Figure 1

The high-risk rs3129882 GG genotype is associated with an increased level of major histocompatibility complex class II (MHC-II) expression in B cells and monocytes and with increased inducibility of surface HLA-DQ expression. (a) Frequency of HLA-DR/DQ double positive, (b) average level of HLA-DR expression, and (c) average level of HLA-DQ expression in B cells and monocytes was determined by flow cytometry staining of total peripheral blood mononuclear cells. One-tailed Student’s t-test between high-risk and low-risk allele groups was used to test for significance. *P<0.05. HLA-DR median fluorescence intensity (MFI): CTRL AA versus CTRL GG B cells t(33)=2.28, P<0.05; monocytes t(34)=2.14, P<0.05. HLA-DQ MFI CTRL AA versus CTRL GG B cells t(28) =1.76, P<0.05; PD AA versus PD GG t(35)=1.82, P<0.05. Surface MHC-II expression in paramagnetically, positively sorted monocytes stimulated with various concentrations of interferon-γ (IFN-γ) was measured by flow cytometry staining to measure increase in (d) frequency of HLA-DR/DQ double-positive cells, (e) level of HLA-DR expression, and (f) level of HLA-DQ expression. Two-way analysis of variance was performed to test for significance between GG and AA groups. ***P<0.001. (d) PD GG versus PD AA F(1,190)=11.97, P<0.001. (f) CTRL GG versus CTRL AA F(1, 163)=10.39, P<0.001. Inset for DQ MFI (f) panel shows sorted monocytes from PD patients stimulated with 1,000 U/ml IFN-γ. One-tailed t-test was performed for significance. t(31)=1.52, P=0.05. PD, Parkinson’s disease.