MO248P-GLYCOPROTEIN EXPRESSING IL-17A+IFN-GAMA+ TH17/1 CELLS ARE REFRACTORY TO GLUCOCORTICOID IN NEPHROTIC SYNDROME*

Abstract

Abstract Background and Aims Th17 cells are critical effectors mediating the autoimmunity in nephrotic syndrome (NS). Elevated IFN-γ has also been involved in NS; however, it remains unclear to what extent Th1 cells contribute to glucocorticoids resistance in NS. P-glycoprotein (P-gp) effluxes glucocorticoids outside the cells and selectively expressed differentially on T cell subtypes. In this study, we investigated the role of P-gp and cellular source of IFN-γ and assessed its contribution to glucocorticoids resistance in NS. Method We analyzed the frequency of pathogenic IL-17A+IFN-γ+ Th17/1 lymphocytes and P-gp expression on their surface by flow cytometry in SSNS (n = 32; mean age: 9.06 ± 5.84) and SRNS (n = 28; mean age: 11.29 ± 3.73) patients. We also included 15 age- and sex-matched healthy controls. All patients were of biopsy proven minimal change disease and all patients were treated with steroids. All patients were recruited as per the criteria of ISKDC. Results We found a significant IL-17A+IFN-γ+ Th17/1 population (P < 0.001) in steroid resistant NS (SRNS) as compared to steroid sensitive NS (SSNS) patients. IL-12 and IL-23 are significantly higher in SRNS as compared to SSNS patients which are require for transition of pathogenic Th17 cells to IFN-γ producers. Of the IL-17A+IFN-γ+ Th17/1 population 95.8% cells were expressed P-gp on their surface in SRNS; however only 30.1% cells expressed P-gp in SSNS group (Figure 1). We also observed that P-gp expression correlate positively with IL-17A+IFN-γ+ Th17/1 population (r= 0.739, p< 0.001) significantly. Conclusion The above findings clearly show that higher expression of P-gp on IL-17A+IFN-γ+ Th17/1 cells associated with steroid resistance in nephrotic syndrome through both IL-17A and IFN-γ.