Monocyte and lymphocyte interaction in patients with advanced cancer. Evidence for deficient IL-1 production

Clinical implications and characteristics of factor forkhead box protein 3 in gastric cancer

Transcription factor forkhead box protein 3 (FOXP3) is a specific marker of naturally occurring regulatory T cells (Tregs). Recently, various reports have suggested that FOXP3 may represent a tumor escape mechanism in cancer cells apart from its roles in Tregs. In the present study, the clinical and biological characteristics of FOXP3 were evaluated in human gastric cancer. The expression and localization of FOXP3 in gastric cancer cell lines was analyzed to evaluate its cellular biological features. Sections of human gastric cancer specimens were stained using immunohistochemistry (IHC) to assess the relationship between FOXP3 expression and tumor differentiation, in order to identify its clinical characteristics in gastric cancer. Expression of FOXP3 mRNA and protein was found in four gastric cancer cell lines (AGS, SGC-7901, MKN-28 and MKN-45). IHC of the gastric cancer sections revealed that more than 56% of gastric cancers displayed nuclear or cytoplasmic FOXP3 staining. Furthermore, a linear relationship between the differentiation of the gastric cancer tissues and FOXP3 expression intensity was shown. IHC and confocal analysis showed that the expression of FOXP3 was mainly present in the nucleus of tumor cells in the tissues and cell lines. Thus, FOXP3 nuclear staining may be associated with the risk of poor tumor differentiation. Apart from the lymphocytes, no FOXP3 staining was noted in the normal gastric tissues and para-tumor tissues. The high frequency of FOXP3 expression in gastric cancer tissue is a significant finding in the investigation of tumor differentiation and immune escape. This mechanism provides a further understanding of gastric cancer and a novel therapeutic strategy is presented.

Cytokines (TH1 and TH2) in patients with advanced cervical cancer undergoing neoadjuvant chemoradiation: correlation with treatment response

BACKGROUND AND OBJECTIVES

Host factors are critical in regulating tumor growth, and cytokines that modulate immunological control may be of importance in cervical cancer. To study this, the cytokines were measured in peripheral blood mononuclear cells in women with cervical cancer, before and after neoadjuvant chemoradiation, and assessed their correlation with therapeutic response.

METHODS

Ninety patients with advanced cervical cancer and 90 healthy controls were enrolled, and human papillomavirus status was determined. Cytokines were estimated by enzyme-linked immunosorbent assay in pretreatment samples after chemotherapy, brachyradiation, and after follow-up. Response to therapy was assessed during and after therapy and after 1 and 3 years of follow-up.

RESULTS

Pretreatment levels of type 1 cytokines (IL-2 and IFN-gamma) showed significant decrease, whereas type 2 cytokines (IL-4 and IL-10) showed significant increase in patients versus controls. After chemotherapy, a mild increase in type 1 cytokine levels was observed in complete responders versus partial/nonresponders, which became highly significant after completion of therapy and remained significant during follow-up. A slight decrease in type 2 cytokine levels was seen in complete responders versus partial/nonresponders, which remained insignificant for IL-10 even after chemoradiation.

CONCLUSIONS

This important finding suggests that pretreatment type 1 cytokine levels and the extent of their change during treatment can predict the therapeutic response to neoadjuvant chemoradiation in advanced cervical cancer.

Cytokine profile in Indian women with cervical intraepithelial neoplasia and cancer cervix

Cervical cancer develops from the preneoplastic cervical intraepithelial neoplasia (CIN). Host factors are critical in regulating tumor growth and cytokines, which modulate immunologic control may be of particular importance. The objective of this study was to assess the production of cytokines by peripheral blood mononuclear cells (PBMCs) in Indian women with cancer cervix and CIN. Sixty patients with cancer cervix (including all FIGO stage I-IV), 35 patients with CIN, and 30 healthy controls were enrolled in this study. The human papillomavirus (HPV) 16 and 18 status was determined in all the study groups. The PBMC culture supernatant was collected for cytokine estimations by enzyme-linked immunosorbent assay (interleukin-2 [IL-2], interferon-gamma [IFN-gamma], interleukin-4 [IL-4], and interleukin-10 [IL-10]). IL-2 levels showed a significant decline in high-grade CIN and cancer patients, whereas IFN-gamma levels were decreased only in patients with advanced cancer cervix. An increase in the levels of IL-4 and IL-10 was found in all cancer cervix and CIN grade III patients, as compared to those with early CIN grades and healthy controls. The cytokine ratios decreased significantly (P < 0.001 for all the ratios), when cervical cancer patients were compared with controls and CIN cases. The type 2 and type 1 cytokine levels were significantly correlated (P < 0.000) with HPV status. We conclude that a pronounced shift from type 1 to type 2 cytokine production is associated with more severe disease. These data reinforce the need for detailed analysis of immune dysregulation in CIN and cancer cervix patients.

Crotapotin induced modification of T lymphocyte proliferative response through interference with PGE2 synthesis

The immunosuppressive property has been demonstrated for the venom of the Crotalus durissus terrificus. Using a simple, novel method for obtaining crotapotin and phospholipase A2 isoforms from venom, it was possible to demonstrate that the addition of crotapotin to cultures of isolated lymphocytes resulted in a significant inhibition of the cellular proliferative response to Concanavalin A. This reduction in blastogenic response of lymphocytes is accompanied by a significant increase in the production of PGE2 by macrophages. This effect on the innate immune response suggests that this compound may modify the subsequent adaptative immune response.

Effect of surgical treatment on the cellular immune response of gastric cancer patients

Patients with gastric cancer have a variety of immunological abnormalities. In the present study the lymphocytes and their subsets were determined in the peripheral blood of patients with gastric cancer (N = 41) both before and after surgical treatment. The percent of helper/inducer CD4 T cells (43.6 +/- 8.9) was not different after tumor resection (43.6 +/- 8.2). The percent of the cytotoxic CD8+ T cell population decreased significantly, whether patients were treated surgically (27.2 +/- 5.8%, N = 20) or not (27.3 +/- 7.3%, N = 20) compared to individuals with inflammatory disease (30.9 +/- 7.5%) or to healthy individuals (33.2 +/- 7.6%). The CD4/CD8 ratio consequently increased in the group of cancer patients. The peripheral blood lymphocytes of gastric cancer patients showed reduced responsiveness to mitogens. The defective blastogenic response of the lymphocytes was not associated with the production of transforming growth factor beta (TGF- ) since the patients with cancer had reduced production of TGF- Beta1 (269 +/- 239 pg/ml, N = 20) in comparison to the normal individuals (884 +/- 175 pg/ml, N = 20). These results indicate that the immune response of gastric cancer patients was not significantly modified by surgical treatment when evaluated four weeks after surgery and that the immunosuppression observed was not due to an increase in TGF- 1 production by peripheral leukocytes.

Detection of intracellular interleukin-2 production in peripheral T lymphocytes by flow cytometry in patients with pancreatobiliary malignancies

BACKGROUND AND AIMS

To date, it has been reported that cellular immunity is decreased in patients with cancer and investigations into cytokine production has been insufficient. Therefore, we examined intracellular cytokine production by using flow cytometry in patients with cancer and discussed the reasons for the impairment of their immune system.

METHODS

Eleven patients with hepatobiliary malignancies (68.5+/-11.8 years of age), eight age-matched controls (70.0+/-12.0 years of age) and 10 young volunteers (31.9+/-3.1 years of age) were used in the present study. Stimulated peripheral blood mononuclear cells from these patients were stained with fluorescence-labeled anticytokine monoclonal antibodies and analyzed with a Fluorescence activated cell sorter (FAC)Scan.

RESULTS

The percentage of positively stained T cells was calculated and compared with controls. Repeated measured ANOVA was used for statistical analysis. Interleukin (IL)-2 production was significantly decreased in patients with cancer compared to controls (P=0.0122), and it may suggest decreased cellular immune activity of the patients. Simultaneously, spontaneous intracellular IL-4 production was observed in patients and age-matched controls, but levels were significantly increased when compared with the young volunteers (P=0.0052, P=0.031, respectively).

CONCLUSIONS

It was of interest that spontaneous intracellular IL-4 production was detected in elderly subjects.

Cytokine production in leukocyte cultures during therapy with Echinacea extract

We measured the levels of the cytokines IL-1-alpha, IL-1-beta, IL-2, IL-6, TNF-alpha, and IFN-gamma in culture supernatants of stimulated whole blood cells derived from 23 tumor patients undergoing a 4-week oral treatment with a spagyric extract from Echinacea angustifolia, Eupatorium perfoliatum, and Thuja occidentalis (Echinacea complex). All patients had had curative surgery for a localized solid malignant tumor. Blood was taken before treatment and after 2 and 4 weeks of therapy. Twelve untreated tumor patients at the same clinical stage, also after curative surgery, served as a control group. In the blood cell cultures of all patients, a rather wide range of cytokine levels was found. After therapy with Echinacea complex, no significant alteration in the production of the cytokines could be seen in comparison to the controls, and also the leukocyte populations remained constant. We conclude that at this application and dosage, the therapy with Echinacea complex has no detectable effect on tumor patients' lymphocytes activity as measured by their cytokine production.

Cytokine production in whole blood cell cultures of patients undergoing therapy with biological response modifiers or 5-fluorouracil

We have measured the levels of interferon gamma (IFN gamma), tumor necrosis factor alpha (TNF alpha), interleukin-1 alpha (IL-1 alpha), IL-1 beta, and IL-2 in the whole blood cell culture supernatants of 43 tumor patients undergoing a treatment with biological response modifiers or a conventional therapy with 5-fluorouracil and leucovorin. In the blood cell cultures of the 16 patients who received 5-fluorouracil and leucovorin IFN gamma levels decreased (P < or = 0.01) and TNF alpha levels rose (P < or = 0.05) during each therapy cycle. However, in the blood samples a declining number of total leukocytes and lymphocytes was measured (P < or = 0.05). Progressive disease could be correlated to a tendency towards lower IFN gamma levels in the pretherapeutic cultures of these patients. The second group analyzed consisted of 8 patients receiving a low-dose IL-1 beta therapy. In this group we found either an unchanged or an augmented IFN gamma production of the blood cells during treatment. In the group of 13 patients receiving low-dose recombinant IL-2 (< or = 4.5 x 10(6) IU m-2 day-1) significantly increasing IFN gamma levels were seen in the blood cell cultures during the therapy (P < or = 0.05), although total leukocyte counts decreased. In this group, 4 had stable disease for at least 2 months and 9 patients had tumor progression under therapy. In the cultures of the latter a tendency towards lower IFN gamma values was found. Finally, the cytokine production in the blood cell cultures of 6 patients receiving a combination therapy of IFN alpha and high-dose IL-2 was studied. During this therapy a dramatically reduced production not only of IFN gamma but also of all other measured cytokines was found. In this group all patients had tumor progression under therapy. It is concluded that the measurements of cytokine production in a reproducible whole blood culture system may be useful for monitoring immunological therapies and may help us to find out which doses of biological response modifiers have enhancing or suppressive effects on the functions of the immune cells.

Impaired cytokine production in whole blood cell cultures of patients with gynaecological carcinomas in different clinical stages

The production of the cytokines IFN-gamma, IL-1-alpha, IL-2 and TNF-alpha was investigated in mitogen-stimulated, whole blood cell culture from 239 untreated patients with primary gynaecological carcinomas (breast, cervix, ovary, endometrium), and 191 healthy female controls. The cytokines were measured in the 4-day post-induction supernatants by a sensitive enzymoimmunological assay. In the blood cell cultures of all four groups of cancer patients, significantly lower values of IFN-gamma (P < or = 0.001), IL-2 (P < or = 0.01) and IL-1 alpha (P < or = 0.01) were found as compared to the controls, although lymphocyte and monocyte counts were almost identical. Grouping the tumour patients into different clinical stages we could show in the four groups of carcinomas a gradual depression of the cytokine production according to growing tumour burden.

Impaired cytokine production in whole blood cell cultures of patients with urological carcinomas

The production of the cytokines interferon gamma (IFN gamma), interleukin-1 alpha (IL-1 alpha) and tumor necrosis factor alpha (TNF alpha) was investigated in the mitogen-stimulated whole blood cell culture media from 51 patients with urinary bladder carcinomas, 52 patients with renal carcinomas, 31 patients with prostatic carcinomas and 360 healthy controls. The cytokines were measured 4 days after induction by a sensitive enzymo-immunological assay. In the blood cell culture supernatants of the patients with urinary bladder carcinomas significant lower levels of IFN gamma (P < or = 0.001), IL-2 (P < or = 0.01) and TNF alpha (P < or = 0.05) were found as compared to the controls. Blood cells of patients with renal carcinomas had lower production of IFN gamma (P < or = 0.01), IL-2 (P < or = 0.001) and IL-1 alpha (P < or = 0.01), whereas the values of the total group of patients with prostatic carcinomas were not significantly different from those of the controls. Lymphocyte and monocyte counts were almost identical in the control and all tumor patient groups. When the patients with renal carcinomas and prostatic carcinomas were analyzed according to their different clinical stages we could show a gradual depression of the IFN-gamma levels, which was related to tumor burden.

The role of cytokines in cancer cachexia

There is, at present, considerable interest in the possible role for the proinflammatory cytokines, tumor necrosis factor-alpha, interleukin-1, interleukin-6, and interferon-gamma in the pathogenesis of cancer cachexia. Indirect evidence for such a role is based on the observation that chronic administration of many of these cytokines, either alone or in combination, can reproduce the myriad of host responses seen in experimental and human cancer cachexia. Elevated plasma levels of tumor necrosis factor-alpha, interleukin-2, and interferon-gamma have rarely been detected in patients or experimental animals with cancer, although interleukin-6 levels appear to correlate with tumor progression in animal models. The strongest evidence for a causal role for cytokines has come from rodent studies in which tumor-bearing animals have been passively immunized with antibodies directed against individual cytokines. Several groups have shown modest but significant improvements in food intake and lean tissue retention with antibodies directed against tumor necrosis factor-alpha, interleukin-1, interleukin-6, and interferon-gamma. However, there has been no consistent finding that one cytokine is universally involved in cancer cachexia in histologically distinct tumor models. One ominous finding in several tumor models has been that the endogenous production of cytokines appears to support tumor growth. Such findings raise the intriguing possibility that these cytokines, although contributors to tissue wasting and anorexia, may also serve the tumor as either direct or indirect cell growth factors.(ABSTRACT TRUNCATED AT 250 WORDS)

Cytokine Levels in Whole Blood Cell Cultures of Oral Contraceptive Users and Pregnant Women

The production of the cytokines IFN-gamma, IL-2, IL-1-alpha and TNF-alpha was investigated in the supernatants of mitogen-stimulated whole blood cell cultures from 52 oral contraceptive users, 33 pregnant women and 75 female controls. Cells from women taking oral contraceptives produced significantly less IFN-gamma (p≤0.05) and TNF-alpha (p≤0.05) compared to the controls. In the cultures of the pregnant women significantly lower levels of IFN-gamma (p≤0.01), IL-2 (p ≤0.001) and TNF-alpha (p≤0.01) were found than in those of the controls. Total and differential leukocyte counts were almost identical in all three groups of women. It is suggested, that lymphocyte and monocyte function as measured by cytokine production is altered in women taking oral contraceptives and in pregnant women.

Impaired cytokine production in whole blood cell cultures from patients with colorectal carcinomas as compared to benign colorectal tumors and controls

Cytokine production was investigated in whole blood cell cultures from 74 patients with colorectal carcinomas, 20 patients with benign colorectal tumors, and 314 healthy controls. In the 4 day post induction supernatants the levels of IFN-gamma, IL-1-alpha, IL-2, and TNF-alpha were measured by a sensitive immunoassay. In the blood cell cultures of the patients with colorectal carcinomas significantly lower values of IFN-gamma (P less than or equal to .001), IL-1-alpha (P less than or equal to .001), and IL-2 (P less than or equal to .01) were found as compared to the patients with benign tumors and the controls, although total and differential leukocyte counts were similar in all three groups. A linear correlation between the levels of IFN-gamma and IL-1-alpha and the tumor stages could be shown. Our results suggest that a growing tumor burden may induce increasing immunological deficiencies as reflected by a decreasing cytokine production of the immune cells.

Contribution of monocytes to the decreased lymphoproliferative response to phytohemagglutinin in patients with lung cancer

Patients with lung cancer (LC) have a reduced T-cell proliferative response to phytohemagglutinin (PHA) compared with that of healthy individuals. This decreased response is a result of an inhibitory effect exerted by the monocytes as evidenced by: (1) a restoration to normal levels of the response to PHA when the peripheral blood mononuclear cells were depleted of adherent cells (AD) and (2) a dose-dependent inhibition of the response to PHA when the nonadherent cell population was co-cultured with increasing numbers of autologous AD cells. The addition of indomethacin to the cultures resulted in only a partial restoration of the response to PHA. Monocyte production of interleukin-1 from patients with LC in response to lipopolysaccharide was normal. These findings support the hypothesis that the AD cell population plays a major role in the low T-cell proliferative response to PHA in patients with LC. This suppressor effect is partially mediated by the prostaglandins released by the monocytes.

Interleukin-1 production by immunologically hyporeactive tumour-bearing mice

Mice bearing progressively growing syngeneic methylcholanthrene-induced sarcomas are immunologically hyporeactive. However, both basal (steady-state) and bacterial lipopolysaccharide (LPS)-induced synthesis of mRNA for interleukin-1 (IL-1) in peritoneal exudate cells (PEC) or spleen cells were comparable in control and tumour-bearing animals. Furthermore, the production of IL-1 by PEC stimulated with LPS in the presence of indomethacin was same in control and tumour-bearing mice. The results thus demonstrate that LPS-stimulated cells from animals bearing progressively growing syngeneic sarcomas synthesise the same quantities of mRNA for IL-1 and produce comparable amounts of IL-1 as do cells from normal animals, in spite of the profound immunological hyporeactivity of the former.

Cryopreservation enhances interleukin-1 production in human mononuclear cells

The effects of cryopreservation on bacterial lipopolysaccharide (LPS)-induced interleukin-1 (IL-1) production by unfractionated mononuclear cells (MNCs), adherent cells (ACs), and nonadherent cells (NACs) were studied. Culture supernatants from cryopreserved cells contained significantly larger concentrations of IL-1 [MNCs, 211 +/- 50; ACs, 640 +/- 41; NACs, 116 +/- 19 U/ml (mean +/- SEM)] as compared with supernatants from fresh cells (69 +/- 22, 427 +/- 69, and 72 +/- 33 U/ml, respectively). In addition, supernatants obtained from cocultures of autologous fresh and frozen cells contained much less than the expected quantities of IL-1 (78 +/- 8%), indicating that suppressor cells in the fresh population are responsible for the decreased IL-1 content. The studies suggest that functional inactivation of cryosensitive suppressor monocytes is associated with an increase in IL-1 production by the other subset. The results provide further evidence that lack of active suppressor monocytes and increased IL-1 production may be responsible for the previously reported enhanced plaque-forming cell responses of cryopreserved cells from normal controls and from patients with lung cancer.

Defective interleukin-1 production of monocytes in patients with bladder cancer

Patients with advanced malignant neoplasms have a variety of abnormal lymphocyte and monocyte functions. We examined the PHA (phytohaemagglutinin) blastogenic response of lymphocytes and interleukin-1 (IL-1) production of monocytes in 40 bladder cancer patients and 16 control subjects. The correlation between the 2 parameters was also studied. The PHA blastogenic response was measured by the incorporation of 3H-thymidine into lymphocytes. IL-1 production was assayed by the murine thymocyte 3H-thymidine incorporation assay. As a result, the PHA blastogenic response and IL-1 production were significantly lower in the high stage bladder cancer patients compared to the control subjects and low stage patients. However, there was no significant correlation between the 2 parameters. Furthermore, with the addition of indomethacin, IL-1 production in the control subjects and low stage patients improved to the same degree, but it did not reach the control level in the high stage patients.

Monocytic production and plasma bioactivities of interleukin-1 and tumour necrosis factor in human cancer

Plasma concentrations and in-vitro production of interleukin-1 and tumour necrosis factor were evaluated in 23 weight-losing patients with cancer, six bacterially infected patients without cancer and six healthy controls. Bioactivity of interleukin-1 was found in the plasma from five of six bacterially infected patients but only from one of 23 cancer patients. Tumour necrosis factor activity was not detected in the plasma of any patient. In four of 23 patients with cancer, in-vitro stimulation of peripheral blood monocytes by either endotoxin or heat-killed Staphylococcus albus resulted in no significant production of interleukin-1. Such a defect was not seen in any of the bacterially infected or control patients. Tumour necrosis factor production by endotoxin-stimulated blood monocytes was unaffected by the presence of cancer or bacterial infections and was normal in the four individuals with defective interleukin-1 production. We can therefore conclude that interleukin-1 bioactivity is not generally found in the plasma of weight-losing cancer patients. Furthermore, in a fraction of such cancer patients, monocytic production of interleukin-1 is markedly down-regulated. However, this defect appears to be specific for interleukin-1 since in-vitro tumour necrosis factor production is normal.

Decreased interleukin generation in patients with cancer of the digestive system. A correlation between interleukin 1 and interleukin 2 production

The generating capacity of interleukin 1 (IL-1) and interleukin 2 (IL-2) by peripheral blood mononuclear cells (PBMNC) was measured in 40 patients with digestive cancer (20 localized and 20 disseminated) and 20 age- and sex-matched control subjects. The localized carcinoma patients showed normal IL-1 production and a significantly depressed IL-2 production (p less than 0.05) when compared to the healthy individuals. The disseminated carcinoma patients exhibited a significant impairment of both IL-1 and IL-2 production in comparison with the healthy controls (IL-1: p less than 0.001, IL-2: p less than 0.001) and the localized carcinoma patients (IL-1: p less than 0.001, IL-2: p less than 0.001). A significant correlation was observed between IL-1 and IL-2 generation in all the cancer patients (r = 0.458, p less than 0.01). These results suggest that progressive tumor growth may result in decreased interleukin production by the host PBMNC, and that related mechanisms, which are more susceptible to lymphocytes than monocytes, may be involved in the impairment of both IL-1 and IL-2 production.

Impairment of monocyte functions in advanced head and neck cancer

Depression of cell-mediated immunity is well established in most malignancies and especially in head and neck cancers, and much information is available concerning the defect in helper T lymphocyte function. We now report on impairment of the monocyte-macrophage system. Compared with normal controls we found that patients displayed, on one hand, an increased number of peripheral blood monocytes and, on the other hand, a smaller percentage of HLA-DR+ monocytes. Such peripheral blood monocytes normally failed to secrete factors, including interleukin 1 (IL-1). In addition, we observed that the in vivo induced blastogenesis of peripheral blood lymphocytes from patients, which is spontaneously depressed, is partly restored by medium containing IL-1. We cannot exclude, however, that the observed monocyte dysfunction involves other cytokines. Whether such an immune deficiency is due to secondary malnutrition or to the malignancy (or both) remains unclear.

Inhibition of cell-mediated immunity by tumour cell products: depression of interleukin-2 production and responses to interleukin-2 by mouse spleen cells

Supernatants from cultures of mouse and human tumour cells inhibited the production of interleukin-2 (IL-2) by stimulated mouse spleen cells. The tumour cells tested, all of which were active, included a mouse and a human melanoma, three methylcholanthrene-induced fibrosarcomas of mice, and human HeLa cells. Supernatants from normal mouse and human fibroblasts were inactive. Inhibition was dose-dependent. Spleen cells from aged mice were more susceptible to inhibition than spleen cells from young mice. When tumour cell culture supernatants were fractionated on Sephacryl S-300, two peaks of activity were found, with apparent molecular weights of approximately 50 and 18 kD. Supernatants from tumour cell and fibroblast cultures caused variable, but generally weak, inhibition of responses of lymphoblasts to IL-2. It is suggested that inhibition of IL-2 production may be an important mode of action of tumour cell products that inhibit cell-mediated immunity.

Interleukin 1, tumour necrosis factor-alpha (cachectin) and the pathogenesis of cancer cachexia

Soluble proteins synthesized and released by phagocytic cells may be responsible for the protein and energy wasting frequently observed during catabolic states, including cancer cachexia. This hypothesis is based upon the observation that many of the hosts's metabolic responses to infection, inflammation, accidental trauma and some forms of cancer are remarkably similar. Anorexia and degradation of skeletal and connective tissue protein, as well as increases in hepatic protein synthesis and energy expenditure, can all be reproduced by the administration of activated macrophage products. During inflammatory states, including active tumour growth, increased production of some cytokines, including interleukin 1 and tumour necrosis factor-alpha (cachectin), have been observed. If these monokines serve as metabolic inducers, then efforts to block therapeutically the actions of macrophage-secreted substances may play a role in slowing the progression of tissue-wasting associated with catabolic states, particularly due to malignant tumours.

Reduced in vitro erythroid progenitor cell growth in bronchial cancer

Peripheral blood and bone marrow were studied in 21 men with disseminated untreated bronchial cancer in an attempt to define abnormalities of erythropoiesis associated with the development of anaemia. Haemoglobin concentration at or below 13 g/dl was present in 13 cases. Marrow morphology was normal in all cases except one, in which small numbers of tumour cells were found. Clonal assay of erythroid progenitors showed a significant decrease in the number of BFU-E (p = 0.03) and CFU-E (p = 0.01) compared with cultures from normal marrow (12 subjects). The growth of granulocyte and macrophage progenitors (GM-CFCs) was similar in patients with bronchial cancer and normal subjects. When normal marrow was incubated in the presence of serum from bronchial cancer patients, no inhibitory factors could be detected either for BFU-E or CFU-E growth. In all patients circulating T8 numbers were significantly raised (p = 0.0002). Consequently, the median T4:T8 ratio in blood was 1.2, and this was significantly lower than the ratio of 1.7 found in 20 normal subjects (p = 0.036). In 18 patients the bone marrow T4:T8 ratio of 1.1 was significantly lower than the ratio of 2.9 found in seven normal subjects (p = 0.04). Total blood white cell counts, neutrophils, and monocyte numbers were also increased (p = 0.0001; p = 0.0001; p = 0.002).