Introduction: Infl uenza vaccination is recommended for all solid organ transplant
recipients. However, some centers are reluctant to give annual vaccination due to
concerns about precipitating rejection. A proposed mechanism of this is vaccineinduced
development of cellular and humoral responses to donor HLA antigens. We
studied the induction of HLA Ab in a cohort of lung transplant recipients receiving
infl uenza vaccination.
Methods: Adult lung transplant recipients were immunized with 0.5 mL
intramuscular seasonal infl uenza vaccine followed by 0.1 mL intradermal booster
at 4 weeks as part of a previous study. Sera were collected pre-vaccination and at 4,
8 weeks post-vaccination. Post-vaccination sera were analyzed for HLA Ab using
fl owPRA specifi c beads (One Lambda Inc). A positive result was defi ned as 5%.
Positive samples were further analyzed for antibody specifi city by single antigen
bead testing. Pre-vaccination sera were tested only only if post-vaccination sample
screen was positive for HLA Ab. The presence of HLA Ab was correlated to vaccine
seroresponse and rejection episodes.
Results: Sixty patients were included with equal numbers of men and women. Mean
age of patients was 47.3 years (range 20.7-72.4). Median time post-transplant was 1.3
years (range 85 days - 17 years). One patient was excluded due to an uninterpretable
baseline screen result. 16/59 (27.1%) patients were positive for HLA Ab both in both
pre- and post-vaccination samples. Of these, 12/16 (75%) had antibody against HLA
Class I (majority A30,A31,B27,B44), 2/16 (12.5%) had antibody against HLA class
II (majority DQ4, DQ7), and 2/16 (12.5%) had antibody against both Class I & II.
There was no signifi cant increase in existing HLA Ab post-vaccination. Of the 16
patients, only one (6.3%) patient had de novo HLA Ab and this was determined to be
non donor specifi c. Factors such as gender, time from transplant, immunosuppression,
and acute rejection episodes did not correlate with presence of HLA Ab. HLA Ab
was not associated with seroconversion to to vaccine antigens.
Conclusions: Our data support that receiving the annual infl uenza vaccine does
not lead to the generation of de novo donor specifi c antibodies in lung transplant
recipients or upregulation of existing HLA Ab.