Abstract: The invention provides methods and compositions relating to identification and use of genetic information from the IL-1 gene cluster—including the structure and organization of novel IL-1-like genes found within the IL-1 locus as well as polymorphisms and associated haplotypes within these genes. The invention thereby expands the repertoire of useful genetic information available from the IL-1 locus—which contains the previously-identified IL-1&agr;, IL-1&bgr; and IL-1RN genes, for predicting IL-1 associated phenotypes (e.g. increased or decreased risks of inflammatory disease) and for treating IL-1 haplotype associated inflammatory phenotypes.