When we stratified our cohort by day-care attendance rather than OM status, we found that the proportion of circulating NK cells, particularly activated CD107a+ cells, was also significantly higher in unstimulated PBMC from the 14 children attending day-care for ≥4h per week compared to the 25 children attending <4h of day-care per week (9.22% versus 5.90% NK cells in total lymphocytes; p<0.05, and 0.14% versus 0.02% CD107a+ NK cells in total lymphocytes; p<0.001). The gene discussed is LAMP1; the disease is ocular melanoma.