients with chronic hepatitis and liver cirrhosis as well as among those with AVH who later entered the chronic stage of the disease, deserves especial consideration. A possible role of e-antigen in the evolution to chronicity and a prognostic significance is suggested.