Extrinsic Allergic Alveolitis: A Systematic Review of HLA-DR in Pigeon Breeder’s Disease

Abstract Introduction: Pigeon Breeder’s Pneumonitis (PBP) results due to a complex pathophysiology that includes exposure to avian antigens. Susceptibility has been linked to human leukocyte antigen (HLA) class II, though consensus has not been reached. The goal of this systematic review is to further elucidate the association between PBP and HLA-DR subtypes. Methods: Databases utilized included PubMed, Google Scholar, ScienceDirect, and Cochrane Library. Inclusion required a minimum of three studies in English presenting HLA-DR alleles of PBP and control subgroups. Exclusion was due to insufficient data or non-feasible control groups. Forest plots were created for HLA-DR subtypes’ association with PBP. The NIH Bias assessment tool and LFK index assessed bias. Results: 4 studies were included in the meta-analysis. HLA-DR3 was associated with the pooled PBP subgroups (OR=1.86 [1.13, 3.05], p Discussion: Limitations included limited sources, with multiple study methodology unacceptable to this review. These findings expand on previous research on HLA variants and PBP frequency, and offer further clarity supporting novel approaches in treatment of PBP