Racca Andrea L, Veaute Carolina M, Bailat Alejandra S, Gaite Luis, Arriola Mariano, Hajos Silvia E, Malan Borel Ileana S
Laboratorio de Inmunología Básica, Facultad de Bioquímica y Ciencias Biológicas, Universidad Nacional del Litoral, Ciudad Universitaria, Pje El Pozo, Santa Fe, Argentina.
Transpl Immunol. 2009 May;21(1):10-2. doi: 10.1016/j.trim.2009.01.002. Epub 2009 Feb 2.
HLA-G is a nonclassical MHC class I antigen that displays tolerogenic functions; MICA is a stress-regulated molecule recognized by NKG2D cytotoxicity-activating receptor expressed by NK and T cells subsets. We evaluated HLA-G isoforms and MICA mRNA levels in peripheral blood mononuclear cells (PBMCs) and in biopsies from kidney allograft recipients with acute rejection (AR), chronic rejection (CR), and stable graft evolution (SE). HLA-G1 was the only transcript resulted from amplification, both in PBMCs as in biopsy samples. HLA-G1 mRNA levels in PBMCs from 9/10 patients with CR, 7/9 with AR and 8/10 healthy volunteers were below the median value of SE patients. The analysis of biopsies revealed that patients with AR (n=6), who overcame rejection had a tendency towards higher HLA-G1 levels than those with nephrotoxic acute tubular necrosis (ATN) (n=3). Similar levels of MICA expression were observed in PBMCs from AR, CR, SE and C groups; MICA expression levels were similar also in biopsy specimens from AR and nephrotoxic ATN patients. No correlation was found between MICA expression and the graft state. These preliminary results suggest that HLA-G1 isoforms, but not MICA mRNA levels, may provide a marker for measuring the state of kidney allograft, and be the basis for further studies that may establish the influence of these molecules in renal allograft rejection or acceptance.
HLA - G是一种具有免疫耐受功能的非经典MHC I类抗原；MICA是一种应激调节分子，可被NK细胞和T细胞亚群表达的NKG2D细胞毒性激活受体识别。我们评估了急性排斥反应（AR）、慢性排斥反应（CR）和移植稳定进展（SE）的肾移植受者外周血单个核细胞（PBMC）和活检组织中HLA - G异构体和MICA mRNA水平。HLA - G1是PBMC和活检样本扩增产生的唯一转录本。9/10例CR患者、7/9例AR患者和8/10例健康志愿者的PBMC中HLA - G1 mRNA水平低于SE患者的中位数。活检分析显示，克服排斥反应的AR患者（n = 6）的HLA - G1水平往往高于肾毒性急性肾小管坏死（ATN）患者（n = 3）。在AR、CR、SE和C组的PBMC中观察到相似水平的MICA表达；AR患者和肾毒性ATN患者的活检标本中MICA表达水平也相似。未发现MICA表达与移植状态之间存在相关性。这些初步结果表明，HLA - G1异构体而非MICA mRNA水平可能为衡量肾移植状态提供一个标志物，并为进一步研究这些分子在肾移植排斥或接受中的影响奠定基础。
