Rheumatoid arthritis(RA) is characterized by the presence of a
relative state of imbalance between pro- and anti-inflammatory
cytokines such as Interleukin(IL)17 and IL4, respectively. IL4 is
supposed to regulate production of IL17 from T-helper (Th)17 cells.
However, this regulatory function might be affected by
singlenucleotide polymorphism (SNP) of IL4 receptor (IL4R) gene,
rs1805010. The current study aimed to assess serum IL17 level in
Egyptian patients with RA according toIL4Rrs1805010 genotypes,and
to detect possibleassociations betweenIL17/ IL4R genotypesand
clinical status, disease activity as well as effect of treatment. Serum
IL17 was assessed by ELISA, and qPCR was used to determine the
genotypes of IL4R SNP rs1805010. Serum IL17 was significantly
increased in patients' samples as compared to controls. According to
IL4R genotypes, patients with AG and GG genotypes showed
significantly higher IL17 levels than control subjects with
corresponding genotypes. Within RA group, significantly higher IL17
were found in GG carriers compared to those with AA genotype. The
G allele was significantly associated with higherythrocyte
sedimentation rate(ESR), increased disease activity score in 28 joints (DAS28), highLarsen score and seropositive rheumatoid factor (RF)as well as C-reactive protein (CRP).Patients with AG and GGgenotypes demonstrated significant positive correlations between serum IL17 and DAS28. Meanwhile, serum IL17 levels and Larsen score had significant positive correlation only in GG patients.The use of different treatment regimens did not affect serum IL17 levels significantly in various genotypes. In conclusion, IL17 may be
implicated in the pathogenesis of RA, being associated with a higher
disease activity parameters, however, its action may be potentiated
due to loss of the functional IL4RA allele (rs1805010), particularly in
carriers ofthe GG genotype. Furthermore, determining the genetic
variants of IL4R rs1805010 may be promising for identification of
patients at risk worse prognosis.