Prevention of Immunosuppression by Sunscreens in Humans Is Unrelated to Protection from Erythema and Dependent on Protection from Ultraviolet A in the Face of Constant Ultraviolet B Protection

Sunscreens have been advocated as an important means of preventing skin cancer. Ultraviolet radiation induced immunosuppression is recognized as an important event in skin cancer development, yet the effectiveness of sunscreens in protecting the human immune system from ultraviolet radiation (i.e. ultraviolet radiation) is still unclear. The only currently accepted method of sunscreen rating is the sun protection factor system based on the prevention of erythema. We determined immune protection factors for six commercially available sunscreens using a nickel contact hypersensitivity model in humans. Both sun protection factor and immune protection factor testing was performed using the same solar simulated ultraviolet radiation source and dose–responses were used to determine endpoints both with and without sunscreens. We found that the immune protection factor did not correlate with the sun protection factor; however, immune protection factor was significantly correlated to the ultraviolet A protective capability of the sunscreens, indicating that sunscreen protection from ultraviolet A is important for the prevention of ultraviolet immunosuppression, when there is constant ultraviolet B protection. We recommend that sunscreens should be rated against their immune protective capability to provide a better indication of their ability to protect against skin cancer

Psoriasis vulgaris flare during efalizumab therapy does not preclude future use: a case series

BACKGROUND: Severe psoriasis vulgaris can be extremely difficult to treat in some patients, even with the newer biological therapies available today. CASE PRESENTATIONS: We present two patients with severe chronic plaque psoriasis who received numerous systemic anti-psoriatic therapies with varied results. Both responded well to initial treatment with efalizumab (anti-CD11a), but then experienced a flare of their disease after missing a dose. However, after disease stablization, both patients responded well to re-introduction of efalizumab, one patient requiring concurrent treatment with infliximab (anti-TNF-α). CONCLUSION: These cases are presented to characterize this "flare" reaction, and to inform health care providers that efalizumab can still be administered after disease flare, and again may be a successful therapy

Dendritic epidermal T-cell involvement in induction of CD8+ T cell-mediated immunity against an ultraviolet radiation-induced skin tumor

Murine epidermis contains 2 distinct cell populations which contribute to the skin immune system, Langerhans cells (LC), and dendritic epidermal T cells (DETC). LCs are important in the induction of immunity against a wide range of antigens; however, the function of DETC is unclear. To investigate the roles of these epidermal cells (EC) in protective antitumor immunity, an in vivo model of an ultraviolet radiation-induced fibrosarcoma, UV-13-1, was used. Mice were immunized with tumor antigen-pulsed EC followed 10 days later by an injection into the ear of 10 tumor cells, which did not lead to formation of a detectable tumor, but was intended to simulate the influence of a developing tumor on the ensuing immune response. The mice were then challenged with 2 x 10 viable tumor cells in each flank, sufficient to result in growth of a measurable tumor. Protective immunity was induced by DETC, and shown to be long-lasting, with tumors inoculated 160 days after immunization being effectively rejected. The effector cells responsible for protective immunity were CD8 T cells. Delayed-type hypersensitivity generated by tumor antigen-pulsed EC was dependent on LCs, with no involvement of DETCs. This response, in contrast to that of DETC, required prior culture of EC with GM-CSF, but failed to inhibit tumor growth or incidence. Thus DETC and LC can both activate antitumor immune responses, although only the DETC-dependent response results in protective immunity in the presence of a developing tumor

Epidermal Langerhans\u27 cell induction of immunity against an ultraviolet-induced skin tumour

Langerhans\u27 cells (LC) have been shown experimentally to induce immune responses against many antigens; however, their role in the initiation of anti-tumour immunity has received little attention. This study examined the ability of murine epidermal LC to induce immunity to an ultraviolet radiation (UV)-induced skin tumour. Freshly prepared epidermal cells (EC) were cultured for 2 or 20 hr with granulocyte-macrophage colony-stimulating factor (GM-CSF), pulsed with an extract of the UV-13-1 tumour, then used to immunize naive syngeneic mice. Delayed type hypersensitivity (DTH) was elicited 10 days after immunization by injection of UV-13-1 tumour cells into the ear pinna, and measured 24 hr later. EC cultured with GM-CSF for 2 hr induced antitumour DTH, as did EC cultured for 20 hr without GM-CSF. Conversely, EC cultured for 2 hr without GM-CSF, or EC cultured for 20 hr with GM-CSF were unable to induce a DTH. Induction of immunity required active presentation of tumour antigens by Ia(+) EC and was tumour specific. Thus Ia(+) epidermal cells are capable of inducing anti-tumour immunity to W-induced skin tumours, but only when they contact antigen in particular states of maturation

Western Lifestyle and Increased Prevalence of Atopic Diseases

Background: Allergic diseases represent an increasing problem in public health in most modern societies as their prevalence has risen markedly during recent decades. Nevertheless, the causes of this increase are not yet fully explained.Objective: We investigated the correlation of Western lifestyle pattern in varying intensity to the prevalence of atopic diseases in 5 small villages on Karkar Island, in northeast Papua New Guinea.Methods: Two hundred forty-eight native people from 5 villages on tropical Karkar Island have been included in this study. The degree of Western lifestyle was assessed (questionnaire and observation) for each village. The prevalence of atopic diseases was evaluated by personal and family history, physical and dermatological examination, skin prick test (10 allergens), and measurement of total and specific immunoglobulin E levels (20 common allergens).Results: The more easily accessible and thus more ''modern'' and westernized coastal villages showed a significantly higher prevalence of habitants suffering from atopic diseases than a traditional mountain village (6.8% vs 0.0%, P = 0.034, Fisher exact test). A total of 4.4% (11/248) of the examined islanders suffered from an atopic disease. Atopic eczema seems to be absent on Karkar Island.Conclusions: The results of this study suggest that so-called Western lifestyle may contribute to the development of atopic diseases. Keywords: allergy prevalence, atopic disease, modern versus traditional lifestyle, Westernization, infections, parasites, public health, tropics, Papua New Guinea, Karkar Islan