Elevation of Vδ1 T cells in peripheral blood and livers of patients with primary biliary cholangitis

Abstract

Primary biliary cholangitis (PBC), hitherto called primary biliary cirrhosis, is a cholestatic liver disease of unclear aetiology with autoimmune features. Accumulating evidence revealed that γδ T cells were involved in the development of autoimmune diseases. As one of γδ T cells subsets, however, the role of Vδ1 T cells in the immunopathogenesis of PBC is poorly understood. We analysed peripheral blood Vδ1 T cells in PBC patients in active stage (ASP, n = 18), adequate responders (AR, n = 10) and inadequate responders (IAR, n = 4) to ursodeoxycholic acid (UDCA) and an age-matched healthy control group (n = 16) by flow cytometric analysis. The ASP group exhibited a significantly higher proportion and absolute number of Vδ1 T cells, which were also observed in immunofluorescence staining of liver biopsy specimens of PBC patients. Moreover, these Vδ1 T cells expressed a series of activation markers and intracellular cytokines, which may contribute to the immunopathogenesis of PBC. Our study will help to clarify the role of Vδ1 T cells in the development of PBC.

Keywords: Vδ1 T cells; autoimmune disease; primary biliary cholangitis; γδ T cells.

Figure 1

Increased Vδ1 T cells and decreased Vδ2 T cells in peripheral blood of active stage patients (ASP). (a), Comparison of the frequencies and absolute numbers of total circulating γδ T cells in ASP (n = 18), adequate responders (AR) (n = 10), inadequate responders (IAR) (n = 4) and healthy controls (HC) (n = 16) with representative plots of flow cytometry for each group in the left panel and scatter‐plot in the right panel. (b,c) Comparison of the percentages and Vδ1, Vδ2 T cell counts in ASP, AR, IAR and HC groups with representative plots of flow cytometry for each group in the left panel and scatter‐plot in the right panel. (d) In ASP, the Vδ1⁺/Vδ2⁺ T cell ratio is greater than that in either AR or HC. *P < 0·05; **P < 0·01; ***P < 0·001. [Colour figure can be viewed at wileyonlinelibrary.com]

Figure 2

Increased percentages of human leucocyte antigen D‐related (HLA‐DR)⁺ Vδ1, CD69⁺ Vδ1 and CD38⁺ Vδ1 T cells in peripheral blood of active stage (ASP) groups. (a–c) Percentages of CD3⁺ Vδ1 T cell cells from ASP (n = 18), adequate responders (AR) (n = 10), inadequate responders (IAR) (n = 4) and healthy controls (HC) (n = 16) were compared with regard to activation markers HLA‐DR (a), CD69 (b) and CD38 (c). Representative plots of flow cytometry for HLA‐DR⁺ Vδ1, CD69⁺ Vδ1 and CD38⁺ Vδ1 T cells in each group are shown in the left panel and the scatter‐plots are shown in the right panel. *P < 0·05; **P < 0·01. [Colour figure can be viewed at wileyonlinelibrary.com]

Figure 3

High expression of tumour necrosis factor (TNF)‐α, interferon (IFN)‐γ, granzyme A (GA) and granzyme B (GB) in Vδ1 T cells in peripheral blood of active stage (ASP) groups. (a–d) Percentages of CD3⁺ Vδ1 T cell cells from ASP (n = 18), active responder (AR) (n = 10), inactive responder (IAR) (n = 4) and healthy control (HC) (n = 16) groups were compared with regard to the intracellular expressions of TNF‐α (a), IFN‐γ (b), GA (c) and GB (d). Representative plots of flow cytometry for TNF‐α⁺, IFN‐γ⁺, GA⁺ and GB⁺ Vδ1 T cells in each group are shown in the left panel and the scatter‐plots are shown in the right panel. **P < 0·01. [Colour figure can be viewed at wileyonlinelibrary.com]

Figure 4

Increased percentages of CD3⁺ Vδ1 T cells in liver biopsy specimens from the active stage (ASP) group. (a) Representative images of haematoxylin and eosin (H&E) staining for liver fine‐needle aspiration biopsy (FNAB) specimens from primary biliary cholangitis (PBC) patients. Stage II PBC showed interface hepatitis and some ductular proliferation. Stage III PBC was marked by a loss of primary bile ducts, bridging necrosis and bridging fibrosis. (b) CD3 (red fluorescence) and Vδ1 T cell receptor (TCR) (green fluorescence) were co‐localized in positive control specimens and aggregated around glands of appendiceal mucosa. Compared with control liver specimens in the hepatic sinusoids (c) and portal areas (e), more CD3⁺ Vδ1 T cells were observed scattered in the hepatic sinusoids (d) and portal areas (f). Magnification ×40. (g) The histogram revealed a significantly increased number of CD3 ⁺ Vδ1 T cells than control livers. Control: n = 3, ASP: n = 5; *P < 0·05. [Colour figure can be viewed at wileyonlinelibrary.com]