STAT3 and hyperinsulinemic hypoglycemia, familial, 4: Severe cutaneous viral infection occurs less commonly than in DOCK8 deficiency, though reactivation of zoster, frequently with disease limited to a single dermatome, occurs in one-third of individuals at a relatively young age; poor immunological memory to varicella may arise from impaired populations of memory CD8 + cytotoxic lymphocytes, which rely on STAT3-dependent IL-10 and IL-21 signaling [60–62].