{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,11,4]],"date-time":"2026-11-04T07:45:03Z","timestamp":1793778303944,"version":"4.6.1"},"reference-count":33,"publisher":"MDPI AG","issue":"19","license":[{"start":{"date-parts":[[2022,9,30]],"date-time":"2022-09-30T00:00:00Z","timestamp":1664496000000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"Medical University of Bia\u0142ystok"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["IJMS"],"abstract":"<jats:p>The aim of this study is to assess the synthesis of kappa (\u03ba) and lambda (\u03bb) free light chains (FLCs) in the serum of patients with COVID-19. All the 120 serum samples were collected from patients with COVID-19 and from healthy controls (vaccinated and non-vaccinated against SARS-CoV-2). FLCs, IgG total, IgG4, IgG anti-Nucleocapsid (N), anti-spike S1 receptor binding domain (S-RBD) antibodies and IL-6 were measured according to the manufacturers\u2019 instructions. The concentrations of anti-N IgG, IgG total, IgG4 and IL-6 were elevated in the COVID-19 group in comparison to the vaccinated and non-vaccinated controls. The levels of anti-S-RBD IgG and \u03baFLC were increased in COVID-19 and healthy vaccinated patients when compared to non-vaccinated controls. \u03bbFLC concentration was higher in the COVID-19 group than in the non-vaccinated group. The \u03ba:\u03bb ratio was lower in both COVID-19 and non-vaccinated groups in comparison to vaccinated controls. \u03baFLC correlated with all tested parameters (anti-S-RBD IgG, anti-N IgG, \u03bbFLC, \u03ba:\u03bb ratio, IgG total, IgG4 and IL-6) except CRP, whereas \u03bbFLC correlated with all examined parameters except IgG4. Elevated levels of FLCs in COVID-19 and healthy vaccinated against SARS-CoV-2 patients, as well as the correlation between free light chains with specific anti-SARS-CoV-2 antibodies and IL-6, reflect hyperactivation of the immune system after contact with coronavirus. Furthermore, it seems that serum levels of FLCs might be used as predictive markers of COVID-19. Our findings suggest that free light chains are involved in SARS-CoV-2 infection. However, understanding the exact mechanism requires further investigation.<\/jats:p>","DOI":"10.3390\/ijms231911589","type":"journal-article","created":{"date-parts":[[2022,10,8]],"date-time":"2022-10-08T22:19:27Z","timestamp":1665267567000},"page":"11589","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":12,"title":["Evaluation of Free Light Chains (FLCs) Synthesis in Response to Exposure to SARS-CoV-2"],"prefix":"10.3390","volume":"23","author":[{"ORCID":"https:\/\/orcid.org\/0000-0003-4854-7155","authenticated-orcid":false,"given":"Monika","family":"Gudowska-Sawczuk","sequence":"first","affiliation":[{"name":"Department of Biochemical Diagnostics, Medical University of Bialystok, Waszyngtona 15A St., 15-269 Bialystok, Poland"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-3994-8785","authenticated-orcid":false,"given":"Anna","family":"Moniuszko-Malinowska","sequence":"additional","affiliation":[{"name":"Department of Infectious Diseases and Neuroinfections, Medical University of Bialystok, Zurawia 14 St., 15-540 Bialystok, Poland"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Sara","family":"P\u0105czek","sequence":"additional","affiliation":[{"name":"Department of Biochemical Diagnostics, University Hospital in Bialystok, Waszyngtona 15A St., 15-269 Bialystok, Poland"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Katarzyna","family":"Guziejko","sequence":"additional","affiliation":[{"name":"2nd Department of Lung Diseases and Tuberculosis, Medical University of Bialystok, Zurawia 14 St., 15-40 Bialystok, Poland"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Monika","family":"Chor\u0105\u017cy","sequence":"additional","affiliation":[{"name":"Department of Neurology, Medical University of Bialystok, M. Sk\u0142odowskiej-Curie 24A St., 15-276 Bialystok, Poland"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-4075-8479","authenticated-orcid":false,"given":"Barbara","family":"Mroczko","sequence":"additional","affiliation":[{"name":"Department of Biochemical Diagnostics, Medical University of Bialystok, Waszyngtona 15A St., 15-269 Bialystok, Poland"},{"name":"Department of Neurodegeneration Diagnostics, Medical University of Bialystok, Waszyngtona 15A St., 15-269 Bialystok, Poland"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2022,9,30]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"153","DOI":"10.24875\/AIDSRev.21000023","article-title":"Differentials of SARS-CoV-2 Viral RNA Re-positivity in Discharged COVID-19 Patients","volume":"23","author":"Xia","year":"2021","journal-title":"AIDS Rev."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"109819","DOI":"10.1016\/j.envres.2020.109819","article-title":"Transmission of COVID-19 virus by droplets and aerosols: A critical review on the unresolved dichotomy","volume":"188","author":"Jayaweera","year":"2020","journal-title":"Environ. 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