Role of platelets in the modulation of kidney allograft recipients' immune systems

Microchimerism as Post-Transplant Marker of a Chronic Rejection Process

The risk of losing a transplanted organ is high, and non-invasive markers to warn of this phenomenon are still being sought. We investigated the impact of post-transplant microchimerism on the function of the transplanted kidney. The study included 100 kidney transplant recipients, mostly women. All transplanted organs were from opposite-sex deceased donors. Microchimerism was assessed using multiplex PCR. Male DNA was detected in all urine samples from female recipients and in 13/56 blood samples from female kidney recipients. Female DNA was found in 31/44 urine samples from male recipients, but in none of the blood samples. Microchimerism in the urine of female recipients correlated positively with blood urea (Rs = 0.45; p = 5.84 × 10^-4) and K⁺ ions (Rs = 0.29; p = 0.03), while microchimerism in the blood of female recipients also correlated positively with blood urea (Rs = 0. 28; p = 0.04), cystatin C (Rs = 0.31; p = 0.02) and the number of incompatible HLA alleles (Rs = 0.42; p = 0.01). A history of DGF was associated with higher urinary donor DNA concentrations in female recipients.: Post-transplant microchimerism may serve as a potential marker of chronic kidney rejection.

Correlation Between Stem and Progenitor Cells Number and Immune Response in Patients After Allogeneic Kidney Transplant

Background

Stem and progenitor cells are of great interest in all medical procedures involving tissue regeneration. There is a consensus that the use of stem cells after solid organ transplantation may play a role in tissue repair and in immunosuppression. The aim of this study was to determine possible relations between stem cell count and the immune response in a group of patients after kidney transplantation.

Material/Methods

The study was conducted on a group of 100 patients who underwent kidney transplantation. The following phenotypic markers of the studied cell subpopulations were adopted: T_reg cells (CD3⁺CD4⁺CD25^high), circulating hematopoietic cells (CD34⁺CD133⁺CD45⁺CD38⁻), and non-hematopoietic cells (Lin⁻CXCR4⁺CD133⁻CD45⁻). Cell subpopulations were assessed using LSRII flow cytometer (BD Biosciences, San Jose, CA, USA).

Results

Positive correlation was observed between non-hematopoietic stem cells percentage and recipient’s platelets count (P=0.04). Moreover, a higher percentage of non-hematopoietic cells was accompanied by lower numbers of B lymphocytes (P=0.03) and T_reg cells (P=0.02).

Conclusions

Our study revealed significant associations between the intensity of ongoing immune response processes and tissue damage, and the release of stem and progenitor cells into circulation. These findings suggest their role in the stimulation of protective processes in terms of graft regeneration.