Phenotypic and Transcriptomic Lymphocytes Changes in Allograft Recipients After Intravenous Immunoglobulin Therapy in Kidney Transplant Recipients

Abstract

High dose intravenous immunoglobulin (IVIG) are widely used after kidney transplantation and its biological effect on T and B cell phenotype in the context of maintenance immunosuppression was not documented yet. We designed a monocentric prospective cohort study of kidney allograft recipients with anti-HLA donor specific antibodies (DSA) without acute rejection on screening biopsies treated with prophylactic high-dose IVIG (2 g/kg) monthly for 2 months. Any previous treatment with Rituximab was an exclusion criterion. We performed an extensive analysis of phenotypic and transcriptomic T and B lymphocytes changes and serum cytokines after treatment (day 60). Twelve kidney transplant recipients who completed at least two courses of high-dose IVIG (2 g/kg) were included in a median time of 45 (12-132) months after transplant. Anti-HLA DSA characteristics were similar before and after treatment. At D60, PBMC population distribution was similar to the day before the first infusion. CD8⁺ CD45RA⁺ T cells and naïve B-cells (Bm2⁺) decreased (P = 0.03 and P = 0.012, respectively) whereas Bm1 (mature B-cells) increased (P = 0.004). RORγt serum mRNA transcription factor and CD3 serum mRNA increased 60 days after IVIG (P = 0.02 for both). Among the 25 cytokines tested, only IL-18 serum concentration significantly decreased at D60 (P = 0.03). In conclusion, high dose IVIG induced limited B cell and T cell phenotype modifications that could lead to anti-HLA DSA decrease. However, no clinical effect has been isolated and the real benefit of prophylactic use of IVIG after kidney transplantation merits to be questioned.

Keywords: donor specific antibodies; high-dose intravenous immunoglobulin; immunomodulation; kidney transplantation; lymphocytes phenotype.

Figure 1

PBMC cells phenotypic analysis. (A) Kinetic of CD3⁺, CD19⁺, CD14⁺, CD56⁺, and CD3⁺CD56⁺ proportion throughout IVIG treatment. Box plot represent % of positive cells with 5–95% Whiskers. (B) B-cell population analysis. On the left, representative dot plots of B cells using the Bm1-5 classification based on CD38 and IgD expression. Gating strategies is shown. On the right % of Bm1 B cells (blanked) vs. % of Bm2 B cells (dark gray) at day 0, 30, and 60. Box plot represent % of positive cells with 5–95% Whiskers. Results were compared with Wilcoxon signed rank test. (C) CD45RA and CD45RO analysis in CD4 and CD8 cells. On the left, % of CD45RA (blanked) vs. % of CD45RO (dark gray) in CD4⁺ cells. On the right, % of CD45RA (blanked) vs. % of CD45RO (dark gray) in CD8⁺ cells. Box plot represent % of positive cells with 5–95% Whiskers. Results were compared with Wilcoxon signed rank test.

Figure 2

Serum cytokines multiplex analysis. IFNγ, IL-1R1A, IL-18, IL-7, and TNFα concentration (pg/mL) detected in patient throughout the treatment, on day 0, 30, and 60. Only IL-18 serum concentration significantly decreased at D60 (P = 0.03). Results were compared with Wilcoxon signed rank test.