Gene Expression Profiles of Inflammatory Mediators in Influenza A and B Virus Infections: Insights from Riyadh, Saudi...

Influenza A (IAV) and influenza B (IBV) viruses pose significant public health threats, with varying epidemiology and immune responses. Limited subtype-specific cytokine data exist for influenza in Saudi Arabia. This study conducted molecular surveillance on 380 NPAs from patients at King Khalid University Hospital (KKUH) in Riyadh, Saudi Arabia, during winter seasons (2020-2023).

NPA samples were collected from hospitalized patients presenting with fever (>38 °C) and respiratory symptoms. RNA was extracted using the QIAamp Viral RNA Kit, followed by RT-PCR for IAV (H1N1, A/H3N2) and IBV detection. Quantitative real-time PCR profiled mRNA expression of 17 cytokines/chemokines in IAV-positive (n = 65) and IBV-positive (n = 20) samples, normalized to GAPDH using the 2^-ΔΔCq method. Appropriate statistical tests were applied (p < 0.05 significant).

Results showed 17.11% IAV positivity (7.89% A/H1N1, 9.21% A/H3N2) and 5.26% IBV. A/H3N2 predominated, increasing from 6.67% (2020/21) to 12.30% (2022/23). Males had higher IAV rates (25.88% vs. 10.00% females, p < 0.05), while IBV was higher in females (6.67% vs. 3.53%). Age-wise, 0-4 years had peak IAV (28.42%, p < 0.05); IBV peaked at 5-14 years (10.91%). IAV elicited higher mRNA expression IFN-α, IL-10, IL-13, and CCL-2 (p < 0.05); IBV showed elevated IL-1α, IL-6, and IL-33 (p < 0.05). Within IAV, A/H1N1 had higher IL-4, IL-10, IL-13, and IL-17; A/H3N2 elevated TNF-α, IL-6, IL-22, CCL-3, and CCL-4 (p < 0.05).

These findings highlight subtype-specific inflammatory profiles and demographic disparities in Saudi Arabia, informing targeted interventions. Post-COVID resurgence underscores surveillance needs amid travel and gatherings. Insights into cytokine dynamics aid prognosis and therapeutics, emphasizing regional molecular monitoring for vaccine optimization and outbreak prevention.