Neutrophils Are the Predominant Infected Phagocytic Cells in the Airways of Patients With Active Pulmonary TB

Abstract

Our results show that neutrophils are the predominant cell types infected with Mtb in patients with TB and that these intracellular bacteria appear to replicate rapidly. These results are consistent with a role for neutrophils in providing a permissive site for a final burst of active replication of the bacilli prior to transmission.

The innate immune response in human tuberculosis

“…Neutrophils are the predominant cell type infected in the airways of individuals with active TB (Eum et al ., 2010). These professional phagocytes play a very complex and conflicting role in the pathology of TB that likely depends upon the host genetics, Mtb virulence factors and also the stage of TB disease.…”

Inflammation and Immunopathogenesis of Tuberculosis Progression

“…In a recent study by Eum and coauthors (Eum et al, 2010), neutrophils present in the sputum and BAL fluids of patients with active pulmonary TB contained Mtb that exhibited signs of replication. Based on these observations, it is concluded that neutrophils have poor antimycobacterial activity and during TB act by hiding Mtb from macrophages and permitting Mtb replication (Eruslanov et al, 2005;Eum et al, 2010).…”

“…It has long been thought that the caseum represents a nutritional site for rapid Mtb replication. However, recent data have shown that: (i) many necrotic areas are devoid of Mtb (Ulrichs & Kaufmann, 2006), (ii) microbes located in the caseum resemble stationaryphase organisms, whereas replicating Mtb are found in sputum and BAL, and in connection with neutrophils (Eum et al, 2010). It is therefore suggested that Mtb replication does not occur in the liquefying cavity, but rather starts upon the exit of the bacilli from that cavity into the sputum.…”

“…It was demonstrated that in sputum and BAL fluids of patients with pulmonary TB neutrophils are more abundant and contain more intracellular bacilli than macrophages (Eum et al, 2010).…”

Resuscitation-promoting factors are important determinants of the pathophysiology inMycobacterium tuberculosisinfection

“…Recent mathematical modeling predicted that as of 2014, 1.7 billion people were latently infected with Mycobacterium tuberculosis (Mtb) (Houben & Dodd, 2016). Mtb is transmitted primarily by respiratory droplet inhalation (Turner & Bothamley, 2015) and upon reaching the alveoli is phagocytosed by macrophages, neutrophils and dendritic cells (DCs) (Dorhoi & Kaufmann, 2014;Eum et al, 2010). Despite internalization, Mtb can continue to replicate intracellularly (Ahmad, 2011).…”