P0432GAMMA DELTA T-CELLS PHENOTYPIC PROFILE IN PATIENTS WITH IGA-NEPHROPATHY
Authors: Nizheharodava Darya , Komissarov Kirill , Pilotovich V , Zafranskaya Maryna 
Published: June 2020

Abstract

Background and Aims
γδТ-lymphocytes are enigmatic minor nonconventional peripheral blood cells population responded to non-peptidic antigens and displayed functional diversity, from effector action to immunoregulation, depending on pathological conditions. Although γδТ-lymphocytes are known to play a key role in chronic inflammation, their phenotype and functions in patients with chronic kidney diseases (CKD) are relatively unknown. The aim of this study was to investigate a surface phenotype of γδТ-lymphocytes in patients with IgA-nephropathy (IgAN) compared to systemic lupus erythematosus (SLE) and chronic glomerulonephritis (CG) due to focal-segmental glomerulosclerosis and minimal change disease patients.

Method
The peripheral blood was obtained from 23 CKD patients (13 IgAN, 5 SLE and 5 GN patients) aged of 32.0 (26.7 ÷ 36.0) y.o., male/female ratio as 12/11. The number of γδТ-lymphocytes was determined using monoclonal antibodies γδТCR-PC5, CD3-PC7 as well as phenotypic profile – with CD45RO-ECD and CD27-PE, CD314-PE (NKG2D), CD8-FITC, CD56-PC7 and CD16-ECD and TLR4-FITC using flow cytometry analysis (Cytoflex, «Beckman Coulter», USA). Statistical analysis was done using Statistica 8.0.

Results
The increased number of γδТ-cells in peripheral blood of IgAN patients (4.85 (4.13÷8.87)%) compared to SLE patients (3.31 (2.88÷3.48)%; p=0.001) and CG patients (1.14 (0.94÷3.15)%; p=0.03) was established. More than half of γδТ-cells in IgAN patients expressed central memory phenotype (γδТCR+CD45RO+: 50.2 (31.6÷61.3)%; γδТCR+CD27+: 58.7 (55.5÷61.8)%) enhancing phosphoantigen-dependent activation, survival, proliferation, and secretion of pro-inflammatory cytokines. Terminally differentiated effector memory γδТCR+CD45RO-CD27- phenotype of γδТ-cells was dominated in GC patients (γδТCR+CD45RO+: 25.7 (24.0÷27.5)%; γδТCR+CD27+: 43.3 (30.4÷56.2)%; р=0.05) regarded as “exhausted senescent” T cells with poor proliferation and severe functional abnormalities. The cytotoxic properties of γδТ-cells in IgAN patients are characterized with significantly higher expression of killer recognition receptor NKG2D (γδТCR+CD314+: 91.7 (51.7÷93.0)%) as well as true effector cytotoxic CD56+ marker (γδТCR+CD56+: 44.4 (27.2÷58.6)%) but not CD16 or CD8 antigens compared the both SLE and CG (р=0.05). Moreover, the number of γδТCR+CD314+ and γδТCR+CD56+ as well as γδТCR+CD45RO+ inversely correlated with glomerular filtration rate (R=-0.6, р=0.05). The increase of pattern recognition receptor TLR4 expression on γδТ-cells was reported in all groups of CKD patients suggested the activated state of γδТ-cells and their important role in the control of infection.

Conclusion
In IgAN patients the phenotypic profile of γδТ-lymphocytes is characterized as central memory γδТCR+CD45RO+CD27+ cells with increased cytotoxic potential (CD314highCD56highCD16lowCD8low) what is functionally differed from ones in SLE and GC patients. The inverse correlation of γδТ-cells phenotype profile with glomerular filtration rate suggests their pathological role and possible contribution to the initiation of autoimmune inflammation in IgAN patients.