Expression of human leucocyte antigen G in peripheral blood of kidney transplantation recipients

Abstract

To investigate the expression of non-classical major histocompatibility complex (MHC)-I molecule, human leucocyte antigen (HLA) G, including membrane-bound HLA-G (mHLA-G), intracellular HLA-G (iHLA-G) and soluble HLA-G (sHLA-G), in peripheral blood of surviving kidney transplantation recipients and understand the relevance between HLA-G and the function of transplanted organ, as well as the onset of acute rejection. A longitudinal study was performed on 175 kidney transplantation recipients. Three groups were involved in this study, including acute rejection group (n = 36), function stable group (n = 139) and healthy control group (n = 30). The expression of mHLA-G1 and iHLA-G1 in the T lymphocytes of peripheral blood was detected by flow cytometry analysis and the sHLA-G5 level detected by ELISA. The average rate of CD4(+)mHLA-G1(+), CD8(+)mHLA-G1(+), CD4(+)iHLA-G1(+), CD8(+)iHLA-G1(+) in T lymphocytes of healthy control group was 0.43% +/- 0.19%, 1.23% +/- 0.41%, 27% +/- 13% and 36% +/- 14% respectively. That of acute rejection group was 0.57% +/- 0.34%, 1.31% +/- 0.56%, 26% +/- 8% and 37% +/- 17%; that of function stable group was 0.61% +/- 0.43%, 1.39% +/- 0.47%, 26% +/- 9% and 37% +/- 17% respectively. There was no significant difference among the three groups (all P > 0.05). The average of sHLA-G5 levels in plasma of control group was (25 +/- 14) ng/ml, acute rejection group (24 +/- 15) ng/ml (pre-operative) and (34 +/- 21) ng/ml (post-operative), function stable group (25 +/- 11) ng/ml (pre-operative) and (56 +/- 32) ng/ml (post-operative). There was no significant difference among the three groups (pre-operative, P > 0.05). The average of sHLA-G5 levels in plasma of function stable group was higher than that of acute rejection group (post-operative, P < 0.05). There is a subset of CD4(+)HLA-G1(+) and CD8(+)HLA-G1(+)T lymphocytes with low percentage in peripheral blood of those surviving kidney transplantation recipients. The expressions of mHLA-G1 and iHLA-G1 have no relevance with the onset of acute rejection. sHLA-G5 is correlated with acute rejection in peripheral blood of surviving transplantation recipients.