Diagnosis of acute renal allograft rejection by analyzing whole blood mRNA expression of lymphocyte marker molecules.
BACKGROUND
Currently, the diagnosis of acute rejection after kidney transplantation is based on a kidney biopsy taken after clinical rejection suspicion. A robust, noninvasive diagnostic method would allow easier and more frequent monitoring of the patient and the graft. Potentially, a straightforward method would be the analysis of lymphocyte marker molecule expression from whole blood samples.


METHODS
Whole blood samples were collected prospectively in a single kidney transplantation center from 50 adult kidney recipients transplanted between 2001 and 2005. The mRNA expression of granzyme B, perforin, FasL, granulysin, CD154, ICOS, CTLA4 and PD-1 were analyzed with real-time quantitative polymerase chain reaction.


RESULTS
The expression of ICOS and CD154 were significantly lower in rejection patients than in control patients (P<0.001). Both genes gave statistically significant area under receiver operating characteristic curve (AUC; 0.87, 0.88) with 84% sensitivity and 100% specificity for CD154 and 76% and 86% for ICOS, respectively. In paired rejection and postrejection therapy samples, the expression of both genes significantly increased during rejection therapy (P<0.001). When rejection patients were compared to patients biopsied because of other reasons of graft dysfunction, both CD154 and ICOS were lower in rejection patients but only CD154 was statistically significant (P=0.028, AUC=0.740, sensitivity 52%, specificity 90%). The other studied genes gave no consistent statistically significant results.


CONCLUSIONS
The whole blood gene expression quantities of costimulatory molecules CD154 and ICOS reasonably robustly differentiated rejection patients from control patients. The clinical use of the analysis is limited by poor capability to differentiate patients with rejection from patients with other causes of graft dysfunction.
Alakulppi
Noora S
NS
Research and Development, Finnish Red Cross Blood Service, Helsinki, Finland.
Kyllönen
Lauri E
LE
Partanen
Jukka
J
Salmela
Kaija T
KT
Laine
Jarmo T
JT
D000293:Adolescent; D000328:Adult; D000368:Aged; D015703:Antigens, CD / Q000097:blood / Q000235:genetics; D000943:Antigens, Differentiation / Q000097:blood / Q000235:genetics; D000945:Antigens, Differentiation, T-Lymphocyte / Q000097:blood / Q000235:genetics*; D051017:Apoptosis Regulatory Proteins / Q000097:blood / Q000235:genetics; D023201:CD40 Ligand / Q000097:blood / Q000235:genetics*; D060908:CTLA-4 Antigen; D053222:Fas Ligand Protein / Q000097:blood / Q000235:genetics; D005260:Female; D006084:Graft Rejection / Q000097:blood* / Q000175:diagnosis*; D053804:Granzymes / Q000097:blood / Q000235:genetics; D006801:Humans; D060889:Inducible T-Cell Co-Stimulator Protein; D016030:Kidney Transplantation; D008297:Male; D008562:Membrane Glycoproteins / Q000097:blood / Q000235:genetics; D008875:Middle Aged; D054353:Perforin; D052899:Pore Forming Cytotoxic Proteins / Q000097:blood / Q000235:genetics; D061026:Programmed Cell Death 1 Receptor; D011446:Prospective Studies; D012333:RNA, Messenger / Q000097:blood* / Q000378:metabolism; D014184:Transplantation, Homologous
D015703:Antigens, CD; D000943:Antigens, Differentiation; D000945:Antigens, Differentiation, T-Lymphocyte; D051017:Apoptosis Regulatory Proteins; D060908:CTLA-4 Antigen; C556706:CTLA4 protein, human; D053222:Fas Ligand Protein; C075005:GNLY protein, human; C556692:ICOS protein, human; D060889:Inducible T-Cell Co-Stimulator Protein; D008562:Membrane Glycoproteins; C105992:PDCD1 protein, human; D052899:Pore Forming Cytotoxic Proteins; D061026:Programmed Cell Death 1 Receptor; D012333:RNA, Messenger; D054353:Perforin; D023201:CD40 Ligand; D053804:Granzymes