The Expression And Significance Of TLR9and BAFF In IgA Nephropathy

Background:IgA nephropathy is the most common primary glomerular diseases,characterized by predominant IgA deposits in the renal mesangium, accounting for20-47%of primary glomerular diseases. Up to15-40%of IgAN patients developing end-stage renal failure (ESRF) within10-20years. However,the precise mechanism is not elucidated at present.In recent years, most investigations show that polyIgA1were the main component of immunoglobulin which deposited on IgA nephropathy glomerular, but the formation mechanism of poly IgAl is not clear.BAFF(B cellactivating factor, also known as B lymphocyte Stimulator, BLyS) is a new member of tumor necrosis factor ligand family which found in1999. It is closely related with autoimmune diseases.BAFF is mainly expressed in bone marrow-derived cells such as macrophages and dendritic cells. Interferon gamma(IFN-gamma) and leukocyte interleukin10(IL-10) can up-regulate Secretion of BAFF.BAFF is a mainly immune regulatory factors of B cell proliferation、differentiation and secretion of immunoglobulin. Many studies show that the CPG-ODN can upregulate the expression of BAFF.The CPG-ODN may be combination with TLR9, and then myeloid cells can increase secretion of IL-12, IL-18, IFN-α, thus contributing to secretion of IFN-y which can increase the secretion of BAFF.So BAFF to promote the proliferation of B cells and antibody secretion. In recent years,many study concerned on the role of BAFF in IgA nephropathy, the study found that IgA nephropathy tonsil mononuclear cells which stimulated by IFN-gamma in vitro can increase secretion of BAFF. But there are less investigation of the expression of TLR9and BAFF on IgA nephropathy peripheral blood mononuclear cells.In this study,we will investigate peripheral blood mononuclear cells TLR9mRNA and protein levels、plasma BAFF and IgAl level in IgA nephropathy. To clarify the involvement of TLR9and BAFF in the pathogenesis of IgA nephropathy.So these reseachs can provide clues to furtherreveal the mechanismof IgA nephropathy, and to explore their clinical value.Objective:(1) To observe plasma BAFF and IgAl levels in IgAN; To explore correlation of BAFF and serum IgA1、the intensity kidney IgA deposition and the intensity of hematuria.(2) To observe the expression of TLR9in peripheral blood mononuclear cells in IgAN. To analysis correlation of TLR9and IgA1、BAFF.Methods:(1)Collected peripheral blood of IgAN patients(30cases), glomerular minor lesion patients(15cases), normal human(15cases).(2) Isolated peripheral blood mononuclear cells、plasma of three groups patients,and extracted mRNA and protein.(3) BAFF and IgAl levels in plasma of IgAN patient were measured in enzyme-linked immunosorbent assay(ELISA).(4)Expression of TLR9mRNA were examined by Reverse Transcription Real-time PCR.(5) Expression of TLR9protein were examined by western-blot.Results:(1) Compared to glomerular minor lesion group、normal human group, BAFF production significantly increased in IgAN patients (P<0.05, P<0.01).(2) Compared to glomerular minor lesion group、 normal human group, IgA1production significantly increased in IgAN patients (P<0.01;P<0.01).(3) Expression of TLR9mRNA in peripheral blood mononuclear cells in IgAN patients compared to minimal glomerular change patients group、normal human group,the difference is no significant (P>0.05)(4)Expression of TLR9protein in peripheral blood mononuclear cells in IgAN patients compared to minimal glomerular change patients group、normal human group,the difference is significant (p<0.05,p<0.01);(5) In IgA nephropathy group, there are positive correlation between the TLR9protein expression and serum BAFF expression serum IgAl expression (p<0.05, p<0.01).(6) In IgA nephropathy group, there are positive correlation between plasma BAFF and the strength of the kidney IgA deposition (p<0.01, p<0.01), but no relation with hematuria (P>0.05);and there are no relation between IgA1expression and hematuria (P>0.05)Conclusion:In this research, it reveals that expression of TLR9 protein in peripheral blood mononuclear cells and BAFF production in plasma significantly increased in IgAN, it may relate to hyperproduction of IgAl in peripheral blood mononuclear cells in IgAN.