Performance and Advancement of the Kidney Solid Organ Response Test

BACKGROUND

The kidney solid organ response test (kSORT) has been investigated for the prediction of acute rejection in kidney transplant recipients with conflicting results. We aimed to investigate if the kSORT assay score is associated with rejection or immune quiescence.

METHODS

The blinded association between rejection and kSORT > 9 were investigated. Optimization of kSORT prediction was evaluated after unblinding to determine the optimal prediction cutoff value of kSORT score. Additionally, the predictive capability of the kSORT gene set was assessed using blinded normalized gene expression data from microarray (Affymetrix) and qPCR assays.

RESULTS

Of the 95 blood samples analyzed, 18 patients had blood samples before transplant, 77 patients after transplant and 71 had clinically indicated biopsies of which 15 biopsies showed acute rejection and 16 showed chronic active antibody-mediated rejection. When 31 patients with rejection were compared to the remaining 64 patients, positive predictive value (PPV) was 54.29% and negative predictive value (NPV) was 75% when stratified using a kSORT score > 9, and PPV was 57.89% and NPV was 78.95% when stratified using a kSORT score > 5. Using the kSORT assay for detection of rejection showed an area under the curve value of 0.71. Microarray data improved prediction accuracy with PPV of 53% and NPV of 84% compared to qPCR results (PPV and NPV were 36% and 66%), respectively.

CONCLUSIONS

The kSORT assay has the potential to be used as a predictive tool for active rejection and/or immune quiescence, but additional studies will be useful in improving and refining the kSORT assay, in particular the prediction algorithm.

Diffuse large-cell lymphoma of B-cell origin and deficient T-cell function in a patient with rheumatoid arthritis

An increased incidence of non-Hodgkin's lymphoma has been described in patients with rheumatoid arthritis. Mechanisms related to abnormal immune regulation have been postulated, but no patients with rheumatoid arthritis and lymphoma have been previously well characterized immunologically. We describe here a patient with long-standing rheumatoid arthritis in whom a B-cell diffuse large-cell lymphoma developed. He was found to have a severe T-cell immunodeficiency and evidence of persistent Epstein-Barr virus infection. Epstein-Barr nuclear antigen was not found to be present within lymphoma cells. The combination of defective T-cell function and persistent Epstein-Barr virus infection may have predisposed this patient with rheumatoid arthritis to the development of a malignant clone of B lymphocytes.

Serum gamma-glutamyl transpeptidase: its specificity and clinical value

The clinical import of the serum gamma-glutamyl transpeptidase (GGTP) level was evaluted in 162 prospectively studied patients. GGTP is helpful in determining the origin of alkaline phosphatase (AP); it clearly separates increased AP of bone and placental origin from that of liver origin. The GGTP level closely parallels the AP level in most instances, but it may be more sensitive in detecting liver disease in anicteric patients. The finding of significantly increased GGTP in patients with chronic aggressive hepatitis as compared to normal levels found in chronic persistent hepatitis may provide a prognostic clue in cases of unresolved hepatitis. The apparent specificity and sensitivity of the GGTP test, combined with ease of performance and low expense, make it a valuable addition to the evaluation of a patient with hepatic disease.