Changes in T and B cell subsets in end stage renal disease patients before and after kidney transplantation

The incidence of kidney transplantation performed in elderly patients has increased steadily recently. Higher risk of infection and mortality, but lower rate of rejection, are reported in older kidney transplant patients. This study aims to analyze the effect of transplantation on aging of T and B cells in kidney transplant patients, with the emphasis on age and Cytomegalovirus (CMV) latency.

We included 36 patients before and after (median 2.7 years) kidney transplantation and 27 age- and sex-matched healthy controls (HC). T and B cell subsets were measured by flow cytometry, with a focus on aged T cells (CD28-), and age associated B cells (ABCs, CD19 + CD21-CD11c+). Three years after transplantation a significant increase of total T cells among the lymphocytes was found compared to pre-transplantation and HC. Among the T cells CD4+ cells were decreased, especially naïve CD4+ cells and regulatory T cells. Total CD8+ cell proportions were increased, and proportions of naïve CD8+ cells were significantly decreased after transplantation, while CD8+ effector memory T cells re-expressing CD45RA were increased. CD28- T cells were significantly higher compared to HC after transplantation, especially in CMV seropositive patients. B cells were significantly decreased, while among B cells memory B cells and especially ABCs were increased after transplantation.

After transplantation T and B cell subsets change towards more terminally differentiated memory cells compared to age-matched HC. Proportions of aged T cells and ABCs were associated with CMV serostatus.