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Studies on the nature of fibrillar nuclei. Distinction from viral nucleocapsid

E J Yunis, R M Agostini, W A Devine

    The American Journal of Pathology
    |April 1, 1984
    PubMed

    Insights

    Fibrillar nuclei, often mistaken for paramyxovirus, are actually chromatin resulting from cell injury and tissue processing. These structures are common in formalin-fixed samples and do not indicate viral infection.

    Area of Science:

    • Pathology
    • Microscopy
    • Virology

    Background:

    • Fibrillar nuclei are sometimes misidentified as paramyxovirus.
    • This misidentification persists despite evidence to the contrary.

    Purpose of the Study:

    • To investigate the nature of fibrillar nuclei.
    • To determine if fibrillar nuclei represent paramyxovirus or another cellular component.

    Main Methods:

    • Review of electron microscopic materials from various tissues.
    • Experimental production of fibrillar nuclei in human lung tissue using formalin fixation and water rinsing.

    Main Results:

    • Fibrillar nuclei were observed in diverse tissues and conditions where viral infection was unlikely.
    • These structures were frequently found in postmortem and formalin-fixed specimens.
    • Fibrillar nuclei were successfully replicated in experimental settings using formalin fixation.

    Conclusions:

    • Fibrillar nuclei do not represent virus but are instead chromatin.
    • The appearance of fibrillar nuclei is linked to cellular injury and tissue processing artifacts.
    • Fibrillar nuclei are likely more prevalent than currently recognized and often overlooked in microscopic examinations.

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