M1 macrophages involved in the pathogenesis of placental chronic villitis of unknown etiology

Abstract

Introduction

Placental villitis is characterized by the presence of inflammatory infiltrate in the placental villous. The objective of this study was to characterize in villitis of unknown etiology (VUE) of the human placentas the subpopulation of M1, important effector cells, and M2 macrophages, immunoregulatory cells.

Methods

Sixteen cases of VUE and three control placentas were examined using immunohistochemistry with antibodies for CD3, CD68, CD11c, and CD163.

Results

CD11c appeared predominantly in the inflamed villi when compared to the normal areas (p<.001). These cells corresponded to 41.2% of the macrophage population in the inflamed area and were mainly present inside the villi (36%). With regards to CD163, these cells tended to be in higher amounts in the inflamed villi when compared to CD11c and normal areas.

Discussion

We conclude that the almost exclusive presence of M1 macrophages in the inflamed areas suggests the influence of these cells in the pathogenesis VUE. The greater amount of M2 in villitis and normal areas suggests a possible immunoregulatory mechanism of the inflammatory process in VUE.

Keywords:

• Placenta
• placental macrophages
• villitis
• villitis of unknown etiology
• chronic villitis

Acknowledgements

The authors would like to thank Ana Cláudia Sparapani Piazza, Arethusa Souza, and Luzia Magalhães Alves for the immunohistochemical assistance.

Author’s contributions

João Figueira Scarini/Natália de Magalhães Rodrigues: research investigation, study resources, editing, analysis, curation, visualization and interpretation data, manuscript writing, and review. Wellington Lima Sabino, Ciro Soares, Thayná Melo de Lima Morais, Reydson Alcides de Lima Souza, Lívia Ramalho Crescencio: research investigation and performed data analysis. Rogério de Oliveira Gondak: statistical analysis. Fernanda Viviane Mariano/Albina Altemani: project conceptualization and data interpretation. Erika Said Abu Egal: project conceptualization, data interpretation, manuscript review, and project supervision. All authors have seen and approved the final version and that they agreed with the submission in its present forms.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This work was supported by the National Council for Scientific and Technological Development (CNPq, Brasilia, Brazil, grant number 153411/2017-1 and 140966/2015-3), and the Coordination of Training of Higher Education Graduate Foundation (CAPES, Brasilia, Brazil, finance code 001).