An additional 447 records were non-eligible for various reasons (e.g., studies involving leprosy, Crohn’s disease, pneumonia, monocyte chemotactic protein-1, interleukin-12, and interleukin-18), 73 records were animal experiments (mouse, calves, warthogs, etc.), 69 records were reviews, abstracts, and letters, 58 records focused on extra-PTB (pleural TB, TB meningitis, osteoarticular TB, etc.), and 5 records were non-English (Chinese, Russian, Polish, etc.). Here, CCL2 is linked to susceptibility to pneumonia measurement.