Exploring Potential COPD Immunosuppression Pathways Causing Increased Susceptibility for MAC Infections among COPD Patients

Abstract

Although there has been a drastic decline in the cases of Tuberculosis in the United States, the prevalence of infections caused by Mycobacterium avium Complex (MAC) has steadily increased in the past decades. Mycobacterium avium (M. avium) is one of the most abundant microorganisms in the MAC species. The mycobacterium genus is divided into two major groups: tuberculosis causing mycobacteria and non-tuberculous mycobacteria. MAC is most prominent among the non-tuberculous mycobacteria. MAC is an opportunistic pathogen that is present in soil, water, and droplets in the air. MAC infections can result in respiratory disease and can disseminate in affected patients. MAC infections are especially prevalent in patients with preexisting respiratory conditions such as Chronic Obstructive Pulmonary Disease (COPD). COPD is one of the most common lung conditions in the world with the primary cause being smoking in developed countries. COPD involves chronic inflammation of lung tissue resulting in increased susceptibility to infection. There is a lack of research regarding the pathophysiology that leads COPD patients to be susceptible to MAC infection. Our review paper therefore aims to investigate how the pathogenicity of MAC bacteria and immune decline seen in COPD patients leads to a greater susceptibility to MAC infection among COPD patients.

Protective Efficacy of BCG Vaccine against Mycobacterium leprae and Non-Tuberculous Mycobacterial Infections

“…Hominissuis, which cause opportunistic infections in immunosuppressed patients. Individuals with pre-existing chronic pulmonary disease, such as chronic obstructive pulmonary disease (COPD), are at increased risk of MAC infection [ 68 , 69 ].…”

“…Furthermore, MAC infections affecting the lungs are most common and manifest as either fibrocavitary disease in older males with a history of smoking, or nodular bronchiecstatic disease in postmenopausal women [ 74 ]. In immunocompromised patients, such as those with inherited immunodeficiency gene defects, leukemias and lymphomas, or infected with HIV/AIDS, MAC disseminates through the lymphatic system and can infect other organ systems, causing hepatosplenomegaly, osteomyelitis, septic arthritis, and generalized lymphadenitis [ 66 , 69 , 75 ]. In addition to chronic pulmonary and disseminated disease, MAC also causes skin and soft tissue infections in affected individuals, which manifest as subcutaneous abscesses, rosacea-like papulopustules, verrucous nodules, crusted ulcers, or polymorphous scaly plaques [ 76 ].…”

“…Treatment for both nodular bronchiecstatic and cavitary disease includes azithromycin, rifampicin, and ethambutol three times weekly for 12 months, with the addition of amikacin for cavitary disease. In the case of disseminated disease involving lymph nodes, surgical excision of the affected nodes may be warranted [ 69 ]. In addition to multidrug therapy, the BCG vaccine has been shown to induce cross-reactive immune responses against M. avium in human peripheral blood mononuclear cells and mouse lymphocytes.…”

Nontuberculous Mycobacteria as Sapronoses: A Review

“…These lifestyle changes are resulting in increased contact with dust and soil in nature through gardening in house gardens, in small greenhouses, in boxes on balconies, or with potting soil in households. These activities are factors for consideration related to the occurrence of threatening pathogens including nontuberculous mycobacteria (NTM) of soil-borne diseases [ 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8 , 9 , 10 , 11 , 12 , 13 ].…”

“…An aging population, an increase in chronic obstructive pulmonary disease (COPD), and the more frequent occurrence of various diseases that results in a decrease in the immune competence (autoimmune diseases, HIV/ADIS pandemics, etc.) of individuals has increased the propensity of being infected by NTM [ 10 , 13 , 14 ]. Environmental related factors are also relevant, with climate change, increased environmental dust in connection with an aridisation of soils and dust erosion, and the pollution of surface and groundwater used for watering agricultural crops all playing a role in increasing the prevalence and potential to be exposed to NTM.…”