IL1A and periodontitis: Socransky et al. researched IL-1 gene polymorphisms in periodontitis patients by linking previous findings regarding the association of IL-1 polymorphisms and severity of adult periodontitis with microbial species found in IL-1 genotype-negative versus IL-1 genotype-positive patients and hence concluded that “those who were IL-1 genotype positive tended to have higher levels of the more damaging microbial species (red and orange complex organisms) associated with periodontal inflammation [90].”