Pulmonary Nontuberculous Mycobacterial Disease

TLDR

Pulmonary nontuberculous mycobacterial disease is rising, yet the factors that predispose individuals remain poorly defined. The study aimed to prospectively identify the morphotype, immunophenotype, and CFTR genotype in a large cohort of PNTM patients. Researchers enrolled 63 patients and performed chest CT, echocardiography, pulmonary function testing, flow cytometry, in vitro cytokine assays, and anthropometric comparisons with NHANES controls. Patients were predominantly female and white, taller and leaner than matched controls, had high rates of scoliosis, pectus excavatum, mitral valve prolapse, and 36 % carried CFTR mutations, yet displayed normal immune cell counts and cytokine responses.

Abstract

Pulmonary nontuberculous mycobacterial (PNTM) disease is increasing, but predisposing features have been elusive.To prospectively determine the morphotype, immunophenotype, and cystic fibrosis transmembrane conductance regulator genotype in a large cohort with PNTM.We prospectively enrolled 63 patients with PNTM infection, each of whom had computerized tomography, echocardiogram, pulmonary function, and flow cytometry of peripheral blood. In vitro cytokine production in response to mitogen, LPS, and cytokines was performed. Anthropometric measurements were compared with National Health and Nutrition Examination Survey (NHANES) age- and ethnicity-matched female control subjects extracted from the NHANES 2001-2002 dataset.Patients were 59.9 (+/-9.8 yr [SD]) old, and 5.4 (+/-7.9 yr) from diagnosis to enrollment. Patients were 95% female, 91% white, and 68% lifetime nonsmokers. A total of 46 were infected with Mycobacterium avium complex, M. xenopi, or M. kansasii; 17 were infected with rapidly growing mycobacteria. Female patients were significantly taller (164.7 vs. 161.0 cm; P < 0.001) and thinner (body mass index, 21.1 vs. 28.2; P < 0.001) than matched NHANES control subjects, and thinner (body mass index, 21.1 vs. 26.8; P = 0.002) than patients with disseminated nontuberculous mycobacterial infection. A total of 51% of patients had scoliosis, 11% pectus excavatum, and 9% mitral valve prolapse, all significantly more than reference populations. Stimulated cytokine production was similar to that of healthy control subjects, including the IFN-gamma/IL-12 pathway. CD4(+), CD8(+), B, and natural killer cell numbers were normal. A total of 36% of patients had mutations in the cystic fibrosis transmembrane conductance regulator gene.Patients with PNTM infection are taller and leaner than control subjects, with high rates of scoliosis, pectus excavatum, mitral valve prolapse, and cystic fibrosis transmembrane conductance regulator mutations, but without recognized immune defects.