MATERIALS AND METHODS: The study included 99 patients with SLE who attended the Rheumatology Unit at Baghdad Teaching Hospital. These subjects were divided into three subgroups according to disease status: inactive, n = 33; active moderate, n = 33; and active severe, n = 33. Additionally, 33 matched controls were studied. Full medical histories, body mass index, gender and clinical disease activity, the latter evaluated with the SLE disease activity index, were collected. Laboratory parameters measured included anti-dsDNA antibodies, C3 and C4 levels, erythrocyte sedimentation rate and C-reactive protein titres. Serum IL-40 levels were quantified using an enzyme-linked immunosorbent assay.
RESULTS: IL-40 levels were significantly higher in patients (12.5420 ± 3.00575 ng/L) than in controls (6.1138 ± 0.59452 ng/L; p < 0.01). Mean serum IL-40 concentration was highest in the active severe group (15.2291 ± 2.26540 ng/L) and decreased, in order of disease severity, in the remaining cohorts: active moderate, 13.0643 ± 1.23927 ng/L; inactive, 9.3325 ± 1.62807 ng/L (P < 0.01); controls, 6.1138 ± 0.59452 ng/L. Serum IL-40 levels showed excellent validity for the diagnosis of SLE with a cut-off value of ≥ 9.3 ng/ml and area under the curve of 0.987. Sensitivity, specificity and accuracy were 99%, 90.9% and 96.97%, respectively (P < 0.001).
CONCLUSIONS: Serum IL-40 levels were elevated in SLE patients. It is therefore proposed that IL-40 is a novel cytokine which is associated with SLE and positively linked with disease severity.
MATERIALS AND METHODS: Eighty-eight patients diagnosed with AS were enrolled from the Rheumatology Unit at Baghdad Teaching Hospital. Participants were categorized into two groups based on disease status: inactive (n = 44) and active (n = 44). Additionally, 44 matched healthy individuals were included as controls. Comprehensive medical histories were obtained, including disease duration, body mass index, sex, and age. Laboratory parameters related to the disease-such as C-reactive protein, human leukocyte antigen (HLA-B27), and rheumatoid factor-were also measured. Serum IL-41 levels were quantified using an enzyme-linked immunosorbent assay.
RESULTS: The study revealed a significant difference in levels of IL-41 in patients with AS (17.721±0.705 ng/L) compared to controls (8.495±0.984 ng/L; P = 0.009). The mean serum IL-41 concentration was highest in the active group (23.037±5.268 ng/L), followed by the inactive group (12.411±1.672 ng/L; p = 0.001) and controls (8.495±0.984 ng/L). Serum IL-41 levels demonstrated strong validity for diagnosing AS, with a cutoff value of ≥ 9.35 ng/mL and an area under the curve of 0.991. The sensitivity, specificity, and accuracy were 97.7%, 79.5%, and 92.38%, respectively (p = 0.002).
CONCLUSIONS: IL-41 is a potential new diagnostic biomarker for AS and associated with patient's disease activity. These insights could potentially transform the way we diagnose and manage AS, offering new avenues for improved patient care and outcomes.