Interleukin-6, interleukin-8, and interleukin-10 in kidney transplantation: improved risk strategy?

Multicolor Flow Cytometry and Cytokine Analysis Provides Enhanced Information on Kidney Transplant Biopsies

Introduction

Current processing of renal biopsy samples provides limited information about immune mechanisms causing kidney injury and disease activity. We used flow cytometry with transplanted kidney biopsy samples to provide more information on the immune status of the kidney.

Methods

To enhance the information available from a biopsy, we developed a technique for reducing a fraction of a renal biopsy sample to single cells for multicolor flow cytometry and quantitation of secreted cytokines present within the biopsy sample. As proof of concept, we used our technique with transplant kidney biopsy samples to provide examples of clinically relevant immune information obtainable with cytometry.

Results

A ratio of CD8⁺ to CD4⁺ lymphocytes greater than or equal to 1.2 in transplanted allografts is associated with rejection, even before it is apparent by microscopy. Elevated numbers of CD45 leukocytes and higher levels of interleukin (IL)−6, IL-8, and IL-10 indicate more severe injury. Antibody binding to renal microvascular endothelial cells can be measured and corresponds to antibody-mediated forms of allograft rejection. Eculizumab binding to endothelial cells suggests complement activation, which may be independent of bound antibody. We compared intrarenal leukocyte subsets and activation states to those of peripheral blood from the same donor at the time of biopsy and found significant differences; thus the need for new techniques to evaluate immune responses within the kidney.

Conclusion

Assessment of leukocyte subsets, renal microvascular endothelial properties, and measurement of cytokines within a renal biopsy by flow cytometry enhance understanding of pathogenesis, indicate disease activity, and identify potential targets for therapy.

Association between IL-6 -174G/C polymorphism and acute rejection of renal allograft: evidence from a meta-analysis

BACKGROUND

Results from published studies on the association of donor or recipient IL-6 -174G/C (rs1800795) polymorphism with acute rejection (AR) of renal allograft are conflicting. We performed a meta-analysis to estimate the possible association.

METHODS

Studies were identified by searching PUBMED and EMBASE until July 1, 2011. Meta-analysis was performed in a fixed/random effects model using Revman 5.0.25 and STATA10.0.

RESULTS

Seven studies addressing the association between donor high producer genotype (G/G and G/C) of IL-6 -174G/C polymorphism and acute rejection of renal allograft were identified. Pooled OR based on 341 cases (whose recipient developed acute rejection) and 702 controls (whose recipient did not develop acute rejection) was 0.59 (95% CI, 0.26-1.33; p=0.20), with a strong between-study heterogeneity. No association was observed in the subgroup analysis based on ethnicity. 13 studies evaluating the association between recipient IL-6 -174G/C polymorphism and acute rejection were identified. Pooled OR based on 451 cases (patients did not develop acute rejection) and 848 controls was 1.00 (95% CI=0.72-1.37; p=0.98), with a weak between-study heterogeneity.

CONCLUSIONS

Donor high producer genotype (G/G and G/C) of IL-6 -174G/C polymorphism had a tendency of decreased risk for acute rejection, although it was not statistically significant. Recipient high producer genotype was not associated with acute rejection of renal allograft. Additional well designed studies with larger sample size are needed to support our findings, especially for the association between donor high producer genotype (G/G and G/C) of IL-6 -174G/C polymorphism and acute renal allograft rejection.