The role of Interleukin -18 / Interleukin -18 BindingProtein in Rheumatoid Arithritis patients

Abstract

Rheumatoid arthritis (RA) is a chronic inflammatory polyarithritic disease
associated with remission and exacerbation with different immunological
features.Rheumatoid factor(RF) screening test was used quantitatively and qualitatively
using an enzyme immunoassay (EIA), RF-isotypes (RF-IgG, RF-IgM, RF-IgA) ,
Interleukin-18 (IL-18) and Interleukin – 18 binding protein (IL-18BP) were detected
quantitatively usingenzyme linked immunosorbent assay(ELISA). Results indicated a
51% positivity in RF among RA patients and a prevalence of the RF-isotype (RF-IgM)
with the highest level at (41.6±16.3 U/ml) (p < 0.05) among other RF-isotypes at a
percentage of 85.5% , results also indicatedan elevated serum level of IL-18 and IL-
18BP(225±24.8 pg/ml), ( 5.2 ± 2.1 ng/ml ) respectively compared to healthy control
(HC)group (65±8.4 pg/ml )(p<0.01) , ( 2.9 ± 1.3 ng/ml ) (p<0.05) respectively, and
ratio of IL-18/IL-18BP serum levels in RA patients were significantly higher than in HC
group (p<0.05) which increased the importance of IL-18BP in therapeutic strategy. In
conclusion RF-IgM may be an important complimentary detection method for RA
among the other isotypes ,IL-18 with its IL-18BP may play an important role in RA
which need to be further investigated.