British Journal of Urology (1975), 47, 97-101
The Diagnostic and Prognostic Significance of Delayed Hypersensitivity Skin Testing in Patients with Urological Cancer GORDON WILLIAMS
and
J. E. CASTRO
Urological Unit, Department of Surgery, Hammersmith Hospital, and Royal Postgraduate Medical School, London
There is considerable evidence for the importance of immunological mechanisms in the control of cancer both in animals (Foley, 1953; Delorme and Alexander, 1964; Rapp, 1968) and man (Hellstrom et a/., 1968; Sophocles and Nadler, 1971). Patients with impaired immunological competence have an increased incidence of tumours (Dent, Petersen and Good, 1968; Penn and Starzl, 1972) and patients with malignant tumours may fail to respond to cutaneous antigenic stimulation (Hughes and MacKay, 1965; Solowey and Rapaport, 1965). This study was undertaken to investigate cellular immunity in patients with cancer of the bladder or prostate by assessing their cutaneous delayed hypersensitivity responses to four antigens, di-nitrochlorbenzene (DNCB), Candida extract, streptokinase/streptodornase (SKSD) and purified protein derivitative (PPD). It is unlikely that patients would have made previous contact with DNCB and the response to sensitisation with it, is a test of the ability to react to a new antigen. The other three antigens are recall antigens and a response to them depends upon previous infection with sensitisation, a negative response may therefore reflect either diminished immunological reactivity or no previous contact with the appropriate antigen. Responses to these antigens in patients with cancers of the bladder and prostate have been compared with controls. The findings have been correlated with the stage of the tumour, the effects of treatment and the survival of the patient.
Materials and Methods Patients All patients attending with symptoms or signs suggestive of bladder or prostatic cancer were studied. After investigation, 15 patients (12 male and 3 female) with ages ranging from 47 to 71 years (mean 62 years) were found not to have a malignant lesion and these were controls. 21 patients with histologically proven prostatic cancer aged 56 to 84 (mean 71 years) and 59 patients (47 male, 12 female) with ages ranging from 40 to 86 years (mean 66 years) who had histologically proven bladder cancer were studied. Certain factors impair the immune response and for this reason patients with blood ureas above 100 mg % and patients who had received radiotherapy or cytotoxic chemotherapy within the previous 3 months were excluded from the study. Tests were not performed within 3 weeks of general anaesthesia.
DCNB Sensitisation and Testing Sensitisation of patients to DNCB was attempted by 01 ml of a 5 % solution of DNCB (BDH Chemicals) in acetone, applied to the absorbent part of a 343 cm* airstrip adhesive dressing (Elastoplast), and allowed to dry. Read at the 30th Annual Meeting of the British Association of Urological Surgeons in Torquay, June 1974. 4711-G 97
98
BRITISH JOURNAL OF UROLOGY
The treated plaster was then placed on the volar aspect of the patient’s right forearm. To test for previous chance sensitisation 0.1 ml of 0.1 % DNCB was applied in the same way to a different part of the forearm. Both plasters were removed 72 hours later. The response to sensitisation was tested 14 to 21 days later by applying 0.1 ml of 0.1 % DNCB as previously described and observing the test 48 hours later. An area of erythema and induration involving more than half the test site was recorded as a positive response. If there was a negative response the test dose was re-applied and read again after 48 hours.
Recall Antigens Candida extract (Hollister Stier Laboratories), SKSD (Lederle Laboratories) and PPD (Evans Laboratories) were given as intradermal injections on the volar aspect of the forearm. A positive reaction was recorded if an area of erythema and induration more than 5 mm in diameter was present 48 hours after injection.
Results No systemic reactions were observed to any of the antigens. 3 patients developed blistering at the site of the sensitising dose of DNCB, but this healed rapidly with no residual scarring after treatment with topical steroids. In some patients pigmentation at the site of sensitisation with DNCB remained for up to 6 weeks. Reactivity to DCNB None of the patients, either control or with tumour, showed chance sensitisation to DNCB (Table I). Table I
Ca. Prostate Response to DNCB Stage 0 Control Overall Incidental Stage 11-111 Stage 1V & & & & & No. No. No. No. No. No. No. No. No. No. Positive Tested Positive Tested Positive Tested Positive Tested Positive Tested 15
15
21
21
5
5
9
9
7
7
Incidence of delayed cutaneous hypersensitivity to DNCB in control group and those with carcinoma of the prostate.
All 15 control patients were sensitised to DNCB and reacted to the test dose. Similarly, all 21 patients with prostatic cancer reacted to the test dose (Table I) despite differences in the stage of the disease and the treatment given. 13 of 16 patients with advanced prostatic cancer were already being treated by oestrogens, orchidectomy or a combination of the two at the time of treatment. 43 of 54 patients (80 %) with carcinoma of bladder showed a positive response to testing with DNCB (Table 11). The incidence of a positive response was related to the stage of the tumour and prognosis. All of the patients who had been free from tumour for more than 1 year responded but a highly significant number of patients with advanced disease (Stages 3 and 4)failed to respond to DNCB (Table 111). Failure to respond to repeated test doses of DNCB was associated with a bad prognosis, for 7 of 8 such patients died within 3 months of the first test. 2 patients who did not respond initially converted to positive responses after total surgical removal of their tumours. 1 patient who had an initial positive response now shows no response and this is associated with recurrence of tumour.
99
DELAYED HYPERSENSITIVITY SKIN TESTING IN PATIENTS WITH UROLOGICAL CANCER
Table II
Ca. Bladder Response to DNCB Control b
-
7
-
No. No. Positive Tested
No. No. Positive Tested 15
Tumour Free 1 Year
Overall
15
43
Tumour Free 5 Years
b
No. No. Positive Tested
54
14
14
No. No. Positive Tested 13
13
Incidence of delayed cutaneous hypersensitivity to DNCB in the control group and those with carcinoma of the bladder who had been free of tumour for more than I year.
Table III Ca. Bladder Response to DNCB ~~~
~
Stage I Stage 111 Stage I1 & & & r d 7 No. No. No. No. No. No. No. No. Positive Tested Positive Tested Positive Tested Positive Tested
~~
Control
_ _
~-
15
15
_
26
28
_
~
12
~
12
~
2
_
Stage IV 7 -
No. No. Positive Tested
__ _ _~ ~
5
1
6
Incidence of delayed cutaneous hypersensitivity to DNCB comparing one control group with 4 stages of bladder carcinoma. Controls v. Stage 111-P by Fishers Extract Test = 0.009. Controls v. Stage IV-P by Fishers Extract Test = 0.0003.
Reactivity to Recall Antigens The responses of patients with cancers of the prostate and bladder to individual recall antigens and to all 3 recall antigens have been observed. The only significant finding was the inability of patients with advanced bladder tumours to mount a response to PPD (Table IV). There was no correlation between the response to candida or SKSD with the stage of the disease or response to treatment. Neither was there a correlation when the collective responses to antigens was observed.
Discussion This study showed that delayed hypersensitivity skin testing could be simply performed with minimal morbidity in patients with urogenital cancer. The results show a clear and previously unreported difference in response to DNCB between those patients with cancer of the prostate and those with cancer of the bladder. The finding that all patients with prostatic cancer reacted to DNCB, irrespective of the extent of the tumour or the therapy, is interesting. 13 of the 16 patients studied had been treated by orchidectomy or oestrogens and both of these treatments may affect immunological reactivity. Orchidectomy increases the immunological response of mice to a variety of antigens particularly those that depend upon cell mediated immunity for their expression (Castro, 1974). Oestrogen administration causes atrophy of lymphoid tissues, but oestrogenic enhancement of natural or induced circulating antibody levels have been observed in many (von Haam and Rosenfeld, 1942) but not all reports 47/ 1-G*
100
BRITISH JOURNAL OF UROLOGY
Table IV Ca. Bladder Response to Skin Test Antigens Controls 7
Antigen PPD SKSD Candida
No. No. Positive Tested
Stage I Stage 11-111 & 7 No. No. No. No. Positive Tested Positive Tested
11
11
7
8
11 11
8 5
7
15 17
17
6 3 5
Stage IV &
No. No. Positive Tested
9
2
9
5
9
2
6 6 6
Incidence of delayed cutaneous hypersensitivityto the recall antigens in patients with carcinoma of the bladder compared with the control group. -P by Fishers Extract Test = 0.007. PPD controls v. Stage I PPD controls v. Stage II/III-P by Fishers Extract Test = 0.07. PPD controls v. Stage IV -P by Fishers Extract Test = 0.006.
(Warr and Slijivic, 1972) and oestrogens have stimulatory effects on macrophage activity. These effects of endocrine manipulations on the immune response could explain most of our results, but 3 patients with advanced prostatic cancer had not received endocrine treatment yet reacted to DNCB. Until the mechanisms of non-specific immune depression (anergy) in patients with advanced tumours are more clearly understood it is not possible to explain these findings. In patients with bladder cancer there was good correlation between reactivity to DNCB and the stage of the tumour and prognosis. However, a number of patients who had advanced bladder cancer but who are not included in this study because they were uraemic or receiving cytotoxic chemotherapy died from their disease whilst still reacting to DNCB. The use of graded test doses of DNCB so that a dose response curve is obtained may be a more accurate method for assessment of such patients. Whilst there is little doubt that host response is important in tumour growth it is not clear whether failure to respond to non-specific antigens is the cause of tumour dissemination or whether it is a consequence of it. Factors within the host which influence immune status are probably legion (Kongshavn and Lapp, 1972) but the immunosuppressive effects of inadequate nutrition (Jose and Good, 1972) and cortisone (Medawar and Sparrow, 1956) are well known and they may contribute to non-specific immune depression in patients with advanced malignancy. The results of skin testing with candida antigen, SKSD and PPD were of little value in the assessment of patients with urogenital cancer. Only the response to PPD showed some correlation with the stage of the bladder cancer. However, response to these recall antigens depends upon previous natural sensitisation; a negative reaction may result from either anergy associated with malignancy or the absence of previous sensitisation. Changes in the response to repeated tests with recall antigens may be more valuable in assessment of patients with malignancy but such testing may be associated with severe allergic reactions.
Summary The responses to several skin test antigens of patients with bladder or prostatic cancer has been compared with responses of normal controls. All of the controls and all of the patients with prostatic cancer (irrespective of the stage of the tumour or the method of treatment) showed responses to dinitrochlorbenzene. 80% of all patients with bladder cancer responded to DNCB, but a highly significant number of patients with advanced disease showed no response. This test appears especially useful in predicting the prognosis in patients with bladder tumours and its routine use is recommended.
DELAYED HYPERSENSITIVITY SKIN TESTING IN PATIENTS WITH UROLOGICAL CANCER
101
Response to candida extract, streptokinase/streptodornase (SKSD) and purified protein derivative (PPD) were also studied. No conclusion could be drawn as to their value as a prognostic index. References CASTRO, J. E. (1974). Orchidectomy and the immune response of orchidectomized mice to antigens. Proceedings of the Royal Society. London, B, 437-451. DELORME, E. J. and ALEXANDER, P. (1964). Treatment of primary fibrosarcoma in the rat with immune lymphocytes. Lancet, 2, 117-120. DENT,P. B., PETERSON, R. D. A. and GOOD,R. A. (1968). In: Immunological Deficiency Diseases in Man, Eds. R. A. Good and D. Bergsma, Birth Defects Original Article Series, Vol. 4, No. 1. New York: National Foundation Press p. 443. FOLEY,E. J. (1953). Attempts to induce immunity against mammary adenocarcinoma in inbred mice. Cancer Research, 13, 578-580. VON HAAM, E. and ROSENFELD, 1. (1942). The effect of estrone on antibody production. Journal of Immunology, 43, 109-117. HELLSTROM, I. E., HELLSTROM, K. E., PIERCE,G . E. and BILL,A. H. (1968). Demonstration of cell-bound and humoral immunity against neuroblastoma cells. Proceedings of the National Academy of Sciences, 60, 12311238. HUGHES, L. E. and MACKAY, W. D. (1965). Suppression of the tuberculin response in malignant disease. British Medical Journal, 2, 1346-1348. JOSE,D. G . and GOOD,R. A. (1972). Immune resistance and malnutrition. Lancet, 1, 314. KONGSHAVN, P. A. L. and LAPP,W. S. (1972). Immunosuppressive effect of male mouse submandibular gland extracts on plaque-forming cells in mice: abolition by orchiectomy. Immunology, 22, 227-230. MEDAWAR, P. B. and SPARROW, E. M. (1956). The effects of adrenocortical hormones, adrenocorticotrophic hormone and pregnancy on skin transplantation immunity in mice. Juurnal of Endocrinology, 14, 240-156. PENN,I. and STARZL, T. E. (1 972). Immunosuppression and cancer. Transplantation Proceedings, 5, 943-947. RAPP,F. (1968). The role of the viral genome in oncogenesis. Cancer Research, 28, 1832-1834. SOLOWEY, A. C. and RAPAPORT, F. T. (1965). Immunologic responses in cancer patients. Surgery Gynecology and Obstetrics, 121, 756-670. SOPHOCLES. A. M. and NADLER. S. H. (1971). Immunologic aspects of cancer. Surgery, Gynecology and Obstetrics, 133, 321-331. WARR,G. W. and SLIJIVIC, V. (1972). Stilboestrol-induced depression of the antibody response. Experientia, 28, 1356-1359.
The Authors Gordon Williams, FRCS, Registrar. J. E. Castro, PhD, MS, FRCS, Senior Registrar.
The Diagnostic and Prognostic Significance of Delayed Hypersensitivity Skin Testing in Patients with Urological Cancer GORDON WILLIAMS
and
J. E. CASTRO
Urological Unit, Department of Surgery, Hammersmith Hospital, and Royal Postgraduate Medical School, London
There is considerable evidence for the importance of immunological mechanisms in the control of cancer both in animals (Foley, 1953; Delorme and Alexander, 1964; Rapp, 1968) and man (Hellstrom et a/., 1968; Sophocles and Nadler, 1971). Patients with impaired immunological competence have an increased incidence of tumours (Dent, Petersen and Good, 1968; Penn and Starzl, 1972) and patients with malignant tumours may fail to respond to cutaneous antigenic stimulation (Hughes and MacKay, 1965; Solowey and Rapaport, 1965). This study was undertaken to investigate cellular immunity in patients with cancer of the bladder or prostate by assessing their cutaneous delayed hypersensitivity responses to four antigens, di-nitrochlorbenzene (DNCB), Candida extract, streptokinase/streptodornase (SKSD) and purified protein derivitative (PPD). It is unlikely that patients would have made previous contact with DNCB and the response to sensitisation with it, is a test of the ability to react to a new antigen. The other three antigens are recall antigens and a response to them depends upon previous infection with sensitisation, a negative response may therefore reflect either diminished immunological reactivity or no previous contact with the appropriate antigen. Responses to these antigens in patients with cancers of the bladder and prostate have been compared with controls. The findings have been correlated with the stage of the tumour, the effects of treatment and the survival of the patient.
Materials and Methods Patients All patients attending with symptoms or signs suggestive of bladder or prostatic cancer were studied. After investigation, 15 patients (12 male and 3 female) with ages ranging from 47 to 71 years (mean 62 years) were found not to have a malignant lesion and these were controls. 21 patients with histologically proven prostatic cancer aged 56 to 84 (mean 71 years) and 59 patients (47 male, 12 female) with ages ranging from 40 to 86 years (mean 66 years) who had histologically proven bladder cancer were studied. Certain factors impair the immune response and for this reason patients with blood ureas above 100 mg % and patients who had received radiotherapy or cytotoxic chemotherapy within the previous 3 months were excluded from the study. Tests were not performed within 3 weeks of general anaesthesia.
DCNB Sensitisation and Testing Sensitisation of patients to DNCB was attempted by 01 ml of a 5 % solution of DNCB (BDH Chemicals) in acetone, applied to the absorbent part of a 343 cm* airstrip adhesive dressing (Elastoplast), and allowed to dry. Read at the 30th Annual Meeting of the British Association of Urological Surgeons in Torquay, June 1974. 4711-G 97
98
BRITISH JOURNAL OF UROLOGY
The treated plaster was then placed on the volar aspect of the patient’s right forearm. To test for previous chance sensitisation 0.1 ml of 0.1 % DNCB was applied in the same way to a different part of the forearm. Both plasters were removed 72 hours later. The response to sensitisation was tested 14 to 21 days later by applying 0.1 ml of 0.1 % DNCB as previously described and observing the test 48 hours later. An area of erythema and induration involving more than half the test site was recorded as a positive response. If there was a negative response the test dose was re-applied and read again after 48 hours.
Recall Antigens Candida extract (Hollister Stier Laboratories), SKSD (Lederle Laboratories) and PPD (Evans Laboratories) were given as intradermal injections on the volar aspect of the forearm. A positive reaction was recorded if an area of erythema and induration more than 5 mm in diameter was present 48 hours after injection.
Results No systemic reactions were observed to any of the antigens. 3 patients developed blistering at the site of the sensitising dose of DNCB, but this healed rapidly with no residual scarring after treatment with topical steroids. In some patients pigmentation at the site of sensitisation with DNCB remained for up to 6 weeks. Reactivity to DCNB None of the patients, either control or with tumour, showed chance sensitisation to DNCB (Table I). Table I
Ca. Prostate Response to DNCB Stage 0 Control Overall Incidental Stage 11-111 Stage 1V & & & & & No. No. No. No. No. No. No. No. No. No. Positive Tested Positive Tested Positive Tested Positive Tested Positive Tested 15
15
21
21
5
5
9
9
7
7
Incidence of delayed cutaneous hypersensitivity to DNCB in control group and those with carcinoma of the prostate.
All 15 control patients were sensitised to DNCB and reacted to the test dose. Similarly, all 21 patients with prostatic cancer reacted to the test dose (Table I) despite differences in the stage of the disease and the treatment given. 13 of 16 patients with advanced prostatic cancer were already being treated by oestrogens, orchidectomy or a combination of the two at the time of treatment. 43 of 54 patients (80 %) with carcinoma of bladder showed a positive response to testing with DNCB (Table 11). The incidence of a positive response was related to the stage of the tumour and prognosis. All of the patients who had been free from tumour for more than 1 year responded but a highly significant number of patients with advanced disease (Stages 3 and 4)failed to respond to DNCB (Table 111). Failure to respond to repeated test doses of DNCB was associated with a bad prognosis, for 7 of 8 such patients died within 3 months of the first test. 2 patients who did not respond initially converted to positive responses after total surgical removal of their tumours. 1 patient who had an initial positive response now shows no response and this is associated with recurrence of tumour.
99
DELAYED HYPERSENSITIVITY SKIN TESTING IN PATIENTS WITH UROLOGICAL CANCER
Table II
Ca. Bladder Response to DNCB Control b
-
7
-
No. No. Positive Tested
No. No. Positive Tested 15
Tumour Free 1 Year
Overall
15
43
Tumour Free 5 Years
b
No. No. Positive Tested
54
14
14
No. No. Positive Tested 13
13
Incidence of delayed cutaneous hypersensitivity to DNCB in the control group and those with carcinoma of the bladder who had been free of tumour for more than I year.
Table III Ca. Bladder Response to DNCB ~~~
~
Stage I Stage 111 Stage I1 & & & r d 7 No. No. No. No. No. No. No. No. Positive Tested Positive Tested Positive Tested Positive Tested
~~
Control
_ _
~-
15
15
_
26
28
_
~
12
~
12
~
2
_
Stage IV 7 -
No. No. Positive Tested
__ _ _~ ~
5
1
6
Incidence of delayed cutaneous hypersensitivity to DNCB comparing one control group with 4 stages of bladder carcinoma. Controls v. Stage 111-P by Fishers Extract Test = 0.009. Controls v. Stage IV-P by Fishers Extract Test = 0.0003.
Reactivity to Recall Antigens The responses of patients with cancers of the prostate and bladder to individual recall antigens and to all 3 recall antigens have been observed. The only significant finding was the inability of patients with advanced bladder tumours to mount a response to PPD (Table IV). There was no correlation between the response to candida or SKSD with the stage of the disease or response to treatment. Neither was there a correlation when the collective responses to antigens was observed.
Discussion This study showed that delayed hypersensitivity skin testing could be simply performed with minimal morbidity in patients with urogenital cancer. The results show a clear and previously unreported difference in response to DNCB between those patients with cancer of the prostate and those with cancer of the bladder. The finding that all patients with prostatic cancer reacted to DNCB, irrespective of the extent of the tumour or the therapy, is interesting. 13 of the 16 patients studied had been treated by orchidectomy or oestrogens and both of these treatments may affect immunological reactivity. Orchidectomy increases the immunological response of mice to a variety of antigens particularly those that depend upon cell mediated immunity for their expression (Castro, 1974). Oestrogen administration causes atrophy of lymphoid tissues, but oestrogenic enhancement of natural or induced circulating antibody levels have been observed in many (von Haam and Rosenfeld, 1942) but not all reports 47/ 1-G*
100
BRITISH JOURNAL OF UROLOGY
Table IV Ca. Bladder Response to Skin Test Antigens Controls 7
Antigen PPD SKSD Candida
No. No. Positive Tested
Stage I Stage 11-111 & 7 No. No. No. No. Positive Tested Positive Tested
11
11
7
8
11 11
8 5
7
15 17
17
6 3 5
Stage IV &
No. No. Positive Tested
9
2
9
5
9
2
6 6 6
Incidence of delayed cutaneous hypersensitivityto the recall antigens in patients with carcinoma of the bladder compared with the control group. -P by Fishers Extract Test = 0.007. PPD controls v. Stage I PPD controls v. Stage II/III-P by Fishers Extract Test = 0.07. PPD controls v. Stage IV -P by Fishers Extract Test = 0.006.
(Warr and Slijivic, 1972) and oestrogens have stimulatory effects on macrophage activity. These effects of endocrine manipulations on the immune response could explain most of our results, but 3 patients with advanced prostatic cancer had not received endocrine treatment yet reacted to DNCB. Until the mechanisms of non-specific immune depression (anergy) in patients with advanced tumours are more clearly understood it is not possible to explain these findings. In patients with bladder cancer there was good correlation between reactivity to DNCB and the stage of the tumour and prognosis. However, a number of patients who had advanced bladder cancer but who are not included in this study because they were uraemic or receiving cytotoxic chemotherapy died from their disease whilst still reacting to DNCB. The use of graded test doses of DNCB so that a dose response curve is obtained may be a more accurate method for assessment of such patients. Whilst there is little doubt that host response is important in tumour growth it is not clear whether failure to respond to non-specific antigens is the cause of tumour dissemination or whether it is a consequence of it. Factors within the host which influence immune status are probably legion (Kongshavn and Lapp, 1972) but the immunosuppressive effects of inadequate nutrition (Jose and Good, 1972) and cortisone (Medawar and Sparrow, 1956) are well known and they may contribute to non-specific immune depression in patients with advanced malignancy. The results of skin testing with candida antigen, SKSD and PPD were of little value in the assessment of patients with urogenital cancer. Only the response to PPD showed some correlation with the stage of the bladder cancer. However, response to these recall antigens depends upon previous natural sensitisation; a negative reaction may result from either anergy associated with malignancy or the absence of previous sensitisation. Changes in the response to repeated tests with recall antigens may be more valuable in assessment of patients with malignancy but such testing may be associated with severe allergic reactions.
Summary The responses to several skin test antigens of patients with bladder or prostatic cancer has been compared with responses of normal controls. All of the controls and all of the patients with prostatic cancer (irrespective of the stage of the tumour or the method of treatment) showed responses to dinitrochlorbenzene. 80% of all patients with bladder cancer responded to DNCB, but a highly significant number of patients with advanced disease showed no response. This test appears especially useful in predicting the prognosis in patients with bladder tumours and its routine use is recommended.
DELAYED HYPERSENSITIVITY SKIN TESTING IN PATIENTS WITH UROLOGICAL CANCER
101
Response to candida extract, streptokinase/streptodornase (SKSD) and purified protein derivative (PPD) were also studied. No conclusion could be drawn as to their value as a prognostic index. References CASTRO, J. E. (1974). Orchidectomy and the immune response of orchidectomized mice to antigens. Proceedings of the Royal Society. London, B, 437-451. DELORME, E. J. and ALEXANDER, P. (1964). Treatment of primary fibrosarcoma in the rat with immune lymphocytes. Lancet, 2, 117-120. DENT,P. B., PETERSON, R. D. A. and GOOD,R. A. (1968). In: Immunological Deficiency Diseases in Man, Eds. R. A. Good and D. Bergsma, Birth Defects Original Article Series, Vol. 4, No. 1. New York: National Foundation Press p. 443. FOLEY,E. J. (1953). Attempts to induce immunity against mammary adenocarcinoma in inbred mice. Cancer Research, 13, 578-580. VON HAAM, E. and ROSENFELD, 1. (1942). The effect of estrone on antibody production. Journal of Immunology, 43, 109-117. HELLSTROM, I. E., HELLSTROM, K. E., PIERCE,G . E. and BILL,A. H. (1968). Demonstration of cell-bound and humoral immunity against neuroblastoma cells. Proceedings of the National Academy of Sciences, 60, 12311238. HUGHES, L. E. and MACKAY, W. D. (1965). Suppression of the tuberculin response in malignant disease. British Medical Journal, 2, 1346-1348. JOSE,D. G . and GOOD,R. A. (1972). Immune resistance and malnutrition. Lancet, 1, 314. KONGSHAVN, P. A. L. and LAPP,W. S. (1972). Immunosuppressive effect of male mouse submandibular gland extracts on plaque-forming cells in mice: abolition by orchiectomy. Immunology, 22, 227-230. MEDAWAR, P. B. and SPARROW, E. M. (1956). The effects of adrenocortical hormones, adrenocorticotrophic hormone and pregnancy on skin transplantation immunity in mice. Juurnal of Endocrinology, 14, 240-156. PENN,I. and STARZL, T. E. (1 972). Immunosuppression and cancer. Transplantation Proceedings, 5, 943-947. RAPP,F. (1968). The role of the viral genome in oncogenesis. Cancer Research, 28, 1832-1834. SOLOWEY, A. C. and RAPAPORT, F. T. (1965). Immunologic responses in cancer patients. Surgery Gynecology and Obstetrics, 121, 756-670. SOPHOCLES. A. M. and NADLER. S. H. (1971). Immunologic aspects of cancer. Surgery, Gynecology and Obstetrics, 133, 321-331. WARR,G. W. and SLIJIVIC, V. (1972). Stilboestrol-induced depression of the antibody response. Experientia, 28, 1356-1359.
The Authors Gordon Williams, FRCS, Registrar. J. E. Castro, PhD, MS, FRCS, Senior Registrar.
