ORIGINAL RESEARCH article
Front. Cell. Infect. Microbiol.
Sec. Clinical Infectious Diseases
Volume 15 - 2025 | doi: 10.3389/fcimb.2025.1664902
Pathological and Immune Features of Non-Tuberculous Mycobacteria and Mycobacterium tuberculosis Cutaneous/Mucosa Infections of Fifty-Four Biopsies
Provisionally accepted
Xiao Ying Zhang1Ying Li1
Jing Zhao2Fang Qi Deng2
Xuhua Tang2Jin Fu Li2Wen Ting Yang1Han Wen Jiang3
Jin-hua He1
Zhuo Wang2*- 1The Affiliated Panyu Central Hospital of Guangzhou Medical University, Guangzhou, China
- 2The First Affiliated Hospital of Sun Yat-sen University, Guangzhou, China
- 3Yunkang Group Limited, Guangzhou, China
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The histopathologic changes associated with cutaneous non-tuberculous mycobacteria (NTM) infections closely resemble those seen in Mycobacterium tuberculosis (MTB) infections, often leading to confusion. This study aimed to enhance clinicopathologic diagnosis and clarify the pathogenesis of NTM and MTB infections by comparing the clinicopathologic features and immunohistochemistry. We conducted a detailed observation and comparative analysis of histomorphological features in 27 biopsies of cutaneous/mucosa NTM infections and 27 biopsies of MTB infections, focusing on macrophage distribution and the infiltration of various macrophage subpopulations. Our findings revealed that NTM disease was more prone to developing small vessel hyperplasia, dilation, congestion, and interstitial edema compared to tuberculosis (TB). Additionally, the counts of lymphocytes, plasma cells, and neutrophils were significantly higher in NTM infections than in TB. NTM disease was primarily characterized by non-necrotizing granulomas, whereas TB was mainly associated with caseous necrotizing granulomas. Distinct macrophage subpopulations were observed in different lesion regions. granuloma epithelioid macrophages induced by NTM infections primarily expressed CD68 and CD206, while macrophages in non-granulomatous regions predominantly expressed CD163. This suggests that these macrophages belong to different subpopulations with distinct roles. Moreover, the positivity rate of PD-L1 in mononuclear inflammatory cells was notably elevated in both NTM and MTB infections. The similarities and differences in histopathological features, macrophage responses, and immune markers between NTMD and TB provide valuable insights into their pathogenic mechanisms. Understanding these variations could inform better diagnostic and therapeutic strategies for managing NTM infections.
Keywords: NTM, MTB, Cutaneous, Granuloma, Macrophages, PD-L1
Received: 13 Jul 2025; Accepted: 06 Oct 2025.
Copyright: © 2025 Zhang, Li, Zhao, Deng, Tang, Li, Yang, Jiang, He and Wang. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
* Correspondence: Zhuo Wang, wangzh25@mail.sysu.edu.cn
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