Immune responses to influenza immunization in children receiving maintenance chemotherapy for acute lymphoblastic leukemia

Purpose. To compare the immune responses to influenza vaccine in children with acute lymphoblastic leukemia (ALL) receiving maintenance chemotherapy with those in healthy children. Methods. Hemagglutinin-inhibition (HAI) antibody titers were determined before and after influenza vaccination in children with ALL and healthy controls. immune responses were measured as geometric mean titers (GMT) and 4-fold rises in HAI titers. Results. Although post-immunization GMT were lower in children with ALL compared to healthy children for the H1N1 antigen (P < 0.001), the H3N2 antigen (P=0.03), and for the influenza B antigen (P=0.003), at least 60% of children with ALL had at least a 4-fold rise in HAI titers to each of the influenza antigens. Conclusions. While the GMT after trivalent influenza immunization in children with ALL were significantly lower than those seen in healthy children, the majority of children with ALL had 4-fold rises in HAI titers. Children receiving maintenance chemotherapy for ALL should receive yearly influenza vaccine. (c) 2003 Wiley-Liss, Inc.