{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,7,30]],"date-time":"2026-07-30T15:55:53Z","timestamp":1785426953237,"version":"3.56.0"},"reference-count":15,"publisher":"MDPI AG","issue":"6","license":[{"start":{"date-parts":[[2026,5,29]],"date-time":"2026-05-29T00:00:00Z","timestamp":1780012800000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100001691","name":"Japan Society for the Promotion of Science","doi-asserted-by":"publisher","award":["23K09676"],"award-info":[{"award-number":["23K09676"]}],"id":[{"id":"10.13039\/501100001691","id-type":"DOI","asserted-by":"publisher"}]},{"award":["23K09676"],"award-info":[{"award-number":["23K09676"]}],"id":[{"id":"https:\/\/ror.org\/00hhkn466","id-type":"ROR","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Pathogens"],"abstract":"<jats:p>Cannonballs, compact aggregates of neutrophils observed in Papanicolaou (Pap) smears, are frequently associated with Trichomonas vaginalis (T. vaginalis) infection but are generally regarded as nonspecific inflammatory findings. To clarify their morphologic features, we analyzed cervicovaginal liquid-based cytology specimens from 29 cervicitis cases, including six positive for T. vaginalis. Cannonballs were evaluated using immunocytochemistry for T. vaginalis and cytokeratin, cell block analysis, and morphometric analysis, with negative cases as controls. All positive cases contained T. vaginalis-associated cannonballs, with a mean positivity rate of 57.4%. Parasites were intermingled with aggregated neutrophils, and cell block analysis demonstrated parasite-centered neutrophilic aggregates. Cytokeratin staining patterns differed morphologically between positive and negative cases. In addition, T. vaginalis-associated cannonballs were significantly smaller than adjacent squamous epithelial cells. These findings suggest that some cannonballs in trichomoniasis may represent parasite-associated neutrophilic structures and provide insight into host\u2013parasite interactions in cervicovaginal inflammation.<\/jats:p>","DOI":"10.3390\/pathogens15060588","type":"journal-article","created":{"date-parts":[[2026,6,3]],"date-time":"2026-06-03T02:37:26Z","timestamp":1780454246000},"page":"588","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["Cannonballs in Trichomonas vaginalis Infection: Morphologic Evidence of Parasite-Associated Neutrophilic Aggregates"],"prefix":"10.3390","volume":"15","author":[{"given":"Ruku","family":"Shinohara","sequence":"first","affiliation":[{"name":"Department of Medical Technology, Faculty of Health Sciences, Kyorin University, 5-4-1 Shimorenjaku, Mitaka-shi 181-8621, Tokyo, Japan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Yukimi","family":"Misawa","sequence":"additional","affiliation":[{"name":"Department of Medical Technology, Faculty of Health Sciences, Kyorin University, 5-4-1 Shimorenjaku, Mitaka-shi 181-8621, Tokyo, Japan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Shuichi","family":"Mizuno","sequence":"additional","affiliation":[{"name":"Department of Medical Technology, Faculty of Health Sciences, Kyorin University, 5-4-1 Shimorenjaku, Mitaka-shi 181-8621, Tokyo, Japan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Saeka","family":"Honda","sequence":"additional","affiliation":[{"name":"Department of Medical Technology, Faculty of Health Sciences, Kyorin University, 5-4-1 Shimorenjaku, Mitaka-shi 181-8621, Tokyo, Japan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Koki","family":"Kikuchi","sequence":"additional","affiliation":[{"name":"Department of Medical Technology, Faculty of Health Sciences, Kyorin University, 5-4-1 Shimorenjaku, Mitaka-shi 181-8621, Tokyo, Japan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Rei","family":"Settsu","sequence":"additional","affiliation":[{"name":"Department of Medical Technology, Faculty of Health Sciences, Kyorin University, 5-4-1 Shimorenjaku, Mitaka-shi 181-8621, Tokyo, Japan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0009-0009-4514-4116","authenticated-orcid":false,"given":"Yosuke","family":"Kato","sequence":"additional","affiliation":[{"name":"Department of Medical Technology, Faculty of Health Sciences, Kyorin University, 5-4-1 Shimorenjaku, Mitaka-shi 181-8621, Tokyo, Japan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-5994-9670","authenticated-orcid":false,"given":"Kaori","family":"Okayama","sequence":"additional","affiliation":[{"name":"Department of Medical Technology and Sciences, School of Health Sciences, International University of Health and Welfare, 2600-1 Kitakanemaru, Otawara-shi 324-8501, Tochigi, Japan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Mizue","family":"Oda","sequence":"additional","affiliation":[{"name":"Department of Gynecology, Genki Plaza Medical Center for Health Care, 1-105 Jinbocho, Chiyoda-ku 101-0051, Tokyo, Japan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-6152-3217","authenticated-orcid":false,"given":"Mitsuaki","family":"Okodo","sequence":"additional","affiliation":[{"name":"Department of Medical Technology, Faculty of Health Sciences, Kyorin University, 5-4-1 Shimorenjaku, Mitaka-shi 181-8621, Tokyo, Japan"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2026,5,29]]},"reference":[{"key":"ref_1","first-page":"1715","article-title":"\u201cCannon balls or pus balls\u201d in Pap smears: A case report","volume":"7","author":"Bodal","year":"2013","journal-title":"J. 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Dis."},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"683","DOI":"10.1016\/j.pt.2018.05.006","article-title":"Trichomonas vaginalis: Pathogenesis, symbiont interactions, and host cell immune responses","volume":"34","author":"Mercer","year":"2018","journal-title":"Trends Parasitol."},{"key":"ref_15","doi-asserted-by":"crossref","unstructured":"Mercer, F., Ng, S.H., Brown, T.M., Boatman, G., and Johnson, P.J. (2018). Neutrophils kill the parasite Trichomonas vaginalis using trogocytosis. 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