Manuela Lopez

CD7 positive acute myeloid leukaemia: a subtype associated with cell immaturity.

Seventeen patients with acute myeloid leukaemia (AML) whose blasts co‐expressed the T‐cell associated CD7 antibody were identified among 160 consecutive AML cases. Fourteen had FAB defined AML according to morphocyto‐chemical criteria, whereas three patients were classified as ‘MO’ on the basis of immunophenotype. The incidence of CD7 positivity was particularly significant in the less differentiated subtypes MO and M1 compared with other FAB groups (P < 0.001). In all cases the myeloid determinants CD13 and/or CD33 were associated with CD7 expression. Other B‐lymphoid (CD10, CD19) or T‐lymphoid (CD2, surface and cytoplasmic CD3) markers were analysed and found to be negative. Five out of 15 cases examined were TdT+. Clonal rearrangements of the immunoglobulin heavy chain (IgH) and/or T‐cell receptor (TcR) β chain genes were identified in only three out of 13 cases. Among these, one out of five coexpressing TdT showed IgH rearrangement when analysed at the DNA level.

Immunological definition of acute promyelocytic leukemia (FAB M3) : a study of 39 cases

Acute promyelocytic leukemia (FAB‐M3) is a distinct entity among acute non‐lymphoid leukemias (ANLL) with peculiar morphological, biological, clinical and prognostic features. An atypical form of M3 (M3v) could be confused with other FAB ANLL and therefore the diagnosis of this variant requires ultrastructural analysis and/or cytogenetic study and/or selective gene rearrangement studies. The immunological phenotype of blast cells in 39 APL patients was studied at diagnosis. The diagnosis of M3 FAB type was ascertained in 32 and the diagnosis of M3v in 7 cases. Using a large series of monoclonal antibodies (mAb), the APL blast cells were B and T cell antigens‐negative, HLA‐DR constantly negative, CD 13‐ and/or CD33‐positive, CD9‐positive. Among ANLL this phenotype seems to be closely related to APL both in M3 type and M3v subtype. Because the diagnosis of APL (M3 or M3v) is important in order to establish the specific therapeutic approach, the discriminant capacity of the immunological typing to identify M3 and mainly M3v (hypogranular) could be determinant for a “quick” diagnosis.

Immunophenotyping of acute myeloid leukaemia: Relevance of analysing different lineage-associated markers

SummaryThe immunophenotype of 135 previously untreated patients with FAB defined acute myeloid leukaemia (AML) was studied at diagnosis. The panel of reagents included monoclonal antibodies (MoAb) recognising myeloid-associated determinants (CD11, CD13, CD14, CD33 and others) as well as MoAb directed towards lymphoid antigens (CD7, CD10, CD19) and TdT. The results indicate that CD13 and/or CD33 are consistently expressed in AML and only rarely in ALL blasts (131/135 +ve cases, versus 4/130 in ALL). Lymphoid antigen expression was rarely detected when CD10 and CD19 were investigated in AML (0.9% and 2% +ve cases, respectively), whereas significant positivities were found for TdT and CD7 (20% and 10% respectively). Concerning FAB subtypes, two new MoAb (LAM3 and LAM7) proved very useful in the specific recognition of AML with monocytic features. The phenotype CD13+ and/or CD33+, CD9+, HLA-DR− was found to be almost exclusive for M3 AML. The response to induction chemotherapy was analysed in CD7+ and in TdT+ patients. In the latter group a statistically significant lower response rate was found with respect to TdT-ve-AML patients.

Surface markers and cytotoxic activities of lymphocytes in monoclonal gammopathy of undetermined significance and untreated multiple myeloma

SummaryTo determine whether monoclonal gammopathy of undetermined significance (MGUS) resembles multiple myeloma (MM) with regard to phenotype and functional activity, 16 patients with MGUS and 16 with untreated MM were studied for surface markers and cytotoxic activities phytohemagglutinin-induced cellular cytotoxicity (PHA-ICC), antibody-dependent cellular cytotoxicity, natural killer (NK) activity. Our data showed a consistent immunological similarity between the two diseases. An increase in OKT8+ cells was evident in both patient groups and a significant reduction in the T4/T8 ratio, more pronunced in MM, was observed. Alterations in NK activity or ADCC were not found in MGUS or MM. A significant increase in PHA-ICC was demonstrated in the two diseases. The increase in PHA-ICC observed seems to be attributable to an increased frequency and/or lytic efficiency of PHA-ICC lymphoid effector cells. These data suggest that similar immunological alterations are common to the two diseases. The greater helper/suppressor ratio reduction observed in MM seems to be related to the more severe clonal proliferation in these patients.

Decreased NK Activity in Hairy Cell Leukemia (HCL): An Analysis at the Cellular Level*

SummaryPeripheral blood lymphocytes (PBL) of eleven patients with Hairy Cell Leukemia were studied for surface phenotype and for NK activity against the K 562 cell line (using both the standard 51Cr Release Assay and the Single Cell Cytotoxicity Assay on poly-L-lysine coated coverslips). A significant reduction in NK activity, target binding cells (TBC) and NK active cells (NKa) was detected. In some cases however, despite a very low percentage of NKa, residual NK activity was observed, suggesting an efficient recycling capacity.

Childhood Abnormal Expansion of Large Granular Lymphocytes

An expansion of large granular lymphocytes (LGL) in the peripheral blood (PB) of a 10-year-old child is described. After a long history of uncertain hematological diagnosis and chemotherapeutic regimens and 2 years after any kind of therapy, the child showed in PB an expansion of LGL E-rosette+, OKT3+, OKT8+, Leu7+. Cytotoxic activities showed high natural killer activity and an increase of PHA-induced cytotoxicity. Histological findings in the spleen, abdominal lymph nodes and bone marrow excluded a lymphoproliferative disease, but liver biopsy revealed a chronic aggressive hepatitis.

T-Helper phenotype chronic lymphocytic leukemia (Thp-CLL): characterization of an italian case with particular biological findings

SummaryA patient with Chronic Lymphocytic Leukemia (CLL) characterized by an expansion of helper phenotype mature T lymphocytes is here described. The phenotype of these cells was OKT3+, OKT4+, Leu 9+, 5/9+, OKT8−, Tac− and functional studies showed a strong helper activity on B cell differentiation; an “in vivo” presence of an IgG-lambda paraproteinaemia has been demonstrated. Cytogenetic studies showed multiple clonal, numerical and structural rearrangements which included a tandem t (14; 14) (q11; 32) translocation. Hybridization showed HTLV I related specific bands indicating the presence of exogenous sequences related to prototype virus but derived from a different Retrovirus (HTLV 1c). The clinical course was aggressive and unsuccessful treatments with various polichemotherapeutic protocols, associated with multiple leukaphereses, were performed. The authors underline that despite the morphological, immunological, biological and virological heterogeneity, the common feature of T-helper CLL is the inexorable clinical course which needs a new therapeutic approach.

B-cell acute lymphoid leukemia (ALL) with lymphoblasts expressing surface immunoglobulins only at relapse☆

Morphological, cytogenetic and immunological studies were performed on lymphoblasts of two patients with acute lymphoid leukemia at onset and at relapse. At onset and before any treatment lymphoblasts had L3-FAB morphology, a 14q+ chromosome abnormality due to a 8;14 translocation in the absence of expression of specific immunologic markers (E-rosette, C3-receptor, surface immunoglobulins). The clinical behaviour of the two patients was characterized by a very short first complete remission and by a short survival. At relapse SIg was expressed by lymphoblasts of both patients. This evolution in immunological phenotype of the dominant blast populations from onset to relapse provides evidence that in vivo, during the course of the leukemic disease, phenotype changes take place that seem to be cell differentiation.

Acute lymphocytic leukemia and complement receptors

SummaryThe expression of complement receptors (C3R) associated or not to sheep erythrocyte receptors (ER) and surface membrane immunoglobulins (SmIg) was determined on lymphoblasts of 45 patients with acute lymphocytic leukemia (ALL) at onset and/or in the first relapse. We found C3R simultaneously expressed with ER or SmIg on lymphoblasts of T cell ALL and B cell ALL. Lymphoblasts were positive for C3R in absence of ER and SmIg only in three patients in the hematological relapse. We stress the importance to find C3R as independent marker on ALL cells at onset and in subsequent relapses.