What does the Human Leukocyte Antigen-DRB1 (HLA-DRB1) indicate?

From the Guidelines

HLA-DRB1 indicates an individual's susceptibility or resistance to various autoimmune disorders, including type 1 diabetes, and is used in transplantation medicine to match organ donors and recipients, as well as in disease risk assessment and prediction of disease severity or treatment response. The HLA-DRB1 gene is part of the human leukocyte antigen (HLA) complex, specifically the class II region, which plays a crucial role in immune response regulation 1. Different variants (alleles) of HLA-DRB1 are associated with susceptibility or resistance to various autoimmune disorders, including rheumatoid arthritis, multiple sclerosis, and type 1 diabetes 1. Some key points to consider about HLA-DRB1 include:

• HLA-DRB1 typing is commonly used in transplantation medicine to match organ donors and recipients, as closer matches reduce the risk of rejection 1
• It's also valuable in disease risk assessment, particularly for autoimmune conditions, and can sometimes help predict disease severity or treatment response 1
• The gene's variations are highly diverse across populations, making it useful in population genetics and ancestry studies 1
• HLA-DRB1 testing typically requires specialized laboratory techniques like PCR or DNA sequencing and is usually interpreted by immunologists or genetic specialists 1
• Specific alleles in the HLA-DRB1 gene can be either predisposing (e.g., DRB10301-DQB10201 [DR3-DQ2] and DRB10401-DQB10302 [DR4-DQ8]) or protective (e.g., DRB11501 and DQA10102-DQB1*0602) for type 1 diabetes 1. In terms of clinical application, HLA-DRB1 typing is not recommended for routine clinical diagnosis or classification of type 1 diabetes, but can be useful in research studies or for identifying high-risk populations 1. Overall, HLA-DRB1 is an important gene that plays a crucial role in the immune system and has significant implications for transplantation medicine, disease risk assessment, and prediction of disease severity or treatment response.

From the Research

HLA-DRB1 Indications

The Human Leukocyte Antigen-DRB1 (HLA-DRB1) is a gene that plays a crucial role in the immune system. It is associated with various autoimmune diseases, including rheumatoid arthritis (RA). The following points highlight the indications of HLA-DRB1:

• Rheumatoid Arthritis Susceptibility: HLA-DRB1 alleles, particularly *04 and *03, are associated with an increased risk of developing RA 2, 3, 4.
• Disease Severity and Mortality: Certain HLA-DRB1 haplotypes, such as those with valine at position 11, are linked to radiological severity and higher mortality rates in RA patients 3.
• Treatment Response: HLA-DRB1 alleles can influence the response to tumor necrosis factor (TNF) inhibitor therapy, with some alleles associated with a better response 3.
• Biomarkers of Inflammation: HLA-DRB1 gene variants are associated with elevated levels of inflammatory biomarkers, such as erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) 4.
• Protective Role: The HLA-DRB1*13 allele has been found to have a protective effect against autoimmune diseases, including RA, systemic lupus erythematosus, and psoriasis 5.

HLA-DRB1 Alleles and Their Associations

Different HLA-DRB1 alleles have been associated with various autoimmune diseases:

• HLA-DRB1*04: Associated with an increased risk of RA and a better response to TNF inhibitor therapy 2, 3.
• HLA-DRB1*03: Linked to an increased risk of RA and systemic lupus erythematosus 4, 5.
• HLA-DRB1*13: Has a protective effect against autoimmune diseases, including RA and systemic lupus erythematosus 5.