- Email: [email protected]
Contact immunotherapy of resistant warts
Therapy I
I I
Contact immunotherapy of resistant warts M a r k Franklin Naylor, M.D.,* Kenneth H. Neldner, M.D.,* Glenn K. Yarbrough, M.D.,** Timothy J. Rosio, M.D.,*** Manuel Iriondo, M.D.,****, and James Yeary, M.D.*
Lubbock, TX, Scottsdale, AZ, Marshfield, WI, and Miami, FL Contact immunotherapy has been proved effective in the treatment of resistant warts. This report chronicles our experience with a new contact immunotherapy agent, diphenylcyclopropenone. We have achieved a cure rate of 62% in 45 patients with resistant warts of all types who came to our general dermatology clinic. Cure rates may be lower in patients who have experienced multiple treatment failures. The majority of cures were obtained within 3 to 4~ months. Although it appears somewhat less effective than published reports ott dinitrochlorobenzene contact immunotherapy, diphenylcyclopropenone contact imrnunotherapy is an effective treatment for resistant warts and avoids any potential problems from mutagenicity. (J AM ACADDERMAXOL 1988;19:679-83.)
In 1973 Lewis reported the first use of dinitrochlorobenzene contact immunotherapy for resistant warts, with a cure rate in compliant patients of 91%. I There have been at least five additional reports of the use of dinitrochlorobenzene published between 1973 and 1984. 2.6 Methods varied greatly but results were similar; cure rates ranged between 69% and 87% in these series (Fig. 1). In 1983 Happle et al. 7 published a series of patients with alopecia areata treated with a new agent, diphenylcyclopropenone. Because the treatm e n t of alopecia areata with dinitrochlorobenzene was one of the known methods of contact immunotherapy, diphenylcyclopropenone seemed a promising agent for wart contact immunotherapy. There has been one report in the German literature of the use of diphenylcyclopropenone for this purpose in a small n u m b e r of patients? In theory, any substance that can reliably induce a type IV hypersensitivity response can be used for
From the Department of Dermatology, Texas Tech University Health Sciences Center, Lubbock*; Seottsdale**; Department of Dermatology, Marshfield Clinic, Marshfield***; and Department of Dermatology and Cutaneous Surgery, University of Miami School of Medicine, Miami.**** Reprint requests to: Dr. Mark Franklin Naylor, Assistant Professor of Dermatology and Internal Medicine, Department of Dermatology, Texas Tech University Health Sciences Center, Lubbock, TX 79430.
treatment. In practice, what is needed is a substance that is available, able to sensitize at least 95% of normal individuals, chemically stable, and economical. More importantly, it should be free of significant adverse effects and not found in human environments. Availability problems are similar for the three compounds that have been used for contact immunotherapy: dinitrochlorobenzene, diphenylcyclopropenone, and squaric acid dibutyl ester. All three are potent sensitizers. Stability is a problem with both of the latter two. Squaric acid dibutyl ester needs refrigeration and possibly special solvents and additives to maintain potency because of its tendency to undergo hydrolysis? Diphenylcyclopropenone must be stored in dark glass in a dark place because of its tendency to undergo photodecomposition.~~ Dinitrochlorobenzene is the most economic of the three agents, listed at $0.15 per gram (100 gm quantity) in the 1986-1987 Aldrich Chemical Company catalog. Diphenylcyclopropenone is available from the same source at $7.83 per gram (5 gm quantity). The cost of squarie acid dibutyl ester was quoted by Case et al. '1 in 1984 at approximately $37.50 per gram (10 gm quantity). With the dilutions commonly used, all these agents are economically feasible, although dinitroehlorobenzene has a considerable pricing advantage. Diphenylcyclopropenone1~ and squaric acid 679
Journal of the American Academy of Dermatology
Naylor et aL
680
Table I. Treatment results by wart subtype
Warttype .. I
No. treated [
Allpatlentseured
Plantar Periungual Multiple glabrous Combined Palmar Genital
16 14 4 6 3 2
12 (75%) 9 (64%) 3 (75%) 3 (50%) 1 (17%) 0 (0%)
Total
45
28 (62%)
dibutyl ester s, ~3-z5are non mutagenic in the Ames test, unlike dinitrochlorobenzene) 3. t6.17 Nonetheless, we are not aware o f any adverse effects of any of these agents, apart from the fact that they are contact allergens. Case et al. tl, ~g were aware of only two patents in the United States that contained squaric acid dibutyl ester. Although diphenylcyclopropenone may someday be useful to chemical engineers as a synthetic intermediate, 19 we do not know of any commercial uses for it presently in this country. MATERIALS AND METHODS Sixty-two consecutive patients with resistant warts seen in the Texas Tech Dermatology Clinic were treated with diphenylcyclopropenone contact immunotherapy. The definition of a resistant wart was left to the judgment of individual physicians, but generally this included large or multiple warts in plantar, periungual, and palmar locations as well as warts in other areas resistant to previous therapy. All sensitizing and treatment solutions of diphenylcyclopropenone were based on dilutions of a 1.0% stock solution in acetone. Patients were sensitized before treatment with 0.2 ml of a 0.1% solution (0.2 mg diphenylcyclopropenone) applied to the medial arm skin under a light bandage for 24 hours. Patients were instructed to keep the area dry for 24 hours and to apply a topical steroid 24 hours after the reaction was initially noted. Patients were seen in 2 weeks. If no reaction had occurred, diphenyleyelopropenone was reapplied, usually with a stronger solution (0.2 ml of a 0.2% solution [0,4 rag]). I f no sensitization had occurred after an additional 2 weeks, a third attempt was made (0.2 ml of a 1.0% solution [2.0 mg]). After sensitization had occurred, a 0.01% diphenylcyclopropenone solution (0.10 mg/ml) was applied once a day to induce a low-grade inflammatory reaction in and
immediately adjacent to the wart. Weaker concentrations of 0.004% (0.04 mg/ml) to 0.01% (0.1 mg/ml) were used initially in sensitive areas such as the face or groin. The concentration selected was applied to wet just the wart and not the surrounding normal skin. After 1 week, if the single application was tolerated, a second application was applied to the wart after allowing the first one to dry. If this was tolerated for a week, a stronger solution was then applied, beginning again as a single application once a day. Patients were followed at intervals of 2 weeks. The sequence of solution strengths followed was 0.01%, 0.025%, 0.1%, 0.5%, and finally 1.0%. Unused solutions of diphenylcyclopropenone were discarded after 3 months. All treatment was carried out at home. Diphenylcyclopropenone solutions were dispensed to the patients in dark glass bottles and stored in a refrigerator. If the warts were markedly hyperkeratotic, a keratolyric agent, usually 100% trichloroaeetic acid, was applied 6 to 12 hours before diphenylcyclopropenone applications, 3 to 7 times a week. This was felt to aid penetration of the diphenylcyclopropenone solution into the wart. Hyperkeratofic warts were usually pared at clinic visits. Compliance was considered satisfactory if the patients generally kept their appointments and followed instructions to the best of their ability. Partially compliant patients were those who did not stop therapy but had irregular follow-up, generally missing more than two scheduled appointments without notifying clinic personnel. Cure was defined as no clinical evidence of warts 1 months after stopping therapy. Patients who noted regrowth of their warts within 1 month of stopping treatment resumed therapy and were not counted as relapses unless they failed to respond to subsequent therapy. RESULTS Our cure rate was 62% in 45 evaluable patients with resistant warts of all types. W e were able to sensitize 60 of 62 patients in whom it was attempted (97%). One patient (2%) required three attempts, 14 patients (23%) required two attempts, and 45 were sensitized on the first attempt (75%). Seventeen of 62 consecutive patients were not included for analysis. Two who did not sensitize were excluded, one because of a spontaneous resolution during sensitization attempts. A third patient was initially misdiagnosed as having multipie palmar and plantar warts and was later found
Volume 19 Number 4 October 1988
Contact immunotherapy of resistant warts 681
~ / / / / / / / / / / / / / / / / / / / ~
~
8
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~%
6
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l
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20
Lewis1
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Golhnum-Yahr et al,6
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Claudyet al. 3
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Dunairin
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& Millikan
't
DPC i
30 40 50 % pafi~t~Cured
I
I
60
70
I0
8
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I
90
1130
Fig. 1. Comparison of immunotherapy series for diphenylcyclopropenone (DPC) treatment. Figure shows only patients who had one or more prior treatment failures (cure rate 60% for diphenylcyclopropenonewith one or more prior treatment failures; cure rate 62% for all patients receiving diphenylcyelopropenone in our series).
to have an unclassified palmoplantar genodermatosis. Six patients were lost to follow-up. In two partially compliant patients therapy was incomplete at the time of this writing. Six patients withdi'ew from therapy for reasons other than side effects or lack of efficacy. The 45 patients included for analysis consisted of 22 men and 23 women (mean age, 22.8 years; range, 5 to 73 years). Cure rates by wart location are listed in Table I. Wart subtypes (anatomic locations) included 16 plantar, 14 periungual, 3 palmar, 2 genital, 4 multiple glabrous, and 6 cases with combinations of wart types. Curiously, partially compliant patients had the same cure rate (10 of 16, or 62.5%) as compliant patients (18 of 29, or 62%), although compliant patients had faster response times. The number of prior treatments was similar in both groups. Treatment duration for compliant patients ranged from 0.8 to 8.6 months (mean, 3.9 months; median, 3.4 months); mean follow-up time for patients whose warts were cured was 5 months (median, 4.1 months; range, 1.5 to 11.9 months). T h e majority of cures occurred within the first 3 to 4 months of therapy. In compliant patients, no additional cures were seen beyond 5.3 months of therapy. Sixty percent of the patients who experienced cure were followed for 3 months or more after the cessation of therapy. One patient relapsed 1 89 months after stopping therapy when she became pregnant. A major factor beating on outcome was location.
The highest cure rates were achieved in multiple glabrous warts (3 of 4, or 75%), plantar warts (12 of 16, or 75%) and in periungual warts (9 of 14, or 64%). Multiple combined warts (usually glabrous plus plantar or palmar skin) had a cure rate of 3 of 6, or 50%. Cure rates differed as assessed by chi-square analysis (p < 0.01; degrees of freedom,
4). While not .conclusive, our experience tended to confirm the negative prognostic effect of prior treatment failures on prognosis (Fig. 2). Palmar warts had the worst outcome; only 1 of 6, or 17% was cured. W h y plantar warts seem to be so much more responsive to topical immunotherapy than palmar warts is not dear, but it may involve mechanical factors such as hand washing, which could remove deposits of the antigenic substance. Because only two cases of genital warts were treated in this series, the numbers were too small for even preliminary conclusions. However, our impression from subsequent experience is that contact immunotherapy may have a role in combined regimens, but it is not dramatically effective when used alone. Side effects were not a problem in the majority of patients and did not prevent a successful outcome in most of those that experienced them. Typically, patients achieved slow wart involution without significant itching or discomfort. Overall, however, 22 of 45 (49%) had at least one side effect. Ten of 45 (22%) developed allergic contact
Journal of the American Academy of Dermatology
682 Naylor et al.
80
6O
r,.)
20
0 0
1
2
3
4
5
N u m b e r of Prior Treatments
Fig. 2. All patients. Boxes within the bars represent the number of patients cured divided by the total who received that number of treatments. dermatitis in a nontreatment site. This was generally not severe and responded in most cases to topical steroid therapy and more careful instruction on handling the solutions. Patients using higher concentrations of diphenylcyclopropenoneor treating multiple warts were more likely to experience this side effect. Ten of 45 (22%) had an unusually severe reaction at the treatment site (vesicular or markedly symptomatic). This was handled by stopping therapy for a few days, making sure the patient understood application instructions, and carefully restarting therapy, usually at a lower concentration. Three of 45 (7%) had unusually severe reactions at the sensitization site. Only two patients had more than one s{de effect. DISCUSSII~,I Contact immunotherapy may work by the induction of a type IV hypersensitivity response in papilloma virus-infected tissue, leading to wart destruction. Precise immunologic mechanisms are unclear 2 but probably involve a non wart-antigenspecific, cell-mediated process triggered by the immune stimulus? Previous investigators have emphasized the role of specific cell-mediated "unmunity?,4 although direct evidence is lacking? In our experience it is unusual to see resolution of warts in areas not actively treated, which makes wart-antigen-specific T cell cytotoxicity seem less likely to be the primary mechanism of action. Furthermore, reinfections occur, suggesting that the long-lasting immunity typical of antigen-specif-
ic cell-mediated immunity is not conferred by therapy. According to present theory of soluble antigen type IV skin hypersensitivity, the cellular mechanism is triggered by hapten conjugation, possibly with Langerhans cell surface proteins followed by presentation of the protein/hapten antigen complex to helper lymphocytes in the lymph nodes.2~ Subsequently, specific helper and cytotoxic lymphocytes are activated)' These specific effector cells recirculate to the site of inoculation, where a very similar or identical protein carrier/hapten antigen complex is still present. 25 Cells displaying antigen complex may be lysed by specific suppressor-cytotoxic lymphocytes~6 and various lymphokines released by effector lymphocytes.24 If a virus-infected cell had the antigen complex bound to it, it might be destroyed directly. It has been suggested that the carrier protein involved in the antigen complex may be viral in origin.4 If the viral antigen-containing complex is recognized because it is conjugated with diphenylcyclopropenone, the diphenylcyclopropenone moiety would be necessary for effector cell recognition and subsequent lysis of the virus-infected cell. Hence, while this may be the primary mechanism, it is not equivalent to naturally acquired, specific viral immunity. Other possibilities exist to explain at least some of the treatment effect. It is plausible that the major role of the specific effector lymphocyte response is to release lymphokines, such as interleukin-2 and interferon, that can augment the functions of nonspecific cell-mediated defenses, such as phagocytes and natural killer cells. 27,28It is known that virus-infected cells are susceptible to lysis by natural killer cells,2. which are thought to be important in defense against viral infections and cancer.29'30 A role for humoral factors is suggested by data from Eriksen,5 who showed an increased incidence in complement-binding wart virus antibodies from 15% before contact immunotherapy with dinitrochlorobenzene to 48% afterward. Natural killer cells, along with macrophages and granulocytes, are effector cells for antibody-dependent cell-mediated cytotoxicity. 27,3' Here the effector cells bind and lyse antibody-bearing target cells, providing a
Volume 19 Number 4 October 1988
plausible involvement for antibodies in the contact immunotherapy mechanism. In general, contact immunotherapy is less painful and scarring than other types of wart treatment. In contrast to most destructive modalities, it can be accomplished without interfering with activities such as jogging, swimming, or other athletic endeavors. In properly selected patients contact immunotherapy is an excellent modality for treating certain types of resistant warts, particularly in plantar and periungual locations. REFERENCES 1. Lewis HM. Topical immunotherapy of refractory warts. Cutis 1973;12:863-67. 2. Bekhor PS, Entwisle BR, McKenzie IFC. Topical DNCB therapy for resistant warts. Australas J Dermatol 1978;19:28-30. 3. Claudy AL, Roche H, Gogue Y. Traitement des verrues multiples et r6cidivantes par induction d'une hypersensibilit6 retard6e. Ann Derrnatol V6n~r~ol 1980;107:551-3. 4. Dunagin WG, Millikan LE. Dinitrochlorobenzene immunotherapy for verrucae resistant to standard treatment modalities. J AM ACADDERMATOL1982;6:40-5. 5. Eriksen K. Treatment of the common wart by induced allergic inflammation. Dermatologiea 1980;160:161-6. 6. Goihman-Yahr M, Fernandez J, Convit J. Immunoterapia de las verrugas vulgares diseminadas con dinitrochlorobenceno. Med Cutan Iber Lat Am 1976;2:187-94. 7. Happle R, Hausen BJ, Wiesner-Menzel L. Diphencyprone in the treatment of alopecia areata. Acta Derm Venereol (Stock.h) 1983;63:49-52. 8. Wiesner-Menzel L, Happle R. Riickbildung von plantarwarzen naeh behandlung mit diphencyprone. Z Hautkr 1983;59:1080-3. 9. Wilkerson MG, Henkin J, Wilkin JK, Smith RG. Squaric acid and esters: Analysis for contaminants and stability in solvents. J AM ACADDERMATOL1985;13:229-34. 10. Wilkerson MG, Henkin J, Wiikin JK, Smith RG. Diphenylcyclopropenone: Examination for potential contaminants, mechanisms of sensitization, and photochemical stability. J AM ACADDERMATOL1984;11:802-7. 11. Case PC, Mitchell A J, Swanson NA, Vanderveen EE, Ellis CN, Hesdington JT. Topical therapy of alopecia areata with squaric acid dibutylester. J AM AcAo DERMATOE 1984;10:447-51. 12. Stute J, Hausen BM, Schulz KH. Dephenylcyclopropenein stark wirksames kontakallergen. Derm Beruf Umwelt 1981;29:12-5. 13. Strobel R, Rohrborn G. Mutagenic and cell transforming activities of 1-chlorc~2,4 dinitrochlorobenzene (DNCB) and squaric acid dibutyl ester (SADBE). Arch Toxicol 1980;45:307-14. 14. Wilkerson MG, Wilkin J-K, Smith RG. Contaminants of dinitrochlorobenzene. J AM ACAD DERMATOL 1983;9: 554-7. 15. Happle R, Kalveram K J, Buchner U, et al. Contact allergy as a therapeutic tool for alopecia areata: Applica-
Contact immunotherapy of resistant warts 683
16. 17. 18. 19.
20. 21. 22.
23.
24.
25. 26.
27.
28.
29.
30.
31.
tion of squaric acid dibutyl ester. Dermatologica 1980;161:289-97. Summer KH, Goggelmann W. 1-Chloro-2,4-dinitrobenzene depletes glutathione in rat skin and is mutagenic in Salmonella typhimuriurn. Murat Res 1980;77:91-3. Kratta J, Goeiz G, Vizethum W, Strobel R. Dinitrochlorobenzene: Influcnce on the cytochrorne P-450 system and mutagenic effects. Arch Dermatol Res 1979;266:315-8. Noster U, Hausen BM, Drische B, et al. Squaricacid-diethylester--a strong sensitizer. Contact Dermatitis 1976;2:99-104. Wadsworth DR. Reagents for cyclopropenium chemistry. In: Kodak laboratory chemicals news. Kodak publ no JJ60-871. Rochester, NY: Eastman Kodak Company, 1987:2. Lever WF, Schaumburg-Lever G, eels. Histopathology of the skin. 6th ed. Philadelphia: JB Lippincott Co, 1983:97. Shelley WB, Juhlin L. Selective uptake of contact allergens by the Langerhans cells. Arch Dermatol 1977; 113:187-92. Silberberg-Sinakin I, Thorbecke G J, Baer RL, Rosenthal SA, Berezowsky V. Antigen-bearing Langerhans cells in skin, dermal lymphatics and in lymph nodes. Cell Immunol 1976;25:137-51. Sonoda Y, Asano S, Miyazaki T, Sagami S. Electron microscopic study on Langerhans cells and related ceils in lymph nodes of DNCB-sensitive mice. Arch Dermatol Res 1985;277:44-54. Stobo JD. Lymphocytes. In: Stites DP, Stobo JD, Fudenberg J J, Wells JV, eds. Basic & clinical immunology. 5th ed. Los Altos, Calif: Lang Medical Publications, 1984:6976. Polak L. Immunological aspects of contact sensitivity. In: Karger S, PD Basel, et al eds. Monographs in allergy, vol 15. Switzerland: Thiir Ag Offsetdruck, Pratteln, 1980. Drutz D J, Mills J. Immunity & infection. In: Stites DP, Stobo JD, Fudenberg J J, Wells JV, eds. Basic & clinical immunology. 5th ed. Los Altos, Calif: Lang Medical Publications, 1984:197-222. Ortaldo JR, Herbermann RR. Augmentation of natural killer activity. In: Lotzovh E, Herberman RB, eds. Imrnunobiology of natural killer cel]s, vol 2. Boca Raton, Fla: 1986:0RC Press, Inc, 145-62. Merrill JE. The implications of aberrant natural killer (ND) cell activity in nonmalignant chronic diseases. In: Lotzovh E, Herberman RB, eds. Immunobiology of natural killer cells, vol 2. Boca Raton, Fla: CRC Press Inc, 1986:75-87. Fitzgerald PA, Lopez C. Natural killer cells active against viral, bacterial, protozoan, and fungal infections. In: Lotzov~t E, Herberman RB, eds. Imrnunobiology of natural killer cells, vol 2. Boca Raton, Fla: CRC Press Inc, 1986:108-31. Herberman RB. Natural killer cell & antibody-dependent cell-mediated cytotoxicity. In: Stites DP, Stobo JD, Fudenberg J J, Wells JV, eds. Basic & clinical immunology. 5th ed. Los Altos, Calif.' 1984: Lang Medical Publications, 149-50. Nater JP, Barr AJM, Bleumink E. De behandleling van verrucae vulgares met 2,4-dinitrochloorbenzeen (DNCB). Ned Tijdsehr Geneeskd 1979;123:603-6.
I I
Contact immunotherapy of resistant warts M a r k Franklin Naylor, M.D.,* Kenneth H. Neldner, M.D.,* Glenn K. Yarbrough, M.D.,** Timothy J. Rosio, M.D.,*** Manuel Iriondo, M.D.,****, and James Yeary, M.D.*
Lubbock, TX, Scottsdale, AZ, Marshfield, WI, and Miami, FL Contact immunotherapy has been proved effective in the treatment of resistant warts. This report chronicles our experience with a new contact immunotherapy agent, diphenylcyclopropenone. We have achieved a cure rate of 62% in 45 patients with resistant warts of all types who came to our general dermatology clinic. Cure rates may be lower in patients who have experienced multiple treatment failures. The majority of cures were obtained within 3 to 4~ months. Although it appears somewhat less effective than published reports ott dinitrochlorobenzene contact immunotherapy, diphenylcyclopropenone contact imrnunotherapy is an effective treatment for resistant warts and avoids any potential problems from mutagenicity. (J AM ACADDERMAXOL 1988;19:679-83.)
In 1973 Lewis reported the first use of dinitrochlorobenzene contact immunotherapy for resistant warts, with a cure rate in compliant patients of 91%. I There have been at least five additional reports of the use of dinitrochlorobenzene published between 1973 and 1984. 2.6 Methods varied greatly but results were similar; cure rates ranged between 69% and 87% in these series (Fig. 1). In 1983 Happle et al. 7 published a series of patients with alopecia areata treated with a new agent, diphenylcyclopropenone. Because the treatm e n t of alopecia areata with dinitrochlorobenzene was one of the known methods of contact immunotherapy, diphenylcyclopropenone seemed a promising agent for wart contact immunotherapy. There has been one report in the German literature of the use of diphenylcyclopropenone for this purpose in a small n u m b e r of patients? In theory, any substance that can reliably induce a type IV hypersensitivity response can be used for
From the Department of Dermatology, Texas Tech University Health Sciences Center, Lubbock*; Seottsdale**; Department of Dermatology, Marshfield Clinic, Marshfield***; and Department of Dermatology and Cutaneous Surgery, University of Miami School of Medicine, Miami.**** Reprint requests to: Dr. Mark Franklin Naylor, Assistant Professor of Dermatology and Internal Medicine, Department of Dermatology, Texas Tech University Health Sciences Center, Lubbock, TX 79430.
treatment. In practice, what is needed is a substance that is available, able to sensitize at least 95% of normal individuals, chemically stable, and economical. More importantly, it should be free of significant adverse effects and not found in human environments. Availability problems are similar for the three compounds that have been used for contact immunotherapy: dinitrochlorobenzene, diphenylcyclopropenone, and squaric acid dibutyl ester. All three are potent sensitizers. Stability is a problem with both of the latter two. Squaric acid dibutyl ester needs refrigeration and possibly special solvents and additives to maintain potency because of its tendency to undergo hydrolysis? Diphenylcyclopropenone must be stored in dark glass in a dark place because of its tendency to undergo photodecomposition.~~ Dinitrochlorobenzene is the most economic of the three agents, listed at $0.15 per gram (100 gm quantity) in the 1986-1987 Aldrich Chemical Company catalog. Diphenylcyclopropenone is available from the same source at $7.83 per gram (5 gm quantity). The cost of squarie acid dibutyl ester was quoted by Case et al. '1 in 1984 at approximately $37.50 per gram (10 gm quantity). With the dilutions commonly used, all these agents are economically feasible, although dinitroehlorobenzene has a considerable pricing advantage. Diphenylcyclopropenone1~ and squaric acid 679
Journal of the American Academy of Dermatology
Naylor et aL
680
Table I. Treatment results by wart subtype
Warttype .. I
No. treated [
Allpatlentseured
Plantar Periungual Multiple glabrous Combined Palmar Genital
16 14 4 6 3 2
12 (75%) 9 (64%) 3 (75%) 3 (50%) 1 (17%) 0 (0%)
Total
45
28 (62%)
dibutyl ester s, ~3-z5are non mutagenic in the Ames test, unlike dinitrochlorobenzene) 3. t6.17 Nonetheless, we are not aware o f any adverse effects of any of these agents, apart from the fact that they are contact allergens. Case et al. tl, ~g were aware of only two patents in the United States that contained squaric acid dibutyl ester. Although diphenylcyclopropenone may someday be useful to chemical engineers as a synthetic intermediate, 19 we do not know of any commercial uses for it presently in this country. MATERIALS AND METHODS Sixty-two consecutive patients with resistant warts seen in the Texas Tech Dermatology Clinic were treated with diphenylcyclopropenone contact immunotherapy. The definition of a resistant wart was left to the judgment of individual physicians, but generally this included large or multiple warts in plantar, periungual, and palmar locations as well as warts in other areas resistant to previous therapy. All sensitizing and treatment solutions of diphenylcyclopropenone were based on dilutions of a 1.0% stock solution in acetone. Patients were sensitized before treatment with 0.2 ml of a 0.1% solution (0.2 mg diphenylcyclopropenone) applied to the medial arm skin under a light bandage for 24 hours. Patients were instructed to keep the area dry for 24 hours and to apply a topical steroid 24 hours after the reaction was initially noted. Patients were seen in 2 weeks. If no reaction had occurred, diphenyleyelopropenone was reapplied, usually with a stronger solution (0.2 ml of a 0.2% solution [0,4 rag]). I f no sensitization had occurred after an additional 2 weeks, a third attempt was made (0.2 ml of a 1.0% solution [2.0 mg]). After sensitization had occurred, a 0.01% diphenylcyclopropenone solution (0.10 mg/ml) was applied once a day to induce a low-grade inflammatory reaction in and
immediately adjacent to the wart. Weaker concentrations of 0.004% (0.04 mg/ml) to 0.01% (0.1 mg/ml) were used initially in sensitive areas such as the face or groin. The concentration selected was applied to wet just the wart and not the surrounding normal skin. After 1 week, if the single application was tolerated, a second application was applied to the wart after allowing the first one to dry. If this was tolerated for a week, a stronger solution was then applied, beginning again as a single application once a day. Patients were followed at intervals of 2 weeks. The sequence of solution strengths followed was 0.01%, 0.025%, 0.1%, 0.5%, and finally 1.0%. Unused solutions of diphenylcyclopropenone were discarded after 3 months. All treatment was carried out at home. Diphenylcyclopropenone solutions were dispensed to the patients in dark glass bottles and stored in a refrigerator. If the warts were markedly hyperkeratotic, a keratolyric agent, usually 100% trichloroaeetic acid, was applied 6 to 12 hours before diphenylcyclopropenone applications, 3 to 7 times a week. This was felt to aid penetration of the diphenylcyclopropenone solution into the wart. Hyperkeratofic warts were usually pared at clinic visits. Compliance was considered satisfactory if the patients generally kept their appointments and followed instructions to the best of their ability. Partially compliant patients were those who did not stop therapy but had irregular follow-up, generally missing more than two scheduled appointments without notifying clinic personnel. Cure was defined as no clinical evidence of warts 1 months after stopping therapy. Patients who noted regrowth of their warts within 1 month of stopping treatment resumed therapy and were not counted as relapses unless they failed to respond to subsequent therapy. RESULTS Our cure rate was 62% in 45 evaluable patients with resistant warts of all types. W e were able to sensitize 60 of 62 patients in whom it was attempted (97%). One patient (2%) required three attempts, 14 patients (23%) required two attempts, and 45 were sensitized on the first attempt (75%). Seventeen of 62 consecutive patients were not included for analysis. Two who did not sensitize were excluded, one because of a spontaneous resolution during sensitization attempts. A third patient was initially misdiagnosed as having multipie palmar and plantar warts and was later found
Volume 19 Number 4 October 1988
Contact immunotherapy of resistant warts 681
~ / / / / / / / / / / / / / / / / / / / ~
~
8
0
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%
~
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Dunairin
% 1
& Millikan
't
DPC i
30 40 50 % pafi~t~Cured
I
I
60
70
I0
8
I
I
90
1130
Fig. 1. Comparison of immunotherapy series for diphenylcyclopropenone (DPC) treatment. Figure shows only patients who had one or more prior treatment failures (cure rate 60% for diphenylcyclopropenonewith one or more prior treatment failures; cure rate 62% for all patients receiving diphenylcyelopropenone in our series).
to have an unclassified palmoplantar genodermatosis. Six patients were lost to follow-up. In two partially compliant patients therapy was incomplete at the time of this writing. Six patients withdi'ew from therapy for reasons other than side effects or lack of efficacy. The 45 patients included for analysis consisted of 22 men and 23 women (mean age, 22.8 years; range, 5 to 73 years). Cure rates by wart location are listed in Table I. Wart subtypes (anatomic locations) included 16 plantar, 14 periungual, 3 palmar, 2 genital, 4 multiple glabrous, and 6 cases with combinations of wart types. Curiously, partially compliant patients had the same cure rate (10 of 16, or 62.5%) as compliant patients (18 of 29, or 62%), although compliant patients had faster response times. The number of prior treatments was similar in both groups. Treatment duration for compliant patients ranged from 0.8 to 8.6 months (mean, 3.9 months; median, 3.4 months); mean follow-up time for patients whose warts were cured was 5 months (median, 4.1 months; range, 1.5 to 11.9 months). T h e majority of cures occurred within the first 3 to 4 months of therapy. In compliant patients, no additional cures were seen beyond 5.3 months of therapy. Sixty percent of the patients who experienced cure were followed for 3 months or more after the cessation of therapy. One patient relapsed 1 89 months after stopping therapy when she became pregnant. A major factor beating on outcome was location.
The highest cure rates were achieved in multiple glabrous warts (3 of 4, or 75%), plantar warts (12 of 16, or 75%) and in periungual warts (9 of 14, or 64%). Multiple combined warts (usually glabrous plus plantar or palmar skin) had a cure rate of 3 of 6, or 50%. Cure rates differed as assessed by chi-square analysis (p < 0.01; degrees of freedom,
4). While not .conclusive, our experience tended to confirm the negative prognostic effect of prior treatment failures on prognosis (Fig. 2). Palmar warts had the worst outcome; only 1 of 6, or 17% was cured. W h y plantar warts seem to be so much more responsive to topical immunotherapy than palmar warts is not dear, but it may involve mechanical factors such as hand washing, which could remove deposits of the antigenic substance. Because only two cases of genital warts were treated in this series, the numbers were too small for even preliminary conclusions. However, our impression from subsequent experience is that contact immunotherapy may have a role in combined regimens, but it is not dramatically effective when used alone. Side effects were not a problem in the majority of patients and did not prevent a successful outcome in most of those that experienced them. Typically, patients achieved slow wart involution without significant itching or discomfort. Overall, however, 22 of 45 (49%) had at least one side effect. Ten of 45 (22%) developed allergic contact
Journal of the American Academy of Dermatology
682 Naylor et al.
80
6O
r,.)
20
0 0
1
2
3
4
5
N u m b e r of Prior Treatments
Fig. 2. All patients. Boxes within the bars represent the number of patients cured divided by the total who received that number of treatments. dermatitis in a nontreatment site. This was generally not severe and responded in most cases to topical steroid therapy and more careful instruction on handling the solutions. Patients using higher concentrations of diphenylcyclopropenoneor treating multiple warts were more likely to experience this side effect. Ten of 45 (22%) had an unusually severe reaction at the treatment site (vesicular or markedly symptomatic). This was handled by stopping therapy for a few days, making sure the patient understood application instructions, and carefully restarting therapy, usually at a lower concentration. Three of 45 (7%) had unusually severe reactions at the sensitization site. Only two patients had more than one s{de effect. DISCUSSII~,I Contact immunotherapy may work by the induction of a type IV hypersensitivity response in papilloma virus-infected tissue, leading to wart destruction. Precise immunologic mechanisms are unclear 2 but probably involve a non wart-antigenspecific, cell-mediated process triggered by the immune stimulus? Previous investigators have emphasized the role of specific cell-mediated "unmunity?,4 although direct evidence is lacking? In our experience it is unusual to see resolution of warts in areas not actively treated, which makes wart-antigen-specific T cell cytotoxicity seem less likely to be the primary mechanism of action. Furthermore, reinfections occur, suggesting that the long-lasting immunity typical of antigen-specif-
ic cell-mediated immunity is not conferred by therapy. According to present theory of soluble antigen type IV skin hypersensitivity, the cellular mechanism is triggered by hapten conjugation, possibly with Langerhans cell surface proteins followed by presentation of the protein/hapten antigen complex to helper lymphocytes in the lymph nodes.2~ Subsequently, specific helper and cytotoxic lymphocytes are activated)' These specific effector cells recirculate to the site of inoculation, where a very similar or identical protein carrier/hapten antigen complex is still present. 25 Cells displaying antigen complex may be lysed by specific suppressor-cytotoxic lymphocytes~6 and various lymphokines released by effector lymphocytes.24 If a virus-infected cell had the antigen complex bound to it, it might be destroyed directly. It has been suggested that the carrier protein involved in the antigen complex may be viral in origin.4 If the viral antigen-containing complex is recognized because it is conjugated with diphenylcyclopropenone, the diphenylcyclopropenone moiety would be necessary for effector cell recognition and subsequent lysis of the virus-infected cell. Hence, while this may be the primary mechanism, it is not equivalent to naturally acquired, specific viral immunity. Other possibilities exist to explain at least some of the treatment effect. It is plausible that the major role of the specific effector lymphocyte response is to release lymphokines, such as interleukin-2 and interferon, that can augment the functions of nonspecific cell-mediated defenses, such as phagocytes and natural killer cells. 27,28It is known that virus-infected cells are susceptible to lysis by natural killer cells,2. which are thought to be important in defense against viral infections and cancer.29'30 A role for humoral factors is suggested by data from Eriksen,5 who showed an increased incidence in complement-binding wart virus antibodies from 15% before contact immunotherapy with dinitrochlorobenzene to 48% afterward. Natural killer cells, along with macrophages and granulocytes, are effector cells for antibody-dependent cell-mediated cytotoxicity. 27,3' Here the effector cells bind and lyse antibody-bearing target cells, providing a
Volume 19 Number 4 October 1988
plausible involvement for antibodies in the contact immunotherapy mechanism. In general, contact immunotherapy is less painful and scarring than other types of wart treatment. In contrast to most destructive modalities, it can be accomplished without interfering with activities such as jogging, swimming, or other athletic endeavors. In properly selected patients contact immunotherapy is an excellent modality for treating certain types of resistant warts, particularly in plantar and periungual locations. REFERENCES 1. Lewis HM. Topical immunotherapy of refractory warts. Cutis 1973;12:863-67. 2. Bekhor PS, Entwisle BR, McKenzie IFC. Topical DNCB therapy for resistant warts. Australas J Dermatol 1978;19:28-30. 3. Claudy AL, Roche H, Gogue Y. Traitement des verrues multiples et r6cidivantes par induction d'une hypersensibilit6 retard6e. Ann Derrnatol V6n~r~ol 1980;107:551-3. 4. Dunagin WG, Millikan LE. Dinitrochlorobenzene immunotherapy for verrucae resistant to standard treatment modalities. J AM ACADDERMATOL1982;6:40-5. 5. Eriksen K. Treatment of the common wart by induced allergic inflammation. Dermatologiea 1980;160:161-6. 6. Goihman-Yahr M, Fernandez J, Convit J. Immunoterapia de las verrugas vulgares diseminadas con dinitrochlorobenceno. Med Cutan Iber Lat Am 1976;2:187-94. 7. Happle R, Hausen BJ, Wiesner-Menzel L. Diphencyprone in the treatment of alopecia areata. Acta Derm Venereol (Stock.h) 1983;63:49-52. 8. Wiesner-Menzel L, Happle R. Riickbildung von plantarwarzen naeh behandlung mit diphencyprone. Z Hautkr 1983;59:1080-3. 9. Wilkerson MG, Henkin J, Wilkin JK, Smith RG. Squaric acid and esters: Analysis for contaminants and stability in solvents. J AM ACADDERMATOL1985;13:229-34. 10. Wilkerson MG, Henkin J, Wiikin JK, Smith RG. Diphenylcyclopropenone: Examination for potential contaminants, mechanisms of sensitization, and photochemical stability. J AM ACADDERMATOL1984;11:802-7. 11. Case PC, Mitchell A J, Swanson NA, Vanderveen EE, Ellis CN, Hesdington JT. Topical therapy of alopecia areata with squaric acid dibutylester. J AM AcAo DERMATOE 1984;10:447-51. 12. Stute J, Hausen BM, Schulz KH. Dephenylcyclopropenein stark wirksames kontakallergen. Derm Beruf Umwelt 1981;29:12-5. 13. Strobel R, Rohrborn G. Mutagenic and cell transforming activities of 1-chlorc~2,4 dinitrochlorobenzene (DNCB) and squaric acid dibutyl ester (SADBE). Arch Toxicol 1980;45:307-14. 14. Wilkerson MG, Wilkin J-K, Smith RG. Contaminants of dinitrochlorobenzene. J AM ACAD DERMATOL 1983;9: 554-7. 15. Happle R, Kalveram K J, Buchner U, et al. Contact allergy as a therapeutic tool for alopecia areata: Applica-
Contact immunotherapy of resistant warts 683
16. 17. 18. 19.
20. 21. 22.
23.
24.
25. 26.
27.
28.
29.
30.
31.
tion of squaric acid dibutyl ester. Dermatologica 1980;161:289-97. Summer KH, Goggelmann W. 1-Chloro-2,4-dinitrobenzene depletes glutathione in rat skin and is mutagenic in Salmonella typhimuriurn. Murat Res 1980;77:91-3. Kratta J, Goeiz G, Vizethum W, Strobel R. Dinitrochlorobenzene: Influcnce on the cytochrorne P-450 system and mutagenic effects. Arch Dermatol Res 1979;266:315-8. Noster U, Hausen BM, Drische B, et al. Squaricacid-diethylester--a strong sensitizer. Contact Dermatitis 1976;2:99-104. Wadsworth DR. Reagents for cyclopropenium chemistry. In: Kodak laboratory chemicals news. Kodak publ no JJ60-871. Rochester, NY: Eastman Kodak Company, 1987:2. Lever WF, Schaumburg-Lever G, eels. Histopathology of the skin. 6th ed. Philadelphia: JB Lippincott Co, 1983:97. Shelley WB, Juhlin L. Selective uptake of contact allergens by the Langerhans cells. Arch Dermatol 1977; 113:187-92. Silberberg-Sinakin I, Thorbecke G J, Baer RL, Rosenthal SA, Berezowsky V. Antigen-bearing Langerhans cells in skin, dermal lymphatics and in lymph nodes. Cell Immunol 1976;25:137-51. Sonoda Y, Asano S, Miyazaki T, Sagami S. Electron microscopic study on Langerhans cells and related ceils in lymph nodes of DNCB-sensitive mice. Arch Dermatol Res 1985;277:44-54. Stobo JD. Lymphocytes. In: Stites DP, Stobo JD, Fudenberg J J, Wells JV, eds. Basic & clinical immunology. 5th ed. Los Altos, Calif: Lang Medical Publications, 1984:6976. Polak L. Immunological aspects of contact sensitivity. In: Karger S, PD Basel, et al eds. Monographs in allergy, vol 15. Switzerland: Thiir Ag Offsetdruck, Pratteln, 1980. Drutz D J, Mills J. Immunity & infection. In: Stites DP, Stobo JD, Fudenberg J J, Wells JV, eds. Basic & clinical immunology. 5th ed. Los Altos, Calif: Lang Medical Publications, 1984:197-222. Ortaldo JR, Herbermann RR. Augmentation of natural killer activity. In: Lotzovh E, Herberman RB, eds. Imrnunobiology of natural killer cel]s, vol 2. Boca Raton, Fla: 1986:0RC Press, Inc, 145-62. Merrill JE. The implications of aberrant natural killer (ND) cell activity in nonmalignant chronic diseases. In: Lotzovh E, Herberman RB, eds. Immunobiology of natural killer cells, vol 2. Boca Raton, Fla: CRC Press Inc, 1986:75-87. Fitzgerald PA, Lopez C. Natural killer cells active against viral, bacterial, protozoan, and fungal infections. In: Lotzov~t E, Herberman RB, eds. Imrnunobiology of natural killer cells, vol 2. Boca Raton, Fla: CRC Press Inc, 1986:108-31. Herberman RB. Natural killer cell & antibody-dependent cell-mediated cytotoxicity. In: Stites DP, Stobo JD, Fudenberg J J, Wells JV, eds. Basic & clinical immunology. 5th ed. Los Altos, Calif.' 1984: Lang Medical Publications, 149-50. Nater JP, Barr AJM, Bleumink E. De behandleling van verrucae vulgares met 2,4-dinitrochloorbenzeen (DNCB). Ned Tijdsehr Geneeskd 1979;123:603-6.