HLA-DQA1

HLA-DQA1 Full Name

major histocompatibility complex, class II, DQ alpha 1

HLA-DQA1 Introduction

HLA-DQA1 encodes the alpha chain of the MHC class II DQ molecule, a critical component of the adaptive immune system responsible for presenting extracellularly derived peptides to CD4+ T cells. This gene plays a central role in orchestrating immune recognition, tolerance, and response to pathogens or self-antigens. Clinically, HLA-DQA1 polymorphisms have emerged as significant biomarkers for predicting disease susceptibility and treatment outcomes across a spectrum of autoimmune and inflammatory conditions. Its expression and allele-specific variations influence how effectively antigens are presented to T cells, affecting both protective immunity and the risk of aberrant immune responses that can lead to autoimmunity or therapeutic complications.

Functionally, HLA-DQA1 facilitates the formation of heterodimeric MHC class II molecules with DQB1, enabling precise antigen presentation to helper T cells. Variants of HLA-DQA1 can alter the stability, surface expression, and peptide-binding specificity of these molecules, thereby modulating immune activation. Dysregulation or certain high-risk alleles can predispose individuals to inappropriate immune activation or reduced tolerance, contributing to autoimmune pathology. In the context of treatment, HLA-DQA1 alleles such as HLA-DQA1*05 have been linked to increased immunogenicity of biologic drugs, including anti-TNF-α therapies, highlighting its importance in pharmacogenomics and personalized medicine strategies.

Disease association studies emphasize HLA-DQA1's clinical relevance across multiple conditions. In inflammatory bowel disease, carriers of HLA-DQA105 alleles show higher rates of anti-drug antibody formation and loss of response to TNF-α inhibitors, which can be mitigated through proactive therapeutic drug monitoring. HLA-DQA105:03 is associated with neuromyelitis optica spectrum disorder in Japanese populations, likely due to enhanced presentation of pathogenic AQP4 peptides. Population studies further link HLA-DQA101:01 to increased susceptibility to type 1 diabetes in Jordanian cohorts, whereas other alleles confer protective effects. In autoimmune skin disorders, HLA-DQA105:05 has been identified as a key susceptibility factor for bullous pemphigoid in German populations. Collectively, these findings establish HLA-DQA1 as a pivotal immune regulator, genetic risk marker, and potential target for precision medicine interventions.

Alternate Names for HLA-DQA1

HLA-DQA1; major histocompatibility complex, class II, DQ alpha 1; HLA DQA; HLA class II histocompatibility antigen, DQ alpha 1 chain; CELIAC1; HLA-DCA; DC-alpha; DC-1 alpha chain; MHC HLA-DQ alpha; MHC class II DQA1

• 1.Rodríguez-Alcolado L, et al.; Impact of HLA-DQA1*05 Genotype in Immunogenicity and Failure to Treatment with Tumour Necrosis Factor-alpha Antagonists in Inflammatory Bowel Disease: A Systematic Review and Meta-analysis. J Crohns Colitis. 2024, 18(7):1034-1052.
  2.Obaied MHR, et al.; Implication of the HLA-DQA1, HLA-DQB1 and CTLA-4 alleles in the susceptibility to type 1 diabetes in Jordanian population. Mol Biol Rep. 2025, 52(1):330.