Muller and Barrieshi-Nusair (2007) assessed the association of a combination of IL1A-889 and IL1B+3954 alleles on plaque associated gingivitis among 50 affected non-smoking Arabs (34 females) between the ages of 18 and 28-years. Reverse hybridization showed that 52% of the sample population was genotype-positive, thus, carrying both alleles. Upon periodontal probing, these genotype-positive subjects were found to have significantly fewer bleeding sites. In a two-level, repeated measures model, adjusted for gender, probing depth, plaque index, and calculus proportion, the IL-1 genotype was the only factor that remained significant.

Snoussi et al. (2005) investigated the potential association of the polymorphism of interleukin 1-alpha (IL1A) with the susceptibility, clinicopathological characteristics, and prognosis of breast carcinoma. The study included 200 unrelated control subjects (191 females and nine males) and 305 unrelated patients with breast carcinoma (301 females and four males). At the time of analysis, 65 patients experienced recurrence and 18 patients among them died from breast carcinoma (27.7%). Genomic DNA was extracted from peripheral blood leukocytes by a salting procedure. By performing polymorphism analysis of the IL1A gene, no significant differences in IL1A genotype distribution were seen between the patients and controls. The estimated 3- and 6-year breast carcinoma- specific overall survival (OVS) rate in the group of patients carrying or not carrying IL1A (-889) TT homozygous genotype was, respectively, 75% and 36.8% versus 94.9% and 70.6%. The 3-year disease-free survival (DFS) rate in the group of patients with IL1A (-889) TT genotype was 80.9% and 98.5% in the group of patients without IL1A (-889) TT genotype. Snoussi et al. (2005) suggested that the genetic variations in IL1A were likely to play an important role in the genetic predisposition to breast carcinoma.