Thymosin reconstitution of T cell deficits in vitro in cancer patients

In vitro immune modulation by thymosin alpha 1 in patients with head and neck squamous cell carcinoma

To determine if patients with head and neck squamous cell carcinoma represent an appropriate population for immune reconstitution with thymosin alpha 1, leukocyte migration inhibition (LMI) in response to phytohemagglutinin was measured in 24 previously untreated patients with head and neck cancer, and the in vitro effects of thymosin alpha 1 on migration inhibition were assessed. Compared to normal subjects, LMI was impaired in the head and neck cancer patients. Thymosin alpha 1, in vitro, was associated with improvement in LMI in the cancer patients. Improvements in migration response with thymosin alpha 1 appeared to be independent of levels of various T-lymphocyte subpopulations. However, patients with a normal LMI response had lower suppressor/cytotoxic cell levels than normal subjects or patients with impaired LMI. The findings confirm prior reports of the effects of thymic hormones on lymphokine production in vitro and provide rationale for further clinical studies of thymosin alpha 1 in patients with head and neck squamous cell carcinoma.

Thymic peptide hormones: basic properties and clinical applications in cancer

The manuscript will provide an in-depth and critical review of the nomenclature, biochemistry, biological properties, and a summary of published and on-going clinical trials with all reported thymic preparations, including both partially purified thymic factors (e.g., thymosin fraction 5, thymostimulin) as well as purified and synthesized thymic peptides (e.g., thymosin alpha 1, thymulin). Particular emphasis will be placed on which thymic peptides should be categorized as true hormones. In addition, the comparative biochemistry and biological activity in animals will be summarized and contrasted for all the currently available thymic factors. The effects, in vitro of thymic factors, on peripheral blood lymphocytes isolated from normal donors and patients with primary immunodeficiency disorders, autoimmune disorders, and neoplastic disorders will also be reviewed. Finally, a detailed critical summary of the clinical trials performed with each of the thymic preparations will be presented with an emphasis on treatment of patients with cancer.

Immunoincompetence in cancer patients. Assessment by in vitro stimulation tests and quantification of lymphocyte subpopulations

The authors performed a variety of lymphocyte-stimulation tests and quantified several lymphocyte subpopulations in 73 healthy controls and 72 patients with advanced cancer who were no longer receiving anticancer therapy. As a group, cancer patients had fewer lymphocytes and helper cells, but a greater proportion of suppressor cells and Ia+ cells than controls. The ratio of helper to suppressor cells was lower in the cancer group. Uptake of 125I-uridine was markedly depressed in cancer patients in the face of stimulation with various plant lectins, foreign lymphocytes, and varicella-zoster antigen. There was little correlation between any of the stimulation tests and any of the lymphocyte subpopulation proportions or numbers. The two tests that were most frequently abnormally low among the cancer patients were percent lymphocytes and number of helper cells (81% each). The most frequently abnormal functional assay in patients was pokeweed mitogen stimulation (59%). Three separate statistical methods selected the combination of percent lymphocytes, percent Ia+ cells, percent suppressor cells, number of helper cells, and pokeweed mitogen stimulation as being the best predictors of cancer/immunoincompetent status. This study confirms the breadth of immunoincompetence in advanced cancer patients as defined by in vitro techniques. A smaller battery of tests can be useful in monitoring the immune status of such patients, especially during therapy with proposed immune modulators.

Immunology of head and neck cancers

Despite the ever growing collection of data concerning the function of the immune system in patients with epidermoid carcinoma of the head and neck, the precise mechanism by which these tumors effect the body's surveillance against foreign antigen is as yet unidentified. If these specific immunological characteristics of the cancer cell can be identified, laboratory analysis of these "markers" could lead to detection and treatment of cancer in its earliest stages. Included in this chapter is a review of the embryological development of the immune system, a description of the components of the immune system and their responses to invasion by tumor antigen. Measurements of immuno responsiveness of the individual are important in determining the pretreatment state of immuno-competence and in predicting prognosis following treatment. Measurements of T-lymphocyte functions and their response to immuno-manipulations can also aid in predicting which patients will benefit from immunotherapy. Finally, categorization of the multiple forms of immunotherapy including active, specific and non-specific, and adoptive mechanisms are discussed. More recent methods of related immunotherapy trials will also be mentioned. As of this writing, the trials of immunochemotherapy have not produced any conclusive results due to the lack of multi-institutional trials and limited quantities of immunotherapeutic agents for these clinical trials.

Levamisole as an adjuvant to chemotherapy in extensive bronchogenic carcinoma: a Veterans Administration Lung Cancer Group Study

A randomized trial of 381 patients with extensive lung cancer compared immunochemotherapy with levamisole (150 mg/m2 orally three times a week), cyclophosphamide (700 mg/m2 IV every three weeks) and CCNU (70 mg/m2 orally every six weeks) with the same chemotherapy without levamisole. When disease progressed, doxorubicin hydrochloride or doxorubicin hydrochloride plus levamisole was used. Hematologic toxicity required reduction of the levamisole dosage to 2.5 mg/kg (100 mg/m2) three times a week, every other week. When corrections are made for all variables, levamisole itself had a negative influence on survival. Patients given 150 mg/m2 had a shorter median time to treatment failure (P = 0.02), lower response rate (P = 0.02) more toxicity (P = 0.08), and shorter median survival (P = 0.08). Patients with 10% or greater weight loss had significantly shorter survival (P = 0.006). The regimen with the reduced dosage of levamisole also was more toxic (P = 0.05) but otherwise did not differ from the control regimen. The cause of the adverse effect of levamisole is unknown. It did not occur because of an excess of toxic deaths or because smaller doses of cytotoxic drugs were given to patients treated with levamisole. Neither the initial lymphocyte count nor the Candida skin test reactions had a significant effect on the study endpoints when correction was made for dominant prognostic factors such as the initial performance status and weight loss.

Improvement of impaired leukocyte migration inhibition by thymosin in patients with head and neck squamous carcinoma

In a preliminary study of the effects of SK-SD and thymosin on leukocyte migration inhibition in patients with squamous carcinoma of the head and neck, the cancer patients had significantly lower leukocyte migration inhibition of SK-SD than normal subjects. Thymosin increased the inhibition to SK-SD in the cancer patients to levels similar to those in normal subjects, and decreased the inhibition in normal subjects. These results confirm and extend the results of previous studies of the effects of thymosin in vitro, which show restoration of immune reactivity in patients with impaired cellular immunity and either no effect or a decrease in immune reactivity in subjects with normal cellular immunity. These combined observations provide a rationale for determining the clinical effects of thymosin in immunoincompetent patients with head and neck cancer and suggest that immunorestorative agents such as thymosin be used with caution in patients with normal cellular immunity.

Thymic hormonal effect on human peripheral blood lymphocytes in vitro. III. Conditions for mixed lymphocyte-tumor culture assay

Conditions for the reproducible measurement of thymic hormonal effect on the functional activity of human peripheral blood lymphocytes (PBL) were determined using a mixed lymphocyte-tumor culture assay. Three thymic hormonal preparations (thymopoietin, thymic humoral factor and TP-1) were tested by this assay and found to have a significant enhancing effect on the blastogenic response. Essential for the demonstration of the hormonal effect was the selection of suboptimal stimulation conditions, with the appropriate cell lines, including the number of stimulating cells and the time in culture. The most reproducible results were achieved when 1 x 10(5) PBL were co-cultured for 4 days with 1 x 10(4) mitomycin-C treated Raji lymphoma cells, after 1 h preincubation with one of the thymic preparations. However, strong enhancing effects of the thymic preparations could also be demonstrated with other tumor cel lines, especially IgR3 melanoma cells.

Nutritional concepts in the treatment of head and neck malignancies

Cancer cachexia should no longer be a contraindication to adequate antineoplastic treatment. Current methods of nutritional assessment allow one to identify malnutrition and to follow the nutritional status of the patient throughout the cancer-management program. Enteral nutritional repletion and maintenance remain the ideal course of action, but the gastrointestinal tract is not always readily available or advisable for use; in such circumstances, intravenous hyperalimentation (IVH) may be indicated. The properly nourished patient better tolerates cancer therapy, experiences fewer complications of malnutrition (e.g., sepsis and poor wound healing), and has a better-functioning immune system than does his malnourished counterpart. This article reviews methods of nutritional assessment, delineates indications and techniques for nutritional repletion, and summarizes the results obtained.

Effect of thymosin in vitro on T cell levels during radiation therapy: correlations with radiation portal and initial T cell levels

The effect of thymosin in vitro on percent T cells was determined in 388 blood specimens from patients with head and neck, mediastinal, and pelvic malignancies during radiation therapy, in 94 untreated patients with these malignancies, and 277 normal adults. Changes in percent T cell levels after incubation of lymphocytes with thymosin did not correlate with tumor histology or cumulative radiation dose, but in all groups correlated with radiation portal and initial T cell levels. T cell levels increased by a similar increment in normals and in the untreated patients. During irradiation, the mean levels after incubation with thymosin did not change in patients with head and neck and pelvic malignancies, but in patients with mediastinal malignancies the levels increased significantly more than in normals. For a given T cell level, the increase in patients with mediastinal malignancies was greater than in patients with pelvic malignancies, and as a group was greater than in patients with head and neck malignancies. The results can be explained by an increase in circulating thymosin-responsive lymphocytes during mediastinal irradiation due to suppression of a function of the thymus important for maturation of these cells, and a decrease in these cells during pelvic irradiation due to a deleterious effect on precursors in pelvic bone marrow. The results thus provide a rationale for clinical trials to assess the efficacy of thymosin in averting declines of T cell levels in patients receiving mediastinal irradiation.