Lower Circulating Cytotoxic T-Cell Frequency and Higher Intragraft Granzyme-B Expression Are Associated with Inflammatory Interstitial Fibrosis and Tubular Atrophy in Renal Allograft Recipients

• Published in: Medicina (Kaunas, Lithuania) Vol. 59; no. 6; p. 1175
• Main Authors: Yadav, Brijesh, Prasad, Narayan, Agrawal, Vinita, Agarwal, Vikas, Jain, Manoj
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI AG 01.06.2023; MDPI
• Subjects: Allografts; Antibodies; Apoptosis; Atrophy; B cells; Biopsy; CD8-Positive T-Lymphocytes; Cell culture; Creatinine - metabolism; Cytokines; cytotoxic T lymphocyte; Cytotoxicity; Fibrosis; granzyme B; Granzymes - metabolism; Histopathology; Humans; Humidity; Inflammation; inflammatory interstitial fibrosis and tubular atrophy; Kidney Diseases - pathology; Kidney Transplantation - adverse effects; Kidney Tubules - metabolism; Kidney Tubules - pathology; Kidneys; Leukocytes, Mononuclear; Lymphocytes; Patients; Proteinuria; RNA; RNA, Messenger - genetics; RNA, Messenger - metabolism; stable graft function; T cells; T-Lymphocytes, Cytotoxic; Transplantation; California; St Louis Missouri; United States > US; granzyme B; cytotoxic T lymphocyte; inflammatory interstitial fibrosis and tubular atrophy; stable graft function
• ISSN: 1648-9144; 1010-660X; 1648-9144
• DOI: 10.3390/medicina59061175

Inflammatory interstitial fibrosis and tubular atrophy (i-IFTA) is an inflammation in the area of tubular atrophy and fibrosis. i-IFTA is poorly associated with graft outcome and associated with infiltration of inflammatory mononuclear cells. A cytotoxic T cell is a granzyme B CD8 CD3 T cell, mainly secret granzyme B. Granzyme B is a serine protease that may mediate allograft injury and inflammatory interstitial fibrosis and tubular atrophy (i-IFTA). However, there is no report identifying the association of granzyme B with i-IFTA after a long post-transplant interval. In this study, we have measured the cytotoxic T-cell frequency with flow cytometry, serum and PBMCs culture supernatants granzyme-B levels with ELISA and intragraft granzyme-B mRNA transcript expression with the RT-PCR in RTRs in 30 patients with biopsy-proven i-IFTA and 10 patients with stable graft function. The frequency of cytotoxic T cells (CD3 CD8 granzyme B ) in SGF vs. i-IFTA was (27.96 ± 4.86 vs. 23.19 ± 3.85%, = 0.011), the serum granzyme-B level was (100.82 ± 22.41 vs. 130.32 ± 46.60, = 0.038 pg/mL) and the intragraft granzyme-B mRNA transcript expression was (1.01 ± 0.048 vs. 2.10 ± 1.02, < 0.001 fold). The frequency of CD3 T cells in SGF vs. i-IFTA was (66.08 ± 6.8 vs. 65.18 ± 9.35%; = 0.68) and that of CD3 CD8 T cells was (37.29 ± 4.11 vs. 34.68 ± 5.43%; = 0.28), which were similar between the 2 groups. CTLc frequency was negatively correlated with urine proteinuria (r = -0.51, < 0.001), serum creatinine (r = -0.28, = 0.007) and eGFR (r = -0.28, = 0.037). Similarly, the PBMC culture supernatants granzyme-B level was negatively correlated with urine proteinuria (r = -0.37, < 0.001) and serum creatinine (r = -0.31, = 0.002), while the serum granzyme-B level (r = 0.343, = 0.001) and intragraft granzyme-B mRNA transcript expression (r = 0.38, < 0.001) were positively correlated with proteinuria. A decrease in the CTLc frequency in circulation and an increased serum granzyme-B level and intragraft granzyme-B mRNA expression shows that cytotoxic T cells may mediate the allograft injury in RTRs with i-IFTA by releasing granzyme B in serum and intragraft tissue.