Lymphocytes and the immune response. I

Cancer-immune interactions in ER-positive breast cancers: PI3K pathway alterations and tumor-infiltrating lymphocytes

Introduction

The presence of tumor-infiltrating lymphocytes (TILs) is correlated with good prognosis and outcome after (immuno)therapy in triple-negative and HER2-positive breast cancer. However, the role of TILs in luminal breast cancer is less clear. Emerging evidence has now demonstrated that genetic aberrations in malignant cells influence the immune landscape of tumors. Phosphatidylinositol 3-kinase (PI3K) is the most common altered pathway in ER-positive breast cancer. It is unknown whether changes in the PI3K pathway result in a different composition of the breast tumor microenvironment. Here we present the retrospective analysis of a prospective randomized trial in ER-positive breast cancer on the prognostic and predictive value of specific tumor-associated lymphocytes in the context of PI3K alterations.

Methods

We included 563 ER-positive tumors from a multicenter trial for stage I to III postmenopausal breast cancer patients, who were randomized to tamoxifen or no adjuvant therapy. The amount of CD8-, CD4-, and FOXP3-positive cells was evaluated by immunohistochemistry and quantified by imaging-analysis software. We analyzed the associations between PIK3CA hotspot mutations, PTEN expression, phosphorylated proteins of the PI3K and MAPK pathway (p-AKT, p-ERK1/2, p-4EBP1, p-p70S6K), and recurrence-free interval after adjuvant tamoxifen or no adjuvant treatment.

Results

CD8-positive lymphocytes were significantly more abundant in PIK3CA-mutated tumors (OR = 1.65; 95% CI 1.03–2.68). While CD4 and FOXP3 were not significantly associated with prognosis, patients with tumors classified as CD8-high had increased risk of recurrence (HR = 1.98; 95% CI 1.14–3.41; multivariable model including PIK3CA status, treatment arm, and other standard clinicopathological variables). Lymphocytes were more often present in tumors with increased PI3K downstream phosphorylation. This was most pronounced for FOXP3-positive cells.

Conclusion

These exploratory analyses of a prospective trial in luminal breast cancer suggest high CD8 infiltration is associated with unfavorable outcome and that PI3K pathway alterations might be associated with the composition of the tumor microenvironment.

Electronic supplementary material

The online version of this article (10.1186/s13058-019-1176-2) contains supplementary material, which is available to authorized users.

In vitro analysis of lymphocytes: markers and functions

Current dermatologic literature is becoming replete with articles elucidating current concepts in the pathophysiology of lymphocytic diseases. Much of this knowledge emanates from the increasingly sophisticated and complex methods of identifying lymphocytes. No longer does it suffice to know that B lymphocytes or T lymphocytes are present, but rather the key information involves knowing what subsets of these cells are present and/or their functional status. The reader attempting to assimilate all this information is thus confronted with an overwhelming, as well as frequently changing, array of analytic methods. This paper is presented as a review of thinking, principles, and methods employed in research on lymphocytic disease.

Changes of adenosinetriphosphatase (ATPase) activities in lymphocytes from patients with carcinomas of the gastrointestinal tract

The activities of both total and Oligomycin-sensitive ATPase in lymphocytes from patients with gastrointestinal tract (GI) carcinomas in different Karnofsky performance status (KPS) were determined to investigate whether or not the changes of these enzyme activities were correlated to those of the immune responsiveness of the patients. In the patients whose KPS indicated more than 50%, the mean value of the total ATPase activity in lymphocytes tended to increase slightly as compared with that determined in the control subjects, but the mean value of the Oligomycin-sensitive ATPase activity in lymphocytes tended to decrease slightly as compared with that determined in the control subjects. In the patients whose KPS indicated less than 30%, the mean values of the activities of both total and Oligomycin-sensitive ATPase in lymphocytes tended to decrease remarkably as compared with those determined in the control subjects. The ATPase activities in lymphocytes were suggested to be useful measures to the immune responsiveness of the patients with GI carcinomas.

Acute experimental canine ehrlichiosis. I. Sequential reaction of the hemic and lymphoreticular systems

Dogs with acute Ehrlichia canis infection showed the established clinical features of acute ehrlichiosis and had thrombocytopenia, anemia, increased serum glutamic pyruvic transaminase activity, and decreased total serum protein and albumin concentrations during the first weeks after infection, and increasing gamma globulin concentrations after the third week. Gross lesions in hemic and lymphoreticular tissues were transient lymphadenomegaly, splenomegaly, and increased red long-bone marrow. Lymphoreticular hyperplasia in the paracortical area of lymph nodes and in the splenic red pulp occurred during the second week of infection. Later, small lymphocytes were replaced by medium-sized lymphocytes and plasma cells. Activity of germinal centers increased initially, as shown by numerous mitotic figures and macrophages, but diminished later, and the follicles blended with interfollicular and paracortical tissue because of a decrease in small lymphocytes in the mantle layer. We saw splenic hemorrhages near the perifollicular sinus, and vasculitis, most often phlebitis, in the kidney between weeks 2 and 4. Multifocal reticuloendothelial hyperplasia occurred in the liver during the early stage and injured adjacent hepatocytes by compression. Lesions typical of ehrlichiosis in these dogs were interstitial pneumonia, subendothelial aggregates of mononuclear cells in pulmonary blood vessels, renal periglomerular and perivenular plasmacytosis, hemopoietic hyperplasia, and perivascular cuffs of lymphocytes and plasma cells in many organs.

Diffuse large cell lymphomas (reticulum cell sarcomas, histiocytic lymphomas). Correlation of morphologic features with functional markers

Electron microscopic findings in 15 cases of diffuse large cell lymphoma were correlated with other morphologic features, surface immunotype and cytoplasmic immunoglobulin content. Immunologically, the cases were: B cell, 8; null, 4; T cell, 2; and H cell (true histiocytic), 1. Ultrastructurally, all B cell and three null lymphomas were characterized by an abundance of polyribosomes and segments of rough endoplasmic reticulum. Concentric rough endoplasmic reticulum was observed in 4 cases of B cell lymphoma containing cytoplasmic immunoglobulin and in a null lymphoma. In 1 case of B cell lymphoma, the diastase-sensitive, periodic-acid-Schiff-positive cytoplasm showed evidence of widely dispersed monoparticulate glycogen granules. The two T cell lymphomas contained hyperlobulated or single round nuclei, and abundant smooth to rough endoplasmic reticulum. One null lymphoma appeared to share the ultrastructural features of T cell convoluted nuclei and the cytoplasmic organelles of myeloid precursor cells. The H cell lymphoma had features of monocytic-macrophagic differentiation. The large cell lymphomas, a morphologically and functionally heterogeneous group, were represented predominantly in this series by neoplasms with follicular center cells or early plasma cells.

Lymphocyte ATPase activity in patients with carcinoma of the larynx. A follow-up study on 45 patients

Mitochondria-related Mg ATPase activity was assayed in lymphocytes isolated from the blood in 45 patients with epidermoid carcinomas of the larynx. Increased activity was found in 11 patients and normal or subnormal activity in the remaining cases. No correlation could be demonstrated between the magnitude or the spreading of the malignancy as recorded by the TNM classification and the ATPase activity. In 36 patients determinations were carried out repeatedly during a period from 6 to 20 months following therapy and after 3 years a final follow-up on all patients was done. All patients received high-voltage radiotherapy and in 7 patients additional partial or total laryngectomia was carried out, one patient had bilateral neck dissection. After radiotherapy the ATPase activity decreased significantly in 17 patients while it either remained normal or increased temporarily in the rest. No correlation was found between the course of the disease and the initial ATPase activity or the pattern of variation in ATPase activity following therapy. Contrary to what resulted from a preliminary study, it is concluded that determination of lymphocyte ATPase activity is of no diagnostic value in patients with laryngeal carcinoma, nor does it offer any prognostic help in determining which patients may relapse or develop metastatic disease.

Cutaneous T cell lymphoma: mycosis fungoides, Sézary syndrome, and other variants

Cutaneous T cell lymphoma (CTCL) is a clinically and immunologically defined neoplasm which encompasses epidermotropic (mycosis fungoides, Sézary syndrome) and nonepidermotropic variants. A natural evolution apparently occurs from the epidermotropic to the nonepidermotropic form. In this review, cellular properties of the neoplastic cells are correlated with specific clinical observations, and recent therapeutic advances are discussed. Advances in our understanding of the pathogenesis of CTCL, including preliminary evidence suggesting that keratinocytes may elaborate a hormonal substance capable of inducing T lymphocyte differentiation, are discussed.

The effects of azathioprine and 6 MP on immunity

The thiopurines, azathioprine and 6 MP are potent inhibitors of both experimental and clinical immune responses. The primary pharmacological activities are mediated by competitive inhibition of enzymes concerned with de novo purine base synthesis; Immunosuppressive activities appear to result from cytotoxic activities directed against antigen-responsive lymphocytes; this inhibition is maximal when the treatment course coincides with the proliferative expansion phase of the response. By contrast, thiopurines are comparatively ineffective if used during an effector phase of an immune response. Furthermore, administration prior to antigenic challenge does not lead to immune inhibition; in fact, it may lead to augmentation of selected immune responses. Treatment with thiopurines does not result in acute lymphopenia; prolonged courses will cause a moderate decrease in circulating lymphocytes. The drug does not selectively deplete peripheral T or B cells but can acutely reduce K (killer) cells, which are effectors in ADCC responses. In addition, short-lived thymocytes and marrow lymphocytes are rapidly depleted by these anti-metabolites. Many in vitro functions of lymphocytes, from treated animals remain normal. Recent studies indicate that, in vitro, azathioprine is specifically able to bind murine T lymphocytes; this can be shown by their ability to inhibit their capacity to rosette with sheep erythrocytes. Azathioprine is also a potent inhibitor of mixed lymphocyte culture responses and can readily suppress the in vitro generation of cytotoxic T cells. These observations suggest that drugs exert preferential toxicities for murine T cells. B lymphocytes for mice appear to vary in their susceptibility for thiopurines. By contrast, the activity of human B cells can be readily suppressed with this drug whereas T helper function is comparatively resistant. In addition to immunosuppressive properties, thiopurines are capable of exerting anti-inflammatory activities, primarily by inhibiting the replication of hematopoietic precursors.

The pattern of lymphocytes in the thymus and spleen after labeling with 3H-thymidine and 3H-deoxycytidine

Adult male untreated mice (NMRI) were investigated after radioactive labeling with 3H-thymidine and 3H-deoxycytidine to find out whether the lymphocytes in the cortex and medulla of the thymus as well as in the perifollicular and periarteriolar regions of the spleen show a labeling pattern which allows a classification into T- and B-lymphocytes. The percentages of radioactively labeled small lymphocytes and their mean grain counts were determined. The percentages of radioactively labeled small lymphocytes after 3H-TdR and 3H-CdR showed no significant differences in both splenic zones. The grain counts over the lymphocyte nuclei in the periarteriolar zone showed lower values after 3H-TdR than after 3H-CdR. The lymphocytes in the perifollicular zone were strongly labeled with 3H-TdR and weakly labeled with 3H-CdR. In the thymus medulla, lymphocytes were weakly labeled with 3H-thymidine and strongly labeled with 3H-CdR. In the cortex no significant differences were observed. 75 to 80% of the small lymphocytes in the peripheral blood were weakly and 20-25% strongly labeled after 3H-TdR. Therefore there are similarities in the radioactive labeling pattern of thymic medulla lymphocytes and that of small lymphocytes of the periarteriolar zone of the spleen by both DNA precursors. The small lymphocytes in the peripheral T-dependent tissue zones, for example in the spleen, as well as in the mixed lymphocyte population of the peripheral blood can be differentiated from the B-lymphocytes through the difference in the amount of incorporation of 3H-thymidine and 3H-deoxycytidine.

Classification of lymphomas

Malignant lymphomas are neoplasms of cells of the lymphoreticular or immune system. Classification of these neoplasms has long been controversial and confusing. In recent years, considerable progress has been made in establishing useful and prognostically significant classifications of lymphomas. Currently, lymphomas may be divided into two main groups: Hodgkin's disease and non-Hodgkin's lymphomas. The Rye classification of Hodgkin's disease is now widely accepted and used throughout most of the world. In contrast, considerable conflict exists about the schemes of non-Hodgkin's lymphomas. The traditional classifications of non-Hodgkin's lymphomas currently used by most pathologists are based purely on morphologic grounds, and, despite the fact that they may be conceptually incorrect, they have often been shown to be useful for clinicopathologic studies. New or modern but yet untested schemes based not only on morphologic criteria, but also on recent immunologic techniques, have been proposed. This work will review the classifications of Hodgkin's disease and the non-Hodgkin's lymphomas, emphasizing the currently used schemes, describe the major modern classifications of lymphomas, and discuss and illustrate the subclasses of lymphomas and the differential diagnoses of the various types of lymphomas from nonlymphomatous proliferations which may mimic them.

Percent distribution of T- and B-cells in tonsils of children, juveniles and adults

The percent distribution of T- and B-lymphocytes in tonsilar tissue of 122 patients from 2--68 years and both sexes was investigated. T-cells were determined by the E-rosetting technique and B-cells by immunofluorescence. We found 50.3% B-cells and 30.6% T-cells in tonsilar tissue. There was a significant decrease of IgM-receptor carrying cells with increasing age and with a converse behavior of the sum of IgA-, IgD-, IgE-receptor B-cells. In tonsils with acute inflammation and with hyperplasia IgM cells were also increased significantly when compared to cell counts in chronic tonsillitis. The results are discussed and compared to data from the literature.

Non-endemic Burkitt's lymphoma. A B-cell tumor related to germinal centers

To investigate the nature of non-endemic Burkitt's lymphoma, we examined neoplastic cells from eight American patients for receptors for sheep erythrocytes (E), complement (EAC), and Fc fragment of lgG (igGEA), and for surface immunoglobulins (Slg) and hydrolytic enzymes. In addition, we reviewed 47 biopsies and 17 autopsies from American patients to ascertain patterns of involvement by tumor in lymph nodes, spleens and Peyer's patches. Neoplastic cells in all cases studies bore monoclonal surface immunoglobulins of the igM class. Receptors for EAC and igGEA were identified on a minority of the cells. Little or no hydrolytic enzyme activity was demonstrable. These results indicate that, like Burkitt's lymphoma in Africans, this histologically identical tumor in American patients consists of B lymphocytes. In 10 biopsies and two autopsies, germinal centers were selectively involved by tumor, suggesting that these neoplastic cells may be related to some B lymphocytes of normal germinal centers.

Dinitrochlorobenzene skin sensitization and peripheral lymphocyte count: predictors of survival in head and neck cancer

Dinitrochlorobenzene (DNCB) is a simple chemical useful to evaluate both afferent (sensitizing) and efferent (reacting) limbs of the delayed, cell-mediated immune system. This system invokes the small lymphocyte (T cell) and is apparently part of the host defense against cancer. Severnty-two patients with new primary squamous cell carcinomas of the larynx, hypopharynx and oropharynx were sensitized to DNCB by contact application, and delayed cutaneous hypersensitivity tested. The T cells were also assessed in this study by lymphocyte count. All patients were treated for cure. Ninety-one percent of DNCB reactors were alive and tumor-free at two years. Forty-five percent of negative reactors had recurrent tumor and died of carcinoma. Cases grouped by site among glottic, supraglottic and inferior hypopharynx showed identical results. Lymphocyte counts showed a trend in the same direction. On statistical analysis, all differrences were significant. Eighty-five percent of recurrent tumors occurred in patients who were nonresponders. The present data suggest DNCB reactivity is helpful in predicting outcome after surgery, or combined radiation and surgery, for mucosal squamous carcinoma of the head and neck.

Transformation of human lymphocytes in vitro by autologous and allogeneic rheumatoid synovial fluids

To assess the possible participation of cellular immune mechanisms in the pathogenesis of rheumatoid arthritis (RA) in vitro studies of the blastogenicity of rheumatoid and non-rheumatoid synovial fluids for human peripheral blood lymphocytes were conducted. In autologous cultures it was found that 13 of 19 rheumatoid fluids induced significant lymphocyte blastogenesis, whereas only 1 of 13 nonrheumatoid fluids induced such a response. In allogeneic cultures rheumatoid fluids induce significant blastogenesis of RA lymphocytes in 18 of 23 experiments, and of non-RA lymphocytes in 8 of 18 experiments. By contrast, nonrheumatoid fluids induced significant blastogenesis of RA lymphocytes in 2 of 13 experiments, and of non-RA lymphocytes in 1 of 14 experiments. The blastogenicity of fluids was found to correlate significantly with the presence therein of immunofluorescent intracellular inclusions of immunoglobulin and complement. These studies support the concept that the presence of immune complexes in the majority of rheumatoid synovial fluids might render the latter blastogenic for human lymphocytes in vivo, thereby perpetuating rheumatoid synovitis.

Effects of cytotoxic immunosuppressants on tuberculin-sensitive lymphocytes in guinea pigs

The immunosuppressive activities of two phase-specific drugs, 6-mercaptopurine (6-MP) and methotrexate, and a cycle-specific agent, cyclophosphamide, were evaluated on the lymphocytic component of established tuberculin hypersensitivity in guinea pigs. In these animals, purified protein derivative (PPD)-sensitive lymphocytes are in an intermitotic phase of their proliferative cycle. Neither phase-specific drug significantly altered either the number or functional activities of these lymphocytes. By two in vitro criteria, PPD-induced lymphoproliferation and elaboration of migration inhibition factor (MIF), the responses of lymph node cells were equivalent to sensitized controls. In addition, these agents did not deplete pools of T lymphocytes, impair responses to phytohemagglutinin (PHA), nor inhibit cutaneous reactivity if employed before sensitization. In contrast, cyclophosphamide showed broader immunosuppressive effects including significant toxicities for intermitotic lymphocytes. This drug depleted pools of T cells and markedly impaired the in vitro proliferative responses of residual lymphocytes. The latter occurred with both PHA and PPD. Suppression of PHA reactivity was a dose-dependent phenomenon but was evident even with small quantities of this alkylating agent. The suppression of antigen-induced responses was independent of the proliferative status of target lymphocytes in vivo, after a single large dose, it persisted for more than 3 wk. In total, these results indicate that the effective use of cytotoxic drugs as immunosuppressants must include consideration of both the cycle specificities of the agent and the proliferative activities of the target lymphoid population.

Increased lymphocyte ATP-ase activity in patients with carcinomas of the oral cavity and larynx

Increased mitochondrial ATP-ase activity was found in circulating lymphocytes from 5 out of 8 patients with carcinoma of the oral cavity or oropharynx and from 5 out of 10 patients with carcinoma of the larynx. In a majority of these cases changes in the ATP-ase activity after treatment paralled to the clinical result of treatment. It is suggested that determination of ATP-ase activity of circulating lymphocytes is of diagnostic value in patients with oral, oropharyngeal and laryngeal carcinomas as well as prognostic value after treatment of the patients.

Anesthesia and the immune system

Anesthesia and operation may impair the immune system so that bacterial growth and tumor spread may occur more readily, and host response to transplanted tissue and allergenic substances may be altered. Suggestions are presented regarding the anesthetic management of patients at risk from infection or tumor spread.

Effects of canine distemper virus infection on lymphoid function in vitro and in vivo

In the present study, the immunodepressive effects of canine distemper virus (CDV) infection of dogs on two parameters of lymphocyte function, namely phytomitogen-induced cellular proliferation and skin allograft rejection, were investigated. Infection of susceptible gnotobiotic dogs with virulent R252-CDV resulted in a depression of peripheral blood lymphocyte mitogen response as measured by (3H)thymidine incorporation for up to 10 weeks after inoculation. This effect coincided with the appearance of viral antigen by immunofluorescence in leukocytes but persisted after the virus was no longer detectable. Loss of mitogen reactivity was seen in all infected dogs. However, when these same CDV-infected dogs were challenged with foreign skin allografts, no significant retention of grafts over controls was observed despite the depressed lymphocyte activity. Considering the in vitro and in vivo data it was concluded that, although immunodepressive effects of CDV were demonstrated in vitro, paralled in vivo experiments indicated that less than complete suppression of immune functions occurs during the course of CDV infection.

Enhancement of human lymphocyte transformation by aggregated human gamma globulin

The effect of heat-aggregated human gamma globulin (aggFII) on the induction of in vitro lymphocyte transformation, measured by the uptake of tritiated thymidine into newly synthesized DNA, was studied with peripheral blood lymphocytes derived from 12 patients with rheumatoid arthritis (RA), six with ankylosing spondylitis (AS), two with systemic lupus erythematosus (SLE), and seven normal subjects. It was found that 200 mug aggFII induced significant transformation of the lymphocytes of eight patients with RA, five with AS, one with SLE, and one normal subject. Neither deaggregated FII nor heat-aggregated human serum albumin induced significant transformation of the lymphocytes of any subject tested. A source of complement appeared necessary to support aggFII-induced blastogenesis, since enhanced transformation occurred only in the presence of fresh plasma. Heat-inactivated plasma and fetal calf serum (FCS), and FCS devoid of hemolytic complement, failed to support enhanced blastogenesis in the presence of aggFII. Since substrates similar to those employed in these studies are present in vivo in the rheumatoid joint, it is suggested that aggFII may enhance intra-articular lymphocyte transformation in subjects with RA.

Differential effects of immunosuppressants on lymphocyte function

In vitro and in vivo parameters of T lymphocyte function were evaluated in guinea pigs following treatment with the "cycle-active" drugs, 6-mercaptopurine (6MP) and methotrexate, and the "non-cycle-active" alkylating agent, cyclophosphamide. Commencing at the time of sensitization to tuberculin protein, animals were treated with an 8 day course of one of the cytotoxic drugs. This regimen either reduced or abolished the cutaneous response to PPD. The two cycle-active drugs inhibited the in vitro lymphoproliferative response to PPD and suppressed the elaboration of migration inhibition factor (MIF) by lymph node cells. However, these agents did not reduce blood lymphocytes, deplete the cellularity of the thymic dependent areas of peripheral tissues, or alter the in vitro response of lymph node cells to the nonspecific mitogen PHA. In contrast, treatment with cyclophosphamide was associated with a reduction in peripheral blood and tissue lymphocytes and impaired responses to PHA by residual lymph node cells. In vitro proliferative responses to PPD were inhibited but the capacity of lymph node cells to elaborate MIF was not suppressed. In addition to their effects on antigen-reactive lymphocytes, all three drugs significantly reduced the number of macrophages in induced peritoneal exudates. With respect to immunosuppressive activities, results of these investigations suggest that the noncycle-active agents affect both intermitotic and dividing T lymphocytes without impairing certain intermitotic functions of residual cells. The cycle-active drugs have a more restricted toxicity limited to those T lymphocytes which have been stimulated to undergo active DNA synthesis by antigenic challenge.

Immunoglobulin and glucose-6-phosphate dehydrogenase as markers of cellular origin in Burkitt lymphoma

Two independent marker systems, G-6-PD isoenzymes and cell membrane-associated IgM, were used to trace the cellular origin of Burkitt lymphoma. Application of the G-6-PD system is dependent upon the fact that, in accordance with inactivity of one X chromosome in each somatic cell, females heterozygous for the usual B gene (Gd(B)) at the X-linked G-6-PD locus and the variant allele Gd(A) (or Gd(A-)) have two types of cells. Gd(B) is active in one cell population, which consequently produces B type enzyme; in the other population Gd(A) is active, producing the variant A enzyme. Therefore, tumors with a clonal origin in a Gd(B)/Gd(A) heterozygote should exhibit only one enzyme type (B or A) whereas those with multicellular origin may show both A and B enzymes. Utilization of the immunoglobulin system is based upon the supposition that in lymphoid neoplasms with clonal origin either all or none of the tumor cells should have surface-associated IgM and kappa-reactivities. 33 of 34 relatively homogeneous (with respect to content of neoplastic cells) individual Burkitt tumors from 19 G-6-PD heterozygotes had single enzyme phenotypes. Similarly, of 95 tumors tested, 92 consisted essentially of IgM(+) or (-) cells. Two neoplasms could not be definitely classified and one tumor had two cell populations. These data suggest a clonal origin for most Burkitt tumors, but the one neoplasm with a double G-6-PD phenotype (A/B) and the one tumor that had two populations of cells with respect to surface IgM, could have originated from multiple cells. G-6-PD was determined in each of two tumors from seven heterozygotes and in all cases both tumors had the same single enzyme phenotype. Surface-associated IgM was tested in four tumors from one patient, three from another, and in two neoplasms from 11 patients. With one exception, all tumors from the same patient were concordant with respect to IgM. These findings suggest that the entire disease has a clonal origin, i.e., it emerges at one focus and then spreads to other parts of the body. Cells from 36 recurrent neoplasms were typed for G-6-PD (in heterozygotes) and/or IgM. In one previously reported patient, initial and recurrent tumors were discordant for G-6-PD. Two other patients had IgM phenotypes in recurrences that were discordant with those found in their initial tumors. Phenotypes from three of nine relapses which occurred after 5 mo were discordant for G-6-PD or IgM but no discordance was detected among 27 earlier recurrences. Thus, some "late" recurrences may be due to emergence of "new" maligant cell lines whereas most early relapses are due to reemergence of the original malignant clones. The probable unicellular origin of Burkitt lymphoma and the findings in tumor recurrences are discussed in terms of the disease's putative viral etiology.

Glucocorticoid-binding proteins in human acute lymphoblastic leukemic blast cells

The first known step in steroid hormone action is the association of the steroid with specific cytoplasmic steroid-binding proteins (SBP). Using a competitive binding assay, we detected, quantified, and partially characterized such a SBP in cytosol from glucocorticoid-sensitive human lymphoblastic leukemic blasts. The affinity of steroids for the SBP was directly related to their known killing potency. For example, steroids without glucocorticoid effect such as androstenedione, etiocholanolone, and tetrahydrocortisol were unable to displace radiolabeled dexamethasone from the SBP in the binding reaction. The dose-response curve for in vitro inhibition of [(3)H]thymidine uptake in leukemic blasts correlated closely with the binding affinity of glucocorticoids to the SBP, providing additional support for an essential physiologic role for SBP in steroid action. SBP activity was either greatly diminished or absent in glucocorticoid-resistant cells. Six patients who intially had SBP in their blasts and were responsive to combinations of drugs including glucocorticoids no longer had SBP activity detectable at a time when they no longer responded to combinations of drugs including glucocorticoids. In vitro [(3)H]thymidine uptake was not inhibited by steroids in leukemic blast cells lacking SBP activity. Other patients who had received some antileukemic therapy including glucocorticoids and who still had SBP in their leukemic blasts, were still responsive to drug combinations that included glucocorticoids. This appears to be the first study demonstrating glucocorticoid receptors in a human tissue.