title: Cellular and humoral immune responses to a tetanus toxoid booster in perinatally HIV-1-infected children and adolescents receiving highly active antiretroviral therapy (HAART).
abstract: BACKGROUND
  Human immunodeficiency virus type 1 (HIV-1) infected children treated with highly active antiretroviral therapy (HAART) may develop a significant reduction of plasma viremia associated with an increase in CD4+ T-cell counts. Functional capacity of this reconstituted immune system in response to recall antigens is important to maintain protective immunity to vaccine-preventable diseases. We therefore determined cellular and humoral immune responses to tetanus toxoid (TT) booster in perinatally HIV-1-infected children and adolescents receiving HAART.
  
  
  METHODS
  Immune responses were prospectively evaluated pre- and post-tetanus booster using lymphocyte proliferation assay (LPA) stimulation index (SI > or = 3.0) and tetanus antibody (TAb > or = 0.15) in 15 patients. The median interval from primary tetanus immunization series was 6 years (range 2-12 years). We compared patients by their virological response to HAART (complete responders, CR, n=7; incomplete responders, ICR, n=8).
  
  
  RESULTS
  There were no significant differences in median age 12.6 years (CR: 12.9; ICR: 10.6) or median CD4 T-cell pre-booster (CR: 35%/819; ICR: 26%/429) between groups. Tetanus LPA responses were observed in one patient prior to booster and in seven patients post-booster. In contrast, 38% of patients had protective TAb pre-booster, but 92% developed protective TAb post-booster. All of the CR and 5/6 ICR patients developed protective TAb.
  
  
  CONCLUSIONS
  HIV-1-infected children and adolescents had modest LPA responses to tetanus following booster, similar to HIV-1-infected adults. However, the majority of patients developed protective TAb levels after booster and maintained the response. Shorter intervals may need to be considered for TT immunization boosters in HIV-1-infected pediatric patients, as only 38% had protective TAb at baseline.
authors.affiliation: Pediatric Infectious Diseases, Department of Pediatrics, David Geffen School of Medicine at UCLA, Mattel Children's Hospital at UCLA, 10833 Le Conte Avenue, 22-442 MDCC, Los Angeles, CA 90095, USA. nching@mednet.ucla.edu
authors.forename: Natascha
authors.initials: N
authors.lastname: Ching
authors.forename: Jaime G
authors.initials: JG
authors.lastname: Deville
authors.forename: Karin A
authors.initials: KA
authors.lastname: Nielsen
authors.forename: Bonnie
authors.initials: B
authors.lastname: Ank
authors.forename: Lian S
authors.initials: LS
authors.lastname: Wei
authors.forename: Myung Shin
authors.initials: MS
authors.lastname: Sim
authors.forename: Steven M
authors.initials: SM
authors.lastname: Wolinsky
authors.forename: Yvonne J
authors.initials: YJ
authors.lastname: Bryson
mesh_terms: D000917:Antibody Formation; D023241:Antiretroviral Therapy, Highly Active; D002648:Child; D005260:Female; D015658:HIV Infections / Q000188:drug therapy* / Q000276:immunology* / Q000635:transmission; D006801:Humans; D007111:Immunity, Cellular; D008297:Male; D011247:Pregnancy; D011251:Pregnancy Complications, Infectious; D011446:Prospective Studies; D013745:Tetanus Toxoid / Q000276:immunology*; D014611:Vaccination
chemical_list: D013745:Tetanus Toxoid