Molecular and immunological evidence of B-cell commitment in "null" acute lymphoblastic leukaemia

Analysis of rearranged immunoglobulin genes indicating a process of clonal evolution in chronic lymphocytic leukaemia

Chronic lymphocytic leukaemia (CLL) is known to be a stable monoclonal neoplasm. In contrast to early studies demonstrating no more than two hybridizing immunoglobulin heavy chain bands corresponding to the two expected alleles, we have demonstrated an unexpected multiband pattern when the HindIII-digested DNA samples from 38 CLL patients were analysed by Southern blot hybridization using JH and C mu gene probes. In order to characterize the genetic basis for the multiband pattern, we molecularly cloned the immunoglobulin heavy chain genes of one of the patients whose leukaemic DNA sample demonstrated three hybridizing JH bands and a loss of the germline band. The cloned rearranged immunoglobulin genes could be divided, based on the restriction mapping and the hybridization with the various probes, into two basic patterns representing two alleles. In one of the cloned rearranged immunoglobulin genes a secondary rearrangement occurred that resulted in the addition of 300 base-pair long sequence into the switch region, and the creation of a HindIII restriction site. The results of the study suggest that clonal evolution occurs in some CLL, and that many of these neoplasms are indeed oligoclonal due to the accumulation of secondary genetic changes.

Immunophenotype of acute lymphoblastic leukemia cells: the experience of the Italian Cooperative Group (Gimema)

The immunophenotype of 304 adult lymphoblastic leukemias (> 18 years) diagnosed on the basis of the FAB criteria was determined at the time of diagnosis using a panel of monoclonal antibodies. The series comprised cases diagnosed and immunophenotyped in 43 Italian centers (GIMEMA Cooperative Group) between April 1988 and June 1991. The immunophenotypic characterization consisted of two consecutive steps. The initial screening was based on the reactivity for TdT, HLA-Dr, CD7, CD10, CD13, CD19, CD24, CD33 and CD41. According to the results obtained, the second level of investigation assessed the positivity for intra cytoplasmic (Cy) Ig, CD1a, CD2, CD3, CD4, CD5, CD8 and CD20. Based on the hierarchical expression of the different B- and T-cell related antigens, each case was assigned to a given differentiation stage. B-lineage ALL were classified in five subgroups (B0-B4) and T-lineage ALL in four subgroups (T0-T3). Cases in which the blasts were lymphoid according to the FAB criteria, but expressed myeloid antigens in association with B- and T-lymphoid markers were defined as hybrid leukemias. As expected, CD10+ cases (B2-B3) were the most frequent within the B-lineage ALL (83.2% of cases). CyIg+ (B3) accounted for about 20% of CD10+ ALL. Twenty eight cases (13.4%) were at a pre-cALL stage (B0-B1) and of these, 8 (3.8% of the total series) were positive only for TdT and HLA-Dr (B0). Intermediate and mature thymic phenotypes (T2-T3) were predominant within the T-ALL (67.2%) groups. Five cases, were positive only for TdT and CD7 (CD5+), and classified as T0. 9.2% of cases fulfilled the definition of hybrid leukemia, largely in view of the co-expression of B-lymphoid and myeloid markers.(ABSTRACT TRUNCATED AT 250 WORDS)

ABL proteins in Philadelphia-positive acute leukaemias and chronic myelogenous leukaemia blast crises

The Philadelphia chromosome (Ph1) is present in 95% of chronic myelogenous leukaemias (CML) and 15% of acute lymphoblastic leukaemias (ALL). This cytogenetic marker is due to a t(9;22) translocation, which causes a rearrangement of the ABL oncogene. In order to better define the relationship between type of genomic rearrangement, variant ABL protein expressed and haematological phenotype, a series of Ph1-positive acute leukaemias, both myeloblastic (AML) and lymphoblastic, and several CML lymphoid blast crises have been analysed at the DNA and protein level. The results confirm the presence of the ABL protein P210 in all cases of CML, ALL and AML positive for rearrangement in the bcr region of chromosome 22, and, surprisingly, in one AML case apparently negative for bcr rearrangement. The ABL protein P190 was found to be present only in cases of ALL negative for bcr rearrangement. Polymerase chain reaction (PCR) analysis of the types of 9/22 junctions present in the mRNA of CML lymphoid blast crises showed no evidence of 'ALL-type' transcripts.

Interleukin 2 does not promote the in vitro and in vivo proliferation and growth of human acute leukaemia cells of myeloid and lymphoid origin

The effect of recombinant interleukin 2 (IL2) on the in vitro and in vivo proliferation and growth of human acute leukaemia cells of both myeloid and lymphoid origin was investigated. In none of the 25 primary samples tested could a continuously in vitro growing cell line be obtained by adding IL2 to the culture medium. Although IL2 induced a proliferative signal in three of the 31 acute leukaemias analysed, the overall 3H-thymidine uptake of the neoplastic cells was significantly reduced (P less than 0.05) in the presence of IL2. The unlikelihood of an important proliferative signal triggered by IL2 was confirmed in a semisolid clonogenic assay, which failed to document an increased colony growth in the 26 samples studied. Furthermore, using a colorimetric assay as a test for cell proliferation and survival, in seven of the 11 fresh acute leukaemia samples tested a 22-40% reduction in viability was observed in the presence of IL2, while in the remaining four, IL2 was ineffective. In order to investigate the effect of IL2 in an in vivo setting, an experimental model in heavily immunosuppressed nu/nu mice was established. In no case did IL2 promote the in vivo proliferation and growth of human myeloid and lymphoid acute leukaemia cells injected in the mice. On the contrary, with seven of the eight leukaemic cell lines which gave rise spontaneously to leukaemic masses, this could be prevented when the mice received locally 300 U of IL2 three times daily for 90 d. IL2 also blocked the growth in vivo of three fresh acute leukaemia samples (two myeloid and one lymphoid). Co-culture experiments using leukaemic cell lines and increasing numbers of normal lymphocytes suggest that the inhibitory effect of IL2 is probably exerted via an indirect mechanism. These findings, coupled to the well-documented ability of IL2 to generate lymphokine activated killer cells cytolytic against leukaemic blasts, further point to the potential role of immunotherapy with IL2 in the management of patients with haematological malignancies.

Immunoglobulin DNA Analysis as a Marker of Clonality in the Follow-up of Patients with Hairy Cell Leukemia Treated with Alpha-Interferon

In fourteen patients with hairy cell leukemia (HCL) the configuration of the immunoglobulin (Ig) heavy chain genes was used as a marker of clonality, to monitor the response of the neoplastic population to treatment with alpha-interferon (a-IFN). In agreement with the morphological, hematological and immunological data, twelve of them showed, after a variable length of therapy, a complete disappearance of rearranged bands in peripheral blood cells. In one patient, who was treated less intensively, the molecularly-defined neoplastic population was still present on two consecutive determinations, whilst in the last patient persistence of disease was repeatedly documented despite prolonged A-IFN treatment. Three further cases were analyzed sequentially: in two, no rearranged bands could be found at repeated determinations; the third, who was in complete remission whilst on 3 × 10(6) U of α-IFN every other day, showed recurrence of disease nine months later when on a maintenance protocol with 3 × 10(6) U/weekly. Nine bone marrow specimens were also analyzed following treatment with α-IFN. In four a monoclonally rearranged band could still be detected, while in another four, reversal of fibrosis and hemopoietic recovery wits coupled with the absence of a molecularly recognizable neoplastic clone. In the last (case, persistence of disease paralleled the findings in the peripheral blood cells. These data indicate that α-IFPJ is capable of producing a specific cytolytic effect on the leukemic population in HCL, which in some cases may lead to complete clonal remissions. Analysis at the DNA level may represent a valuable tool towards monitoring the clinical course of HCL patients and for optimal individual therapeutic scheduling.

Immunoglobulin heavy chain gene rearrangements in chronic lymphocytic leukaemia: correlation with clinical stage

A search for a correlation between the clinical stage of chronic lymphocytic leukaemia (CLL) and the pattern of immunoglobulin heavy chain gene rearrangements was undertaken. DNA samples from the leukaemic cells of 38 CLL patients were analysed by Southern blot hybridization. Using probes for the immunoglobulin heavy chain J (JH) and C mu regions a marked heterogeneity of the hybridization patterns was observed in both regions. The number of JH hybridization bands varied from one to four and more than two were found in 58% of the patients. In 42% of the patients no germline JH genes were found. One to three additional C mu bands were observed in 34%, but the germline was preserved in all samples. There was no correlation between the clinical stage and the number of hybridizing JH bands; however, a significant correlation was found between the loss of JH germline band or a C mu multiband pattern and advanced stage of the disease. The genetic events in the immunoglobulin genes observed in advanced CLL patients are assumed to result from clonal evolution and tumour progression.

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

The 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.

Incidence of lineage promiscuity in acute myeloblastic leukemia: diagnostic implications of immunoglobulin and T-cell receptor gene rearrangement analysis and immunological phenotyping

Sixty-nine blood or bone marrow samples from both children and adults with acute myeloblastic leukemia (AML) were investigated to elucidate the frequency of immunoglobulin (IG) and T-cell receptor (TCR)-gene rearrangements. Non-germline configuration for the IG heavy chain (h) gene was detected in the specimens of nine patients of various subtypes according to the French-American-British classification (FAB), including FAB M1, M2, M4 and M5. Rearrangement of the IG kappa chain (k) gene was present in one of these cases which simultaneously revealed a rearranged TCR-beta (b) chain gene. In another two AML samples we found TCR-b gene rearrangements, in one case in combination with an IG-h gene rearrangement. IG-h gene rearrangements were detected in 10 cases, in one case in conjunction with an IG-kappa (k) and TCR-b gene rearrangement. A highly significant correlation between the occurrence of DNA rearrangements of the IG-h locus and nuclear staining with the enzyme terminal deoxynucleotidyl transferase (TdT) and surface expression of the CD 19 and CD 34 antigen could be identified: all 10 TdT positive AML samples rearranged IG-h. Similarly, six out of 69 AML samples exhibited surface expression of CD 19, five of these in combination with CD 34 and all of them rearranged the IG-h gene. The one leukemia with TCR-b gene rearrangement only was TdT positive as well, but did not express CD 19 or CD 34. We conclude that IG-h gene is rearranged in a substantial proportion of AML, strongly associated with a specific immunophenotype (TdT+, CD19+, CD34+), whereas TCR-b gene rearrangement appears more rarely. No positive correlation between occurrence of IG-h and TCR-b gene-rearrangements and one AML FAB-subtype was found, although a clustering of M1 and M4 FAB subtypes in the AML group showing reconstructed IG-h gene became evident.

The lymphoproliferative disease of granular lymphocytes. A heterogeneous disorder ranging from indolent to aggressive conditions

A multiparameter analysis, which included the evaluation of clinical features, cell morphology, karyotype, phenotypic and functional immunologic findings, and T-cell receptor beta-chain configuration was performed on 34 patients with lymphoproliferative disease of granular lymphocytes (LDGL). The two-fold aim of the study was to identify the most useful tools that would more accurately characterize these patients and to deal with the problem of classifying these lymphoproliferative disorders. The data presented in this article suggest that a single parameter may not be sufficient to define the nature of the proliferating cells or to predict the clinical course of the disease and prognosis for the patient. The use of a multiparameter approach, however, may reach this goal, thus providing important prognostic and therapeutic information. Our study supports the concept that lymphoproliferative disease of granular lymphocytes is a heterogeneous disorder that ranges from indolent and possibly reactive conditions to the manifestation of aggressive malignancies.

Germ-line configuration of the T-cell receptor beta-chain gene in B-cell chronic lymphoproliferative disorders which co-express T-cell antigens

In 7 cases of chronic B-cell lymphoproliferative disorders-6 chronic lymphocytic leukaemias and 1 non-Hodgkin lymphoma in leukaemic phase--which co-expressed T-cell markers (CD3, CD2) the clonal origin was investigated at the DNA level. In accordance with the diagnosis, all cases showed a monoclonally rearranged configuration of the immunoglobulin genes. On the contrary, the T-cell receptor beta chain gene always retained a germ-line organization. These findings demonstrate that B-cell chronic lymphoproliferative disorders which co-express T-cell-related markers are truly composed of monoclonal B-cell elements.

Rearrangements of immunoglobulin and T cell receptor beta and gamma genes are associated with terminal deoxynucleotidyl transferase expression in acute myeloid leukemia

The cell origin of the rare terminal deoxynucleotidyl transferase (TdT)-positive acute myeloid leukemias (AML) was investigated at the molecular level, by examining the configuration of the Ig H (Igh) and L (Ig kappa, Ig lambda) chain gene regions, and of the T cell receptor (TCR) beta and T cell rearranging (TRG) gamma loci. In 8 of the 10 TdT+ AML analyzed (classified as myeloid according to morphological and cytochemical criteria, and to the reactivity with one or more antimyeloid mAbs), a rearrangement of the Igh chain gene was found. In TdT- AML, evidence of an Igh gene reorganization was instead observed only in 2 of the 42 patients studied. Furthermore, evidence of TCR-beta and/or TRG-gamma gene rearrangement was observed in four AML, all of which belonged to the Igh-rearranged TdT+ group. In three cases (one TdT+ and two TdT-), the Ig kappa L chain gene was also in a rearranged position. These findings demonstrate a highly significant correlation between TdT expression and DNA rearrangements at the Igh and TCR chain gene regions and support the view that this enzyme plays an important role in the V-(D)-J recombination machinery. Overall, the genomic configuration, i.e., JH gene rearrangement sometimes coupled to a kappa L chain and TCR gene reorganization, similar to that found in non-T-ALL, suggests that in most cases of TdT+ AML, the neoplastic clone, despite the expression of myeloid-related features, is characterized by cells molecularly committed along the B cell lineage.