['Rejection in renal transplantation is the most frequent event causing transplant failure. It is important to identify parameters to predict rejection, which are helpful in a timely fashion.', 'Fifty-nine renal transplant recipients were divided into two groups: group 1 (stable renal function) and group 2 (acute rejection episodes). The levels of HLA-A mRNA in peripheral blood lymphocytes (both pre- and posttransplantation) were measured by reverse transcriptase-polymerase chain reaction (RT-PCR) with glucose-6-phosphate dehydrogenase (G6PDH) as an internal reference. The TEST software was used to analyze the relative expressions of HLA-A mRNA.', 'There was no statistical significance between features of the two groups pretransplant versus normal controls. Posttransplant, the HLA-A mRNA levels decreased significantly compared to those of pretransplant and normal control individuals. The levels of HLA-A mRNA among the 10 patients with acute rejection episodes were significantly increased. There was no significant change in the lymphocyte populations in the early stage of an acute rejection episode compared with the prerejection value.'] Is lymphocytic HLA-A mRNA a reliable indicator of acute rejection in renal transplantation?