IL4 haplotypes were associated with levels of A. actinomycetemcomitans before and after periodontal treatment [37] while IL17A polymorphism was associated with increased counts of T. forsythia and T. denticola in healthy Czech patients with periodontitis and in those with type 1 diabetes mellitus and periodontitis, respectively [20]. This evidence concerns the gene IL4 and type 1 diabetes mellitus.