MICA and Hyperkeratosis: With the exception of an early report, which found weight loss, hyperkeratosis, and increased white blood cell numbers in mice ubiquitously expressing MICB (71), studies involving transgenic expression of MICA, RAE-1, or H60a have shown effects limited to downregulation of NKG2D expression, impaired NKG2D-dependent NK cell and CD8+ T cell functions, and decreased MHC class I expression (15, 61, 65, 72–76), with limited effects on immune responses.