Detection of the Tim-3 ligand, galectin-9, inside the allograft during a rejection episode.
BACKGROUND
Tim-3 is a Th1 lymphocytes membrane protein with inhibitory function. Its ligand, galectin-9, was recently identified and it is expressed in some lymphocyte subpopulation. In addition, endothelial cells and fibroblasts can also express galectin-9 according to the local cytokine milieu. Both molecules can act as important regulatory tools in the immune system.


OBJECTIVE
Evaluate the expression of these immunoregulatory molecules inside kidney allografts during acute rejection episodes.


METHODS
By using a quantitative polymerase chain reaction assay, we measured the levels of messenger RNA (mRNA) for galectin-9 and Tim-3 in 21 samples obtained at allograft nephrectomy. Five samples received the histological diagnosis of acute non-vascular rejection (ANVR), twelve of acute vascular rejection (AVR), and five of loss of non-immune cause (LNIC; as control). As cytolytic response markers we measured mRNA levels of granzyme B, interferon-gamma and perforin. The statistic analysis was performed using one way analysis of variance (ANOVA) and Pearson correlation.


RESULTS
The mean levels of Tim-3 mRNA expression were 13.99+/-6.99 for LNIC, 48.13+/-54.47 for RACNV and 238.63+/-333.14 for RAV (p=0.004). For galectin-9, the mean values were 0.57+/-0.49 for LNIC, 0.66+/-0.36 for RACNV and 2.34+/-1.62 for RAV (p=0.006). Furthermore, there was a positive correlation between both molecules (r=0.526, p=0.016). Also, granzyme B, perforin and interferon-gamma mRNA expression were different among the three groups.


CONCLUSIONS
Messenger RNA level expressions of all the studied molecules were higher inside allografts with more severe rejection. Moreover, there was a positive correlation between galectin-9 and Tim-3 mRNA levels. The simultaneous expression of galectin-9 and Tim-3 may indicate an immunoregulatory function, during the ongoing cytotoxic response.
Naka
Erika Lamkowski
EL
Laboratory of Clinical and Experimental Immunology, Division of Nephrology, Federal University of São Paulo, São Paulo, Brazil.
Ponciano
Viviane Campos
VC
Cenedeze
Marcos Antônio
MA
Pacheco-Silva
Alvaro
A
Câmara
Niels Olsen Saraiva
NO
D000328:Adult; D005260:Female; D037161:Galectins / Q000032:analysis / Q000096:biosynthesis*; D006084:Graft Rejection / Q000175:diagnosis*; D053804:Granzymes / Q000276:immunology / Q000378:metabolism; D000072597:Hepatitis A Virus Cellular Receptor 2; D006801:Humans; D007371:Interferon-gamma / Q000276:immunology / Q000378:metabolism; D016030:Kidney Transplantation / Q000276:immunology*; D008297:Male; D008565:Membrane Proteins / Q000032:analysis / Q000096:biosynthesis*; D008875:Middle Aged; D054353:Perforin / Q000276:immunology / Q000378:metabolism; D014184:Transplantation, Homologous / Q000276:immunology
D037161:Galectins; C448908:HAVCR2 protein, human; D000072597:Hepatitis A Virus Cellular Receptor 2; C105032:LGALS9 protein, human; D008565:Membrane Proteins; D054353:Perforin; D007371:Interferon-gamma; D053804:Granzymes