HLA-G polymorphisms and HLA-G expression in sarcoidosis.
BACKGROUND
The MHC class Ib molecule Human Leukocyte Antigen (HLA)-G may be important in induction and maintenance of immunological tolerance, and HLA-G expression may have a role in different cancers, in certain diseases with associations to HLA, and in organ transplantation. Sarcoidosis is a systemic granulomatous disease with unknown etiology but at the molecular level several studies have shown HLA associations.


METHODS
In the present study, HLA-G alleles/polymorphisms were studied in sarcoidosis patients (n = 47) and controls (n = 129) by PCR techniques and HLA-G protein expression was investigated in granulomas from sarcoidosis patients with the use of immunohistochemistry.


RESULTS
The HLA-G*010102/-G*0106 alleles were observed more often in sarcoidosis patients (39.4%) than in controls (26.4%), p = 0.025 (Fisher's exact test); however, not significant after correction (p(c) = 0.15). When HLA-G expression was investigated by immunohistochemistry in granulomas from sarcoidosis patients, weak HLA-G expression was observed in only one patient.


CONCLUSIONS
HLA-G alleles that include a 14-bp sequence polymorphism in exon 8 of the HLA-G gene are observed more often in sarcoidosis patients than in controls. The sequence variation may influence HLA-G mRNA stability and influence the expression of soluble isoforms of HLA-G. Only rare and weak expression of HLA-G was observed in granulomas from sarcoidosis patients. More studies are needed to further elucidate the possible role for HLA-G in sarcoidosis.
Hviid
Thomas Vauvert F
TV
Department of Clinical Biochemistry, Copenhagen University Hospital, Rigshospitalet, Denmark. hviid@dadlnet.dk
Milman
Nils
N
Hylenius
Sine
S
Jakobsen
Kirsten
K
Jensen
Michael S
MS
Larsen
Lise Grupe
LG
D000328:Adult; D000368:Aged; D000483:Alleles; D005260:Female; D005787:Gene Frequency; D006680:HLA Antigens / Q000235:genetics*; D015395:Histocompatibility Antigens Class I / Q000235:genetics*; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D008875:Middle Aged; D011110:Polymorphism, Genetic; D012333:RNA, Messenger / Q000378:metabolism; D012507:Sarcoidosis / Q000235:genetics* / Q000276:immunology*; D017422:Sequence Analysis, DNA
D006680:HLA Antigens; D015395:Histocompatibility Antigens Class I; D012333:RNA, Messenger