Ethnic origin, genetics, gender and environmental factors have been shown to influence some immunologic indices, so that development of reference values for populations of different backgrounds may be necessary. We have determined the distribution of lymphocyte subsets in healthy Brazilian individuals from birth to adulthood. Lymphocyte subsets were determined using four-colour cytometry in a cross-sectional study of 463 human immunodeficiency virus-unexposed children and adults from birth through 49 years of age. Lymphocyte subsets varied according to age, as previously observed in other studies. However, total CD4+ T cell numbers were lower than what was described in the Pediatric AIDS Clinical Trials Group P1009 (PACTG P1009), which assessed an American population of predominantly African and Hispanic backgrounds until the 12-18 year age range, when values were comparable. Naïve percentages and absolute values of CD8+ T cells, as assessed by CD45RA expression, were also lower than the PACTG P1009 data for all analysed age ranges. CD38 expression on both CD4+ and CD8+ T cells was lower than the PACTG P1009 values, with a widening gap between the two studies at older age ranges. Different patterns of cell differentiation seem to occur in different settings and may have characteristic expression within each population.

A diminuição da resposta à vacinação contra hepatite B já foi relacionada a algumas condições clínicas, inclusive à obesidade. Indivíduos que não responderam à série de três doses devem ser revacinados. Caso continuem não-respondedores após duas séries de vacina, não há indicação de doses adicionais. Esta é a descrição de mulher obesa que não havia soroconvertido após ter recebido seis doses de vacina contra hepatite B. Ela foi submetida à gastroplastia em Y de Roux, pela técnica de Capella. Após a redução de peso, a paciente recebeu mais três doses de vacina contra hepatite B e soroconverteu. Novos estudos poderão indicar a necessidade de avaliação de níveis de anticorpos contra antígenos vacinais e eventualmente revacinar esta população cada vez maior de pacientes que se submetem à cirurgia para redução de peso.

Decreased responses to hepatitis B vaccine have been associated with some host conditions including obesity. Susceptible non-responders to a primary three-dose vaccine series should be revaccinated. Those who maintain a non-responder condition after revaccination with three vaccine doses are unlikely to develop protection using more doses. This is a description of an obese woman who received six doses of hepatitis B vaccine and persisted as a non-responder. She was submitted to a vertical banded gastroplasty Roux-en-Y gastric bypass Capellas's technique. After weight reduction, she received three additional doses of vaccine and seroconverted. Further studies should help clarify the need to evaluate antibody levels and eventually revaccinate the increasing population of individuals who undergo weight reduction.

A prevalência de anticorpos contra o vírus da hepatite A foi avaliada em adolescentes de 10,4 a 19,9 anos atendidos no Ambulatório de Adolescentes da Universidade Federal de São Paulo. Entre 253 indivíduos analisados, a prevalência de anticorpos foi de 54,2%. Quando os adolescentes foram separados em duas faixas etárias, a prevalência foi maior no grupo de 15 a 19 anos (64%) em comparação com os de 10 a 14 anos (46%) (Qui-quadrado: p = 0,004). Estes resultados sugerem que muitos adolescentes de São Paulo estão sob risco de infecção pelo vírus da hepatite A e alguns deles estão provavelmente se infectando durante a adolescência.

The prevalence of hepatitis A virus (HAV) antibodies was assessed in adolescents (age ranging from 10.4 to 19.9 years) at an Adolescent Outpatient Clinic in São Paulo, Brazil. Anti-HAV was detected in 137 (54.2%) out of 253 individuals. When separated into two age groups, anti-HAV frequency was higher in the 15 to 19 year-old group (64%) in comparison to the 10 to 14 year-old group (46%) (Chi-square test: p = 0.004). These results suggest that adolescents in São Paulo are at risk of hepatitis A infection and are probably contracting HAV infection during this age period.