Relationship between pro-inflammatory Interferon-γ level and disease severity in pericardial tuberculosis

Objective: Tuberculous pericarditis accounts for 60% of all cases of pericarditis in Africa. We aimed to correlate pericardial disease severity with cytokine expression from blood and pericardial fluid in patients with tuberculous pericarditis.

Methods: 44 patients presenting with tuberculous pericardial effusions (PE) were prospectively recruited in Cape Town, Rep South Africa. Enzyme-linked immunosorbent assays were performed on PE and serum samples for the following cytokines: TNF, IFN-γ, IL-10, IL-1β, and TGF-β. Correlations were ascertained between PE and serum cytokine levels and clinical data indicative of ventricular dysfunction and pericardial disease severity such as ejection fraction, NYHA-stage, right atrial pressure, effusion size, degree of arterial paradox, E/A-ratio, opening pressure at pericardiocentesis and left ventricular shortening fraction (LVSF).

Results: Levels of the pro-inflammatory cytokines (IFN-γ, TNF, IL-1β) were higher in PE compared to serum while levels of the anti-inflammatory cytokines (TGF-β and IL-10) were higher in serum than in PE. The serum concentration of TGF-β was higher in HIV infected patients compared to HIV uninfected patients (p=0.0007). There was a positive correlation between the pericardial IFN-γ level and PE size, atrial pressure and degree of arterial paradox. Of these the strongest correlation was with effusion size (Spearman r=0.47, p=0.0024).

Discussion: In tuberculous pericarditis the magnitude of the TH1-type immune response against Mycobacterium tuberculosis is associated with the severity of the clinical pericardial disease.