HLA class II histocompatibility antigen, DQ alpha 1 chain (HLA-DQA1) (HLA-DQA1)

HLA-DQA1 (Major Histocompatibility Complex, Class II, DQ Alpha 1) is a protein-coding gene that encodes the alpha chain of the HLA-DQ heterodimer, a critical component of the MHC class II system [1, 3]. This receptor is primarily expressed on the surface of professional antigen-presenting cells (APCs), such as dendritic cells, B cells, and macrophages, where it functions to present exogenous peptide antigens to CD4+ T helper cells [2, 9]. The HLA-DQ molecule is highly polymorphic, and specific allelic variations are strongly associated with susceptibility to various autoimmune diseases, most notably Celiac disease and Type 1 diabetes [6, 8]. In Celiac disease, the DQ2 (often DQA1*05:01/DQB1*02:01) and DQ8 (DQA1*03/DQB1*03:02) heterodimers preferentially bind deamidated gluten peptides, triggering a pathogenic T-cell response [7, 8]. Beyond its role as a disease susceptibility factor, HLA-DQA1 serves as a vital pharmacogenomic biomarker; for instance, the HLA-DQA1*05 allele is a predictor of increased risk for developing anti-drug antibodies (ADAs) against TNF-alpha inhibitors like infliximab and adalimumab [12, 19]. Additionally, the HLA-DQA1*02:01 variant is linked to an increased risk of lapatinib-induced hepatotoxicity [6, 27]. Therapeutic development targeting HLA-DQA1 focuses on the use of specific blockers, such as the investigational antibody DONQ52, which aims to prevent the presentation of gluten peptides and thus arrest the autoimmune cascade in Celiac disease [15, 24]. These strategies represent a shift toward precision medicine, utilizing genetic screening to optimize treatment selection and mitigate adverse immune reactions [18, 23].

Other names

CELIAC1DQ-A1GSEHLA-DQADC-1 alpha chainDC-alphaHLA-DCAMHC class II DQA1

Inhibition of antigen presentation by blocking the peptide-binding groove of the HLA-DQ heterodimer; modulation of immune response through specific allele-peptide complex recognition.