Human leukocyte antigen genes

The Human Leukocyte Antigen genes or HLA genes are a group of genes created by the human leukocyte antigen proteins. HLA genes help the "immune system distinguish the body's own proteins from proteins made by foreign invaders such as viruses and bacteria". It is the human version of the Major Histocompatibility Complex (MHC), which is also found in certain non-human species. HLA associations are considered "hallmarks of autoimmune disease".

HLA class I genes
In humans these are: The class I proteins produced from these genes are found on the surface of almost all cells, and display these protein fragments (peptides) to the immune system. The immune system then identifies any proteins it recognizes as foreign (such as viral or bacterial peptides), and triggers the destruction of the cell.
 * HLA-A
 * HLA-B
 * HLA-C

HLA class II genes
In humans these are:
 * HLA-DPA1
 * HLA-DPB1
 * HLA-DQA1
 * HLA-DQB1
 * HLA-DRA
 * HLA-DRB1

ME/CFS
Lande et al. (2020) found two HLA associations that were more common in people with ME/CFS, with 19.2% of ME/CFS patients carrying one of the two HLA associations identified, compared to 12.2% of the control group. The HLA associations more common in ME/CFS patients were HLA-C*07:04 and HLA-DQB1*03:03. The 426 ME/CFS patients in the study met the Canadian Consensus Criteria for ME/CFS, except for four who met the International Consensus Criteria for ME.

A small Norwegian trial found patients positive for HLA-DQB1*03:03 and/or HLA-C*07:04 were more likely to respond to cyclophosphamide than patients without those alleles, 83 vs. 43%.

Notable studies

 * 2020, Intravenous Cyclophosphamide in Myalgic Encephalomyelitis/Chronic Fatigue Syndrome. An Open-Label Phase II Study - (Full text)

Learn more

 * Histocompatibility complex - Genetics home reference - US Library of Medicine