Effects of NGF and CGRP_8-37 on HLA-DR expression. HLA-DR expression was measured by flow cytometry analysis in LPS-stimulated monocytes after 24 hours of treatement with anti-NGF antibodies, control IgG, and CGRP_8-37. NGF neutralization induces a significant increase in the specific HLA-DR immunoreactivity in LPS-stimulated monocytes, and a similar enhancement in HLA-DR expression was observed also in LPS-stimulated cells after CGRP_8-37 treatment. The data represent the mean of 6 independent experiments and the results were expressed as increments relative to the controls of ΔMFI plus or minus SEM (LPS+aNGF vs LPS+IgG, ^*P < .05; LPS+CGRP8-37 vs LPS, ^**P < .01 according to Tukey-Kramer test).