Role of Microbial Agents in Pulmonary Fibrosis

Abstract

Pulmonary fibrosis is a form of lung disease that develops due to aberrant wound-healing following repeated alveoli injury in genetically susceptible individuals, resulting in chronic inflammation, excess deposition of the extracellular matrix components, mainly collagen, and scarring of lung tissue. In addition to irradiation, environmental agents such occupational inhalants, and chemotherapeutic agents, microbial agents also play a role in the etiology of the disease. While viruses have received the most attention, emerging evidence suggest that bacteria and fungi also play a part in the etiology of pulmonary fibrosis. Furthermore, successful use of antibiotics, antiviral and antifungal drugs in several studies to attenuate fibrosis progression is also an indication of microbial involvement in the pathogenesis of the disease and could be a promising therapeutic modality for treating pulmonary fibrosis initiated or exacerbated by infectious agents.

Keywords: Idiopathic Pulmonary Fibrosis; Microbial agents; Pulmonary Fibrosis.

Figure 1

Evidence of Microbial Involvement in Pulmonary Fibrosis. (A) Induction of pulmonary fibrosis by infectious agents using animal models (B) Presence of infectious agents or their products in cases of PF (C) Exacerbation of PF by infectious agents (D) Success of antimicrobial drug therapy in cases of PF (E) Secondary infection of microbial etiology can induce PF (F) other evidence.
 PF: Pulmonary Fibrosis, HCV: Hepatitis C Virus, EBV: Epstein - Barr virus, CMV: Cytomegalovirus, HHV: Human Herpes Virus, TTV: Torque-Teno Virus, RA: Rheumatoid Arthritis, MCTD: Mixed Connective Tissue Disease, PM: Polymyositis, DM: Dermatomyositis.