Artificial reproduction of atypical hydRoa vacciniforme caused by latent EpStein-Barr virus infection

BACKGROUND

Cases of hydroa vacciniforme-like eruptions caused by latent Epstein-Barr virus (EBV) infection have been reported in Asia and Mexico, some of which progressed to lymphoproliferative disorders. The precise clinical features of the disease are not, however, clear.

METHODS

We performed an artificial provocation test with repeated exposures of ultraviolet A (UVA) and UVB in an 8-year-old Korean girl who had severe hydroa vacciniforme-like skin eruptions on exposed areas.

RESULTS

The patient showed features of latent EBV infection serologically, and an in situ hybridization study indicated that most infiltrating mononuclear cells in the dermis were positive for EBV. After three exposures to UVA irradiation with a total dose of 90 J/cm2, erythema and vesicles appeared on the UVA-irradiated site but not on the UVB-irradiated site.

CONCLUSIONS

Atypical hydroa vacciniforme caused by latent EBV infection could be reproduced by repeated UVA irradiation. Further study on the photo-protection would be necessary to prevent its progression to lymphoproliferative malignancies.

Pefloxacin and ciprofloxacin increase UVA-induced edema and immune suppression

BACKGROUND

Quinolone antibiotics are popularly prescribed antibiotics because of their wide antibacterial spectrum and lowered bacterial resistance. Quinolone antibiotics are one of the well-known photosensitizers that induce phototoxicity. Their role in photocarcinogenesis has been suggested in some studies.

MATERIAL AND METHODS

Mice were treated with two quinolone antibiotics (ciprofloxacin, which is less phototoxic, and pefloxacin, which is more phototoxic) to study the effect of the antibiotics on sunburn and immune suppression by ultraviolet A (UVA) irradiation. The effects of a combined treatment with UVA and these quinolone antibiotics were measured on back skin swellings, sunburn cell formations, depletion of epidermal Langerhans cells, and local and systemic suppression of contact hypersensitivity.

RESULTS

Mice treated with both UVA and quinolone showed significantly increased back skin swellings and decreased epidermal Langerhans cells than mice treated with UVA only. Sunburn cells were increased significantly in mice treated with pefloxacin and 50 J/cm2 of UVA. Combination of pefloxacin and UVA suppressed local contact hypersensitivity significantly, but not systemic contact hypersensitivity.

CONCLUSION

Phototoxic quinolones augmented the effect of UVA by increasing sunburn and apoptosis, depleting Langerhans cells and suppressing local immune response. By affecting apoptosis and immune suppression, they may facilitate photocarcinogenesis caused by UVA.

Increased phototoxicity of hydrochlorothiazide by photodegradation

The photodegradation products of hydrochlorothiazide produced by ultraviolet (UV) radiation were investigated for their phototoxicity utilizing the photohemolysis and Candida albicans tests. Hydrochlorothiazide was irradiated for 30, 60, 90 and 120 min with a 250 W xenon arc lamp using a WG295 cut-off filter. Irradiation of hydrochlorothiazide resulted in the gradual decrease of all three absorption bands (225, 270 and 320 nm), the blue shift of the 225 nm band, and the appearance of a new band around 290 nm. Since previous results demonstrated that photosubstitution of chloride could occur, the main product of this photolysis most likely is ethoxyhydrochlorothiazide. The photohemolysis test revealed a significant increase in photohemolysis observed in the photodegradation products produced after 60, 90 and 120 min of UV irradiation. This increase in hemolysis value directly correlated with the UV-irradiation time. However, there was no significant phototoxic killing of yeast in the Candida albicans test. This suggests photodegradation products of hydrochlorothiazide may play an important role in phototoxicity by acting on the cell membrane, but not on DNA. Considering the high in vitro phototoxicity observed in bendroflumethiazide and the data presented here, substitution of chloride seems to be responsible for the increased phototoxicity of hydrochlorothiazide.