World J. Surg. 1,617-623, 1977

9 1977 by the Soci~t6 Internationale de Chirurgie

Transfer Factor: a Potential Agent for Immunotherapy of Cancer C. RICHARD MEIER, M.D. and ALBERT F. LOBuGLIO, M,D.

Divbion of Hematology and Oncology, Department of Medicine, The Ohio State University, Columbus. Ohio. U.S.A.

Transfer factor (TF) is an extract from human leukocytes which has been shown to transfer specific skin test reactivity to previously nonreactive human recipients, and to produce measurable increases in in Vitro tests of lymphocyte activity. The results of the experimental use of TF as an immuno- therapeutic agent for cancer are reviewed. TF therapy has been associated with tumor regression, temporary stabiliza- tion or reduced need for other treatment modalities in several reported cancer patients, and may have value as an adjuvant therapy in certain malignancies. However, most of the re- ports involve uncontrolled studies, and no agreement exists about the definition of TF donors. Controlled studies and the use of well characterized TF donors are essential before any conclusions can be drawn about the value of TF in the therapy of cancer and other diseases.

The concept of immunotherapy for cancer has in- trigued clinicians for a long time. An ideal immuno- therapy agent, besides being effective against cancer. is one that "should be nonantigenic, nontoxic and could be given in large doses repeatedly." Indeed. Lawrence believed that these last criteria were met by transfer factor [1]. In the early 1950's he originally described the transfer of skin reactivity to tuberculin [2, 3] and streptococcal antigen [2] to previously non- reactive subjects by administration of a leukocyte ex- tract obtained from peripheral leukocytes of reactive individuals. He named the responsible agent transfer factor (TF).

A latency period of several years followed these re- ports. That tuberculin skin reactions were different f rom antibody-mediated skin reactions [4] and re- sembled experimental contact hypersensitivity [5] had been known for a long time, but these findings gained perspective only after the essential role of lyre-

Reprint requests: Albert F. LoBuglio, M.D., University Hospital N-1022, 410 West Tenth Avenue, Columbus, Ohio 43210, U.S.A.

617

phocytes in the rejection of experimental tumor allo- grafts was demonstrated by Mitchison [6]. Indeed. in another important series of animal experiments, the allograft reaction was shown to closely resemble tu- berculin and contact hypersensitivity in its timing, histological appearance, and independence of anti- body [7]. Subsequently, a series of studies [8, 9] re- vealed the existence of 2 or more functionally differ- ent lymphocyte subpopulations. B (bursa-equivalent or bone marrow-derived) cells and T (thymus-depen- dent) cells. It is now known that B lymphocytes are involved in the humoral (antibody) immune re- sponse, while T cells are responsible for skin hyper- sensitivity reactions and graft rejection. Additionally, T cells have the capacity to destroy target cells (tumor cells) by several mechanisms involving both specific sensitization as well as mitogen-dependent cyto- toxicity [10]. In the light of these findings, a signifi- cant observation was that humans with advanced ma- lignancies often have decreased or absent cutaneous hypersensitivity reactions [11. 12], and that vigorous skin reactivity may be correlated with a better prog- nosis relative to patients with the same malignancy who are skin test negative [13, 14]. Consequently, an effective immunotherapeutic agent might be expected to reinstitute skin reactivity while enhancing the pa- tient's lymphocyte reactivity against his malignant cells. In this context, the observations of Lawrence gained intriguing perspective and stimulated consid- erable research activity.

General Character ist ics o f TF

The transfer phenomenon was originally described in humans. To date, no reliable in vitro assay exists despite considerable efforts [15]. Animal models are presently under investigation [16] and may eventually help to clarify some of the problems associated with

618 World J. Surg. Vol. 1, No. 5, September, 1977

design and interpretation of new and old TF experi- melats. However, most information regarding the properties of TF has come from attempts to transfer bacterial or fungal hypersensitivity in man. The ac- tive component(s) of TF have a low molecular weight, since TF is dialyzable and shows delayed elu- tion on Sephadex G-25 chromatography [17, 18]. In the lyophilized state TF remains active for years and DNAse, RNAse, and trypsin do not destroy its activ- ity [2, 19]. Evidence indicates that it contains a nucle- otide peptide hybrid [20] and that hypoxanthine is one component [21]. TF preparations are not immunogenic by themselves and do not contain his- tocompatibiiity antigen [19]. Hepatitis infection asso- ciated with TF therapy is rare, but pain at the site of injection and fever have been reported to be common [22]. TF activity is destroyed by heating at 56 ~ for 30 minutes [23]. Table 1 summarizes the procedures usu- ally employed in transfer factor studies in humans [241.

Therapy of Immunodeficiency States and Infections with Transfer Factor

Certain patients with immunodeficiency states have been regarded as good candidates for TF ther- apy, and these cases presently provide the most con- vincing evidence of the therapeutic value of TF. About 50% of patients with chronic mucocutaneous candidiasis have shown a degree of response to TF treatment [25-28], and improved immune status has also been reported in patients with Wiskott-Aldrich syndrome [29, 30], ataxia telangiectasia [29], chronic coccidioidomycosis [31, 32], and generalized viral in- fections [33-35].

Transfer Factor Therapy in Cancer

Generally, TF therapy has been tried in two cir- cumstances. TF has been used as an adjuvant to con- ventional therapy, i.e., surgery, radiotherapy and/or chemotherapy, at a period of presumably low tumor cell load. The other circumstance has involved pa- tients with widely metastatic disease.

Table 1. Design of transfer factor studies in man. Donor identification Donation of leukocytes (phlebotomy or blood cell

separator) Leukocyte disruption (freeze thaw or sonication) Harvest of low molecular weight components (dialysis,

Ultrafiltration, or chromatography) Volume reduction (lyophilization) Administration (intradermal, subcutaneous, or

intramuscular injection) Documentation of effects (skin tests, in vitro assays,

clinical response)

Most of the trials of TF adjuvant therapy have in- volved patients with osteosarcoma. Levin et al. [36] reported that all of 7 patients responded to adminis- tration of TF as an adjuvant to surgical resection dur- ing a follow-up period of from 7 to 28 months. In our series, 3 out of 5 osteosarcoma patients have done well for 7, 8, and 17 months after surgery combined with adjuvant TF therapy, while the other 2 patients relapsed 4 and 12 months, respectively, after entering the program. Another 2 patients with metastatic osteosarcoma achieved complete remission on com- bination chemotherapy, and remain disease free on TF therapy alone for 11 and 28 months, respectively. In another study of osteosarcoma, TF was compared to adjuvant chemotherapy after surgery for clinically localized disease [37]. In a preliminary report, 4 of 8 TF-treated patients and 4 of 18 chemotherapy pa- tients had relapsed. The cumulative incidence of me- tastases was 8.7 for the TF group and 5.1 for the chemotherapy group per 100 patient-months. Bearden et al. [38] reported 3 out of 6 patients on ad- juvant TF therapy combined with adjuvant chemo- therapy free of recurrence for 7, 11, and 17+ months; the others had relapsed at 4, 6, and 14 months after amputation. It appeared that the patients who re- lapsed had been started on the adjuvant therapy rela- tively late (i.e., more than 2 months after surgery). In the treatment of metastatic osteogenic sarcoma with TF, Levin et al. [36] reported 1 out of 6 responses, and LoBuglio et al. [39] reported 1 patient with sta- tionary disease for 6 months.

Regarding other metastatic cancers, patients with malignant melanoma have been most often treated with TF. Cumulative results from various series [22, 40-47] indicate an overall response rate of 16 out of 64 patients. Obviously, however, not all patients were treated in the same fashion. For example, Krementz et al. [40] transfused viable lymphocytes rather than TF in most of their patients, and some patients from other series had additional radiotherapy [43] or BCG immunization [47] along with TF. "Response" was defined variably or not at all, and was itself reported as quite variable in duration and degree. Other prob- lems concerning the design of such studies in general are discussed below, but especially in melanoma pa- tients a spontaneous coincidental regression is diffi- cult to rule out [47, 48].

TF therapy for metastatic breast cancer has been generally unsuccessful, with only 2 of 12 patients re- sponding in 3 reports [42, 45, 49]. Goldenberg et al. [50, 51] have reported tumor regression or temporary arrest in 2 of 3 patients with nasopharyngeal carci- noma treated with TF from donors assumed to have a history of infection with Ebstein-Barr virus. Silva et al. [45] reported 1 patient with a 10-month remission after TF therapy for metastatic vulvar carcinoma, but

C.R. Meier and A.F. LoBuglio: Immunotherapy of Cancer with Transfer Factor 619

no responses were seen in patients with ovarian can- cer, lung carcinoma, or thymoma (1 each). Quick et al. [52] reported 2 pediatric patients with chronically recurrent obstructing laryngeal papillomatosis. After treatment with TF prepared from family members or from a papillomatosis patient in remission, the inter- vals between required surgical excisions appeared to be longer.

Measurable Effects of Transfer Factor Treatment

Based on the originally described properties of TF, many researchers have tried to develop laboratory methods for quality control of TF preparations be- cause skin reactivity testing is not always practical. In vitro methods include the blastogenic response of do- nor and recipient lymphocyte cultures before and af- ter TF therapy [39, 45, 53, 54], transfer of migration inhibition to certain antigens [39, 54], spontaneous rosette formation with sheep red blood cells (T cells) [47, 54-57], and in vitro cytotoxicity [58]. Curiously, there has been a poor correlation between clinically observed responses, results of skin reactivity tests, and these in vitro laboratory tests. Experience has shown that in the face of clinically unsuccessful treat- ment, one or more of the laboratory indicators may [47, 53] or may not [45, 47, 53, 56, 58] decrease or turn out negative, while the skin reactivity remains negative [59] or increases [56, 59]. Conversely, in pa- tients who have responded to TF therapy, skin test reactivity has increased in some patients [51-53, 59, 60] but decreased in others [53, 59], and in vitro labo- ratory tests have yielded higher [36, 39, 47, 52, 53, 58] or lower values [45, 57, 53]. Several questions are im- portant, as follows:

1. What is the specificity of TF? In Lawrence's original experiments, specific skin reactivity was in- duced in previously unreactive recipients, which in- dicates that careful donor selection is a logical neces- sity. However, some researchers [22, 53] have made use of readily accessible blood bank leukocytes which, by definition, could not be expected to contain the capacity to transfer specific reactivity. The major- ity of researchers have selected as donors patients in remission [52, 54], household contacts [30, 36, 39, 47, 52, 59], or individuals with a history of etiologically related illness [50, 51]. These donors are presumed to have or were demonstrated by in vitro assay to have lymphocytes reactive to the tumor antigens in ques- tion. Other investigators have prepared TF from lym- phocytes of other patients who had actively growing tumors of the same type [61], and still others have im- munized pairs of patients with different cancers against each other's tumor antigens before harvesting the lymphocytes [46]. In summary, there is not gen- eral agreement about the ideal method of donor se-

lection. Of course, this raises serious questions about many aspects of TF therapy. We believe that for spe- cific transfer, specific donors must be chosen; yet, the selection may have to be made individually based on indications of specific reactivity in the donor. Unless there is uniformity in donor selection and donor specificity, controlled studies will be difficult to carry out and interpret.

2. Can effectiveness of TF therapy be demon- strated in controlled studies? This is the crucial point. After all these years, there have been only 3 con- trolled studies of the clinical efficacy of TF. These have involved children with immunodeficiency [62], patients with rheumatoid arthritis [53], and subjects with common warts [63]. In none of these trials was TF therapy superior to saline placebo. The arthritis patients improved subjectively while on either saline placebo or TF therapy, although objective parame- ters did not reflect improvement [53]. A point of pos- sibly greater importance was made in the arthritis study, namely, that patients on placebo may develop positive skin reactions to tuberculin, apparently caused by the repetitive skin testing alone. These findings suggest that a strictly objective approach to TF trials is needed. As long as we cannot quantitate or assay TF activity, the 3 controlled trials represent examples of how to conduct meaningful clinical in- vestigations for the evaluation of TF, which might well be a potential therapeutic modality for cancer therapy.

R~sum~

Le facteur de transfert (TF) est un extrait de leu- cocytes humains. I1 a 6t6 d6montr6 qu'il transf~re l'homme anergique une capacit6 de r6action cutan6e sp6cifique et qu'il augmente la r6ponse des tests d'activit6 lymphocytaire in vitro. Le TF a 6t6 utilis6, titre exp6rimental, pour l'immunoth6rapie anti- canc6reuse. Dans plusieurs cas, l'administration de TF a 6t6 suivie de r6gression de tumeurs, de stabilisa- tion temporaire, et l'on a 6galement observ6 qu'il 6tait possible, sous TF, de r6duire les autres besoins thdrapeutiques. Le TF est donc peut-6tre valable en tant que th6rapeutique adjuvante de certains cancers. Cependant, la plupart des travaux publi6s sont des 6tudes non contrSldes, et il n'existe aucun accord quant aux crit6res de d6finition du donneur de TF. II sera impossible de tirer des conclusions quant/t la va- leur des traitements par TF dans le cancer ou d'autres maladies, aussi longtemps que des 6tudes contrSl6es n'auront pas 6t6 rdalis6es et que les caract~res des donneurs de TF ne seront pas ddfinis.

References

1. Lawrence, H.S.: In Workshop on Basic Properties and Clinical Applications of Transfer Factor, C.H. Kirk-

620 World J. Surg. Vol. 1, No. 5, September, 1977

patrick, D. Rifkind, editors. University of Arizona College of Medicine, Tucson, Arizona, 1973, p. 15

2. Lawrence, H.S.: The transfer in humans of delayed skin sensitivity to streptococcal M substance and tu- berculin with disrupted leukocytes. J. Clin. Invest. 34:219, 1955

3. Lawrence, H.S.: The cellular transfer of cutaneous hy- persensitivity to tuberculin in man. Proc. Soc. Exp. Biol. Med. 71:516, 1949

4. Zinsser, H.: Bacterial allergy and tissue reactions. Proc. Soc. Exp. Biol. Med. 22:35, 1925

5. Chase, M.W.: The cellular transfer of cutaneous hyper- sensitivity to tuberculin. Proc. Soc. Exp. Biol. Med. 59:134, 1945

6. Mitchison, N.A.: Studies on the immunological re- sponse to foreign tumor transplants in the mouse. II. The relation between hemagglutinating antibody and graft resistance in the normal mouse and mice pre- treated with tissue preparations. J. Exp. Med. 157:179, 1955

7. Brent, L., Brown, J., Medawar, P.B.: Skin trans- plantation immunity in relation to hypersensitivity re- actions of the delayed type. In Biological Problems of Grafting, F. Albert, P.B. Medawar, editors. Oxford, Blackwell Scientific Publications, 1959, p. 64

8. Greaves, M.F., Roitt, I.M., Torrigiani, G., Brostoff, J., Playfair, J.H.L.: The cellular basis of immunological responses. Lancet 2:367, 1969

9. Raft, M.D.: T and B lymphocytes and immune respon- ses. Nature 242:11, 1973

10. Allison, A.C., Ferluga, J.: How lymphocytes kill tumor cells. Lancet 2:165, 1976

11. Levin, A.G., McDonough, E.F., Jr., Miller, D.G., Southam, C.M.: Delayed hypersensitivity responses to DNFB in sick and healthy persons. Ann. N.Y. Acad. Sci. 120:400, 1964

12. Aisenberg, A.C.: Manifestations of immunologic unre- sponsiveness in Hodgkin's disease. Cancer Res. 26:1152, 1966

13. Gutterman, J.U., Rossen, R.D., Butler, W.T., McCredie, K.B., Bodey, G.P., Freireich, E.J., Hersh, E.M.: Immunoglobulin on tumor cells and tumor-in- duced lymphocyte blastogenesis in human acute leu- kemia. N. Engl. J. Med. 288:169, 1973

14. Mavligit, J.M., Hersh, E.M., McBride, C.M.: Lym- phocyte blastogenesis induced by authochthonous hu- man tumor cells: relationship to stage of disease and serum factors. Cancer 34:1712, 1974

15. Erickson, A.D., Holzman, R.S., Valentine, F.T., Law- rence, H.S.: In vitro comparison of TF obtained from skin test positive and negative individuals. In Transfer Factor. Basic Properties and Clinical Applications, M.S. Ascher, A.A. Gottlieb, C.H. Kirkpatrick, editors. New York, Academic Press, 1976, p. 23.

16. Klesius, P.H., Kristensen, F., Ernst, J.V., Kramer, T.T.: Bovine transfer factor: isolation and character- istics. In Transfer Factor. Basic Properties and Clinical Applications. M.S. Ascher, A.A. Gottlieb, C.H. Kirk- patrick, editors. New York, Academic Press, 1976, p. 311

17. Lawrence, H.S., A1-Askari, S., David, J.R., Franklin, E.C., Zweiman, B.: Transfer of immunologic informa- tion in humans with dialysates of leukocyte lysates. Trans. Assoc. Am. Physicians 76:84, 1963

18. Neidhart, J:A., Schwartz, R.S., Hurtubise, P.E., Mur- phy, S.G., Metz, E.N., Balcerzak, S.P., LoBuglio,

A.F.: Transfer factor: isolation of a biologically active component. Cell. Immunol. 9:319, 1973

19. Lawrence, H.S.: Transfer factor in cellular immunity. In The Harvey Lectures, Vol. 68. New York, Academic Press, 1974, p. 239

20. Dunnick, W., Bach, F.H.: Guinea pig transfer factor in vitro: physico-chemical properties and partial purifica- tion. In Transfer Factor. Basic Properties and Clinical Applications, M.S. Ascher, A.A. Gottlieb, C.H. Kirk- patrick, editors. New York, Academic Press, 1976, p. 185

21. O'Dorisio, M.S., Neidhart, J.A., Daniel, F.B., Balcer- zak, S.P., LoBuglio, A.F.: Identification of hypoxan- thine as the major component of a chromatographic fraction of TF. Cell. Immunol. 23:191, 1976

22. Grob, P.J., Reymond, J.F., H~icki, M.A., Frey-Wett- stein, M.: Some physicochemical and biological proper- ties of a TF preparation and its clinical application. In Transfer Factor. Basic Properties and Clinical Appli- cations, M.S. Ascher, A.A. Gottlieb, C.H. Kirk- patrick, editors. New York, Academic Press, 1976, p. 247

23. Lawrence, H.S., Rapaport, F.T., Converse, J.M., Til- lett, W.S.: Transfer of delayed hyposensitivity to skin homografts with leukocyte extracts in man. J. Clin. In- vest. 39:185, 1960

24. LoBuglio, A.F., Neidhart, J.A.: Transfer factor: a po- tential agent for chemotherapy. Med. Clin. North Am. 60:585, 1976

25. Hitzig, W.H., Fontanellaz, H.P., Miintener, U., Paul, S., Spitler, L.E., Fudenberg, H.H.: Transfer factor. Schweiz. Med. Wochenschr. 102:1237, 1972

26. Kirkpatrick, C.H.: Chronic mucocutaneous can- didiasis: model building in cellular immunity. Ann. In- tern. Med. 74:955, 1971

27. Kirkpatrick, C.H., Rich, R.R., Smith, T.K.: Effect of transfer factor on lymphocyte function in anergic pa- tients. J. Clin. Invest. 51:2948, 1972

28. Schulkind, M.L., Adler, W.H., III, Altemeier, W.A., III, Ayoub, E.M.: Transfer factor in the treatment of a case of chronic mucocutaneous candidiasis. Cell. Immunol. 3:606, 1972

29. Griscelli, C., Revillard, J.B., Betuel, H., Herzog, C., Touraine, J.L.: Transfer factor in immunodeficiencies. Biomedicine 18:220, 1973

30. Spitler, L.E., Levin, A.S., Stites, D.P., Fudenberg, H.H., Pirofsky, B., August, C.S., Stiehm, E.R., Hitzig, W.H., Gatti, R.A.: The Wiskott-Aldrich syndrome: re- sults of transfer factor therapy. J. Clin. Invest. 51:3216, 1972

31. Catanzaro, A., Spitler, L.E., Moser, K.M.: Immuno- therapy of coccidiomycosis. J. Clin. Invest. 54:690, 1974

32. Graybill, J.R., Silva, J., Jr., Alford, R.H., Thor, D.E.: Immunologic and clinical improvement of progressive coccidiomycosis following transfer factor. Cell. Immunol. 8:120, 1973

33. Kempe, C.H.: Studies on smallpox and complications of smallpox vaccination. Pediatrics 26:176, 1960

34. O'Connell, C.J., Karzon, D.T., Barron, A.L., Plaut, M.E., Ali, V.M.: Progressive vaccinia with normal antibodies. A case possibly due to deficient cellular im- munity. Ann. Intern. Med. 60:282, 1964

35. Moulias, R.: Facteur de transfer de l'immunit6 cellu- laire. Nouv. Presse Med. 2:1341, 1973

36. Levin, A.S., Byers, V.S., Fudenberg, H.H., Wybran, J.,

C.R. Meier and A.F. LoBuglio: Immunotherapy of Cancer with Transfer Factor 621

Hackett, A.J., Johnston, J.O., Spitler, L.E.: Osteogenic sarcoma--immunologic parameters before and during immunotherapy with tumor specific transfer factor. J. Clin. Invest. 55:487, 1975

37. Ivins, J.C., Ritts, R.C., Jr., Pritchard, D.J., Gilchrist, G.S., Miller, G.C., Taylor, W.F.: Transfer factor ver- sus combination chemotherapy: a preliminary report of a randomized postsurgical adjuvant treatment study in osteogenic sarcoma. Ann. N.Y. Acad. Sci. 277:558, 1976

38. Bearden, J.D., III, Thor, D.E., Coltman, C.A., Jr.: Ad- junctive transfer factor in osteogenic sarcoma. I. Clin- ical implications of chemotherapy and immunother- apy. In Transfer Factor. Basic Properties and Clinical Applications, M.S. Ascher, A.A. Gottlieb, C.H. Kirk- patrick, editors. New York, Academic Press, 1976, p. 553

39. LoBuglio, A.F., Neidhart, J.A., Hilberg, R.W., Metz, E.N., Balcerzak, S.P.: The effect of transfer factor ther- apy on tumor immunity in alveolar soft part sarcoma. Cell. Immunol. 7:159, 1973

40. Krementz, E.T., Mansell, P.W.A., Hornung, M.O., Samuels, M.S., Sutherland, C.A., Benes, E.N.: Immu- notherapy of malignant disease: the use of viable sensi- tized lymphocytes or transfer factor prepared from sensitized lymphocytes. Cancer 33:394, 1974

41. Brandes, L.J., Galton, D.A.G., Wiltshaw, E.: New ap- proach to immunotherapy of melanoma. Lancet 2:203, 1971

42. Smith, J.V., Morse, P.A., Jr., Deraps, G.D., Raju, S., Hardy, J.D.: lmmunotberapy of patients with cancer. Surgery 74:59, 1973

43. Vetto, R.M., Burger, D.R., Nolte, J.E., Vandenbark, A.A.: Transfer factor immunotherapy in cancer. In Transfer Factor. Basic Properties and Clinical Appli- cations, M.S. Ascher, A.A. Gottlieb, C.H. Kirk- patrick, editors. New York, Academic Press, 1976, p. 523

44. Bukowsky, R.M., Deodhar, S., Hewlett, J.S.: Immuno- therapy of human neoplasms with transfer factor. In Transfer Factor. Basic Properties and Clinical Appli- cations, M.S. Ascher, A.A. Gottlieb, C.H. Kirk- patrick, editors. New York, Academic Press, 1976, p. 543

45. Silva, J., Allen, J., Wheeler, R., Bull, F., Morley, G., Plouffe, J.: Transfer factor therapy in disseminated neoplasms. In Transfer Factor. Basic Properties and Clinical Applications, M.S. Ascher, A.A. Gottlieb, C.H. Kirkpatrick, editors. New York, Academic Press, 1976, p. 573

46. Morse, P.A., Jr., Deraps, G.D., Smith, G.V., Raju, S., Hardy, J.D.: Transfer factor therapy of human cancer. Clin. Res. 21:71, 1973

47. Spitler, L.E., Levin, A.S., Wybran, J.: Combined im- munotherapy in malignant melanoma--regression of metastatic lesions in two patients concordant in timing with systemic administration of transfer factor and BCG. Cell. Immunol. 21:1, 1976

48. Cole, W.H.: Spontaneous regression of cancer: the metabolic triumph of the host? Ann. N.Y. Acad. Sci. 230:111, 1974

49. Oettgen, H., Old, L.J., Farrow, J.H., Valentine, F.T., Lawrence, H.S., Thomas, L.: Effects of dialysable

transfer factor in patients with breast cancer. Proc. Natl. Acad. Sci. 71:2319, 1974

50. Goldenberg, B.J., Brandes, L.J,: Immunotherapy of nasopharyngeal cancer with transfer factor from do- nors with previous infectious mononucleosis. Clin. Res. 20:947, 1972

51. Goldenberg, B.J., Brandes, L.J.: In vivo and in vitro studies of immunotherapy of nasopharyngeal carci- noma with transfer factor. Cancer Res. 36:720, 1976

52. Quick, C.A., Behrens, H.W., Brinton-Darnell, M., Good, R.A.: Treatment of papillomatosis of the larynx with transfer factor. Ann. Otol. Rhinol. Laryngol. 84:607, 1975

53. Maini, R.N., Scott, J.T., Hamblin, A., Roffe, L., Du- monde, D.C.: Is the clinical benefit from transfer factor in rheumatoid arthritis a placebo effect? In Transfer Factor. Basic Properties and Clinical Applications, M.S. Ascher, A.A. Gottlieb, C.H. Kirkpatrick, editors. New York, Academic Press, 1976, p. 601

54. Ng, R.P., Moran, C.J., Alexopoulos, C.G., Belling- ham, A.J.: Transfer factor in Hodgkin's disease. Lan- cet 2:901, 1975

55. Hayes, A., Borella, L., Mauer, A.M.: Transfer factor activity in children receiving combination chemother- apy. Proc. Am. Assoc. Cancer Res. 16:108, 1975

56. Khan, A., Thaxton, S., Hill, J.M., Hill, N.O., Loeb, E., MacLellan, A.: Clinical trials with transfer factor. In Transfer Factor. Basic Properties and Clinical Appli- cations, M.S. Ascher, A.A. Gottlieb, C.H. Kirk- patrick, editors. New York, Academic Press, 1976, p. 583

57. Wybran, J., Levin, A.S., Spitler, L.E., Fudenberg, H.H.: Rosette-forming cells, immunologic deficiency diseases and transfer factor. N. Engl. J. Med. 288:710, 1973

58. Thor, D.E., Coltman, C.A., Jr., Bearden, J.D., III, Williams, T.E., Flippen, J.H.: Adjunctive transfer fac- tor in osteogenic sarcoma. II. Methodology and results of the immunological studies. In Transfer Factor. Basic Properties and Clinical Applications, M.S. As- cher, A.A. Gottlieb, C.H. Kirkpatrick, editors. New York, Academic Press, 1976, p. 563

59. Cozine, W.S., Stanfield, A.B., Stephens, C.A.L., Par- sons, J.L., Holbrook, J.P., Strong, J.S., Wongsri, C., Mazur, M.T., Raymond, L.N.: Transfer factor immu- notherapy of rheumatoid arthritis. In Transfer Factor. Basic Properties and Clinical Applications, M.S. As- cher, A.A. Gottlieb, C.H. Kirkpatrick, editors. New York, Academic Press, 1976, p. 617

60. Zachariae, H., Grunnet, E., Ellegaard, J., et al.: Trans- fer factor as an additional therapeutic agent in mycosis fungoides. Acta Allergol. (Kbh) 30:272, 1975

61. Pizza, G., Viza, D., Boucheix, C., Corrado, F.: In vitro production of a transfer factor specific for transitional cell carcinoma of the bladder. Br. J. Cancer 33:606, 1976.

62. Walker, A.M., Garcia, R., Pate, P., Mata, L.J., David, J.R.: Transfer factor in the immune deficiency of pro- tein calorie malnutrition: a controlled study with 32 cases. Cell. Immunol. 15:372, 1975

63. Stevens, D.A., Ferrington, R.A., Merigan, T.C., Ma- rinkovich, V.A.: Randomized trial of transfer factor treatment of human warts. Clin. Exp. Immunol. 21:520, 1975