The study is aimed at assessing the safety and efficacy of an inactivated and non adjuvanted Influenza A (H1N1) vaccine in renal transplant recipients.

120 renal transplant recipients under triple immunosuppression will be immunized against influenza H1N1v.

The primary endpoint will be the humoral immunity assessed 21 days after each injection on day 0 and day 21:

• seroprotection rate, defined as the percentage of patients with an antibody title against Hemaglutinin ≥ 1/40e after immunization
• seroconversion rate, defined as the the percentage of patients with an antibody title against Hemaglutinin < 1/10e before immunization and ≥ 1/40e after or with a prevaccine title ≥1/10e increasing at least 4 fold after immunization
• seroconversion factor, defined as the ratio between pre and post vaccine geometrical means of the antibody titles.

Secondary endpoints will be:

• Seroconversion rate, seroprotection rate and seroconversion factor on day 182
• Percentage of patients with an antibody title > 1/40e on day 182 (Immune memory)
• Number and severity of clinical and biological adverse events
• Number of cases of pandemic H1N1v influenza virologically confirmed
• Study of associated parameters influencing the results of H1N1v vaccination in terms of seroprotection, seroconversion and seroconversion factor
• Assessment of the cellular immune response against H1N1v
• Assessment of the H1N1v vaccination on graft function and on humoral anti-HLA response.

Inclusion criteria:

• Age > 18 and < 60 years old
• Signed information consent
• Social security coverage
• Renal transplantation > 6 months with a creatinine clearance > 20 ml/mn
• Stable renal function defined as serum creatinine variation < 20 % for the last three months
• Receiving a triple immunosuppression regimen including steroids, Calcineurine inhibitors (cyclosporine or Tacrolimus), and IMPDH inhibitors (Mycophenolate Mofetil or mycophenolic acid)
• Regular follow-up

For child bearing aged female:

• Negative urinary HCG
• Contraception during the first three months of the study

Exclusion criteria:

• Poor renal function defined as creatinine clairance < 20 ml/mn
• Unstable renal function defined as serum creatinine variations > 20 % during the last 3 months
• Cellular or humoral acute rejection episode during the last 3 months before inclusion
• Known HIV, HBV or HCV infection
• Other vaccine administered during the last 3 weeks before inclusion or scheduled in the month after the second vaccine injection
• Known allergy to egg proteins or to one the vaccine compounds
• Severe adverse events after prior administration of any influenza vaccine
• Multiple sclerosis
• Past history of Guillain Barre syndrome
• Fever at inclusion
• H1N1 influenza episode with positive virological tests during the last 6 months
• Contact with people infected with H1N1 influenza during the week prior to inclusion
• Cancer requiring radiotherapy or chemotherapy during the last 6 months
• Blood transfusion during the last 3 months
• Pregnancy during the last 3 months
• No follow-up