Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2025 Mar 3;18(1):92.
doi: 10.1186/s13104-025-07109-2.

Morphological characteristics of microenvironment in the human thymus during fetal development

Nemanja Maletin  1 , Nikola Denda  2 , Stefan Borocki  2 , Zoran Golušin  2 , Aleksandar Rašković  2 , Aleksandra Fejsa-Levakov  2 , Bojana Andrejić Višnjić  2 , Jelena Amidžić  2
Affiliations

Morphological characteristics of microenvironment in the human thymus during fetal development

Nemanja Maletin et al. BMC Res Notes. .

Abstract

Background: The thymus is a key organ for the development of T cells. T cell precursors first migrate from the bone marrow to the thymus. During maturation, these precursors require interactions with various types of cells that form the thymic microenvironment, such as epithelial, mesenchymal, and other immune cells not belonging to the T lineage. The aim of this study was to examine the changes in the number and diameter of Hassall's corpuscles, as well as the density and distribution of epithelial cells (p63+) and macrophages (CD68+).

Methods: Twenty-five fetal thymus samples were examined, divided into five groups according to gestational age. The samples were processed using standard histological methods and immunohistochemical staining.

Results: The study showed that the number and diameter of Hassall's corpuscles gradually increased during fetal development, with a significant increase from the 14th to the 38th gestational week. The average diameter of Hassall's corpuscles was largest in the age group of 34-38 weeks. The density of p63 + epithelial cells decreased in correlation with gestational week, while the density of CD68 + macrophages significantly increased, particularly in the thymic medulla, towards the end of the fetal period.

Conclusions: An increase in the number and size of Hassall's corpuscles during fetal development was recorded, while the density of epithelial cells decreased and the density of macrophages increased.

Keywords: Epithelial cells; Hassall's corpuscles; Macrophages; Thymus.

PubMed Disclaimer

Conflict of interest statement

Declarations. Ethics approval and consent to participate: All steps of the study were conducted in accordance with the Declaration of Helsinki [9]. The study protocol was reviewed and approved by the Ethics Committee of the University Clinical Center of Vojvodina, Novi Sad (decision from December 31, 2019, decision number: 00-1212). All samples were processed anonymously, respecting the privacy and confidentiality of information about the fetuses and their families. The material used in the study was collected exclusively from the archives of the Center for Pathology and Histology and from autopsies conducted in accordance with legal and ethical guidelines. All tissue analysis procedures were performed under laboratory conditions with strict adherence to ethical and professional standards. No aspect of the study compromised the physical or psychological well-being of the families, and all data were used solely for scientific purposes, without identifying personal information. Consent for publication: Not applicable. Competing interests: The authors declare no competing interests.

Figures

Fig. 1
Fig. 1
Number of Hassall’s corpuscles in the fetal thymus
Fig. 2
Fig. 2
Regression analysis: number of Hassall’s corpuscles in relation to GW
Fig. 3
Fig. 3
Average diameter of Hassall’s corpuscles in the thymus
Fig. 4
Fig. 4
Linear regression: average diameter of Hassall’s corpuscles in relation to GW
Fig. 5
Fig. 5
Density of p63 + cells in the thymus by GW
Fig. 6
Fig. 6
Regression analysis: density of p63 + cells in relation to GW
Fig. 7
Fig. 7
Histological sections of the thymus showing p63+ immunohistochemistry at 20x magnification: (A) cortex at 24 GW and (B) medulla at 18 GW
Fig. 8
Fig. 8
Density of CD68 + cells in the thymus by gestational age
Fig. 9
Fig. 9
Histological sections of the thymus stained for CD68 + immunohistochemistry at 20x magnification: (A) cortex at 21 GW and (B) medulla at 19 GW
See this image and copyright information in PMC

References

    1. Perez YE, Moran CA. The thymus: General concepts on embryology, anatomy, histology and immunohistochemistry. Semin Diagn Pathol. 2022;39(2):86–91. - PubMed
    1. Rebelatto MC. Chapter 24 - spleen, Lymph Nodes, and Thymus. In: Suttie AW, editor. Boorman’s Pathology of the Rat. 2nd ed. Academic; 2018. pp. 575–600.
    1. Gruver AL, Hudson LL, Sempowski G. Immunosenescence of ageing. J Pathology: J Pathological Soc Great Br Irel. 2007;211(2):144–56. - PMC - PubMed
    1. Jablonska-Mestanova V, Sisovsky V, Danisovic L, Polak S, Varga I. The normal human newborns thymus. Bratisl Lek Listy. 2013;114(7):402–8. - PubMed
    1. Ventevogel MS, Sempowski GD. Thymic rejuvenation and aging. Curr Opin Immunol. 2013;25(4):516–22. - PMC - PubMed

LinkOut - more resources