The aim of this study was to measure the level of interleukin-17A (IL-17A) in the serum and synovial fluid of patients with rheumatoid arthritis (RA) and its relation to disease activity.
Patients and methods
A total of 100 patients suffering from RA were chosen from the outpatient clinic, Department of Physical Medicine and Rehabilitation, Menoufia University Hospital. The patient group was divided into three subgroups — mild, moderate, and severe — according to the disease activity score. All patients were subjected to clinical, laboratory, and ultrasound evaluation and to measurement of IL-17A in the serum and synovial fluid by means of the enzyme-linked immunosorbent assay technique. Fifty healthy individuals were evaluated for IL-17A level in the blood, and served as the control group.
The present study revealed an increase in serum (P = 3.1) and synovial fluid (P = 5.2) IL-17A levels in RA patients with increased disease activity. The ultrasound study showed an increase in serum IL-17A levels with increased erosion of the knee (P= 5.99) and wrist (P= 5.03). There was an increase in serum IL-17A with increased effusion of the knee (P = 22.6) and wrist (P = 33.3). There was an increase in serum IL-17A with increased synovial hypertrophy of the knee (P = 6.39), wrist (P = 12.23), and second metacarpophalangeal (MCP) (P = 53.34). Finally, there was an increase in the blood IL-17A level, dryness of the eye (P = 3.8), dryness of the mouth (P = 3.2), and number of subcutaneous nodules (P = 2.5).
In our study; the mean serum and synovial IL-17A levels were found in high titers in patients with disease activity, and with extra-articular manifestations like dry eyes, dry mouth, and subcutaneous nodules. Also erosions, synovial hypertrophy, and effusions were found with significantly high titers of IL-17A, denoting its usefulness as a measurement tool for high disease activity and destruction. Also targeting IL-17A may be useful as a treatment option for aggressive disease and for rheumatoid patients with poor prognosis.