Lung Microbiome Dysbiosis and Airway Inflammation in Chronic Obstructive Pulmonary Disease in the Nigerian Savanna Belt: A Mechanistic Investigation

The lung microbiome is increasingly recognised as a modulator of airway inflammation in chronic obstructive pulmonary disease, yet no study has characterised lung microbiome composition or its inflammatory consequences in Nigerian patients with chronic obstructive pulmonary disease, particularly those from the dust-laden Savanna belt environment. This study investigated lung microbiome composition and its relationship to airway inflammation and disease severity in chronic obstructive pulmonary disease patients in Jos, Plateau State, and Bauchi, Bauchi State, North Central and North East Nigeria. A cross-sectional mechanistic design enrolled 60 confirmed chronic obstructive pulmonary disease patients and 30 healthy controls matched by age and smoking history. Induced sputum samples were analysed by metagenomic 16S rRNA V3-V4 sequencing. Sputum inflammatory markers including interleukin-8, interleukin-17, and matrix metalloproteinase-9 were quantified by enzyme-linked immunosorbent assay. Spirometry provided disease severity staging. Respiratory symptom burden was assessed by COPD Assessment Test. Multivariate community analysis, negative binomial regression, and partial correlation approaches were applied. Results revealed significant lung microbiome dysbiosis in chronic obstructive pulmonary disease, characterised by reduced alpha diversity and expansion of Pseudomonas, Haemophilus, and Moraxella at the expense of commensal Prevotella species. Microbiome dysbiosis correlated positively with interleukin-8 and matrix metalloproteinase-9 concentrations. Moraxella abundance was independently associated with disease severity stage. Savanna-specific dust microparticulate exposure correlated with Haemophilus enrichment. This study makes an original discovery contribution to lung microbiome physiology in African chronic obstructive pulmonary disease. Microbiome-targeted therapies are proposed for investigation. Keywords: lung microbiome, chronic obstructive pulmonary disease, airway inflammation, dysbiosis, Savanna Nigeria.