Major histocompatibility complex class I loss due to the abnormality of β2-microglobulin gene is one of the mechanisms underlying delayed relapses in melanoma patients long after the initial positive responses to anti-PD-1 therapy.
We studied cytokine profile of cellular Th1 (IL-2, IL-12, IFN-γ) and humoral Th2 (IL-4, IL-10) immune response, vascular endothelial growth factor (VEGFA), transforming growth factor-β 2 (TGF-β 2), S100 protein (S100A1B and S100BB), adhesion molecule CD44 and serum cytokines β2-microglobulin to analyze different peripheral blood mononuclear cell subpopuations of patients treated with dendritic vaccines and/or cyclophosphamide in melanoma patients in the course of adjuvant treatment.
APM component expression correlated with melanoma Breslow's thickness and SLN metastases: HLA-A,B,C level was significantly lower in SLN LCs from thick lesions patients compared with those from thin/intermediate lesions (p<0.05); β2-microglobulin level was significantly higher in positive SLN LCs compared to negative ones (p<0.05).
The coincidence of chromosome 15 aberrations and beta2-microglobulin gene mutations is causative for the total loss of human leukocyte antigen class I expression in melanoma.
beta 2-Microglobulin (beta 2-mu) gene-null human melanoma FO-1 cells display lower reactivity with anti-HLA class I monoclonal antibodies (mAb) following transfection with a wild-type mouse beta 2-mu gene (referred to as FO-1C cells) than following transfection with a wild-type human beta 2-mu gene (referred to as FO-1H cells).
We report that human leukocyte interferon preparations increase the expression of beta 2-microglobulin by 100-200% on the surface of normal fibroblast and melanoma cell lines sensitive to interferon.