Kawasaki disease (KD) is the leading cause of acquired heart disease in children in the developed world. Despite available treatment, 25% of children in San Diego County appropriately treated for KD develop coronary artery abnormalities that may lead to complications later in life, including heart attack. Although the investigators can identify children with KD that have these coronary artery abnormalities, there is no approved additional treatment to decrease coronary artery inflammation and arrest or prevent damage to the coronary arteries. Anakinra, a therapy that blocks the high levels of interleukin 1 (IL1) that lead to inflammation during acute KD, has been shown in the KD mouse model to prevent the development of coronary artery damage. Therefore, the investigators propose to study the safety and activity of anakinra in infants and children < 2 years old with coronary artery abnormalities from KD.

Inclusion Criteria:

1. Infant or child aged 1 month to 17 years, who meets clinical criteria for KD according to American Heart Association guidelines (Table 2): Fever (T≥38oC or 100.4oC) ≥ 3 days and ≥ 2 clinical criteria with left anterior descending (LAD)/right coronary artery (RCA) Z score ≥ 3.0 or an aneurysm (≥ 1.5 x the adjacent segment) of one of the coronary artery segments
2. Patient presents within the first 20 days after fever onset
3. Parent or legal guardian able and willing to provide informed consent; adolescent or child assent as appropriate
4. Post-menarchal females: Negative pregnancy test at screening and willing to use two forms of contraception during the study
5. Males engaging in sexual activity that could lead to pregnancy willing to use a condom.

Exclusion Criteria:

1. Use of an IL-1 antagonist within the 3 months prior to enrollment
2. History of chronic disease, except asthma, atopic dermatitis, autism or controlled seizure disorder
3. History of hypersensitivity to anakinra
4. History of tuberculosis (TB) or TB exposure

6 weeks

The definition does not differ