Estudo da imunogenicidade de esquemas alternativos de vacinação contra influenza em receptores de transplante de células tronco hematopoiéticas

INTRODUCAO: Influenza e uma doenca potencialmente grave apos o transplante de celulas tronco hematopoieticas (TCTH). A vacinacao e a principal estrategia profilatica, mas a resposta imune e menor do que em individuos saudaveis. Em geral os pacientes nao respondem a vacinacao nos primeiros seis meses apos transplante, o que torna o periodo de maior vulnerabilidade. OBJETIVOS: Neste estudo avaliaram-se diferentes esquemas de vacinacao contra influenza em TCTH alogenico relacionado, com imunizacao do doador e/ou do receptor no pre transplante. Determinou-se a resposta a vacina comparando-se as taxas de soroconversao entre os grupos de intervencao. Foram avaliados tambem os niveis de anticorpos considerados soroprotetores alcancados. METODOS: Realizou-se ensaio clinico randomizado nao cego, em populacao de candidatos ao TCTH e seus doadores do Hospital das Clinicas da Faculdade de Medicina da Universidade Federal de Minas Gerais/BH-MG e Hospital Amaral Carvalho/Jau-SP. Quatro grupos de pares receptor-doador receberam diferentes esquemas de imunizacao de influenza no pre transplante: 1- sem vacinacao, 2 - vacinacao do doador; 3 - vacinacao do receptor e 4 - vacinacao de doador e receptor. Todos os pacientes receberam vacina a partir do 6o mes apos transplante. Acompanhamento sorologico do par foi realizado no pre e no dia do transplante, e nos dias 30, 60, 100, 180 e apos vacina apenas para os receptores. Titulos dos anticorpos sorotipo - especificos foram determinados pela reacao de inibicao de hemaglutinacao. Niveis 1:40 foram considerados protetores e INTRODUCTION: Influenza is a potentially severe illness after hematopoietic stem cell transplantation (HSCT). Vaccination is the main prophylactic strategy, but the immune response is limited in the compromised host. Existing data support the recommendation of influenza vaccination after the 6th month of HSCT. OBJECTIVES: The study evaluated different schedules of influenza vaccination in HSCT. Recipient and/or their donors were randomized to receive influenza vaccine before transplant. The primary outcome was the comparison of serotype response between groups at baseline, 30 days and 6 months after transplantation. METHODS: A randomized, non-blind trial was conducted in patients undergoing HSCT and respective donors at Hospital das Clinicas, Universidade Federal de Minas Gerais /BH-MG and at Hospital Amaral Carvalho/Jau-SP. Four groups of donor and recipient pairs received different influenza immunization at least 7 days before HSCT: group 1 no vaccination, group 2 donor received a single dose of influenza vaccine; group 3 recipients received a single dose of influenza vaccine and group 4 recipients and donor received influenza vaccine. Following transplantation, all study patients were immunized with influenza vaccine at 6 months. Donor serum samples were collected at baseline (pre transplantation) and in the day of transplantation. Recipients serum samples were taken at baseline, 30, 60, 100, 180 days after transplantation, and at least 2 weeks after 6-month vaccination. The hemagglutination inhibition assay (HIA) was performed to evaluate immune response. HI antibodies titers 1:40 were considered protective. Titers