{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,7,30]],"date-time":"2026-07-30T08:41:45Z","timestamp":1785400905913,"version":"3.56.0"},"reference-count":27,"publisher":"MDPI AG","issue":"7","license":[{"start":{"date-parts":[[2026,7,22]],"date-time":"2026-07-22T00:00:00Z","timestamp":1784678400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"Rheumatology Research Foundation Innovative Research Award"},{"id":[{"id":"https:\/\/ror.org\/03sdr0263","id-type":"ROR","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Pathogens"],"abstract":"<jats:p>Chronic chikungunya arthritis is a debilitating post-viral inflammatory arthritis with no established evidence-based therapy. Regulatory T cell (Treg) dysfunction may contribute to persistent inflammation, and low-dose interleukin-2 (IL-2) may restore immune regulation. We evaluated the immunomodulatory effects of low-dose IL-2 using peripheral blood mononuclear cells from adults with laboratory-confirmed chronic chikungunya arthritis in Atl\u00e1ntico, Colombia. Cells were treated ex vivo with recombinant IL-2 or an IL-2\/anti-IL-2 monoclonal antibody complex in the presence of CD2\/CD3\/CD28 stimulation beads, followed by flow cytometric assessment of effector T cells and Tregs. Low-dose IL-2 treatments ex vivo did not increase total Treg frequency but selectively increased activated suppressor Tregs while decreasing activated T effector cells, enhancing Treg CTLA-4 and HLA-DR expression, and reducing Ki67 expression in effector T cells. IL-2 complex treatment decreased cytokine-secreting Tregs, and IL-10 and TGF-\u03b2 were not associated with IL-2 treatment status or with Teff\/Treg balance, suggesting limited utility as pharmacodynamic biomarkers of low-dose IL-2 treatments. These findings support the use of activated suppressor Tregs, Treg CTLA-4, and HLA-DR expression as candidate biologic endpoints for evaluation in future trials of low-dose IL-2 in chikungunya arthritis.<\/jats:p>","DOI":"10.3390\/pathogens15070770","type":"journal-article","created":{"date-parts":[[2026,7,22]],"date-time":"2026-07-22T10:48:28Z","timestamp":1784717308000},"page":"770","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["Low-Dose Interleukin-2 Enhances Activated Suppressor Regulatory T Cells and CTLA-4 and HLA-DR Expression in Chronic Chikungunya Arthritis"],"prefix":"10.3390","volume":"15","author":[{"given":"Sarah R.","family":"Tritsch","sequence":"first","affiliation":[{"name":"Department of Global Health, Milken Institute School of Public Health, George Washington University, Washington, DC 20052, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0009-0005-5063-1411","authenticated-orcid":false,"given":"Jose Forero","family":"Mejia","sequence":"additional","affiliation":[{"name":"Department of Medicine, George Washington University, Washington, DC 20052, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-4586-3753","authenticated-orcid":false,"given":"Evelyn","family":"Mendoza-Torres","sequence":"additional","affiliation":[{"name":"Advanced Biomedicine Research Group, Faculty of Health, Exact and Natural Sciences, Universidad Libre de Colombia, Seccional Barranquilla, Barranquilla 080020, Atl\u00e1ntico, Colombia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Alfonso","family":"Sucerquia","sequence":"additional","affiliation":[{"name":"Department of Medicine, George Washington University, Washington, DC 20052, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-9221-234X","authenticated-orcid":false,"given":"Abebawork","family":"Adem","sequence":"additional","affiliation":[{"name":"Department of Medicine, George Washington University, Washington, DC 20052, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0009-0001-6686-8377","authenticated-orcid":false,"given":"Juan David","family":"Alzate-Alvarez","sequence":"additional","affiliation":[{"name":"Department of Medicine, George Washington University, Washington, DC 20052, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-6939-5077","authenticated-orcid":false,"given":"Rimjhim","family":"Agarwal","sequence":"additional","affiliation":[{"name":"Center for Vaccine Innovation, La Jolla Institute for Immunology (LJI), La Jolla, CA 92037, USA"},{"name":"Biomedical Sciences Graduate Program, School of Medicine, 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Atl\u00e1ntico, Colombia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-9590-6099","authenticated-orcid":false,"given":"Maria Jose Viera","family":"Contreras","sequence":"additional","affiliation":[{"name":"Centro de Investigaci\u00f3n, Cl\u00ednica de la Costa SAS, Barranquilla 080020, Atl\u00e1ntico, Colombia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0009-0000-5344-5124","authenticated-orcid":false,"given":"Maria Jose Sarmiento","family":"Alvarez","sequence":"additional","affiliation":[{"name":"Centro de Investigaci\u00f3n, Cl\u00ednica de la Costa SAS, Barranquilla 080020, Atl\u00e1ntico, Colombia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Nicolle Suarez","family":"Otero","sequence":"additional","affiliation":[{"name":"Allied Research Society, Barranquilla 080020, Atl\u00e1ntico, Colombia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Diego Garcia","family":"Ba\u00f1ol","sequence":"additional","affiliation":[{"name":"Centro de Investigaci\u00f3n, Cl\u00ednica de la Costa SAS, Barranquilla 080020, Atl\u00e1ntico, Colombia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0009-0002-4579-7378","authenticated-orcid":false,"given":"Lin Tan","family":"Kuang","sequence":"additional","affiliation":[{"name":"Centro de Investigaci\u00f3n, Cl\u00ednica de la Costa SAS, Barranquilla 080020, Atl\u00e1ntico, Colombia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Lucia Su\u00e1rez","family":"Maestre","sequence":"additional","affiliation":[{"name":"Centro de Investigaci\u00f3n, Cl\u00ednica de la Costa SAS, Barranquilla 080020, Atl\u00e1ntico, Colombia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Belkis Meneses","family":"Rueda","sequence":"additional","affiliation":[{"name":"Centro de Investigaci\u00f3n, Cl\u00ednica de la Costa SAS, Barranquilla 080020, 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USA"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2026,7,22]]},"reference":[{"key":"ref_1","unstructured":"(2026, March 27). 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