The spread of Influenza H1N1 has prompted the development of vaccines against this virus. Immunocompromised patients are at increased risk of developing complications of Influenza H1N1. The efficacy and safety of H1N1 vaccination have not been evaluated in this population of patients.

100 patients with Rheumatoid Arthritis (RA), 50 patients with Systemic Lupus Erythematosus (SLE), 50 patients with spondyloarthropathies (Psoriatic arthritis (PsA) and Ankylosing Spondylitis (AS) and 200 healthy subjects will participate in the study.

All the subjects will be vaccinated with Focetria (Novartis) and will be evaluated the day of vaccination and 4 weeks later.

The evaluation will include:

Efficacy of the vaccine: Blood will be drawn on day 0 and 4 weeks later and tested for the presence of antibodies against A/California17/2009/H1N1 by hemagglutination inhibition test.

Safety of the vaccine:

• Records of adverse event
• Assessment of disease activity : RA - Disease activity score (DAS 28), SLE - SLEDAI, PsA - DAS 28 and PASI, AS- BASDAI, ESR, CRP

Inclusion Criteria:

• Patients suffering from: Rheumatoid Arthritis, Systemic Lupus Erythematosus, Ankylosing Spondylitis, Psoriatic Arthritis
• Able to firm an informed consent
• Aged - 18-65
• Candidates to receive vaccination against H1N1, according to the recommendation of the Ministry of Health

Exclusion Criteria:

• Allergy to eggs
• Known allergy to seasonal influenza vaccine
• Pregnant women