Type I Diabetes Mellitus: Genetic Factors and Presumptive Enteroviral Etiology or Protection

Table 2

The major histocompatibility complex and the human leukocyte antigens^*.

	HLA loci			Combinations most associated with T1D	Cell type	Functions
MHC I	A			A24	Mainly cytotoxic CD8+ T-cells, also other types of nucleated cells	Peptide binding protein for antigen presentation
	B			B8, B18, B39
	C					Processing of antigens
MHC II	DP	DP-alpha	DP1		Helper CD4+; antigen-presenting cells (dendritic cells, macrophages, some endothelial cells, thymic epithelial cells, and B-cells)	Peptide binding protein
		DP-beta	DP1	DP1
	DQ	DQ-alpha	DQ1
		DQ-beta	DQ1
	DR	DR-alpha				Helper activity for specific MHC II proteins
		DR-beta	DR1	DR1, DQ1, DR-DQ combinations, DR1-DQ1-DQ1 subset combinations
			DR2
			DR3
			DR4
MHC III	Are flanked by the MHC I and MHC II coding regions			Novel area for research	Various	Components of the complement systems C2, C4a, and C4b; Cytokines; Heat shock proteins
MHC IV	Exist at the telomeric end of MHC III genes			Novel area for research	Dendritic cells, natural killer cells	Morphogenesis of dendritic cells, natural killer cells

References [9, 29–36, 41–50].