Pathogenesis and Pathology of Intraocular Tuberculosis

Area of Science:

• Ophthalmology
• Infectious Diseases
• Immunology

Background:

• Intraocular tuberculosis (TB) is a rare, paucibacillary form of extrapulmonary TB.
• It is hypothesized to arise from hematogenous dissemination from the lungs, followed by ocular tissue localization and later reactivation.
• The guinea pig model partially supports this dissemination-reactivation hypothesis.

Purpose of the Study:

• To elucidate the pathogenesis and immune mechanisms of intraocular tuberculosis.
• To describe the histopathological findings in ocular TB.
• To review recent findings in TB retinal vasculitis.

Main Methods:

• Review of existing literature and case reports.
• Histopathological analysis of ocular tissues from patients with bacteriologically confirmed TB.
• Examination of immune responses, including Th1 and Th17 pathways.

Main Results:

• Histopathology shows granulomatous inflammation with caseous necrosis and acid-fast bacilli in ocular TB tissues.
• Evidence suggests mycobacterial recognition by antigen-presenting cells activates Th1 and Th17 immune pathways.
• Recent findings include intraretinal granulomas and T-cell infiltration in TB retinal vasculitis.

Conclusions:

• Intraocular TB pathogenesis likely involves dissemination, localization, and reactivation.
• Immune responses, particularly Th1 and Th17, play a crucial role in ocular TB.
• Histopathological findings and recent observations in TB retinal vasculitis provide insights into the disease.