HIVEP2-DT and ocular melanoma: Expression of PilA, the major subunit of the NTHI Tfp, is tightly regulated and influenced by environmental conditions, including pH (5) and even the subtle three-degree temperature difference between the site of asymptomatic colonization, the human nasopharynx (34°C), and the site of infection during OM, the middle ear (37°C) (9).