{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,10,11]],"date-time":"2025-10-11T01:48:55Z","timestamp":1760147335034,"version":"build-2065373602"},"reference-count":36,"publisher":"MDPI AG","issue":"3","license":[{"start":{"date-parts":[[2023,1,28]],"date-time":"2023-01-28T00:00:00Z","timestamp":1674864000000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"European Union\u2019s Horizon 2020 research and innovation programme under the Marie Sklodowska-Curie","award":["101023721"],"award-info":[{"award-number":["101023721"]}]},{"name":"Fondazione Maria Piaggio Casarsa, Genova, Italy","award":["101023721"],"award-info":[{"award-number":["101023721"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["JCM"],"abstract":"<jats:p>Recently, cases of fortuitous discovery of Chronic Lymphocytic Leukemia (CLL) during hospitalization for Coronavirus disease (COVID-19) have been reported. These patients did not show a monoclonal B cell expansion before COVID-19 but were diagnosed with CLL upon a sudden lymphocytosis that occurred during hospitalization. The (hyper)lymphocytosis during COVID-19 was also described in patients with overt CLL disease. Contextually, lymphocytosis is an unexpected phenomenon since it is an uncommon feature in the COVID-19 patient population, who rather tend to experience lymphopenia. Thus, lymphocytosis that arises during COVID-19 infection is a thought-provoking behavior, strikingly in contrast with that observed in non-CLL individuals. Herein, we speculate about the possible mechanisms involved with the observed phenomenon. Many of the plausible explanations might have an adverse impact on these CLL patients and further clinical and laboratory investigations might be desirable.<\/jats:p>","DOI":"10.3390\/jcm12030998","type":"journal-article","created":{"date-parts":[[2023,1,30]],"date-time":"2023-01-30T11:19:53Z","timestamp":1675077593000},"page":"998","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["Unexpected CD5+ B Cell Lymphocytosis during SARS-CoV-2 Infection: Relevance for the Pathophysiology of Chronic Lymphocytic Leukemia"],"prefix":"10.3390","volume":"12","author":[{"ORCID":"https:\/\/orcid.org\/0000-0003-2167-8817","authenticated-orcid":false,"given":"Andrea","family":"Mazzarello","sequence":"first","affiliation":[{"name":"Department of Experimental Medicine, University of Genoa, Via De Toni 14, 16132 Genova, Italy"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Brisejda","family":"Koroveshi","sequence":"additional","affiliation":[{"name":"Laboratory of Clinical Pathology, ASL2 Liguria, S. Paolo Hospital, 17100 Savona, Italy"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Daniela","family":"Guardo","sequence":"additional","affiliation":[{"name":"Haematology Unit, IRCCS Istituto Giannina Gaslini, Via Gerolamo Gaslini 5, 16148 Genova, Italy"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Lorella","family":"Lanza","sequence":"additional","affiliation":[{"name":"Anatomical Pathology, ASL2 Liguria, Santa Corona Hospital, 17027 Pietra Ligure, Italy"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-2301-8698","authenticated-orcid":false,"given":"Fabio","family":"Ghiotto","sequence":"additional","affiliation":[{"name":"Department of Experimental Medicine, University of Genoa, Via De Toni 14, 16132 Genova, Italy"},{"name":"IRCCS Ospedale Policlinico San Martino, 16132 Genoa, Italy"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Silvia","family":"Bruno","sequence":"additional","affiliation":[{"name":"Department of Experimental Medicine, University of Genoa, Via De Toni 14, 16132 Genova, Italy"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Enrico","family":"Cappelli","sequence":"additional","affiliation":[{"name":"Haematology Unit, IRCCS Istituto Giannina Gaslini, Via Gerolamo Gaslini 5, 16148 Genova, Italy"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2023,1,28]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"eabc8511","DOI":"10.1126\/science.abc8511","article-title":"Deep Immune Profiling of COVID-19 Patients Reveals Distinct Immunotypes with Therapeutic Implications","volume":"369","author":"Mathew","year":"2020","journal-title":"Science"},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"89","DOI":"10.1007\/s00292-021-00945-6","article-title":"Histomorphological Patterns of Regional Lymph Nodes in COVID-19 Lungs","volume":"42","author":"Haslbauer","year":"2021","journal-title":"Pathologe"},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"661052","DOI":"10.3389\/fimmu.2021.661052","article-title":"SARS-CoV-2 Induces Lymphocytopenia by Promoting Inflammation and Decimates Secondary Lymphoid Organs","volume":"12","author":"Xiang","year":"2021","journal-title":"Front. 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