UV Immunosuppression and Skin Cancer

706

LETTERS TO THE EDITOR

substance P, and nitric oxide) have also been shown to contribute to UVB-induced erythema (Benrath et al, 1995), immunosuppression (Gillardon et al, 1995), and production of cytokines like TNF-α in mast cells (Ansel et al, 1993; Niizeki et al, 1997). Because GABA is an inhibitory neurotransmitter, it might be possible that cis-UCA binds as an antagonist to possible cutaneous GABA receptors. Such function could disinhibit the secretion of cutaneous neuropeptides modulating local immune reactions. Because no reports of GABA receptors in the skin have been found, our next goal will be to study whether GABA receptors exist in the skin. Jarmo K. Laihia, Martti Attila,†‡ Kari Neuvonen,* Paavo Pasanen,* Leena Tuomisto,‡ and Christer T. Jansen, Departments of Dermatology and *Chemistry, University of Turku, Turku, Finland †Pharmacology and Toxicology, Department of Clinical Sciences, Faculty of Veterinary Medicine, University of Helsinki, Helsinki, Finland ‡Department of Pharmacology and Toxicology, University of Kuopio, Kuopio, Finland REFERENCES Ansel J, Brown J, Payan D, Brown M: Substance P selectively activates TNF-α gene expression in murine mast cells. J Immunol 150:1–8, 1993 Beissert S, Mohammad T, Torri H, Lonati A, Yan Z, Morrison H, Granstein RD: Regulation of tumor antigen presentation by urocanic acid. J Immunol 159: 92–96, 1997 Benrath J, Eschenfelder C, Zimmerman M, Gillardon F: Calcitonin gene-related peptide, substance P and nitric oxide are involved in cutaneous inflammation following ultraviolet irradiation. Eur J Pharmacol 293:87–96, 1995 Bruls WAG, Slaper H, van der Leun JC, Berrens L: Transmission of human epidermis and stratum corneum as a function of thickness in the ultraviolet and visible wavelengths. Photochem Photobiol 40:485–494, 1984 Enna SJ, Wood JH, Snyder SH: Gamma-aminobutyric acid (GABA) in human cerebrospinal fluid: radioreceptor assay. J Neurochem 28:1121–1124, 1977 Gillardon F, Moll I, Michel S, Benrath J, Weihe E, Zimmermann M: Calcitonin generelated peptide and nitric oxide are involved in ultraviolet radiation-induced immunosuppression. Eur J Pharmacol 293:395–400, 1995 Gilmour JW, Norval M, Simpson TJ, Neuvonen K, Pasanen P: The role of histamine-

THE JOURNAL OF INVESTIGATIVE DERMATOLOGY

like receptors in immunosuppression of delayed hypersensitivity induced by cisurocanic acid. Photodermatol Photoimmunol Photomed 9:250–254, 1993a Gilmour JW, Vestey JP, Norval M: The effect of UV therapy on immune function in patients with psoriasis. Br J Dermatol 129:28–38, 1993b Hart PH, Jones CA, Jones KL, Watson CJ, Santucci I, Spencer LK, Finlay-Jones JJ: Cis-urocanic acid stimulates human peripheral blood monocyte prostaglandin E2 production and suppresses indirectly tumor necrosis factor-α levels. J Immunol 150:4514–4523, 1993 Hill SJ: Distribution, properties, and functional characteristics of three classes of histamine receptor. Pharmacol Rev 42:45–83, 1990 Hosoi J, Murphy GF, Egan CL, Lerner EA, Grabbe S, Asahina A, Granstein RD: Regulation of Langerhans cell function by nerves containing calcitonin gene-related peptide. Nature 363:159–162, 1993 ¨ yra¨s P: A Jansen CT, Lammintausta K, Pasanen P, Neuvonen K, Varjonen E, Kalimo K, A non-invasive chamber sampling technique for HPLC analysis of human epidermal urocanic acid isomers. Acta Derm Venereol (Stockh) 71:143–145, 1991 Kavanagh G, Crosby J, Norval M: Urocanic acid isomers in human skin: analysis of site variation. Br J Dermatol 133:728–731, 1995 Matheson GK, Freed E, Tunnicliff G: Novel GABA analogues as hypotensive agents. Neuropharmacol 25:1191–1195, 1986 Matheson GK, Freed E, Tunnicliff G: Central receptor binding and cardiovascular effects of GABA analogues in the cat. Gen Pharmacol 18:269–273, 1987 Mitra RS, Shimizu Y, Nickoloff BJ: Histamine and cis-urocanic acid augment tumor necrosis factor-α mediated induction of keratinocyte intercellular adhesion molecule1 expression. J Cell Physiol 156:348–357, 1993 Morrison H, Avnir D, Zarella T: Analysis of Z and E isomers of urocanic acid by highperformance liquid chromatography. J Chromatogr 183:83–86, 1980 Niizeki H, Alard P, Streilein JW: Calcitonin gene-related peptide is necessary for ultraviolet B-impaired induction of contact hypersensitivity. J Immunol 159:5183–5186, 1997 Norval M: Chromophore for UV-induced immunesuppression: urocanic acid. Photochem Photobiol 63:386–390, 1996 Norval M, Gilmour JW, Simpson TJ: The effect of histamine receptor antagonists on immunosuppression induced by the cis-isomer of urocanic acid. Photodermatol Photoimmunol Photomed 7:243–248, 1990 ¨ yra¨s P: Urocanic acid Pasanen P, Reunala T, Jansen CT, Ra¨sa¨nen L, Neuvonen K, A isomers in epidermal samples and suction blister fluid of nonirradiated and UVBirradiated human skin. Photodermatol Photoimmunol Photomed 7:40–42, 1990 ¨ yra¨s P, Jansen CT: Snellman E, Koulu L, Pasanen P, Lammintausta K, Neuvonen K, A Effect of psoriasis heliotherapy on epidermal urocanic acid isomer concentrations. Acta Derm Venereol (Stockh) 72:231–233, 1992 Snellman E, Jansen CT, Laihia JK, Mila´n T, Koulu L, Leszczynski K, Pasanen P: Urocanic acid concentration and photoisomerization in Caucasian skin phototypes. Photochem Photobiol 65:862–865, 1997 Tunnicliff G, Welborn KL, Ngo TT: Identification of potential GABA-mimetics by their actions on brain GABA recognition sites. Gen Pharmacol 16:25–29, 1985 Vink AA, Yarosh DB, Kripke ML: Chromophore for UV-induced immunesuppression: DNA. Photochem Photobiol 63:383–386, 1996

UV Immunosuppression and Skin Cancer To the Editor: We read with considerable interest the paper by Yamawaki et al ‘‘Genetic variation in low-dose UV-induced suppression of contact hypersensitivity and in the skin photocarcinogenesis response,’’ published in the Journal of Investigative Dermatology (109:716, 1997). The data in Figs 4 and 5 of this paper compare tumor incidence and tumor yield in C3H/HeN and C3H/HeJ mice treated with either UV alone (Fig 4) or a single dose of UV followed by 12-O-tetradecanoylphorbol-13-acetate promotion (Fig 5). These two mouse strains differ in the Lps gene that is defective in C3H/HeJ mice and controls a variety of B lymphocyte and macrophage responses. These mice have also been reported to differ in susceptibility to the ‘‘local’’ immunosuppressive effects of UV radiation, proposed to be an important factor in UV carcinogenesis. We have some comments on this paper. Statistical analysis It is stated (p. 719) that there are significant differences in tumor incidence and yield between the two strains in Fig 5, i.e., after treatment with UV and 12-O-tetradecanoyl-phorbol13-acetate, but not in Fig 4, i.e., after treatment with UV alone. By visual inspection this would appear to be the case, but we were unable to find any mention of any statistical test for significance. It is essential to see the results of the application to this data, e.g., survival analysis with censoring, which accounts for any tumor-free deaths during the experiment, and appropriate statistical analysis, e.g., Kaplan–Meier

logrank test, before it can be concluded that significant differences do in fact exist. Strain differences in UV immunosuppression There is not universal agreement that C3H/HeN and C3H/HeJ strains do differ in susceptibility to the immunosuppressive effects of UV. The UV dose– responses for suppression of contact hypersensitivity in these two strains are in fact identical if the ‘‘systemic’’ model is used (Noonan and De Fabo, 1990) and would have predicted the findings in Fig 4. ‘‘Low-dose’’ versus ‘‘high-dose’’ immunosuppression It is simply incorrect to say, as is stated in the Introduction (p. 716), that ‘‘A relatively low dose of UV radiation is all that is required to produce immunosuppression if the antigen is applied directly to the UV-exposed skin site (local or low-dose immune suppression). On the other hand, when a greater UV dose is administered, immunosuppression results even if the antigen is applied to a non-UV exposed skin site (systemic or high-dose immune suppression).’’ In fact, a direct comparison between UV-induced ‘‘local’’ and ‘‘systemic’’ immunosuppression of contact hypersensitivity showed that the UV dose–responses for these effects are the same (Noonan and De Fabo, 1990). The UV dose–responses differ, however, between mouse strains (Noonan and De Fabo, 1990; Noonan and Hoffman, 1994) and the kinetics of ‘‘local’’ and ‘‘systemic’’ suppression differ. A time lag of 2–3 d after UV before antigen application has long been known to be necessary for the detection of systemic suppression (Noonan et al,

VOL. 111, NO. 4 OCTOBER 1998

1981; Molendijk et al, 1987), presumably to allow the generation of systemic mediators of immunosuppression. Further, it has also long been known that 50% ‘‘systemic’’ suppression can be generated by UV doses as low as 420 J per m2 of 270 nm (61.5 nm HBW) narrow band UV in the ‘‘UV-resistant’’ strain BALB/ C (De Fabo and Noonan, 1983). Finally, we would strongly suggest that use of the terms ‘‘low-dose’’ and ‘‘high-dose’’ are qualitative and therefore intrinsically unsatisfactory. As far as we can establish neither term has been quantitatively defined. Strain differences and hapten dose We disagree with the conclusion (p. 720, para 2) that ‘‘strain differences are observed only when excessive amounts of hapten are used for immunization.’’ The dose of hapten appears to change the doses of UV required for UV immunosuppression (Figs 1–3), as reported (Miyauchi and Horio, 1995) and cited in the current paper; however, unless UV dose– responses for immunosuppression are established for each mouse strain at each hapten dose, it cannot be stated that the strain differences in susceptibility to UV-induced immunosuppression are observed ‘‘only’’ when excessive amounts of hapten are used for immunization. Frances Noonan, Edward C. De Fabo Laboratory of Photoimmunology and Photobiology, Dermatology Research, George Washington University Medical Center, Ross Hall, Washington, DC, U.S.A. REFERENCES De Fabo EC, Noonan FP: Mechanism of immune suppression by ultraviolet irradiation in vivo- I. Evidence for the existence of a unique photoreceptor in skin and its role in photoimmunology. J Exp Med 157:84–98, 1983 Miyauchi H, Horio T: Ultraviolet B-induced local immunosuppression of contact hypersensitivity is modulated by ultraviolet irradiation and hapten application. J Invest Dermatol 104:364–369, 1995 Molendijk A, van Gurp R, Donselaar I, Benner R: Suppression of delayed-type hypersensitivity to histocompatibility antigens by ultraviolet radiation. Immunology 62:299–305, 1987 Noonan FP, De Fabo EC: Ultraviolet-B dose–response curves for local and systemic immunosuppression are identical. Photochem Photobiol 52:801–810, 1990 Noonan FP, Hoffman HA: Susceptibility to immunosuppression by ultraviolet B radiation in the mouse. Immunogenetics 39:29–39, 1994 Noonan FP, Kripke ML, Pedersen GM, Greene MI: Suppression of contact hypersensitivity in mice by ultraviolet irradiation is associated with defective antigen presentation. Immunology 43:527–533, 1981

Reply: Drs. Noonan and DeFabo raise several relevant questions with respect to our manuscript ‘‘Genetic variation in low-dose UV-induced suppression of contact hypersensitivity and in the skin photocarcinogenesis response’’ that was recently published in the Journal of Investigative Dermatology (109:716, 1997). Statistical analysis Statistical analysis was performed on the carcinogenesis experiments employing Chi square analysis and was not statistically significant for the two strains when they were subjected to the chronic UV irradiation protocol, but were highly significant (p , 0.01) when panels were given the single dose of UV radiation followed by repeated applications to 12-O-tetradecanoyl-phorbol13-acetate. ‘‘Low-dose’’ versus ‘‘high-dose’’ immunosuppression Although we agree that ‘‘low dose’’ and ‘‘high dose’’ may not be the ideal terms for the two different protocols used to produce UV-induced immunosuppression, they are the generally accepted terms. It would only add further confusion to the literature to change the terms at this point. Although we have not performed the experiments ourselves, we have no reason to disagree with the statement that systemic immunosuppression of the contact hypersensitivity response can be produced at considerably lower doses than are generally employed. It is important to note that Drs. Noonan and De Fabo have reported that lower doses of UV radiation can produce ‘‘high-dose’’ immunosuppression, not every investigator has found this to be the case (Toews et al, 1980; Elmets et al, 1983; Jun et al, 1988). Moreover, whether those lower doses can be used to suppress the response to

LETTERS TO THE EDITOR

707

other immunogens – e.g., to Herpes simplex virus – remains to be determined (Ross et al, 1986). It is important to emphasize that there are clear-cut differences in the mechanisms by which these two UV irradiation protocols produce immunosuppression (Elmets and Bergstresser, 1982; Cruz and Bergstresser, 1992). First, ‘‘low dose’’ UVinduced suppression of contact hypersensitivity is mediated at least in part by an alteration in the antigen-presenting function of epidermal Langerhans cells and other antigen-presenting cells in the skin (Toews et al, 1980). In contrast, Langerhans cell antigen-presenting function in the skin to which hapten is applied in the ‘‘high-dose’’ UV irradiation regimen is normal (Noonan et al, 1988). Second, the soluble mediators associated with the two regimens differ. TNF-α has been shown to suppress induction of contact hypersensitivity in the ‘‘low-dose’’ model (Streilein, 1995), whereas IL-10 is a major mediator of the immunosuppression in the ‘‘high-dose’’ model (Rivas and Ullrich, 1992, 1994; Ullrich, 1995). Third, there may be differences in the chromophores that mediate the immunosuppressive effects in the two regimens (Applegate et al, 1989; Norval et al, 1989; Kripke et al, 1992). Finally, Dr. Noonan’s own data suggest that the two regimens are mechanistically different, because the strains of mice that exhibit immunosuppression following treatment with the ‘‘high-dose’’ regimen (Noonan and Hoffman, 1994a, b) are quite different from those with the ‘‘low-dose’’ regimen (Streilein and Bergstresser, 1988; Yoshikawa and Streilein, 1990). Strain differences in UV immunosuppression As referred to above, the fact that Dr. Noonan did not find differences in the immunosuppressive whereas we and others have most likely relates to differences in the ‘‘low-dose’’ and ‘‘high-dose’’ UV-irradiation regimens. We disagree with Drs. Noonan’s and DeFabo’s conclusion that our findings would have been predicted from the ‘‘systemic’’ model, because the ‘‘systemic’’ model was not used in this situation. The presumed tumor antigens to which the immune response is deficient were present only at the irradiated skin site. Strain differences and hapten dose What we meant to say was that ‘‘at the UV-dose employed strain differences are observed only when excessive amount of hapten are used for immunization.’’ Mitsuo Yamawaki, Santosh Katiyar, Cathy Y. Anderson, Karen A. Tubesing, Hasan Mukhtar, Craig A. Elmets Department of Dermatology, University of Alabama at Birmingham, School of Medicine, Birmingham Alabama, U.S.A. REFERENCES Applegate LA, Ley RD, Alcalay J, Kripke ML: Identification of the molecular target for the suppression of contact hypersensitivity by ultraviolet radiation. J Exp Med 170:1117–1131, 1989 Cruz PDJ, Bergstresser PR: Effects of UVB radiation on cutaneous photocarcinogenesis and allergic contact sensitivity. In: Lim H, Soter NA (eds). Photomedicine for Clinical Dermatologists, New York: Marcel Dekker, 1992, pp. 137–151 Elmets CA, Bergstresser PR: Ultraviolet radiation effects on immune processes. Photochem Photobiol 36:715–719, 1982 Elmets CA, Bergstresser PR, Tigelaar RE, Wood PJ, Streilein JW: Analysis of mechanism of unresponsiveness produced by haptens painted on skin exposed to low dose ultraviolet radiation. J Exp Med 158:781–794, 1983 Jun BD, Roberts LK, Cho BH, Robertson B, Daynes RA: Parallel recovery of epidermal antigen-presenting cell activity and contact hypersensitivity responses in mice exposed to ultraviolet irradiation: the role of a prostaglandin-dependent mechanism. J Invest Dermatol 90:311–316, 1988 Kripke ML, Cox PA, Alas LG, Yarosh DB: Pyrimidine dimers in DNA initiate systemic immunosuppression in UV-irradiated mice. Proc Natl Acad Sci USA 89:7516– 7520, 1992 Noonan FP, Hoffman HA: Control of UVB immunosuppression in the mouse by autosomal and sex-linked genes. Immunogenetics 40:247–256, 1994a Noonan FP, Hoffman HA: Susceptibility to immunosuppression by ultraviolet B radiation in the mouse. Immunogenetics 39:29–39, 1994b Noonan FP, DeFabo EC, Morrison H: Cis-urocanic acid, a product formed by ultraviolet B irradiation of the skin, initiates an antigen presentation defect in splenic dendritic cells in vivo. J Invest Dermatol 90:92–99, 1988 Norval M, Simpson TJ, Ross JA: Urocanic acid and immunosuppression. Photochem Photobiol 50:267–275, 1989 Rivas JM, Ullrich SE: Systemic suppression of DTH by supernatants from UV irradiated keratinocytes: an essential role for interleukin-10. J Immunol 149:3865–3871, 1992 Rivas JM, Ullrich SE: The role of IL-4, IL-10 and TNF-alpha in the immune suppression induced by ultraviolet radiation. J Leuk Biol 56:769–775, 1994