Natural cytotoxicity and serum blocking in malignant cervical neoplasia

Role of Immune Response in the Prognosis of Carcinoma of the Uterine Cervix: Can in Vitro Analysis Provide a better Framework for more Effective Management?

Cancer of the uterine cervix is the single largest female malignancy in India and also remains a major problem facing oncologists in other parts of the world. While advances in radiation therapy and surgical techniques have made the treatment of cervical carcinoma impressive, limitations to successful management still remain. In fact, the 5-year survival rate, stage for stage, has not improved in the United States or world wide in the past 40 years. With an estimated half a million women developing this disease annually, this lack of improved survival poses an international unresolved health problem. Immune response has been shown to be a major factor involved In the course of the disease for this cancer. Immunologic monitoring was also shown to be of effective value in assessing the prognosis for cervical carcinoma. We studied the various immunologic abnormalities in cervical cancer, the effects of radiation therapy on immune function, prospects of an immunologic staging system, the relationship between human papillomavirus infection and the Immune response, and the possibility of using in vitro Immunologic assessment to provide a better framework for more effective management of cancer of the uterine cervix.

Signaling defects and functional impairment in T-cells from cervical cancer patients

The ability of T-lymphocytes to recognize antigens and transduce signals to the nucleus successfully is a key component in the initiation and maintenance of an immune response. The present study addressed the expression status of the signal-transducing proteins in relation to the immune impairment in cervical cancer patients. Immune response was measured by evaluating lymphocyte subpopulations CD3(+), CD4(+), and CD8(+), using flowcytometry, natural killer cell activity, using the single-cell cytotoxicity assay, lymphocyte function, using mitogenic response to PHA and T-cell activation following anti-CD3 stimulation, and production of IL-2. Expression of the T-cell signal transduction proteins, TCR-zeta, CD3-epsilon, zap-70, p(56)lck, PKC, NFkappabeta p50, Rel-A, Rel-B, and c-rel, was evaluated by using Western blot assay. A generalized depression of the immune response with respect to the different parameters evaluated was observed. Exogenous interleukin-2 (IL-2) could increase the response in all the controls and in 30% of the patients to different degrees varying from 10% to 90%. Low levels of the signaling molecules (TCR-zeta, CD3-epsilon, zap-70, p(56)lck, and PKC) and impairment in the transduction of NFkappabeta components (p50, Rel-A, Rel-B, and c-rel) to the nuclei were observed in these lymphocytes. Decreased CD4(+)/CD8(+) ratio with an increase in suppressor cells, reduced lymphocyte proliferation, and production of IL-2 suggest a defective immune regulation in cervical cancer. Impairment in the translocation of NFkappabeta p50, Rel-A, and Rel-B to the nucleus and the reduced levels of signal-transducing proteins might be responsible for the decreased production of IL-2 and immune impairment in cervical cancer patients.

In vitro inhibition of natural-killer-mediated lysis by chromatin fragments

A qualitative impairment of natural killer (NK) function and the presence of circulating DNA have been independently reported in clinical situations such as cancer and lupus. The existence of receptors for chromatin fragments at the leukocyte membrane raised the question of the relation between the presence of chromatin fragments in the extracellular medium and the impairment of NK function. The present study shows that plasmas from patients with metastatic cancer and with pathological DNA concentrations inhibited significantly the NK activity of normal lymphocytes as compared to cancer plasmas with DNA concentrations in the normal range. In vitro, it was demonstrated that chromatin fragments inhibited the NK-mediated cytotoxicity in a dose-dependent manner. Inhibitory concentrations of nucleosomes (2.5-10 micrograms/ml) were lower than those of DNA and histones alone (100 micrograms/ml). Inhibitory effects of nucleosomes, DNA and histones differed also according to the effector population used: nucleosomes were effective whatever the CD56+ cell enrichment of the effector population, while DNA inhibition needed T cells, and histone inhibition probably resulted from a subtoxic effect, prevented by the presence of adherent cells. Finally we found that nucleosomes could inhibit the NK function only when they were present in the extracellular medium. Taken together, these data suggest that the persistence of nucleosomal DNA at sites of cell death or in the blood might be responsible, at least partly, for the NK activity impairment observed in pathological circumstances characterized by a high rate of cell death phenomena such as cancer.

Interferon and interleukin-2 induced spontaneous cell-mediated cytotoxicity: a preliminary evaluation

The contribution of natural cell-mediated cytotoxicity and its modulation with biological response modifiers in antitumour immunity was evaluated in patients with precancers and cancers of the oral cavity. The results were compared to those in normal controls. Both groups of patients showed highly significant depression of the natural killer cell activity. This depression was stage-related, suggesting an influence of tumour or tumour products on this activity. Depression in augmentation of this cytotoxicity was evident in both patient groups with cancers and precancers, suggesting a defect in the response of killer cells to biological response modifiers for reasons other than the tumour per se.

Pathogenesis of oral submucous fibrosis. Relationship to risk factors associated with oral cancer

Oral submucous fibrosis (OSF) is a chronic disease of the oral mucosa characterized by inflammation and a progressive fibrosis of the lamina propria and deeper connective tissues. It is a condition predominantly seen among people of Indian origin, and an epidemiologic survey done a decade ago showed no less than 250,000 cases in India, a figure that must have increased sharply. OSF is a condition with a high risk of malignant transformation; to date, no conclusive etiologic agent has been identified, although plenty of data have been generated on various aspects of the disease. These include genetic, carcinogenic, immunologic, viral, nutritional, and autoimmune possibilities, all of which also have been implicated in the development of oral cancer. This article reviews existing evidence on the pathogenesis of OSF and its relation to oral cancer and suggests a possible multifactorial model to explain the disease process.

Stimulation of natural killer cell activity by murine retroviral infection and cocaine

The effects of cocaine and murine AIDS on natural killer (NK) cell activity in C57BL/6 mice was studied. Cocaine may play a major role in the development and progression to AIDS in the human population. Chronic intraperitoneal injection of cocaine was shown to cause an increase in NK cell activity over those of saline-treated animals. Infection with LP-BM5 murine leukemia retrovirus was also shown to increase NK cell activity. NK cell activity was increased in retrovirally infected mice treated with cocaine beyond that of mice treated with cocaine alone. This study indicates an important immunomodulatory effect of cocaine on NK cell activity, especially when combined with the effects caused by retroviral infection.

Lymphocyte subset distribution after radiation therapy for cancer of the uterine cervix. Possible prognostic implications and correlation with disease course

An analysis of lymphocyte subpopulations was done in patients with cancer of the uterine cervix before and at different intervals after the commencement of radiation therapy. A common feature was a duration of T-cell and B-cell lymphopenia after therapy. The findings relating to the T-cell subsets were interesting. Although the CD4/CD8 ratio remained unchanged in Stages I/IIA for 24 months after treatment, patients with Stages IIB and III showed a lowering of the ratio immediately after treatment. Distinctive patterns of lymphocyte subset distribution were seen in a comparison between patients who were disease-free and those with recurrent disease. The CD4+ cell counts and CD4/CD8 ratio differed between the two groups, with consistent lowered values during the follow-up associated with recurrent disease. This study demonstrates the effects of radiation therapy in altering lymphocyte subset distribution, resulting in characteristic patterns which could be used as clinical and prognostic indicators.

In vitro immunotoxicology and immunopharmacology: studies on drugs of abuse

The application of immunotoxicology to the toxicologic assessment of drugs of abuse is a field of increasing importance. Interest in the effects of drugs of abuse on the immune system has greatly increased as a result of the AIDS epidemic. If drugs of abuse compromise the immune system, their use may well become a predisposing factor in the development or enhancement of AIDS in high-risk groups. Therefore development and validation of newer methods of assessment of immunotoxicology and their adaptation to routine analysis is an absolute necessity. An important feature in toxicology in general, and in immunotoxicology in particular, is the need to develop in vitro assessment systems. Recent research has provided newer models, data on correlations of immune function variables, and a better understanding of the biologic relevance of certain immune function parameters. This paper analyzes these features in relation to the role of drugs of abuse in the modulation and alteration of the immune system and reviews the various in vitro techniques that could be used to evaluate immunotoxicity.

Interferon activation of latent natural killer cells and alteration in kinetics of target cell lysis: clinical implications for oral precancerous lesions

Reduced natural killer cell activity was observed in patients with oral leukoplakia and submucous fibrosis compared with normal control subjects. However, the number of target binding lymphocytes was found to be normal in these precancers. Treatment of effector cells with interferon-alpha resulted in highly elevated active killer cell activity, although no change was observed in target binding lymphocyte counts. This finding could imply that precytotoxic cells that are activated by interferon exist in peripheral blood or that direct recruitment of a new cell population takes place. In addition, altered target lysis kinetics was observed, with interferon-activated killer cells demonstrating a tremendous lytic activation that is completed so quickly that a statistical kinetic analysis could not be accurately done. Because natural killer cell activity is an important effector system in immunosurveillance against tumors, its modulation with interferon may be an exciting clinical possibility in the control of malignant transformation or oral precancers.

Development of an immunological staging system to prognosticate disease course in malignant cervical neoplasia

A multiparameter analysis of immune function was done on patients with squamous cell carcinoma of the uterine cervix to look for any variable(s) that could be correlated with the clinical stage of the disease. Five immunological variables, viz., CD4+ lymphocytes, CD4/CD8 ratio, natural killer cells, concanavalin A-induced suppressor index, and circulating immune complexes, were found to consistently vary with tumor load. When these variables were subjected to a multiple regression and multivariate analysis, an equation for a diagnostic index curve was derived. Application of this equation led to an immunological staging system which could be used as an excellent prognostic indicator. The immunological staging system showed that patients classified into a particular clinical (FIGO) stage behaved in a heterogeneous way immunologically and that patients developing recurrent disease could easily be identified from those remaining disease free, even before treatment. Subsequent follow-up of these patients further confirmed this observation, with the recurrent disease group easily identifiable. These results point out the immense potential of such a staging system and the importance of immunological evaluation in the preliminary management of patients with malignant cervical neoplasia.

Clinical and prognostic significance of concanavalin-A-induced suppressor cell activity in malignant cervical neoplasia

Peripheral blood lymphocytes from patients with different stages of cancer of the uterine cervix were analysed for concanavalin-A-induced suppressor cell activity. All cancer patients had high levels of suppressor activity, the increase corresponding to tumour load. Radiotherapy resulted in further increase of suppressor activity. About six months after radiotherapy, patients who remained disease free returned to pretreatment levels of suppressor cell activity and later showed even lewer levels of suppression. On the other hand, patients who developed recurrent disease maintained sustained high levels of suppression and for all stages they always had higher suppressor activity than the patients who remained disease free in the corresponding stage. These results stress the importance of a possible deranged immune system in these patients and also shows the clinical and prognostic significance of the assay.

Inhibition of lymphokine-activated killer cell generation by blocking factors in sera of patients with head and neck cancer

Cytolytic activation of peripheral blood lymphocytes by recombinant interleukin-2 (rIL-2) in patients with squamous cell carcinoma (SCC) of the head and neck may be inhibited by serum blocking factors, and this could influence therapeutic efficacy. Peripheral blood lymphocytes from 21 patients with this disease and 17 controls were incubated with 10-1000 U rIL-2 for 6 days in supplemented complete medium (containing 10% fetal calf serum) or the same medium plus 10% autologous serum. After washing the effector cells, we determined their cytotoxicity against K562 and MDA1386, a lymphokine-activated-killer(LAK)-sensitive SCC cell line, using a 51Cr-release assay. Patient sera inhibited LAK-generated lysis of both MDA1386 and K562, while control sera from healthy persons inhibited LAK-generated lysis of MDA1386. The blocking activity of patient sera tended to be greater than that of control sera. The sera of patients with untreated or recurrent disease and those who were free of disease had equivalent inhibitory capacity. The serum blocking factor acted in a dose-dependent manner, and inhibition was overcome by increasing the dose of rIL-2. Levels of circulating immune complexes (measured by the C1q binding method) did not correlate significantly with inhibition. A clinical protocol of repeated plasma exchange in patients with advanced and recurrent squamous cell carcinoma of the head and neck allowed sequential study of one patients's serum before, during, and after treatments. Plasmapheresis removed serum inhibitory factors, albeit temporarily. The activity of serum blocking factors in patients with this disease can be modulated by increasing doses of rIL-2 and by plasma exchange. This modulation may be important to improving clinical response rates for patients undergoing immunotherapy.

Immune reactive proteins as prognostic and clinical markers in malignant cervical neoplasia

The significance of immune reactive proteins in malignant cervical neoplasia, with particular reference to its prognostic and clinical relevance, was studied in 229 patients. All stages of the disease showed elevated levels of circulating immune complexes (CIC). Patients with stages I/IIA showed elevated levels of IgG, whereas those with stages III and IV showed depressed IgM levels. In the case of IgA, the situation was reversed: patients with advanced disease showed increased levels. Radiotherapy resulted in highly elevated levels of CIC, IgG, and IgA. However, in patients who remained disease-free after radiation treatment, levels of these proteins came down, often falling below pretreatment levels. On the other hand, patients developing recurrent disease showed sustained, high levels of CIC and IgA, with IgG as an isolated case in stage I/IIA. The present study therefore shows that although these increases were non-tumour-specific, patients with persistent elevation of CIC and IgA levels were at much greater risk of developing recurrent disease, thereby proving the merit of these substances as markers in prognosticating the course of disease in malignant cervical neoplasia.

Interleukin 2 production in lymphocyte cultures: a rapid test for cancer-associated immunodeficiency in malignant cervical neoplasia

Peripheral blood lymphocytes of patients with malignant cervical neoplasia were studied for their capacity to produce interleukin-2 (IL-2) upon in vitro mitogen stimulation. Patients with early disease (Stage I/IIA) showed levels comparable to normal controls but those with advanced disease showed reduced levels, the reduction increasing with tumour load. These findings excellently correlated with our previous observations on a depressed cellular immunity in these patients. On follow up of the patients it was noticed that those who developed recurrent disease showed sustained lower levels of IL-2 production compared to those who remained disease free. These results stress the importance of a deranged immune system in these patients and also shows the clinical and prognostic value of such an assay.