CD8A and hydrops fetalis: Interferon (IFN)-γ-mediated upregulation of MHC class I and II antigen-presenting molecules is a key phenotypic change in HF-IP collapse, especially triggering CD8+ cytotoxic T lymphocytes cell-mediated autoimmune responses against follicular autoantigens associated with AA, such as tyrosinase-related protein, trichohyalin, melanoma antigen, retinol binding protein 4 (31, 40, 41).