Suppression of contact sensitivity by local hyperthermia treatment due to reduced Langerhans cell population in mice

Local Hyperthermia Versus Cryotherapy for Treatment of Plantar Warts: A Prospective Multi-centre Non-randomized Concurrent Controlled Clinical Trial

Cryotherapy is one of the most common treatments for warts; however, pain during treatment and relatively high recurrence rates limit its use. Local hyperthermia has also been used successfully in the treatment of plantar warts. The aim of this study was to compare the clinical effectiveness of local hyperthermia vs cryotherapy for the treatment of plantar warts. This multi-centre, open, 2-arm, non-randomized concurrent controlled trial included 1,027 patients, who received either cryotherapy or local hyperthermia treatment. Three months after treatment, local hyperthermia and cryotherapy achieved complete clearance rates of 50.9% and 54.3%, respectively. Recurrence rates were 0.8% and 12%, respectively. Pain scores during local hyperthermia were significantly lower than for cryotherapy. Both local hyperthermia and cryotherapy demonstrated similar efficacy for clearance of plantar warts; while local hyperthermia had a lower recurrence rate and lower pain sensation during treatment.

Regulation of a lymphocyte-endothelial-IL-6 trans-signaling axis by fever-range thermal stress: hot spot of immune surveillance

The pleiotropic cytokine, interleukin-6 (IL-6), has emerged in recent years as a key regulator of the transition from innate to adaptive immunity through its ability to modulate leukocyte recruitment at inflammatory sites. This review highlights a newly identified role for IL-6 trans-signaling, initiated by an agonistic complex of IL-6 and a soluble form of IL-6 receptor alpha, in heightening immune surveillance of peripheral lymphoid organs during febrile inflammatory responses. Inflammatory cues provided by the thermal component of fever trigger IL-6 trans-signaling to act at discrete levels in the multistep adhesion cascade that governs the entry of blood-borne lymphocytes across 'gatekeeper' high endothelial venules (HEVs) in lymph nodes and Peyer patches. IL-6 trans-signaling-dependent mechanisms have been elucidated during thermal stimulation of primary tethering and rolling of lymphocytes along the lumenal surface of HEVs as well as during secondary firm arrest of lymphocytes in HEVs prior to their migration into the underlying parenchyma. These mechanisms profoundly increase the probability that lymphocytes that continuously patrol the body will engage in productive encounters with target antigens sequestered within lymphoid organs. Findings that the lymphocyte-HEV-IL-6 trans-signaling biological axis functions as a thermally-sensitive alert system that promotes immune surveillance provide insight into one of the unresolved mysteries in immunology regarding the benefits of mounting a febrile reaction during inflammation.

Impact of fever-range thermal stress on lymphocyte-endothelial adhesion and lymphocyte trafficking

The evolutionarily conserved febrile response has been associated with improved survival during infection in endothermic and ectothermic species although its protective mechanism of action is not fully understood. Temperatures within the range of physiologic fever influence multiple parameters of the immune response including lymphocyte proliferation and cytotoxic activity, neutrophil and dendritic cell migration, and production or bioactivity of proinflammatory cytokines. This review focuses on the emerging role of fever-range thermal stress in promoting lymphocyte trafficking to secondary lymphoid organs that are major sites for launching effective immune responses during infection or inflammation. Specific emphasis will be on the molecular basis of thermal control of lymphocyte-endothelial adhesion, a critical checkpoint controlling lymphocyte extravasation, as well as the contribution of interleukin-6 (IL-6) trans-signaling to thermal activities. New results are presented indicating that thermal stimulation of lymphocyte homing potential is evident in evolutionarily distant endothermic vertebrate species. These observations support the view that the evolutionarily conserved febrile response contributes to immune protection and host survival by amplifying lymphocyte access to peripheral lymphoid organs.

Effects of near-infrared radiation on the epidermal proliferation and cutaneous immune function in mice

While ultraviolet radiation alters various cutaneous cell functions, little is known about the photobiological effects of infrared radiation (IR) on the skin except its local thermal effect. This study demonstrated that single exposure of mouse skin to near IR (0.7-1.3 microns) reversibly suppressed the proliferating activity of the epidermis, the density of Langerhans cells, and the ability of skin to induce contact hypersensitivity reaction. During the exposure, the ear surface temperature was elevated from a mean of 27 to 31.2 degrees C. The results suggest that near IR can modulate the epidermal proliferation and part of the skin immune system, with a mild thermal effect.

Contact hypersensitivity is suppressed after sensitisation by dinitrofluorobenzene of early stage iso-skin grafts

Isologous free skin grafts were applied to the backs of BALB/c mice and contact hypersensitivity studied by epicutaneous application of DNFB (2,4-dinitro-1-fluorobenzene) to the grafted skin. In the first experiment, the grafted skin was sensitised and the elicitation reaction assessed by measuring the ear swelling after five days. Sensitisation was not successful until two weeks after grafting. In such non-responding animals, re-sensitisation with DNFB on the ungrafted skin area was also unsuccessful, indicating the establishment of immunological tolerance. This tolerance was considered antigen-specific, as re-sensitisation with oxazolone was successful. In the second experiment, spleen cell suspension, both untreated and treated in vitro with antiThy 1.2, antiLyt 1.2, and antiLyt 2.2 antibody, from non-DNFB-responding mice was transferred into normal mice. Subsequently these mice were sensitised with DNFB. Sensitisation was not successful in the untreated group or in those treated with antiLyt 1.2 antibody. On the other hand, the groups treated with antiThy 1.2 and antiLyt 2.2 antibody did become sensitised. These results indicate that the unsuccessful delayed hypersensitivity of the grafted skin was caused by suppressor T cells. In addition, the density of epidermal Langerhans cells was reduced in the early stages of skin grafting and morphological abnormalities were present. From these results, we conclude that contact sensitisation during the early stage of grafting skin not only produces suppression of ear swelling but also induces antigen-specific tolerance. These results also suggest that the suppression depends on the antigen-specific suppressor cells and that acquirement of tolerance is associated with a reduction in the number of epidermal Langerhans cells in the grafted skin and abnormalities in their structure.

Electron-microscopic and immunohistochemical studies of Langerhans cells and Thy-1-positive cells in mouse tongue epithelium subjected to local hyperthermia

Local hyperthermia via skin has been used to treat cancer but may suppress local immune responses as a side-effect. To examine effects of heat on immunologically responsive cells in oral mucosa, mouse tongues were heated by an implant system at 43 degrees C for 20 min. The densities of Langerhans cells and Thy-1-positive cells rapidly increased within 3 h after the treatment, then returned to a normal level after 7 days. Electron microscopy confirmed that Langerhans cells in the tongue epithelium formed clusters with lymphocytic cells, suggesting an active response to the hyperthermia.

Role of Langerhans cells and other dendritic cells in viral diseases

Langerhans cells are part of a vast system of potent antigen-presenting cells known under the name of dendritic cells. During the last decade, much has been learned on dendritic cell involvement in the immune response to infectious diseases. This review briefly summarizes our current understanding of the role played by Langerhans cells and other dendritic cells in the pathogenesis of DNA and RNA virus infections. These data may form the basis for the development of innovative approaches in the diagnosis, prevention, and treatment of viral diseases.

Effects of local hyperthermia on natural killer activity in mice

The effect of local hyperthermia on natural killer (NK) activity in C3H mice was investigated, because there have been reports on both the enhancing and suppressing effects of hyperthermia on NK activity. When right hind legs of mice were treated at 43 degrees C for 45 min, NK activity was first suppressed. It reached its lowest level 2 days after the treatment, then recovered, and was significantly enhanced on the 7th day. When mice were treated at a lower temperature (41 degrees C), NK activity was enhanced even 2 days after the treatment. In addition, the suppression of NK activity, which was observed 2 days after the treatment at 43 degrees C, was diminished to some extent by i.p. injection of liposomal recombinant human superoxide dismutase (L-r-hSOD). From these results it is suggested that local hyperthermia had an enhancing effect on NK activity, which plays an important role in the anti-tumour mechanism of hyperthermia, and that transient suppression of NK activity after hyperthermia at 43 degrees C was partially cancelled by the administration of L-r-hSOD.