A human leukemia cell with both B and T cell surface receptors

T-Cell Chronic Lymphocytic Leukemia

A case of T-cell chronic lymphocytic leukemia (T-CLL) is reported. The surface receptor for sheep erythrocytes and acid phosphatase staining confirmed the diagnosis of T-CLL. This report provides evidence that T-CLL, a rare variant of CLL, is an aggressive disease with relative resistance to therapy and short survival.

Single-cell screening of multiple biophysical properties in leukemia diagnosis from peripheral blood by pure light scattering

Histology and histopathology are based on the morphometric observations of quiescent cells. Their diagnostic potential could largely benefit from a simultaneous screening of intrinsic biophysical properties at single-cell level. For such a purpose, we analyzed light scattering signatures of individual mononuclear blood cells in microfluidic flow. In particular, we extracted a set of biophysical properties including morphometric (dimension, shape and nucleus-to-cytosol ratio) and optical (optical density) ones to clearly discriminate different cell types and stages. By considering distinctive ranges of biophysical properties along with the obtained relative cell frequencies, we can identify unique cell classes corresponding to specific clinical conditions (p < 0.01). Based on such a straightforward approach, we are able to discriminate T-, B-lymphocytes, monocytes and beyond that first results on different stages of lymphoid and myeloid leukemia cells are presented. This work shows that the simultaneous screening of only three biophysical properties enables a clear distinction between pathological and physiological mononuclear blood stream cells. We believe our approach could represent a useful tool for a label-free analysis of biophysical single-cell signatures.

Viral DNA contamination is responsible for Epstein-Barr virus detection in cytotoxic T lymphocytes stimulated in vitro with Epstein-Barr virus B-lymphoblastoid cell line

Epstein-Barr virus (EBV)-transformed B-lymphoblastoid cell lines (LCLs) are used to prepare human EBV-specific T lymphocytes (EBV-CTL) in vitro. Within an LCL, up to 5-7% the cells release infectious EBV, and this has fostered safety concerns for therapeutic applications because of the exposure of T cells to EBV. The release of infectious viruses can be prevented by ganciclovir, but this drug may seriously affect LCL growth. In the wake of these concerns, the present work was designed to compile safety data on EBV-CTL preparation for the purpose of submission to a regulatory agency. We showed that further to supernatant exclusion, the number of EBV genome copies (EBVc) associated with the EBV-CTL always made up a constant proportion of the EBVc number detected in the culture supernatant. In addition, such was the case whether infectious virus could be produced by the LCL or not, suggesting that the EBV signal detected was due to a DNA contamination rather than an infection. Furthermore, we demonstrated that the number of EBVc associated with the EBV-CTL was highly sensitive to DNAse treatment, and finally that EBVc could no longer be detected after the EBV-CTL had been amplified in the absence of LCL. Consequently, during in vitro EBV-CTL preparation, either T cells cannot be infected or they die rapidly after EBV infection.

Infection of human thymocytes by Epstein-Barr virus

The Epstein-Barr Virus (EBV) causes infectious mononucleosis, and has been strongly associated with certain human cancers. The virus is thought to exclusively bind to B lymphocytes and epithelial cells via receptors (CR2/CD21) that also interact with fragments of the third component of complement (C3). Recent evidence, however, has challenged this belief. We have used two-color immunofluorescence analysis using biotin-conjugated EBV and streptavidin-phycoerythrin along with fluorescein-conjugated anti-T cell antibodies and demonstrated that CD1-positive, CD3-dull (immature) human thymocytes express functional EBV receptors. In four replicate experiments, the binding of EBV to thymocytes ranged between 8 and 18%. This interaction is specific as evidenced by inhibition with nonconjugated virus, anti-CR2 antibodies, aggregated C3, and an antibody to the gp350 viral glycoprotein that the virus uses to bind to CR2. EBV can infect the thymocytes as evaluated by the presence of episomal EBV-DNA in thymocytes that had been incubated with the virus as short as 12 days or as long as 6 weeks. Episomal DNA analysis was performed by Southern blotting with a EBV-DNA probe that hybridizes to the first internal reiteration of the viral DNA. The presence of the EBV genome is also supported by the detection of EBV nuclear antigen 1 in infected thymocytes, assessed by Western blotting with EBV-immune sera. The EBV infection is specific as determined by blocking experiments using anti-CR2 and anti-gp350 antibodies. Finally, virus infection of thymocytes can act synergistically along with interleukin 2 and induce a lymphokine-dependent cellular proliferation. In view of previously reported cases of EBV-positive human T cell lymphomas, the possibility is raised that EBV may be involved in cancers of T lymphocytes that have not been previously appreciated.

B-cell chronic lymphocytic leukaemia with aberrant expression of CD8 antigen

The monoclonal antibodies against CD8 (T suppressor/cytotoxic) antigen (Leu2/OKT8) were found to bind to leukaemic lymphocytes from a patient with chronic lymphocytic leukaemia. The cells also had an unusual type of rod-like cytoplasmic immunoglobulin of IgM/lambda type as seen by light, fluorescence and electron microscopy, and displayed several antigens characteristic for B lymphocytes. Gene rearrangement analysis showed rearrangement of mu heavy chain gene. In spite of an expression of CD8 antigen, T-cell receptor genes were not rearranged.

A reappraisal of Richter's syndrome. Development of two phenotypically distinctive cell lines in a case of chronic lymphocytic leukemia

Richter's syndrome, the development of a malignant lymphoma in a patient with preexisting chronic lymphocytic leukemia (CLL) is an infrequent but well-documented phenomenon generally thought to represent a monoclonal proliferation of B-lymphocytes arising from the CLL. A heterogeneous population of cells consisting of sheets of transformed lymphocytes in combination with clusters of bizarre, atypical histiocytes developed in a patient with a history of longstanding CLL. Immunocytochemistry using a panel of monoclonal and polyclonal antibodies by immunoperoxidase techniques identified the presence of both B-lymphocytic and monocytic-histiocytic cell lines of differentiation. A mechanism of multiple differentiation is proposed to account for the dual cell population observed in this patient. Review of the literature appears to indicate that this phenomenon often may be involved in cases diagnosed as Richter's syndrome. The demonstration of cellular heterogeneity in the current case underscores the need for establishing a more precise definition for the histologic characterization of the terminal malignancy in Richter's syndrome.

Secretory leukemic B cells express T cell markers in vitro. A phenomenon suppressed by TPA

Immunological and biochemical markers of leukemia/lymphoma cells have provided valuable insight into hematopoietic malignancy and normal differentiation. The general assumption is that as early lymphoid cells become committed towards terminal differentiation they lose their capacity for bimodal differentiation and cells become restricted to B or T cell development and function. We have observed that phenotypically "late" leukemic B cells close to secretory stage can spontaneously express mature T cell antigens (T11, T4 and T8) after culture in vitro. In further studies of these cells, it was found that the biochemical marker lactate Dehydrogenase (LD) follows the intermediate pattern expressed by thymocytes rather than that of typical B cells. The expression of T cell antigens can be blocked by incubating these cells with the phorbol ester TPA (12-0-tetradecanoyl phorbol 13 acetate) which promotes unidirectional B cell maturation to plasmacytoid cells in a way that mimics normal B cell differentiation. These observations indicate that presecretory malignant B cells are still programmed to express T cell biochemical and antigenic markers and this expression can be influenced by environmental conditions in vitro.

Granulocyte and lymphocyte membrane receptors in aseptic meningitis, infectious mononucleosis and other viral infections

Granulocytes and lymphocytes from 44 patients with acute viral infections were examined for membrane receptors for sheep erythrocytes (E-R), for the Fc portion of IgG (Fc gamma-R) and for complement component C3b (C3b-R). Aseptic meningitis was associated with a decrease in Fc gamma-R and C3b-R bearing granulocytes but an increase in the proportions of lymphocytes bearing the same receptors. Patients with infectious mononucleosis (IM) had a decreased percentage of C3b-R bearing granulocytes, an increase of E-R bearing T lymphocytes and a slight decrease in the proportion of Fc gamma-R and C3b-R bearing lymphocytes. Cerebrospinal fluid from IM patients contained 92-98% T lymphocytes. The group of patients with other viral infections showed a decreased percentage of granulocytes bearing Fc gamma-R and C3b-R, and of E-R bearing lymphocytes. The decrease of Fc gamma-R and C3b-R bearing granulocytes in viral infections may be of importance in relation to the increased risk of bacterial superinfection in these patients.

Cytochemical pattern of alpha-mannosidase, alpha-fucosidase and neutral maltase in normal blood cells

The activity of alpha-mannosidase, alpha-fucosidase and neutral maltase was studied by cytochemical techniques in blood cells of 20 controls and of 4 T and B lymphocyte concentrates. All granulocytes, monocytes and platelets showed fine or coarse reaction product deposition, whereas lymphocytes were negative or showed various positivity patterns. A significant difference of the positivity between T and B subpopulations was observed only for the fucosidase reaction. It is possible that the different positivity patterns of the lymphoid cells are related to different functional activities. Further studies will probably confirm the interest of the alpha-fucosidase reaction for the characterization of normal and pathological lymphoid cells.

Chronic T cell lymphocytosis: a review of 21 cases

Twenty-one patients are described with a proliferation of morphologically mature T lymphocytes. The clinical course was chronic in most, and splenic enlargement the main clinical finding; skin involvement and lymphadenopathy were rare. The mean lymphocyte count at presentation was 8 X 10(9)/1 (range 0.75-24 X 10(9)/1). Nineteen of these patients showed some form of cytopenia (18 neutropenia, two red cell aplasia, eight thrombocytopenia) and one had hypogammaglobulinaemia. Seven patients had long-standing arthropathy serologically proven to be rheumatoid arthritis and these had previously been considered to have Felty's syndrome. Five of the group have died (three with an aggressive course), but most have remained stable for prolonged periods with a slow increase in peripheral lymphocyte count and marrow infiltration. Spontaneous regression was never observed but in two patients a prolonged remission was achieved by chemotherapy. The lymphocytes were morphologically and phenotypically homogeneous at presentation and remained so post-splenectomy; they contained azurophilic granules, stained with acid phosphatase but weakly or not at all with alpha napthyl acetate esterase. Membrane phenotyping shows the majority of the cells to be E+, Fc gamma+, OKT3+, OKT8+. Most cells do not stain with OKT1-like reagents and a significant number express HLA-Dr. From these and other reported cases it is clear that this condition represents a distinct entity resulting from the expansion of a subset of cytotoxic/suppressor T cells--the question of the benign or neoplastic nature of the disease remains open. Using T cell-specific antisera and E-rosetting techniques, a small percentage of CLL cases have been shown to be of T-cell origin (TCLL) (Dickler et al, 1973; Lille et al, 1973). Estimates of the percentage vary but in most series T-CLL has been diagnosed in less than 5% (Brouet & Seligmann, 1981), and this is supported by date from the M.R.C. Leukaemia Unit which found T-CLL in only 1.5% of 600 cases of CLL examined by marker studies (D. Catovsky, unpublished). Amongst the published reports of T-CLL a variety of clinical and morphological entities have been described including T prolymphocytic leukaemia (TPLL) (Brouet et al. 1975) and adult T cell disease in Japanese (Uchiyama et al, 1977) and West Indian Caribbean groups (ATLL) (Catovsky et al, 1982). In the original series of Brouet & Seligmann (1981) the group was defined as presenting in middle age with marked hepatosplenomegaly, some lymphadenopathy, skin involvement and with an aggressive disease course; peripheral blood and marrow lymphocytosis were variable.(ABSTRACT TRUNCATED AT 400 WORDS)

Reactivity of monoclonal antibodies Leu 1 and OKT1 with malignant human lymphoid cells. Correlation with conventional cell markers

This study delineated the distribution of reactivity of malignant human lymphoid cells with monoclonal antibodies Leu 1 and OKT1, and correlated this expression with that of conventional lymphoid cell markers. The presence of Leu 1 on benign lymph nodal T-cells and its absence from benign lymph nodal B-cells was confirmed. Twenty-two T-cell neoplasms, expressing a variety of intrathymic and mature peripheral phenotypes, expressed Leu 1, but this expression was heterogeneous with respect to percent-positive cells and antigenic density, and appeared to correlate with stages of T-cell differentiation. This study demonstrated the expression of Leu 1 by 33 of 36 cases of B-CLL, by 10 of 15 cases of the closely allied small lymphocytic cell lymphoma, and by 9 of 29 follicular center-cell lymphomas. This included B-cell malignancies of each surface immunoglobulin isotype, and some cases associated with a monoclonal protein spike. Leu 1 was not expressed by myeloma plasma cells, and was absent from non-B, non-T acute lymphoblastic leukemia cells in each of 15 cases studied. Finally, Leu 1 and OKT1 were expressed in parallel, with respect to percent-positive cells and staining intensity, on benign and malignant T-cells, and on malignant B-cells, wherever studied. Possible explanations for this shared antigen are the existence of a minor Leu 1+ B-cell subset, a transformation-associated event, or glycosylation.

Effect of AET treatment of sheep erythrocytes on the rosette test in various diseases

180 patients with neurological or infectious diseases and 90 normal controls were examined for blood T lymphocyte percentage by the standard method using rosette formation with untreated sheep erythrocytes (E) and a technique using 2-amino-ethyl-thio-isouronium bromide hydrobromide (AET)-treated E, with fetal calf serum (FCS) in the medium. Patients with acute meningitis had a decrease and those with infections mononucleosis had an increase in T lymphocyte percentage as measured by both assays. However, patients with active MS and with cerebral tumours had a decrease in T cell percentage by the E but not by the EAET technique. The T lymphocyte percentages of the other 4 patient groups did not differ significantly from those of the controls, regardless of the technique used. In certain diseases, the use or not of AET-treated indicator cells may thus influence the results of the rosette test.

The expression of surface antigen Leu 1 by ocular adnexal lymphoid neoplasms

Leu 1 is a surface membrane antigen expressed by benign systemic T cells, most cases of B-cell-derived chronic lymphocytic leukemia, and approximately one half of the systemic B-cell lymphomas. Benign systemic B cells are Leu 1-. Our studies showed that the percentage of Leu 1+ cells was essentially the same as the percentage of OKT3+E+ (T) cells in six ocular adnexal pseudolymphomas, strongly suggesting that the benign B cells in these lesions were similarly Leu 1-. These studies also showed that malignant B cells in six of 15 (40%) ocular B-cell lymphomas were Leu 1+. Thus, the expression of Leu 1 by some malignant ocular adnexal B cells but not by benign ocular adnexal B cells appears to be analogous to the situation for lymph nodal and other systemic B cells. Although the explanation for the existence of this shared determinant is unknown, Leu 1 expression may possess clinical and diagnostic significance as a marker of neoplastic B cells.

Cerebrospinal fluid and blood lymphocyte subpopulations in acute aseptic meningitis

Lymphocyte subpopulations were determined in cerebrospinal fluid (CSF) from 11 patients with acute aseptic meningitis. The patients had a significantly higher percentage of T lymphocytes (as determined by rosette assays for sheep erythrocyte (E) receptor-bearing cells) in their CSF (86%) than in blood (62%). The percentage of complement (C) receptor-bearing cells was also higher in the CSF (47%), and the sum of E and C receptor positive cells was 133%, indicating a considerable number of cells carrying both receptors in the CSF in contrast to in peripheral blood. However, 8 patients with various neurological diseases had a mean of 65% C receptor-bearing cells in their CSF, while 17 others had 78 +/- 9% E receptor positive cells. Meningitis patients had a lower percentage of CSF Fc receptor-bearing cells (EA-RFC) than other patients. These results indicate the presence of a large percentage of CSF lymphocytes with both E and C receptors also in patients without meningeal disease, and suggest the recruitment of such cells into the CSF.

Immunologic characterization and ultrastructural correlations for 125 cases of B- and T-cell leukemias: studies of chronic and acute lymphocytic, prolymphocytic, lymphosarcoma cell and hairy cell leukemia, Sézary's syndrome, and other lymphoid leukemias

Peripheral blood from 125 patients (160 specimens) with various types of lymphoid leukemias was evaluated for B- and T-cell markers (E rosettes, C3 and Fc receptors, and surface immunoglobulin). B-cell leukemias (comprised 82% of the series and included chronic lymphocytic leukemia (69/71 cases), acute lymphocytic leukemia (1/18 cases), lymphosarcoma cell leukemia (15/18 cases), prolymphocytic leukemia (one case), plasma cell leukemia (one case), hairy cell leukemia (12/12 cases), and leukemic phase of "histiocytic" lymphoma and Waldenström's macroglobulinemia (one case each). Within the B-cell group, certain leukemias exhibited distinct patterns of lymphocyte surface markers. Three cases of lymphosarcoma cell leukemia revealed both T and B cell markers (E-rosette formation and monoclonal SIg). T-cell leukemias comprised 12% of the series and included chronic lymphocytic leukemia (2/71 cases), acute lymphocytic leukemia (11/18 cases), and Sézary's syndrome (2/2 cases). In eight cases of acute lymphocytic leukemia, the majority of the cells demonstrated no definable markers (non-B, non-T cell type). Ultrastructural studies, performed in selected cases, were correlated with immunologic findings. Distinctive morphologic features were observed for different variants of B- and T-cell leukemias. Neoplastic cells of T-cell leukemias revealed a greater nuclear irregularity than B-cell proliferations, as assessed by the nuclear contour index (ratio of circumference to the square root of the nuclear area). The cytoplasmic feature most predictive of immunologic cell type was abundant rough endoplasmic reticulum, suggesting plasmacytoid differentiation, observed in some B-cell proliferations.

Subclassification in acute lymphoblastic leukaemia: acid phosphatase reaction and immunological markers in relation to clinical features. A comparative study of 44 patients

A prospective, comparative study of cytochemical and immunological markers and clinical features was undertaken in 44 patients with ALL (children and adults). 12 patients (27%) had T-ALL, 1 patient (2%) B-ALL and 31 patients (71%) (non-T, non-B)-All. E-rosetting lymphoblasts ranged from 35 to 96% (median: 61), highest when AET-treated SRBC were used as indicator cells. All 12 E-rosette positive cases were strongly acid phosphatase (AcP)-positive, showing a homogeneous pattern of distinct granular AcP-activity in more than 85% of the lymphoblasts (median: 96%) significantly different from the median of 26% granulated blasts found in (non-T, non-B)-ALL cases. Counting blasts with granular AcP-activity proved to be both easier than using a scoring system for the AcP-reaction and more efficient in terms of discriminating ability between the subgroups. Significant clinical and haematological features characterizing the T- and AcP-positive cases included: (1) Predominance of young adult men, (2) presence of a mediastinal mass, (3) involvement of skin and serous membranes, (4) only slightly affected haemoglobin concentration at presentation, (5) difficulty in obtaining complete remission, (6) shorter duration of first complete remission and (7) shorter survival rate. It is confirmed that AcP-staining of lymphoblasts is an easy, reproducible and inexpensive method for identifying the T-cell variety of ALL.

Terminal deoxynucleotidyl transferase (TdT) and membrane receptors in human leukemia and lymphoma -- first experience with lyophilized cells

Surface marker analyses and TdT assays were performed on cells from 31 patients. A variety of diagnoses were made and categorized as follows: acute leukemia (group I), non-Hodgkin lymphoma (group II) and diverse diagnoses (group III). Levels of TdT in the range from 0 to 7.9 U/mg lyophilized blasts from the peripheral blood were found in AL. This corresponds to 0-95 U/10(8) cells. Preparations of mononuclear cells from the peripheral blood of healthy donors showed TdT values up to 0.88 U/mg or 10.6 U/10(8) cells. High TdT activity was observed in a patient with AML, type M1 according to the FAB classification. In a patient with ALL (L1) cytostatic treatment effected the clearance of TdT activity from the peripheral blood cells and at the same time induced a significant increase of E rosette forming cells. Combined studies of the TdT activity and cell surface markers may enable us to define remissions and relapses of AL more precisely than it is possible by conventional cytological methods. Within the group II two patients with moderate TdT activities of 1.2 and 1.28 U/mg, respectively, were observed whose cells were of prolymphocytic or unclassifiable appearance, respectively. The TdT assay may be helpful to identify such cells of unknown origin and in addition may provide the means of discrimination between such cases and ALL patients who mostly show high TdT activities. Another result of our studies was the finding of moderate TdT activity of 1.2 U/mg with cells from the pleural effusion of a patient with Hodgkin's disease. Cells from malignant effusions from a patient with melanoma and a patient with teratoid carcinoma showed no TdT activity. Cells form the peripheral blood and from the bone marrow of a patient with blast crisis of CML showed TdT activity of 1.52 and 2.72 U/mg, respectively. Two other patients with blast crisis were negative. Not TdT activity was found in leukemic plasma cells. Our results show that lyophilized cells can be used for determinations of TdT activity. This greatly facilitates multi-parameter studies including cytological, cell surface marker and biochemical analyses.

The immunological and cytochemical characterization of T-cell lymphoproliferative diseases

Surface markers, terminal transferase, cytochemical staining, and function of peripheral blood lymphocytes were examined in nine patients with T-cell lymphoproliferative disease. Anti-T-cell antiserum proved useful in characterizing the phenotypes of the abnormal cells when only a minority of the abnormal cells formed E-rosettes. Anti-B-cell antiserum was consistently unreactive with the abnormal cells. Terminal transferase was elevated in T-cell ALL but low in T-cell CLL, lymphoma-leukemia, or Sézary syndrome. Lymphocyte proliferative response to nonspecific mitogens was generally depressed as was the response to allogeneic cells. The cells also failed to stimulate in mixed lymphocyte culture, implying a lack of Ia antigens on their surface. Acid phosphatase stain was positive in three patients tested. Peroxidase and esterase stains were negative, whereas PAS was positive in five of eight patients tested. Prognosis in general, regardless of the clinical picture, (ie, acute, chronic, or lymphoma-leukemia), was poor with seven of the nine patients dying within 14 months of diagnosis. Therefore, the use of anti-T-cell antisera and the E-rosette surface marker should be used to characterize the phenotype of the malignant cells in lymphoproliferative disease to enable more vigorous treatment of those that are of T-cell origin and that therefore carry a poor prognosis.

Preliminary evidence of dual-marked lymphocytes in thoracic duct lymph fluid

Thoracic duct lymphocytes from patients receiving thoracic duct drainage as a pretransplant therapy were examined for cell surface markers. Patients followed over the drainage time period showed a variable but decreasing percentage of E-rosette-positive cells in the lymph fluid. A substantial percentage of these E-rosette-positive cells also had C3 receptors on their cell surface. Reactions of the whole lymphocytes with a heteroantisera to human B-lymphocyte antigens reflected the increasing proportion of B cells in the samples, but also indicated that a fraction of the T cells have Ia-like antigens on their surface marker characteristics. Significance of these cells with respect to graft survival is discussed.

Fluctuations in the T and B characteristics of two cases of T-cell hairy-cell leukaemia

A new case of hairy-cell leukaemia (HCL) in which the hairy cells (HCs) formed spontaneous sheep erythrocyte (E) rosettes is described, and this E-rosette formation is shown to be an active process independent of surface immunoglobulin (SIg). Sequential studies with a panel of markers of this and of a case of HCL with T-cell features previously described from this laboratory show that both these cases, at certain times of study, possessed combined T- and B-cell features. Extensive follow-up study revealed wide fluctuations in the surface phenotype of peripheral blood (PB) mononuclear cells, while the total leucocyte count remained stable. At various times, the PB mononuclear cells showed the following phenotypes: E+SIg+gamma Fc+C3-, E-SIg-gamma Fc+C3-, E+SIg-gamma Fc+/-C3-, and the significance of these phenotypic changes is discussed. The importance of sequential studies with a panel of markers in the characterization of lymphoproliferative disorders is emphasized.

Immunocytological studies in a case of Bruton's disease

Immunopathological findings in a case with infantile X-linked agamma globulinemia (Bruton's disease) are reported and compared to similar data from two cousins of the patient. Besides a severe decrease in B-lymphocytes in blood and lymph node, residual B-cells showed an almost total defect in Ig surface receptor expression. In addition, there was an unusual lymphocyte population which apparently exhibited E-rosette formation (i.e. T-cell characteristics) and phagocytosis. The data suggest that in Bruton's disease there may be a disturbance of the T-cell system besides the well known B-cell deficiency.

Subset derivation of T-cell acute lymphoblastic leukemia in man

Normal human peripheral blood T cells can be characterized as belonging to either the TH+2 or TH-2 T-cell subset. Approximately 20% of T cells are TH+2, whereas 80% are TH-2 utilizing specific heteroantisera. To determine shether human T-cell acute lymphoblastic leukemia (T-ALL) cells belong to one or another T-cell subset, cell surface phenotyping was performed on tumor populations from 25 patients with T-ALL. Tmuor cells from these 25 individuals were either TH+1 or TH-2, but not both. 5 of 25 patients had TH+2 T-ALL cells. These TH+2 tumor populations were found exclusively in children and often without an accompanying thymic mass. TH-2 T-ALL, in contrast, occurred in both children and adults and was almost always associated with thymic enlargement. Although children with TH+2 T-ALL had as high or higher peripheral blast counts on presentation than their TH-2 T-ALL counterparts, overall survival was greater for the TH+2 group (greater than 36 mo) than the TH-2 group (less than 12 mo). These studies demonstrate that T-cell leukemias in man arise from distinct T-cell subsets and that cell surface characterization of T-cell malignancies may provide useful clinical data related to prognosis.

A simple method to detect complement receptors using baker's yeast: Y C rosettes

A technique is described to identify complement-receptor-bearing cells, using serum-treated baker's yeast as a ligand. The method consists of incubation of heat-killed baker's yeasts with fresh AB normal serum, freezing, thawing, and washing of the particles, followed by mixing with the cells. Serum is required to coat the yeasts for the rosette formation. Experiments designed to establish the serum factors responsible for the attachment of the particles to cells show that heat inactivation, chelating agents, or anti-C3 treatment prevent rosette formation. This is taken as evidence that yeasts (Y) are coated with complement (C) to compose the reagent for the YC rosette technique. The application of this technique to twenty-five normal individuals demonstrated that a mean of 11.6 per 100 lymphocytes (+/- 4.3) form rosettes; absolute number: 275 (+/- 160) rosette-forming lymphocytes per mm3. Either AB or autologous fresh serum can be used to coat the yeasts. A combined technique for YC plus E rosettes can be performed allowing the identification and enumeration of four populations of lymphocytes: (a) those having receptors for sheep erythrocytes, (b) complement-receptor-bearing lymphocytes, (c) those having both receptors (D lymphocytes), and (d) non-rosette-forming non-phagocytic cells.

Human B-lymphocyte heteroantigens: direct evidence for specificities not shared by monocytes

A heterologous anti-human B-lymphocyte serum was raised in the rabbit and rendered specific by extensive absorptions. After absorptions with erythrocytes and thymocytes, the antiserum was cytotoxic for an average of 18·5% of normal peripheral blood lymphocytes. Most chronic lymphatic leukaemia cells and `hairy cells' were sensitive to this antiserum but `null cells' were not. E-rosette-forming cells were insensitive to the antiserum, while EAC-rosettes and rosettes with mouse erythrocytes were partially or totally inhibited. In ultrastructural characterization studies after immunoperoxydase labelling, it was demonstrated that not only B lymphocytes, but also virtually all monocytes having phagocytized latex particles, were stained. A further absorption with monocytic cells from a patient with subacute myelomonocytic leukaemia was thus performed and the resulting antiserum was then specific for human B lymphocytes only and did not label any latex-phagocytizing monocyte. These results demonstrate that besides antigens common to monocytes, B lymphocytes express specificities characteristic of the B-cell population only, at their surface.

Cell studies in prolymphocytic leukaemia

A case of prolymphocytic leukaemia, showing several features not yet reported in this disease, is reported. The majority of lymphocytes in the peripheral blood and bone marrow had markers of both B- and T-lymphocytes. The simultaneous presence of receptors for sheep RBC and surface immunoglobulins on individual cells was demonstrated and the endogenous origin of these markers was established. The lymphocytes had some of the functional characteristics seen in chronic lymphocytic leukaemia (CCL). In vitro cell death in the presence of colchicine (colchicine ultrasensitivity) and polystyrene bead column retention were of the same order as seen in CLL. In contrast with the findings in CLL, these cells were markedly radioresistant in vitro. The dominant clinical features--anaemia and constitutional symptoms--appeared to be related to hypersplenism associated with massive splenomegaly. The relevance of these findings is discussed.

Receptors for immunoglobulin and complement on sheep RBC-binding lymphocytes in newborn infants

Sheep erythrocyte-binding human peripheral blood lymphocytes bearing receptors for the Fc-part of IgG and/or complement were studied in twenty newborn pre-term and term infants and fifteen adult controls. A technique with mixed rosettes and fluorescein-labelled sheep erythrocytes was used. The newborn infants had a significantly lower proportion of lymphocytes with receptors for sheep erythrocytes and the Fc-part of IgG (1.6%) than the adults (6.7%). Also the percentage of lymphocytes binding both sheep erythrocytes and complement-coated indicator cells was significantly lower in the newborn infants (2.6%) than in the adults (8.9%). A significantly higher proportion of lymphocytes had receptors for sheep erythrocytes and complement than for sheep erythrocytes and the Fc-part of IgG in both newborn infants and adults. There was no correlation between the values of lymphocytes binding sheep erythrocytes, or the Fc of IgG or complement and the proportion of mixed rosettes.

Surface membrane determinants on childhood acute lymphocytic leukemia cells: immunoglobulin, Fc and C3 receptors

Most reports have now described two populations of childhood ALL patients: those with thymic (T) cell receptors and those lacking receptors on their neoplastic cells. Assays for the surface receptors of the T and thymic-independent (B) system were used to study forty-seven patients with ALL whose bone marrow contained a mean of 85% leukaemic cells. Two patients had T-cell disease and thirty-six were non-T and non-B. nine patients were identified whose leukaemic cells had membrane properties associated with the B-cell system: surface immunoglobulin, Fc receptors and/or complement receptors. Combined T and B receptors were found in one case. The same surface characteristics were found on leukaemic cells from these patients' bone marrow, blood, pleural and cerebrospinal fluid. Studies showed that the leukaemic cells were not of monocytic or granulocytic origin. Although a remission was obtained in each patient, the relapse rate of the B-cell group was worse than a similarly treated group of thirty-six non-T, non-B ALL patients (P less than 0.001). Initial total leucocyte counts of the B-cell group were greater than the non-T, non-B group (P 0.05), but when the patients in both groups with total leucocyte counts greater than 25,000/mm3 were compared, the relapse rate of the B-cell patients was significantly worse (P less than 0.025). The results show that patients with leukaemic cells possessing B-cell properties comprise a significant proportion of ALL cases, and their presence on leukaemic cells has an ominous significance.

Prolymphocytic leukaemia of T-cell type: immunological, enzymatic and ultrastructural morphometric characteristics

A case of prolymphocytic leukaemia with immunological characteristics of T-cell type is reported. Three noteworthy findings can be emphasized: the presence of C3 receptors on the T-prolymphocytes, the study of the acid-phosphatase isoenzymatic pattern, which showed an increased band 3 with absence of band 3b, and the morphometric ultrastructural investigation. Cytochemistry and ultrastructural morphometry may be useful for a more precise characterization of prolymphocytic leukaemia and help to distinguish it from other lymphoproliferative disorders.

A hypotetraploid human T lymphoid cell line established by cell fusion

A human T lymphoid cell line was established by cell hybridization technique from peripheral blood leucocytes of a patient with Sezary syndrome. The cells beared the surface antigens of human T lymphocyte specificity as demonstrated by immune cytolysis tests, but did not form E rosettes with sheep red blood cells. Isozyme patterns of enzymes in this line such as lactate dehydrogenase, glucose 6-phosphate dehydrogenase and esterase were of human type. The line had 79 chromosomes in modal number. This case supports the proposal that the production of tetraploids is favourable for establishment of cell lines.

T-cell and B-cell identification in the diagnosis of lymphoproliferative disease. A review

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Immunological characteristics of lymphoblasts and lymphocytes in acute lymphoblastic leukaemia in children

By analysing the electrophoretic mobility (EM) of lymphocytes and by comparing their surface charge it is possible to distinguish rapid-moving lymphocytes (T) and slow-moving lymphocytes (B). The authors studied the EM of blood lymphocytes in children suffering from acute lymphoblastic leukaemia, before they underwent treatment. At the same time they carried out a study of classical immunological markers (E rosettes, membrane immunoglobulins, and blastic-transformation ability). The authors were able to distinguish three types of lymphocytes according to their EM i.e., rapid, slow or intermediate. This heterogeneousness could be explained by the fact that the origin of leukaemic proliferation may vary according to different stages in the maturation of the lymphoid cells. It would seem premature to establish any correlation between the initial clinical signs of the disease and its evolution.

Simultaneous presence of receptors for complement and sheep red blood cells on human fetal thymocytes

The cells of four thymus glands, two at 12 weeks, one at 16 weeks and one at 22 weeks gestational age, were examined cytochemically for enzymic activity and for surface markers. The reactions for chloroacetate esterase, peroxidase, and alkaline phosphatase were negative and the reaction for nonspecific esterase was only weakly positive in some of the cells. In contrast, nearly all thymocytes at the 12th gestational week showed strong focal acid phosphatase (acP) activity. The number of acP-stainable cells and the staining intensity declined progressively. A high percentage of thymocytes in early fetal life express a complement receptor (CR); the proportion of CR-bearing cells decreased while cells forming rosettes with sheep erythrocytes (possessing erythrocyte receptors: ER) correspondingly increased during fetal life. Using a mixed rosette assay, up to 30% of the thymocytes at 12 weeks gestation were found to bear CR and ER simultaneously. The number of CR- and ER-positive cells also declined progressively with fetal age. These findings show that CR-positive, ER-negative thymus cells mature into CR-negative, ER-positive thymocytes via a CR-positive and ER-positive intermediate cell, indicating that mature ER-positive thymocytes do not originate from another cell line lacking CR. The changes in surface markers during early T cell maturation is relevant to certain lymphomas whose cells also show strong focal acP activity and also express both CR and ER. These lymphoma cells may correspond to fetal thymocytes or T precursor cells present in small numbers after birth.

Immunologic surface markers in non-Hodgkin's lymphomas

Tissues from 21 patients with non-Hodgkin's lymphomas were examined for immunologic cell surface markers. Patterns of distribution of complement receptor (CR) B lymphocytes and Fc receptor (FcR)-bearing histiocytes in tumor tissue were evaluated and compared to routine histologic preparations of the tumors and to normal tissue. The lymphomatous infiltrates from all 6 cases of nodular, poorly differentiated lymphocytic lymphoma (NPDLL) consisted of dense populations of CR B lymphocytes. Involved tissue from 7 of 8 patients with diffuse, poorly differentiated lymphocytic lymphoma (DPDLL) was predominately comprised of CR B lymphocytes. Discrete nodules of CR B cells were present in a lymph node replaced by DPDLL. FcR were identified on the cells from 1 of 3 cases of histiocytic lymphoma. None of the 4 cases of undifferentiated lymphoma possessed demonstrable surface markers in tissue section; however, the cell suspension from 1 case contained a high percentage of CR B cells. Both CR and T cell markers were present on the cells of DPDLL of childhood.

Combined T and B lymphocyte marker test in lymphoproliferative disorders

The combined T and B lymphocyte marker test of Mendes et al (1974) has been developed to provide an easy, reproducible test for clinical practice. It has been used to study subpopulations of peripheral lymphocytes in patients with lymphoid malignancies. Significant increases in the numbers of lymphocytes which bind both sheep erythrocytes (E) and the fixed, third component of complement (C3) have been found using this test, in the peripheral blood of all untreated lymphosarcoma (L/SA) patients and T cell acute lymphoblastic leukaemia (ALL) patients. Such increases were not found in blood from patients with chronic lymphatic leukaemia (CLL), other non-lymphoid malignancies, null-cell ALL or normal individuals. These mixed E and C3 receptor bearing cells may be Fc receptor positive and represent a separate subpopulation of lymphocytes.

Immunologic characterization of chronic lymphocytic leukemia cells

Immunologic characterization of the neoplastic cells in the circulation of patients with CLL suggests these cells show significant differences in membrane characteristics from normal B lymphocytes. Although the leukemic cells bear a homogenous membrane-associated immunoglobulin, they also react with an anti-human T cell serum. In all patients studied, 60-90% of the cells, were stained by this antiserum. This suggests that the leukemic cells share antigenic determinants with T lymphocytes. CLL cells, unlike normal B cells, showed a marked increase in mouse-complement receptors. No increase in receptors for guinea pig complement was observed in the leukemic cells. The population of SIg-bearing lymphocytes was significantly greater than that of complement-receptor bearing lymphocytes. The total number of E-rosetting cells was increased in all CLL patients. Mitogenic responses of the leukemic cells were depressed and delayed. These results suggest that neoplastic lymphocytes cannot be classified as T- or B-derived on the basis of criteria used to define normal lymphocytes.

T lymphocytes bearing complement receptors in a patient with chronic lymphocytic leukaemia

A patient is described who presented with a disease clinically resembling chronic lymphocytic leukaemia, characterized by generalized lymphadenopathy, pleural and peritoneal effusions, a blood lymphocyte count of 700,000/mul and failure to respond to conventional therapy. At least 95% of these cells formed rosettes with sheep erythrocytes (E) and with erythrocytes coated with 19S antibodies and complement (EAC). All of these cells bound rabbit anti-human thymocyte serum; this serum bound to 0--22% of the lymphocytes from twenty other patients with chronic lymphocytic leukaemia. These unusual cells did not bear surface immunoglobulin detectable by immunofluorescence. The clinical and cellular features of this malignancy are compared to previously reported cases of T cell chronic lymphocytic leukaemia. As this case illustrates, T-cell chronic lymphocytic leukaemia may present without skin lesions and may be a more aggressive disease than the more common B-cell neoplasm.