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Pathophysiological mechanism of non-HIV Pneumocystis jirovecii pneumonia

Nobuhiro Asai1, Shinji Motojima2, Yoshihiro Ohkuni3

  • 1Department of Clinical Infectious Diseases, Aichi Medical University, Nagakute, Aichi, Japan; Department of Pathology, University of Michigan, Ann Arbor, MI, 48109, USA.

Respiratory Investigation
|May 2, 2022
PubMed

Insights

Non-HIV Pneumocystis pneumonia (PCP) carries a high mortality rate due to distinct pathophysiological mechanisms. Factors like gut microbiome dysbiosis and altered macrophage polarization contribute to severe lung injury in these patients.

Area of Science:

  • Infectious Diseases
  • Immunology
  • Pulmonology

Background:

  • Pneumocystis jirovecii pneumonia (PCP) typically affects immunocompromised individuals, particularly those with HIV.
  • Non-HIV PCP presents a significant clinical challenge with a high mortality rate (30%-75%) and distinct pathophysiology compared to HIV-associated PCP.

Purpose of the Study:

  • To review the poor prognostic factors in non-HIV PCP.
  • To explore novel aspects of non-HIV PCP, including gut microbiome dysbiosis and macrophagic polarization.
  • To discuss the limitations of current predictive values in general pneumonia practice for non-HIV PCP.

Main Methods:

  • This is a review article, synthesizing existing literature on non-HIV PCP.
  • Analysis of pathophysiological mechanisms, including host immune dysregulation.
  • Examination of factors such as aging, comorbidities, gut microbiome, and macrophage polarization.

Main Results:

  • Non-HIV PCP exhibits a poor prognosis due to unique pathophysiological pathways.
  • Aging, underlying diseases, gut dysbiosis, and a shift in macrophage polarization (M2 to M1) contribute to immune dysregulation.
  • These factors lead to severe lung injury and increased mortality in non-HIV PCP patients.

Conclusions:

  • The pathophysiology of non-HIV PCP involves complex interactions between host factors and the pathogen.
  • Targeting gut microbiome dysbiosis and modulating macrophage polarization may offer new therapeutic strategies.
  • Current predictive models for general pneumonia may not adequately capture the risks associated with non-HIV PCP.
Keywords:
Human immunodeficiency virusMacrophage polarizationMicrobiomePneumocystis jirovecii pneumoniaTh1-predominance

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