Immunological classification of T-cell acute lymphoblastic leukaemia using monoclonal antibodies

Correlations between acute lymphoid leukemia (ALL) immunophenotype and clinical and laboratory data at presentation. A study of 350 patients

The phenotypes of malignant cells from 350 untreated patients with acute lymphoblastic leukemia (ALL) were determined at diagnosis with the use of a panel of monoclonal antibodies to leukocyte antigens. According to the phenotypes seen, the cases were divided into five groups, pre-B ALL, B-ALL, T-ALL, MO-ALL, and undifferentiated ALL. Each group was subdivided, resulting in 11 defined immunologic subtypes. Correlations between clinical and laboratory features were investigated at presentation. ALL of early-B phenotype associated with elevated cell counts occurred more often in female and infant patients than in male patients. Involvement of the central nervous system was frequent in B-ALL, which occurred mostly in male patients. A male prevalence was also seen in ALL of T-lineage in which significant differences regarding clinical characteristics and leukocyte counts appeared among the four subtypes. The clinical relevance of phenotypic subcategorization is supported by our observations.

The prognostic implications of an immunological classification of acute lymphoblastic leukemia

Thirty-one patients with newly diagnosed acute lymphoblastic leukemia were examined before receiving any treatment and their clinical and laboratory data were analyzed in order to determine the possible correlation between clinical presentation, morphologic sub-classes, cytochemical reactions, immunological phenotypes and cytogenetic findings. Each of the previous parameters and response to therapy were also examined for correlation. The analysis of clinical and laboratory characteristics of patients according to their immunological phenotype did not show any significant male sex bias, age distribution, hepatomegaly or splenomegaly at diagnosis. The analysis of clinical response of patients did not demonstrate any significant influence of sex, age, initial WBC count or the presence of a big tumor mass at diagnosis. There were no significant differences between our two major immunological subclasses Non-T CALLA+ ALL, and Pre-T ALL regarding proportions of patients in continuous remission, and relapse-free survival durations. The analysis of clinical and laboratory characteristics of patients on the basis of their chromosome categories did not show any significant sex bias, age distribution, initial WBC count, tumoral presentation or morphological subtypes at diagnosis, although there was an apparent male predominance in the pseudodiploid category and female predominance in the hyperdiploid category. Our results concerning the prognostic implication of CALLA were contradictory to those of several other investigators.

Laboratory and clinical applications of monoclonal antibodies for leukemias and non-Hodgkin's lymphomas

Important insights into leukocyte differentiation and the cellular origins of leukemia and lymphoma have been gained through the use of monoclonal antibodies that define cell surface antigens and molecular probes that identify immunoglobulin and T-cell receptor genes. Results of these studies have been combined with markers such as surface membrane and cytoplasmic immunoglobulin on B lymphocytes, sheep erythrocyte receptors on T lymphocytes, and cytochemical stains. After using all of the aforementioned markers, it is now clear that acute lymphoblastic leukemia (ALL) is heterogeneous. Furthermore, monoclonal antibodies that identify B cells, such as the anti-CD20 and anti-CD19 antibodies in combination with studies of immunoglobulin gene rearrangement, have demonstrated that virtually all cases of non-T-ALL are malignancies of B-cell origin. At least six distinct subgroups of non-T-ALL can now be identified. T-ALL is subdivided by the anti-CD7, anti-CD5, and antibodies that separate T lymphocytes subsets into three primary subgroups. Monoclonal antibodies are also useful in the subclassification of non-Hodgkin's lymphoma, and certain distinct markers can be correlated with morphological classification. Although monoclonal antibodies are useful in distinguishing acute myeloid from acute lymphoid leukemias, they have less certain utility in the subclassification of acute myelogenous leukemia (AML). Attempts to subclassify AML by differentiation-associated antigens rather than by the French-American-British (FAB) classification are underway in order to document the potential prognostic utility of surface markers. Therapeutic trials using monoclonal antibodies in leukemia and lymphoma have been reported. Intravenous infusion of unlabeled antibodies is the most widely used method; transient responses have been demonstrated. Antibodies conjugated to radionuclides have been quite successful in localizing tumors of less than 1 cm in some studies. Therapy trials with antibodies conjugated to isotopes, toxins, and drugs have shown promise. Purging of autologous bone marrow with monoclonal antibodies and complement in vitro has been used in ALL and non-Hodgkin's lymphoma; preliminary data suggest that this approach may be an effective therapy and may circumvent many of the obstacles and toxicities associated with in vivo monoclonal antibody infusion.

An analysis of morphological, cytochemical, immunological and clinical features of adult T cell acute lymphoblastic leukemia

Morphological, cytochemical, immunological and clinical features of 19 adult patients with T cell acute lymphoblastic leukemia (T-ALL) were investigated at the time of diagnosis and were compared with those of 34 adult patients affected by B cell acute lymphoblastic leukemia (B-ALL). Immunophenotypic studies employing a wide panel of monoclonal antibodies (mAbs) revealed a heterogeneous pattern of antigen expression in the five T-ALL groups that were identified on the basis of blast T cell differentiation levels. PAS (periodic acid Schiff) negativity and focal AP (acid phosphatase) positivity, as well as white blood cell count and serum lactic dehydrogenase levels, were significantly related to T-ALL when compared with B-ALL. On the contrary, no statistically significant difference was demonstrated in the clinical outcome.

Characterization of a precursor T-cell line (THP-6) with rearranged T-cell receptor beta chain gene

A previously established human leukemia cell line, designated THP-6, was further characterized with respect to cell surface antigen expression and immunoglobulin(Ig) and T-cell receptor(TCR) gene status. THP-6 cells were positive for CD7 and CD5 antigens and terminal deoxynucleotidyl transferase, but negative for CD2, CD1, CD4, CD8, CD10, cytoplasmic and surface CD3 and HLA-DR antigens, suggesting a precursor T-cell line. Analysis of Ig and TCR beta chain genes revealed that THP-6 had a rearranged TCR beta chain gene and a germline Ig gene. These results, in agreement with its phenotype, confirmed that THP-6 was of the T-cell lineage.

Reactive histiocytosis in acute lymphoblastic leukemia and non-Hodgkin's lymphoma

An extensive hemophagocytic syndrome in the termination of one case of pre-T acute lymphoblastic leukemia (ALL) and another case of non-Hodgkin's lymphoma (NHL), are described. Since most of the proliferating cells were mature macrophages and these cells were limited in the mononuclear phagocytic system (MPS), it was determined to be a reactive histiocytosis rather than histiocytic medullary reticulosis (HMR) or malignant histiocytosis (MH). The pathogenesis of the HMR or MH-like syndrome in these patients is discussed, and it is considered that this might be a reaction of the bacterial sepsis related to their immunosuppressed state secondary to the pre-existing malignancies and/or the cytotoxic therapy. The literature was reviewed. Based on a proposal for differential diagnosis between reactive histiocytosis and MH (or HMR), the heterogeneity of HMR-like syndrome complicating the malignancies are clarified.

Lineage-related polypeptide markers in acute lymphoblastic leukemia detected by two-dimensional gel electrophoresis

We have utilized two-dimensional polyacrylamide gel electrophoresis, coupled with ultrasensitive silver staining, to identify lineage-related polypeptide markers in lymphoblasts from children with acute lymphoblastic leukemia. Twelve polypeptides were detected that could distinguish between the major subgroups of acute lymphoblastic leukemia. These included a new marker for common acute lymphoblastic leukemia and markers for cells of B and T lineages. Analysis of the two-dimensional patterns also allowed the tentative identification of T-cell lineage in two cases with an otherwise undifferentiated non-T-cell non-B-cell phenotype. Two-dimensional electrophoresis thus provides a powerful tool for the delineation of the cell of origin in leukemia.

The human T-cell leukemias: clinical, cytomorphologic, immunophenotypic, and genotypic characteristics

The distribution of the conventional lymphoid cell markers on T lymphocytes and the principal panels of monoclonal antibodies used to recognize distinctive T-lymphocyte-associated differentiation antigens are discussed. These reagents have been used to probe the early and late stages of T-cell differentiation, and a hypothetical schema of T-cell differentiation has been constructed. Application of these reagents to the investigation of neoplastic T cells has resulted in the determination of the subset of origin and the stage of differentiation of the neoplastic cells in T-cell-derived lymphoproliferative malignancies. Recent advances in molecular biology have made possible the Southern blot hybridization analysis of DNA extracted from neoplastic T cells for patterns of T-cell-receptor gene rearrangements. Examination of these patterns in benign and malignant T and non-T cell has provided the basis for the use of T-cell-receptor gene rearrangements as specific genetic markers of T-cell lineage, clonality, and differentiation. These and other advances have resulted in the delineation of a new category of T-cell neoplasia, the adult T-cell leukemia/lymphoma syndrome. They have also demonstrated that the majority of clinically indolent neoplasms composed of large granular lymphocytes in so-called T gamma-lymphoproliferative disease are monoclonal proliferations. Further phenotypic, functional, and genotypic analyses of the T-cell malignancies should provide better understanding of T-lymphocyte differentiation and heterogeneity. Such studies should also lead to better clinicopathologic correlations and greater understanding of the basis for the clinical diversity of the T-cell-derived lymphoproliferative malignancies.

Surface marker analysis of acute lymphocytic leukaemia in Taiwan, Republic of China

Acute lymphocytic leukaemia (ALL) is heterogeneous in clinical characteristics and immunological properties. Standard surface marker analysis has enabled us to subclassify 121 cases of ALL into four subtypes, i.e. T-ALL, common ALL, null ALL and B-ALL. We have also tried to correlate these subtypes with their clinical characteristics. Our patients had younger ages with a mean age of 13.75. A slight male predominance was observed. There were consistently higher incidences in northern Taiwan in each subtype, but no significant differences in incidences between rural and urban areas. Although there were high incidences of L1 type cell in each immunological subtype, there was no correlation between FAB classification and each subtype, nor did morphologic features relate to cellular origins. Clinical manifestations revealed significantly high incidence of CNS involvement and thymic mass in T-ALL. Hepatosplenomegaly was more common and complete remission rate was higher in children with ALL than in adults.