A spatial model to understand tuberculosis granuloma formation and its impact on disease progression

Tuberculosis (TB) is caused by a bacterium called Mycobacterium tuberculosis (Mtb). When Mtb enters inside the pulmonary alveolus, it is phagocytosed by the alveolar macrophages, followed by a cascade of immune responses. This leads to the recruitment and accumulation of additional macrophages and T cells in the pulmonary tissues. A key outcome of this is the formation of granuloma, the hallmark of TB infection. In this paper, we develop a mathematical model of the evolution of granuloma by a system of partial differential equations that is based on the classical Keller–Segel chemotaxis equation. We investigate the effect of different parameters on the formation of granuloma. We present numerical simulation results that illustrate the impact of different parameters. The implication of our result on the disease progression is also discussed.