Dispase is a bacterial neutral protease which is obtained from the culture filtrate of Bacillus polymyxa. After 24-h treatment of the human skin with 500 and 1000 U/ml dispase, the epidermal sheet was easily peeled from the dermis, and its undersurface retained rete ridges. Electron microscopic observation showed that the basal surface was composed of cells with numerous slender villi and cytoplasmic projections. Although the intercellular spaces of the spinous as well as the basal layers were wide, all desmosomes were intact with their accompanying tonofilaments. An epidermal cell suspension was obtained by incubating the dispase-separated epidermal sheet in trypsin solution for 15 min and the viability of the cells was more than 95% as measured by the trypan blue dye exclusion test. A culture of keratinocytes was established by seeding the dissociated cells in the usual way.

Active forms of vitamin D3, 1 alpha-hydroxyvitamin D3 and 1 alpha,25-dihydroxyvitamin D3, were administered in an open-design study to 40 patients with psoriasis vulgaris in three ways: to 17 patients 1 alpha-hydroxyvitamin D3 was given orally at a dose of 1.0 micrograms/day for 6 months, to four patients 1 alpha,25-dihydroxyvitamin D3 was given orally at a dose of 0.5 microgram/day for 6 months, and 19 patients were given 1 alpha,25-dihydroxyvitamin D3 applied topically at concentration of 0.5 microgram/g of base for 8 weeks. Improvement was observed at the end of the individual study periods in 13 (76%) patients in Group 1 with a mean period of treatment (+/- SD) of 2.7 +/- 0.6 months, in one patient in Group 2 at 3 months after the start of treatment, and in 16 (84%) patients in Group 3 when the chemical was applied for 3.3 +/- 1.2 weeks. No side-effects were observed in any of these trials. These data suggest that psoriasis may respond to active metabolites of vitamin D3 and that abnormalities in vitamin D metabolism or in responsiveness of the skin cells to active metabolites of vitamin D may be involved in the pathogenesis of this skin disease.

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The effects of topical administration of 1,25-dihydroxyvitamin D3, as 0.1 and 0.5 microgram per g base, and control base applied to contralateral skin lesions in five patients with persistent psoriasis were compared. In all five, definite and in some cases remarkable improvement of the lesions was seen when 1,25-dihydroxyvitamin D3 at concentration of 0.5 microgram per g base was applied for two to five weeks. No local or systemic toxicity was detected in any patient. Although the mechanism of the improvement is yet to be elucidated, these results show the possible effectiveness of topical 1,25-dihydroxyvitamin D3 on psoriatic skin lesions.

An immediate reaction was investigated during repeated challenge testing for contact hypersensitivity to dinitrofluorobenzene (DNFB) in BALB/c mice. The mice were sensitized to DNFB on back skin and repeatedly challenged with the same hapten on the left ear at 1 week intervals. The ear after the 5th challenge showed biphasic responses which consisted of an immediate and a delayed-type reaction. The reactions were hapten specific. Mast cell-deficient WBB6F1 W/WV mice did not show any immediate reaction, while congenic normal mice showed both immediate and delayed-type reactions. Histologically, numerous dermal mast cells were found in the left ear of repeatedly challenged BALB/c and WBB6F1 normal mice, while there were few mast cells in the ear of WBB6F1 W/WV mice. Anti-DNP IgE antibodies were detected in BALB/c, WBB6F1 normal and W/WV mice after repeated challenge with DNFB. Intradermal injection of anti-IgE antibodies in the repeatedly DNFB-challenged ear elicited an immediate reaction. These results suggest that immediate contact hypersensitivity develops through the production of anti-DNP IgE antibodies and an increase in dermal mast cells after repeated challenge with DNFB.

Thirty cases of X-linked ichthyosis (XLI) and 32 cases of ichthyosis vulgaris (IV) were diagnosed by measuring the steroid sulphatase activity of peripheral blood lymphocytes or the electrophoretic mobility of serum LDL or both. The clinical features of the two conditions were then compared. In both diseases 60-66% of patients had a family history of the condition. Ichthyosis was noted at birth or immediately afterwards in 59% of the patients with XLI while it appeared in infancy in 68% of those with IV. Scales were mostly large and brown or dark brown in patients with XLI, while the majority of patients with IV had small brown or light brown scales. The distribution of the ichthyotic lesions differed in the two types of ichthyosis. On the trunk, the abdomen was more severely involved than the back in 63% of the cases with the XLI, whereas the back was more scaly than the abdomen in 44% of those with IV. On the extremities, the extensor surface was more severely affected than the flexor surface in both types. X-linked ichthyosis was characterized by the presence of lesions in the pre-auricular area, which were found in 93% of the cases with XLI, while only 17% of the IV patients had ichthyotic lesions at this site. Involvement of the preauricular area could be an important clinical feature for distinguishing XLI from IV.

Virological studies were performed on 12 patients with epidermodysplasia verruciformis (EV). Three types of lesions were observed: red plaques, pityriasis versicolor (PV)-like macules and plane warts. Human papillomavirus (HPV) 14, 20 and 21 were isolated from the plaques, HPV 3, 14 and 38 from flat warts and HPV 5, 12, 17, 20 and 38 from PV-like lesions. No clear relationship could be established between the different lesions and the types of HPV. Types 17 and 20 have been isolated most frequently from Japanese EV patients and HPV 5, frequently detected in other countries, is less common, whereas HPV 8 has not been isolated. Skin cancers occurred in six of the cases (50%) and all had benign lesions that were PV-like. At least one type of HPV 5, 17 or 20 could be isolated from these benign lesions and HPV 17 or 20 detected in the cancers. These three types of HPV in EV patients appear to be involved in the malignant transformation.