Impact of HLA-G analysis in prevention, diagnosis and treatment of pathological conditions

Table 1 Summary of the main studies on human leukocyte antigen G and pathological conditions

Topics	HLA-G genetics and polymorphism	Protein	Ref.
Autoimmune and inflammatory pathologies
Rheumatoid arthritis		Lower plasma sHLA-G levels than in controls	71
		Higher sHLA-G levels in the synovia	73
		Plasma level of sHLA-G correlates with disease activity parameters	2
	Increase in 14 bp DEL/DEL genotype frequency in responsive patients to MTX treatment		41
	Increase in 14 bp DEL allele frequency in patients with improved disease status		2
Systemic lupus erythematosus		Higher level of sHLA-G and IL-10 in plasma that in controls	77,78
	Higher frequency of 14 bp INS allele and 14 bp INS/INS genotype than in controls	Lower concentration of sHLA-G in serum than in controls	66
		Decrease in HLA-G expression in monocytes and DCs	80
	14 bp INS/INS genotype is associated to the highest disease activity		82
	+3142 G allele and +3142 GG genotype are more frequent in SLE and associated to SLE susceptibility		84,85
Multiple sclerosis		sHLA-G levels in MS CSF are higher than in controls	87,88
	sHLA-G levels in MS could be influenced by HLA-G 14 bp and +3142 C < G polymorphisms		67
		sHLA-G level are increased in serum of CFS of MRI inactive MS	65,90
		HLA-G expression in monocytes is lower than in controls	91
		Presence of HLA-Gpos Treg cells in peripherial blood	92
Inflammatory bowel disease Crohn’s disease and ulcerative colitis		HLA-G is present on UC intestinal cells but not in CD biopsies	95
	14 bp INS/DEL and 14 bp INS/INS are increased in UC in comparison with CD patients		96
		PBMCs from CD patients secrete spontaneously sHLA-G	97
		Different modulation of HLA-G by therapy in UC and CD	98
Asthma	-964 G < A and +3142 C < G SNPs are associated with asthma	Expression of HLA-G in airway epithelium and airway system	99,100
		sHLA-G plasma levels are higher in atopic asthmatic children	101
		sHLA-G secretion is increased in asthma induced by isocyanates	103
Allergic rhinitis		Higher sHLA-G serum levels than controls	106-110
Pathological pregnancy		Decreased HLA-G expression in placenta than uncomplicated pregnancies	46-48,112,113
Pre-eclampsia	Increased 14 bp INS/INS genotype frequency than uncomplicated pregnancies		120-125
Tumors		Increased HLA-G expression in tumor cells	1,45,128-143
		Higher sHLA-G serum levels than controls	142
Viral infection		Increased HLA-G expression in viral infected cells	145
HIV-1		Increased HLA-G expression in infected monocytes and T cells	147
HCMV		Increased HLA-G expression in infected monocytes	56
		Increased sHLA-G serum levels than controls	151

sHLA-G: Soluble human leukocyte antigen G; IL-10: Interleukine-10; SNPs: Single nucleotide polymorphisms; RA: Rheumatoid arthritis; SLE: Systemic lupus erythematosus; MS: Multiple sclerosis; IBD: Inflammatory bowel disease; CD: Crohn’s disease; UC: Ulcerative colitis; AR: Allergic rhinitis; HCMV: Human cytomegalovirus; HIV-1: Human immunodeficiency virus-1; MRI: Magnetic resonance imaging; HLA-G: Human leukocyte antigen G; INS/DEL: Insertion/deletion; CFS: Chronic fatigue syndrome.