Humoral and cellular response to influenza vaccine in HIV-infected children with full viroimmunologic response to antiretroviral therapy.
OBJECTIVE
It is unclear whether the ability to respond to vaccines is restored by antiretroviral therapy. We evaluated the influenza-specific immune responses elicited by a virosomal vaccine in HIV-infected children on long-term successful highly active antiretroviral therapy (HAART).


METHODS
This was an observational, prospective, open-label study enrolling 24 HIV-infected, HAART-treated (85 months' mean exposure), vaccine-naive children (median age=11.9 years) and 14 age- and gender-matched healthy controls. Mean CD4 T-cell counts (>900 cells/microL) and percentages (>37%) were comparable. The HIV RNA level was <50 copies/mL in all patients. Children received a single dose of trivalent virosome-adjuvanted influenza vaccine. A/H3N2-, A/H1N1-, and B-antigen-specific antibody (Ab) titers and subclasses and vaccine-specific interferon-gamma (IFNgamma)- and interleukin (IL)-2-producing T lymphocytes were analyzed at baseline and 1 and 6 months after immunization.


RESULTS
Seroconversion (>or=4-fold Ab titer raise in >40% of patients) and seroprotection (Ab titer>or=1:40 in >70% of patients) was achieved at 1 month in both groups; however, fewer HIV-infected children fulfilled these criteria. The A/H3N2- and A/H1N1-specific Ab geometric mean titers were lower in HIV-infected children compared with healthy controls at 1 and 6 months; interestingly, a boost in vaccine-specific IgG3 T helper 1 type Ab was seen in healthy controls alone. Finally, vaccine specific-IFNgamma- and IL-2-producing T lymphocytes were reduced at both time points in HIV-infected children compared with healthy controls.


CONCLUSIONS
One injection of virosomal-adjuvanted influenza vaccine stimulates good immune responses, although the humoral and cellular immune responses are reduced in HIV-infected children compared to healthy children. This indicates that immunologic function impairments may persist upon HIV infection even if HIV-positive viremia is suppressed and immune recovery seems to be achieved.
Clinic of Pediatrics, Luigi Sacco Hospital, University of Milan, Milan, Italy.
Alessandra
A
Viganò
Gian Vincenzo
GV
Zuccotti
Michela
M
Pacei
Paola
P
Erba
Eleonora
E
Castelletti
Vania
V
Giacomet
Antonella
A
Amendola
Elena
E
Pariani
Elisabetta
E
Tanzi
Mario
M
Clerici
D000914:Antibodies, Viral / Q000032:analysis*; D023241:Antiretroviral Therapy, Highly Active; D018791:CD4 Lymphocyte Count; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology*; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology*; D002648:Child; D005260:Female; D015483:HIV Antibodies / Q000032:analysis*; D015658:HIV Infections / Q000188:drug therapy / Q000276:immunology*; D006801:Humans; D007252:Influenza Vaccines / Q000008:administration & dosage* / Q000009:adverse effects; D008297:Male; D019562:Viral Load
D000914:Antibodies, Viral; D015483:HIV Antibodies; D007252:Influenza Vaccines