Rilonacept for Deficiency of the Interleukin-1 Receptor Antagonist (DIRA)

* INCLUSION CRITERIA 1. Male or female pediatric and adult subjects with mutation positive IL1RN indicating DIRA. For the first five patients enrolled, they must have been on a stable dose of anakinra during the 2-week period prior to screening visit. If the subject is on other medications such as NSAIDs, methotrexate and/or oral steroids, it is a requirement that these doses have been stable during the 2-week period prior to screening visit. 2. Subjects greater or equal to 3 months of age (however the first 5 patients enrolled will be over 2 years of age). Subjects 3 months old or older will be enrolled after SMC data review of the first 5 enrolled patients. 3. Participation in NIH study #03-AR-0173 ( Studies of the Natural History, Pathogenesis and Outcome of Autoinflammatory Diseases (NOMID/CAPS, DIRA, CRMO, Still s Disease, Behcet s Disease, and other Undifferentiated Autoinflammatory Diseases ) 4. Subjects currently treated with anakinra may be enrolled in this study even though their DIRA may be quiescent. For these subjects, a history of active DIRA prior to treatment with anakinra will be sufficient. Subjects will not take anakinra 24 hours before initiation of drug treatment. Treatment naive patients will also be enrolled after SMC data review of the first 5 enrolled patients. 5. Females of childbearing potential (young women who have had at least one menstrual period regardless of age) must have a negative serum pregnancy test at screening and a urine pregnancy test prior to administration of study medication. 6. Females of childbearing age and men able to father a child and who are sexually active, who agree to use two forms of effective birth control, including abstinence. 7. Negative Purified Protein Derivative (PPD) test using 5 T.U. intradermal testing or the QuantiFERON(SqrRoot) - TB Gold test per the Centers for Disease Control and Prevention (CDC) guidelines, and no evidence of active tuberculosis (TB) on chest X-ray. Subjects with latent TB (positive PPD or QuantiFERON - TB Gold test) currently treated with adequate therapy for at least one month prior to first dose of study medication may be included. Full prophylaxis regimens will be continued while on the study. Subjects who have had active TB in the past with documentation of adequate treatment may be included with strict clinical and radiological follow-up as per current guidelines. The Infectious diseases service will be consulted regarding all patients with evidence of TB infection (latent or active, current or history) prior to enrollment, and as appropriate during the study. Subjects who have been BCG-vaccinated will also be tested. Interpretation of PPD and QuantiFERON - TB Gold test in BCG recipients will be the same as for subjects who have not received BCG vaccine. Guardian/parent able to understand, and complete study-related questionnaires. Guardian/parent able and willing to give informed consent and abide with the study procedures. EXCLUSION CRITERIA <!-- --> 1. Treatment receiving a live virus vaccine (such as the measles, mumps, and rubella vaccine) during the 3 months prior to baseline visit. No live vaccines will be allowed throughout the course of this study. 2. Presence of active infections or a history of pulmonary TB infection without documented adequate therapy. Subjects with current active TB, or recent close exposure to an individual with active TB, are excluded from the study. Exceptions include patients with latent TB treated with adequate therapy for at least one month prior to the first dose of study medication, and patients with history of TB with documentation of adequate treatment. 3. Positive test for, or prior history of, HIV, or Hepatitis B or C. 4. History of malignancy. Subjects deemed cured of superficial malignancies such as cutaneous basal or squamous cell carcinomas, or in situ cervical cancer may be enrolled. 5. Known hypersensitivity to Chinese Hamster Ovary cell-derived biological or any components of rilonacept. 6. Presence of any additional rheumatic disease or significant systemic disease. For example, major chronic infectious/ inflammatory/ immunologic disease (such as inflammatory bowel disease, psoriatic arthritis, spondyloarthropathy, SLE in addition to autoinflammatory disease). 7. Presence of any of the following laboratory abnormalities at enrollment visit: creatinine greater than 1.5xULN WBC less than 3.0x103/mm3 ANC less than 800 cells/mL platelet count less than 150,000 mm3 ALT or AST greater than 2.0x ULN. 8. Lactating, breastfeeding or pregnant females. 9. Enrollment in any other investigational treatment study or use of an investigational agent, or has not yet completed at least 4 weeks or 5 half-lives, whichever is longer, since ending another investigational device or drug trial. 10. Subjects for whom there is concern about compliance with the protocol procedures. 11. Presence of other severe acute or chronic medical or psychiatric condition, or significant laboratory abnormality requiring further investigation that may cause undue risk for the subject s safety, inhibit protocol participation, or interfere with interpretation of study results, and in the judgment of the Investigator would make the subject inappropriate for entry into this study. 12. Subjects who have received a DMARDs (except methotrexate) and or TNFblocking agent within 4 half-lives prior to study entry. 13. Men able to father a child and who are sexually active, who do not agree to use 2 form of effective birth control, including abstinence during the duration of the study an for at least 28 days following the last dose of rilonacept. 14. Females of childbearing potential (woman greater than 12 or who have had at least 1 menstrual period regardless of age) who are sexually active and who do not agree to use 2 effective methods of birth control, including abstinence during the duration of the study an for at least 28 days following the last dose of rilonacept.