Leukocytes from Patients with Drug-Sensitive and Multidrug-Resistant Tuberculosis Exhibit Distinctive Profiles of Chemokine Receptor Expression and Migration Capacity

Abstract

Tuberculosis (TB), caused by Mycobacterium tuberculosis (Mtb), remains as a leading infectious cause of death worldwide. The increasing number of multidrug-resistant TB (MDR-TB) cases contributes to the poor control of the TB epidemic. Currently, little is known about the immunological requirements of protective responses against MDR-TB. This is of major relevance to identify immune markers for treatment monitoring and targets for adjuvant immunotherapies. Here, we hypothesized that MDR-TB patients display unique immunophenotypical features and immune cell migration dynamics compared to drug-sensitive TB (DS-TB). Hence, we prospectively conducted an extensive characterization of the immune profile of MDR-TB patients at different time points before and after pharmacological therapy. For this purpose, we focused on the leukocyte expression of chemokine receptors, distribution of different monocyte and lymphocyte subsets, plasma levels of chemotactic factors, and in vitro migration capacity of immune cells. Our comparative cohort consisted of DS-TB patients and healthy volunteer donors (HD). Our results demonstrate some unique features of leukocyte migration dynamics during MDR-TB. These include increased and prolonged circulation of CD3+ monocytes, CCR4+ monocytes, EM CD4+ T cells, EM/CM CD8+ T cells, and CXCR1+CXCR3+ T cells that is sustained even after the administration of anti-TB drugs. We also observed shared characteristics of both MDR-TB and DS-TB that include CCR2+ monocyte depletion in the blood; high plasma levels of MPC-1, CCL-7, and IP-10; and increased responsiveness of leukocytes to chemotactic signals in vitro. Our study contributes to a better understanding of the MDR-TB pathobiology and uncovers immunological readouts of treatment efficacy.

Mycobacterium tuberculosis H37Rv Strain Increases the Frequency of CD3+TCR+ Macrophages and Affects Their Phenotype, but Not Their Migration Ability

“…The frequency of CD3 + myeloid cells has been reported to be increased upon mycobacterial infections [ 7 , 8 , 9 ]. Therefore, to evaluate the effect of Mtb virulence on the induction of these subpopulations, MDMs were infected with H37Ra (multiplicity of infection (MOI) = 1 and 10) and H37Rv (MOI = 1 and 5) for a short time (24 h).…”

“…The activation of the chemokine/chemokine receptor axis is one of the most important processes in the regulation of cell migration [ 18 ]. Recently, we reported that CD3 + monocytes from patients with TB poorly express CCR2; nevertheless, they are able to migrate in response to IP-10 stimuli [ 9 ]. Therefore, the expression of CCR2, CXCR1, and CCR7 chemokine receptors inside the gate of CD3 − , CD3 + TCRαβ + , and CD3 + TCRαβ − MDMs was evaluated by flow cytometry, and that of CCL2 (ligand to CCR2), IL-8 (ligand to CXCR1), and CCL19 (ligand to CCR7) was evaluated in the culture supernatant by ELISA.…”

“…Previously, we reported that the levels of circulating CD3 + monocytes are increased in patients with multidrug-resistant or drug-sensitive TB compared with levels in healthy subjects. Interestingly, although these CD3 + monocytes display the ability to migrate, they do not strongly express CCR2 [ 9 ]. It is known that granulomas in patients with TB are rich in CD3 + macrophages.…”

“…As the migration of cells to the lung is an important feature of the innate immune response for the control of microorganisms, our group previously reported that CD3 + monocytes from patients with TB are weak regulators of CCR2 in vitro but can migrate in response to MCP-1 and CCL-17 [ 9 ]. Therefore, in the present study, we evaluated the effect of Mtb virulence on the expression and migration patterns in CD3 + MDMs.…”

“…Recently, it was reported that heathy donors have approximately 3% of CD3 + monocytes in the peripheral blood, whereas patients with pulmonary TB have an increased frequency of this newly discovered subpopulation (13%). More interestingly, the circulating CD3 + monocyte frequency had normalized at the sixth month of treatment in patients with TB sensitive to first-line drugs [ 9 ]. Thus, a growing body of evidence indicates that the frequency of CD3 + myeloid cells increase as a response to mycobacterial infections, and that TNF/TNFR axis plays an essential role in the maintenance of these cells; however, little is known about the specific mechanism used by these cells to migrate to the site of infection.…”