Lung macrophages and dendritic cells express HLA-G molecules in pulmonary diseases.
HLA-G is selectively expressed in extravillous trophoblast of human placenta, which does not express classical HLA-A and -B molecules. Several studies report the role of HLA-G as a molecule involved in immune tolerance. By interacting with NK and T cells inhibitory receptors, HLA-G may downregulate their cytotoxicity functions. To appreciate the biologic and clinical relevance of HLA-G expression in lung diseases, HLA class I and HLA-G expression were analyzed in a panel of 36 ex vivo neoplastic tissues and 8 non-neoplastic lung tissues. Immunohistochemical analysis was performed using a pan-HLA class I antibody (W6/32) and three different specific anti-HLA-G antibodies (87G, MEMG/9 and 4H84). These findings demonstrated that HLA-G products were not expressed in pulmonary structural cells. However, HLA-G molecules were detected in activated macrophages and dendritic cells infiltrating lung carcinomas (33%) and nontumoral pulmonary diseases (25%). HLA-G expression was not correlated with classical HLA alterations. No statistical correlation was found between HLA-G expression and clinical or biologic parameters except high tumor size. The expression of HLA-G in myelo-monocytic cells infiltrating lung pathologic tissues could alter antigenic presentation and contribute to decrease immune response efficiency, subsequently favoring the progression of tumoral or inflammatory processes.
Pangault
Celine
C
Laboratoire Universitaire d'Hématologie et de la Biologie des Cellules Sanguines, Faculté de Médecine, Université de Rennes I, Rennes Cedex, France. celine.pangault@univ-rennes1.fr
Le Friec
G
G
Caulet-Maugendre
S
S
Léna
H
H
Amiot
L
L
Guilloux
V
V
Onno
M
M
Fauchet
R
R
D003713:Dendritic Cells / Q000378:metabolism*; D005260:Female; D006680:HLA Antigens / Q000378:metabolism; D059951:HLA-G Antigens; D015395:Histocompatibility Antigens Class I / Q000378:metabolism; D006801:Humans; D008168:Lung / Q000166:cytology / Q000378:metabolism*; D008171:Lung Diseases / Q000378:metabolism*; D008175:Lung Neoplasms / Q000378:metabolism; D008264:Macrophages / Q000378:metabolism*; D008297:Male
D006680:HLA Antigens; D059951:HLA-G Antigens; D015395:Histocompatibility Antigens Class I