Research Article

Study of Regulatory Immune Responses, Including Serum FOXP3 Levels and Clinical Severity of COVID-19: A Cross-Sectional Study

Abstract

Background: Respiratory diseases can be severe and are caused by dysregulated inflammatory and immune responses due to COVID 19. Forkhead box P3 (FOXP3) is an important transcription factor of regulatory T cells and may play a role in regulating excessive inflammation during viral infection. In this study, we measured serum FOXP3 levels in COVID-19 patients with severe and non-severe disease and explored the relationship between the severity of COVID-19 and clinical and demographic parameters. Materials and Methods: A cross-sectional study was conducted in November–December 2021, with 76 patients with confirmed COVID-19 in Al-Hillah, Babylon Province, Iraq. Patients were categorized into severe (n=38) and non-severe (n=38) groups based on their respiratory status, oxygen saturation, and chest computed tomography. We used a sandwich enzyme-linked immunosorbent assay (ELISA) to measure serum FOXP3 concentration. Demographic variables included age, sex, geographic residence, and vaccination status. The data were analyzed using SPSS version 27, with independent-samples t-tests and chi-square tests. Serum FOXP3 was evaluated for severe disease using receiver operating characteristic analysis. Results: Severe cases were significantly older than non-severe cases (42.15 ± 19.69 versus 25.66 ± 6.39 years; p < 0.0001). The rural population (68.4%) and non-vaccinated patients (76.4%) had more severe disease. However, there was no significant difference between severe and non-severe cases in the mean serum FOXP3 level (2.507 ± 2.742 versus 1.827 ± 1.697; p=0.1977). No differences were detected between the mean FOXP3 concentrations in either severity group in relation to sex. Conclusion: Serum FOXP3 levels showed no significant correlation with COVID-19 severity in this cohort and may not prove to be a standalone severity marker. Factors independently associated with severe disease were older age, rural residence, and non-vaccination status. 

Authors affiliation:

Muthanna Saleem Abdulameer (ORCID): Department of Surgery, Hammurabi College of Medicine, University of Babylon, Babylon, Iraq.

How To Cite: M.S. Abdulameer. Study of Regulatory Immune Responses, Including Serum FOXP3 Levels and Clinical Severity of COVID-19: A Cross-Sectional Study. Healthcare Studies, 4(2):60–67, 2026. https://doi.org/10.58612/hs429