[Severity of SARS-CoV-2 infection in children with kidney disease undergoing immunosuppressive therapy].

<b>Objective:</b> To investigate the impact of immunosuppressive therapy on the severity of SARS-CoV-2 infection and cytokine levels in pediatric patients with kidney diseases. <b>Methods:</b> A retrospective analysis was conducted on the clinical data of 40 hospitalized pediatric patients who were diagnosed with SARS-CoV-2 infection at the 900th Hospital of PLA Joint Logistic Support Force from December 2022 to February 2023. Based on their immunosuppressive status prior to SARS-CoV-2 infection, these patients were categorized into immunosuppressive group and non-immunosuppressive group. Independent sample <i>t</i>-tests, Mann-Whitney <i>U</i> tests, and <i>χ</i>² test were employed to compare the clinical baseline characteristics and laboratory data, the severity of SARS-CoV-2 infection, and the levels of cytokines between the 2 groups. <b>Results:</b> Among the 40 patients, 11 were in the immunosuppressive group (aged 13 (8, 14) years, 9 males and 2 females) and 29 in the non-immunosuppressive group (aged 2 (1, 4) years, 15 males and 14 females). In the immunosuppressive group, 2 were asymptomatic cases, 8 were mild cases, and 1 was moderate case, and there was no severe or critical cases. In the non-immunosuppressive group, 8 were mild cases, 5 were moderate, 15 were severe cases, 1 was critical case, and no asymptomatic cases. The underlying diseases in the immunosuppressive group included nephrotic syndrome (6 cases), IgA vasculitis nephritis (2 cases), lupus nephritis (1 case), post-renal transplantation (1 case), and renal failure (1 case), with a mean total immunosuppression score (TIS) of (3.6±1.4) points. In the non-immunosuppressive group, 2 patients had a history of epilepsy, and the remaining 27 cases had no underlying conditions, all with TIS scores of 0. Compared to the children in the non-immunosuppressive group, those in the immunosuppressive group were more likely to exhibit asymptomatic or mild infection, with lower risks of severe disease, cytokine storm, fever, and cough, but a higher risk of fatigue (<i>OR=</i>1.22, 2.66, 0.48, 0.12, 0.12, 0.13, 1.22; 95%<i>CI</i> 0.93-1.62, 0.99-7.15, 0.33-0.70, 0.03-0.57, 0.03-0.57, 0.03-0.65, 0.93-1.62; all <i>P<</i>0.05). The levels of cytokine IL-6, interferon-α and interferon-γ in the immunosuppressive group were all lower than those in the non-immunosuppressive group (<i>Z</i>=2.23, 2.51, 2.92, respectively; all <i>P<</i>0.05). <b>Conclusion:</b> Pediatric patients with kidney diseases receiving appropriate immunosuppressive therapy may mitigate the severity of SARS-CoV-2 infection by suppressing the expression of cytokines.