{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,9,3]],"date-time":"2026-09-03T04:52:43Z","timestamp":1788411163615,"version":"build-2803163510"},"reference-count":30,"publisher":"Frontiers Media SA","license":[{"start":{"date-parts":[[2025,10,9]],"date-time":"2025-10-09T00:00:00Z","timestamp":1759968000000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":["frontiersin.org"],"crossmark-restriction":true},"short-container-title":["Front. Cell. Infect. Microbiol."],"abstract":"<jats:sec><jats:title>Background<\/jats:title><jats:p>Long COVID manifests with heterogeneous clinical outcomes, potentially linked to immune dysfunction. However, the recovery of immune-cell subsets during convalescence remains incompletely understood.<\/jats:p><\/jats:sec><jats:sec><jats:title>Methods<\/jats:title><jats:p>In this longitudinal cohort, 279 unvaccinated patients with confirmed SARS-CoV-2 infection (13 mild, 218 moderate, 48 severe) were enrolled. Peripheral lymphocyte subsets were analyzed by flow cytometry at admission and at 50 days post-symptom onset (DPSO 50).<\/jats:p><\/jats:sec><jats:sec><jats:title>Results<\/jats:title><jats:p>Total T-cell counts normalized in 90\u201398% of patients in the moderate and severe groups by DPSO 50. Nevertheless, a subgroup exhibited persistent B-cell lymphopenia (&amp;lt;90 cells\/\u00b5L) in 7.3% of moderate cases (median 77.1 cells\/\u00b5L, IQR 51.9\u201383.8) and 12.5% of seltvere cases (median 54.5 cells\/\u00b5L, IQR 28.4\u201379.3). Patients with B-cell deficiency also showed concurrent reductions in total T cells, CD4<jats:sup>+<\/jats:sup> T cells, and CD4<jats:sup>+<\/jats:sup>CD25<jats:sup>+<\/jats:sup>CD127low\/FOXP3<jats:sup>+<\/jats:sup> regulatory T cells (Tregs). In moderate cases, CD4<jats:sup>+<\/jats:sup> T cell and Treg counts correlated positively (r = 0.72, p &amp;lt; 0.001), independent of B-cell status, whereas this relationship was absent in severe cases, indicating severity-dependent immune dysregulation.<\/jats:p><\/jats:sec><jats:sec><jats:title>Conclusions<\/jats:title><jats:p>Approximately 7\u201312% of moderate-to-severe COVID-19 survivors displayed persistent lymphopenia affecting B cells, CD4<jats:sup>+<\/jats:sup> T cells, and Tregs at ~50 days post-symptom onset. These findings highlight distinct recovery trajectories and provide insights into Long COVID pathogenesis that may inform therapeutic strategies.<\/jats:p><\/jats:sec>","DOI":"10.3389\/fcimb.2025.1693743","type":"journal-article","created":{"date-parts":[[2025,10,9]],"date-time":"2025-10-09T05:28:38Z","timestamp":1759987718000},"update-policy":"https:\/\/doi.org\/10.3389\/crossmark-policy","source":"Crossref","is-referenced-by-count":3,"title":["Persistent lymphocytopenia in convalescent patients with COVID-19: dysregulated B cell, CD4+ T cell, and treg compartments in 7\u201312% of moderate-severe cases"],"prefix":"10.3389","volume":"15","author":[{"given":"Hui","family":"An","sequence":"first","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Tongtong","family":"Yu","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Anlan","family":"Wang","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Hao","family":"Hu","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Chen","family":"Zhang","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Yongyu","family":"Wang","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Ming","family":"Li","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1965","published-online":{"date-parts":[[2025,10,9]]},"reference":[{"key":"B1","doi-asserted-by":"publisher","first-page":"4382","DOI":"10.1074\/jbc.M004559200","article-title":"Transcriptional mechanisms for induction of 5-HT1A receptor mRNA and protein in activated B and T lymphocytes","volume":"276","author":"Abdouh","year":"2001","journal-title":"J. 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