Background: Renal transplant recipients (RTRs) are at increased risk of infections due to immunosuppressive therapies used to prevent organ rejection. Upper respiratory tract infections (URTIs), caused by various viral pathogens, are common in pediatric populations but can pose significant health risks for RTRs, leading to complications such as graft dysfunction, prolonged hospitalization, or mortality. This study compares viral infections in RTRs and children with URTIs to identify clinical and laboratory differences between the groups.
Materials and Methods: This retrospective cohort study analyzed data from 111 pediatric patients who underwent URTI PCR panels, complete blood count, kidney and liver function tests, and acute phase reactants between January 2023 and March 2025 at the Başkent University Department of Pediatrics. Patients were categorized into RTRs and normal pediatric patients presenting with URTI symptoms. Additionally, systemic inflammatory markers, including Neutrophil-to-Lymphocyte Ratio (NLR), and Systemic Inflammation Index , were compared between the groups.
Results: A total of 31 RTRs and 80 URTI patients who underwent URTI PCR testing along with laboratory evaluations were included in the study. RTRs patients were significantly older than the URTI control group (12.0 vs. 7.5, p < 0.001), while gender distribution was comparable (p = 0.333). RTRs patients exhibited significantly higher BUN (p < 0.001), Creatinine (p < 0.001), and Uric Acid (p = 0.002), indicating altered renal function. Liver enzyme markers, ALT (p < 0.001) and AST (p = 0.010), were also significantly elevated in the RTRs group. Among inflammatory markers, NLR (4.3 vs. 2.7, p = 0.001) was higher, while Platelet counts were lower (279.0 vs. 289.5, p = 0.004) in RTRs patients. Additionally, C-Reactive Protein levels  and SII levels (p > 0.05) did not show significant variation between groups. Regarding viral infections, Influenza A prevalence was comparable (p = 0.107), while SARS-CoV-2 was detected exclusively in RTRs patients (p < 0.001). No significant differences were found in other viral infections (Influenza B, RSV, Adenovirus, Rhinovirus/Enterovirus, and S. pyogenes). Hospitalization rates and mean hospital stay were comparable between groups (p = 0.261 and p > 0.05, respectively). All RTR patients achieved renal function normalization, and all recovered without long-term complications.
Conclusion: While viral infection rates were generally comparable, RTRs exhibited increased systemic inflammation and renal dysfunction, suggesting a distinct immunological response. Despite initial differences in renal function tests, all RTRs showed recovery over time. These findings emphasize the importance of early diagnosis, and targeted interventions for RTRs.