Activation of HIV in Human Skin by Ultraviolet B Radiation and its Inhibition by NFκB Blocking Agents

To determine whether ultraviolet B (UVB) irradiation leads to activation of HIV in human skin, we conducted prospective and controlled studies in two academic medical centers in Texas from July 1995 to April 1999. HIV-positive patients with UV-treatable skin diseases were enrolled at each center, 18 subjects at one and 16 at the other. In one center, specimens from lesional and nonlesional skin biopsies were taken before and after sham- or UVB-irradiation administered in vivo or in vitro. In the other center, UVB phototherapy was administered three times weekly and specimens from skin biopsies were taken before and after 2 weeks (six treatments). Cutaneous HIV load was assessed using reverse transcriptase-polymerase chain reaction and reverse transcriptase-polymerase chain reaction in situ hybridization. UVB irradiation led to a 6–10-fold increase in the number of HIV in skin. To ascertain a role for nuclear factor kappa B (NFκB) in UVB-inducible HIV activation, two types of blockers, NFκB oligonucleotide decoy and sodium salicylate, were tested; each inhibited UVB-inducible HIV activation in skin partially. We conclude that UVB irradiation leads to increased numbers of HIV in human skin via processes that include release of cytoplasmic NFκB.