Population Pharmacokinetic Analysis of the BTK Inhibitor Zanubrutinib in Healthy Volunteers and Patients With B-Cell Malignancies

Zanubrutinib is a potent, second-generation Bruton's tyrosine kinase inhibitor that is currently being investigated in patients with B-cell malignancies and recently received accelerated approval in the United States for treatment of relapsed/refractory mantle cell lymphoma. The objective of this analysis was to develop a population pharmacokinetic (PK) model to characterize the PKs of zanubrutinib and identify the potential impact of intrinsic and extrinsic covariates on zanubrutinib PK. Data across nine clinical studies of patients with B-cell malignancies and data of healthy volunteers (HVs) were included in this analysis, at total daily doses ranging from 20 to 320 mg. In total, 4,925 zanubrutinib plasma samples from 632 subjects were analyzed using nonlinear mixed-effects modeling. Zanubrutinib PKs were adequately described by a two-compartment model with sequential zero-order then first-order absorption, and first-order elimination. A time-dependent residual error model was implemented in order to better capture the observed maximum concentration variability in subjects. Baseline alanine aminotransferase and health status (HVs or patients with B-cell malignancies) were identified as statistically significant covariates on the PKs of zanubrutinib. These factors are unlikely to be clinically meaningful based on a sensitivity analysis. No statistically significant differences in the PKs of zanubrutinib were observed based on age, sex, race (Asian, white, and other), body weight, mild or moderate renal impairment (creatinine clearance ≥ 30 mL/minute as estimated by Cockcroft-Gault), baseline aspartate aminotransferase, bilirubin, tumor type, or use of acid-reducing agents (including proton pump inhibitors). These results support that no dose adjustment is considered necessary based on the aforementioned factors.

SERS-based dynamic monitoring of minimal residual disease markers with high sensitivity for clinical applications

Minimal residual disease (MRD) measurement is important for the diagnosis and prognosis of B cell hematological malignancies in the clinic. Thus, a sensitive and accurate method for monitoring the corresponding surface markers is in high demand for early diagnosis and treatment instruction. Herein, we developed a surface enhanced Raman scattering (SERS)-based sandwich-type immunoassay for the simultaneous detection of two surface markers (i.e., CD19 and CD20) in Raji cell lines as well as in clinical blood samples. First, to compare with the results obtained by flow cytometry, we evaluated the sensitivity and reproducibility of the SERS immunoassay for real-time detection of CD19 and CD20 expressions in Raji cells and blood samples. Then, we conducted follow-up tests on 13 B cell hematological malignancy patients for one month and dynamically monitored their CD19 and CD20 expressions by the SERS immunoassay. In addition to the improved sensitivity of the SERS method, good linear correlations between the SERS intensities and flow cytometry results were also observed for both CD19 and CD20, which indicated the accuracy of this SERS-based strategy. Therefore, this SERS-based simultaneous detection approach shows great potential for accurate and early diagnosis of MRD in B cell hematological malignancies.

Defective collagen-induced platelet activation in two patients with malignant haemopathies is related to a defect in the GPVI-coupled signalling pathway

The occurrence of a thrombocytopathy concomitantly to the development of a malignant haemopathy has been reported for some time, but little is known about the mechanism(s) involved in the platelet dysfunction. Platelet glycoprotein VI (GPVI) has now been identified as a principal platelet receptor for collagen. In this paper, we report the cases of two patients with a myelodysplasia and a B lymphopathy, respectively, who presented with thrombocytopathy in relation to a defective GPVI-mediated platelet reactivity to collagen. Thus, with regard to the different steps of adhesion, activation secretion or aggregation, patients’ platelet responses to collagen and to the GPVI specific agonists, collagen related peptide (CRP) or convulxin were null or dramatically impaired. Platelet responses to other agonists ADP, TRAP,Arachidonic acid were normal or showed only a moderate decrease. GPVI content was repeatedly normal, and binding of specific ligands, such as convulxin, satisfactory. Nevertheless, specific activating monoclonal antibodies and convulxin failed to induce platelet secretion; collagen, CRP or convulxin were unable to provoke calcium mobilisation. Furthermore, using a perfusion chamber model, we showed that ex vivo collagen-induced thrombi formation was very impaired.Taken together,these data provide evidence, for the first time, of an acquired defect in GPVI-mediated platelet reactivity to collagen, which reflects data observed in constitutional GPVI deficiencies, in two patients with malignant haemopathies.

Detection of leukemia markers using long-range surface plasmon waveguides functionalized with Protein G

A novel optical biosensor based on long-range surface plasmon-polariton (LRSPP) waveguides is demonstrated for the detection of leukemia markers in patient serum using a functionalization strategy based on Protein G. The sensor consists of thin straight Au waveguides (5 μm × 35 nm × 3.2 mm) embedded in fluoropolymer CYTOP™ with a fluidic channel etched into the top cladding. B-cell leukemia is characterized by a high B-cell count and abnormal distribution of immunoglobulin G kappa (IgGκ) and lambda (IgGλ) light chains in serum. The detection of leukemic abnormalities in serum was performed based on determining IgGκ-to-IgGλ ratios (κ : λ). Three patient sera were tested: high kappa (HKS, κ : λ ~12.7 : 1), high lambda (HLS, λ : κ ~6.9 : 1) and normal (control) sera (NS, κ : λ ~1.7 : 1). Au waveguides were functionalized with Protein G and two complementary immobilization approaches were investigated: a) the reverse approach, where the Protein G surface is functionalized with patient serum and then tested against goat anti-human IgG light chains in buffer, and b) the direct approach, where the Protein G surface is functionalized with goat anti-human IgGs first and then tested against patient serum. The reverse approach was found to be more effective and robust because Protein G-functionalized surface performs as an "immunological filter" by capturing primarily IgGs out of the pool of serum proteins. For the reverse approach, the ratios measured were 3.7 : 1(κ : λ), 9.7 : 1(λ : κ) and 1.9 : 1(κ : λ) for HKS, HLS and NS, respectively, which compare favorably with corresponding protein densitometry measurements. The respective ratios for the direct approach were 2.6 : 1(κ : λ), 2.6 : 1(λ : κ) and 1.7 : 1(κ : λ). The binding strength and cross-reactivity of goat anti-human IgGs light chains were also determined using pure solutions. The LRSPP biosensor along with the innovative "reverse approach" can provide a low-cost and compact solution to B-cell leukemia screening.

IRF4 is a suppressor of c-Myc induced B cell leukemia

Interferon regulatory factor 4 (IRF4) is a critical transcriptional regulator in B cell development and function. We have previously shown that IRF4, together with IRF8, orchestrates pre-B cell development by limiting pre-B cell expansion and by promoting pre-B cell differentiation. Here, we report that IRF4 suppresses c-Myc induced leukemia in EμMyc mice. Our results show that c-Myc induced leukemia was greatly accelerated in the IRF4 heterozygous mice (IRF4^+/−Myc); the average age of mortality in the IRF4^+/−Myc mice was only 7 to 8 weeks but was 20 weeks in the control mice. Our results show that IRF4^+/−Myc leukemic cells were derived from large pre-B cells and were hyperproliferative and resistant to apoptosis. Further analysis revealed that the majority of IRF4^+/−Myc leukemic cells inactivated the wild-type IRF4 allele and contained defects in Arf-p53 tumor suppressor pathway. p27^kip is part of the molecular circuitry that controls pre-B cell expansion. Our results show that expression of p27^kip was lost in the IRF4^+/−Myc leukemic cells and reconstitution of IRF4 expression in those cells induced p27^kip and inhibited their expansion. Thus, IRF4 functions as a classical tumor suppressor to inhibit c-Myc induced B cell leukemia in EμMyc mice.

Different levels of CD52 antigen expression evaluated by quantitative fluorescence cytometry are detected on B-lymphocytes, CD 34+ cells and tumor cells of patients with chronic B-cell lymphoproliferative diseases

BACKGROUND

The success of treatment using monoclonal antibodies in oncology is influenced by, among other factors, the level of target antigen expression on tumor cells. The authors analyzed the intensity of the CD52 antigen expression in patients with chronic lymphoproliferative diseases and compared them with B-lymphocytes of a healthy population and CD34(+) cells in peripheral blood stem cells (PBSC) grafts.

METHODS

Recently diagnosed and previously untreated patients with B-cell chronic lymphocytic leukemia (B-CLL), mantle-cell lymphoma (MCL), or small lymphocytic lymphoma (SLL) were evaluated and compared with control group and CD34(+) cells. The intensity of CD52 was expressed in molecules of equivalent soluble fluorochrome units (MESF) and antibody-binding capacity (ABC).

RESULTS

In the group of patients with B-CLL, the CD52 level on tumor cells (245 x 10(3) MESF; 107 x 10(3) ABC) was significantly lower than on B-lymphocytes of the control group (446 x 10(3) MESF; 194 x 10(3) ABC; P < 0.001) and SLL tumor cells (526 x 10(3) MESF; 229 x 10(3) ABC; P < 0.001). The CD52 antigen was expressed on a majority of CD34(+) cells, but its expression intensity was low (101 x 10(3) MESF; 44 x 10(3) ABC).

CONCLUSIONS

Our data demonstrate differences in the intensity of the CD52 antigen expression between B-lymphocytes and tumor lymphocytes of B-CLL patients, and between B-CLL and SLL tumor cells. CD52 antigen is expressed at low level on CD34(+) cells.

A new automated flow cytometry data analysis approach for the diagnostic screening of neoplastic B-cell disorders in peripheral blood samples with absolute lymphocytosis

Currently, multiparameter flow cytometry immunophenotyping is the selected method for the differential diagnostic screening between reactive lymphocytosis and neoplastic B-cell chronic lymphoproliferative disorders (B-CLPD). Despite this, current multiparameter flow cytometry data analysis approaches still remain subjective due to the need of experienced personnel for both data analysis and interpretation of the results. In this study, we describe and validate a new automated method based on vector quantization algorithms to analyze multiparameter flow cytometry immunophenotyping data in a series of 307 peripheral blood (PB) samples. Our results show that the automated method of analysis proposed compares well with currently used manual approach and significantly improves semiautomated approaches and, that by using it, a highly efficient discrimination with 100% specificity and 100% sensitivity can be made between normal/reactive PB samples and cases with B-CLPD based on the total B-cell number and/or the sIgkappa+/sIglambda+ B-cell ratio. In addition, the method proved to be able to detect the presence of pathologic neoplastic B-cells even when these are present at low frequencies (<5% of all lymphocytes in the sample) and in poor-quality samples enriched in 'noise' events.

Usefulness of CD45 density in the diagnosis of B-cell chronic lymphoproliferative disorders

BACKGROUND

Although many B-cell chronic lymphoproliferative disorders (BCLPDs) including B-cell chronic lymphocytic leukemia (B-CLL) have characteristic clinical and biological features, the overlapping morphologic and immunophenotypic profiles of various BCLPDs, is still the main problem.

AIM

Our aim was to evaluate the usefulness of CD45 expression in the immunological classification of BCLPDs.

SETTING AND DESIGN

A prospective study was set in a university hospital to investigate the CD45 intensity, particularly in B-CLL.

MATERIALS AND METHODS

The expression of CD45 in 37 patients with BCLPD including typical B-CLL (Group I), atypical B-CLL and CLL/PLL (II), and hairy cell leukemia (HCL), B-prolymphocytic leukemia (B-PLL), and B-non Hodgkin's lymphoma (B-NHL) as non-CLL BCLPDs (III) and in eight healthy age matched controls (IV) was quantitatively compared by flow cytometric CD45/RALS gating strategy.

STATISTICAL ANALYSIS

The mean, median, and peak channel scores of CD45 obtained for the four groups were compared using one-way analysis of variance test. A P value

RESULTS

Lower CD45 density is associated highly with typical CLL and differences between typical CLL and other groups were significant (P< 0.001, 0.001, and 0.001). Non-CLL cases had significantly brighter CD45 expression than atypical CLL (P=0.014). No differences were found between normal lymphocytes and non-CLL BCLPD cases.

CONCLUSIONS

CD45 is a useful marker, to discriminate the typical CLL from the non-CLL BCLPD and from atypical CLL.

APRIL promotes B-1 cell-associated neoplasm

A tumor-supporting role for the TNF-like ligand APRIL has been suggested. Here we describe that 9- to 12-month-old APRIL transgenic mice develop lymphoid tumors that originate from expansion of the peritoneal B-1 B cell population. Aging APRIL transgenic mice develop progressive hyperplasia in mesenteric lymph nodes and Peyer's patches, disorganization of affected lymphoid tissues, mucosal and capsular infiltration, and eventual tumor cell infiltration into nonlymphoid tissues such as kidney and liver. We detected significantly increased APRIL levels in sera of B cell chronic lymphoid leukemia (B-CLL) patients, indicating that APRIL promotes onset of B-1-associated neoplasms and that APRIL antagonism may provide a therapeutic strategy to treat B-CLL patients.

Near-triploidy and near-tetraploidy in hematological malignancies and mutation of the p53 gene

Hyperdiploidy of > or =58 chromosomes is reported in 0.5-3% of hematological malignancies, but reports of near-triploidy (58-80 chromosomes) and near-tetraploidy (81-103 chromosomes), are few. We examined these chromosome abnormalities and analyzed the relationship with the mutation of the p53 gene. Thirty-one of 979 adult patients (3.2%) with hematological malignancies were identified as having near-triploid or near-tetraploid (tri-/tetraploid) chromosomes. These included 11 with B-cell neoplasms, seven with Hodgkin's lymphoma, five with T-cell neoplasms, four with myelodysplastic syndromes and four with acute myeloid leukemias. All patients had concurrent complex chromosome aberrations. Deletion of one allele of the p53 gene was found in two patients and a point mutation of the p53 gene was detected in five patients. Although abnormalities of the p53 gene have been reported in about 10% of hematological malignancies, these were found in seven of 31 (23%) patients with tri-/tetraploidy. These findings suggest that the abnormality of the p53 gene may be closely related with tri-/tetraploidy. The four myelodysplastic syndrome (MDS) patients with tri-/tetraploidy had a significantly worse prognosis than those with diploid cytogenetics (n = 35; P < 0.002). In B-cell neoplasms (n = 3), triploidy was associated with a worse prognosis than tetraploidy (n = 8) and diploidy (n = 130; P < 0.02).

The role of soluble CD23 in distinguishing stable and progressive forms of B-chronic lymphocytic leukemia

Soluble CD23 (sCD23) has been recognized as an important prognostic parameter in patients with chronic lymphocytic leukemia (B-CLL) at early clinical stages. There is, however, no clear information on its prognostic significance in advanced stages and on its role as an indicator for aggressive or indolent courses of disease. Therefore, sCD23 was measured in the serum of 145 patients at diagnosis and serial determinations were carried out for 8 years in 38 patients. The results indicate that in patients with identical clinical stages at first presentation the disease could take different courses depending on initial sCD23 concentrations below or above specific threshold levels (860 and 5900U/ml). sCD23 higher than these thresholds was associated with faster progression into upper clinical stages. Furthermore, sCD23-doubling time (sCD23-DT) indicated that patients with long DT progressed slowly, while those with short DT had more aggressive disease. Particularly in patients with advanced disease stages, long sCD23-DT indicated development of smoldering disease. Since sCD23 levels reflect total tumor mass, determination of sCD23-DT has probably a better predictive value than lymphocyte doubling time. It appears that B-CLL patients can be divided into different risk categories according to initial determinations of sCD23 and that sCD23-DT is an additional important parameter in predicting disease progression.

European experience in the treatment of hyperuricemia

The nonrecombinant form of urate oxidase has been routinely used in France since 1975 as standard practice in the initial management of non-Hodgkin's lymphoma (NHL) and acute lymphoblastic leukemia (ALL), and for prevention of tumor lysis syndrome (TLS). A retrospective study was performed to evaluate the frequency of metabolic complications and dialysis in 410 patients with B-cell stage III and IV NHL and L-3 ALL treated in France according to the LMB89 protocol, and to compare these results to those of other series of patients treated without urate oxidase. Of the 57 patients treated at Institut Gustave-Roussy, only five had metabolic complications occurring in the first cycle of chemotherapy. Two patients (3.5%) underwent dialysis: one because of oliguria, the second for preventive reasons. In all the other cases, metabolic problems were successfully resolved or prevented, using nonrecombinant urate oxidase (Uricozyme, Sanofi-Sythélabo, Inc, Paris, France) in combination with hyperhydration. Nonrecombinant urate oxidase is generally well tolerated. However, allergic reactions may occur, with rates varying from 0% to 4.5%. In addition, the extraction technology used to produce the product is limited by a low yield. A recombinant form of urate oxidase (rasburicase) was therefore developed. European clinical development results indicate that this agent produces a sharp and consistent decrease in uric acid levels in patients undergoing cytoreductive therapy. Additionally, there is a very low incidence of anaphylaxis. Studies have demonstrated the efficacy of urate oxidase in lowering uric acid levels, preventing hyperuricemia after the initiation of cytoreductive therapy, and preserving renal function in patients with B-cell advanced stage NHL and ALL.

Massive immune haemolysis after allogeneic peripheral blood stem cell transplantation with minor ABO incompatibility

Immune haemolysis as a result of minor ABO incompatibility is an underappreciated complication of haematopoietic transplantation. The increased lymphoid content of peripheral blood stem cell (PBSC) transplants may increase the incidence and severity of this event. We observed massive immune haemolysis in 3 out of 10 consecutive patients undergoing HLA-identical, related-donor PBSC transplants with minor ABO incompatibility. Non-ablative conditioning had been given in 9 of these 10 cases, including two with haemolysis. Cyclosporin alone was used as prophylaxis against graft-vs.-host disease (GVHD). Catastrophic haemolysis of 78% of the circulating red cell mass led to anoxic death in the first case seen, but severe consequences were avoided by early, vigorous donor-compatible red cell transfusions in the subsequent two cases. Haemolysis began 7-11 d after PBSC infusion and all patients with haemolysis had a positive direct antiglobulin test (DAT), with eluate reactivity against the relevant recipient antigen. However, neither the intensity of the DAT, the donor isohaemagglutinin titre, nor other factors could reliably be used to predict the occurrence of haemolysis. Our data indicate that haemolysis may be frequent and severe after transplantation of minor ABO-incompatible PBSCs when utilizing cyclosporin alone to prevent GVHD. Meticulous clinical monitoring and early, vigorous donor-compatible red cell transfusions should be practiced in all instances.

Flow cytometry and the study of central nervous disease in patients with acute leukaemia

Central nervous system (CNS) leukaemia is still a matter of debate and new technologies are required to improve the classic morphological definition. One hundred and sixty-eight cerebrospinal fluid (CSF) samples from 31 patients with acute leukaemia were analysed by flow cytometry and conventional cytology. Concordant positive and negative findings were found in 158 samples but 10 produced discrepant results. Cytology seemed to offer more precise information in one CSF sample and flow cytometric accuracy could be demonstrated in five samples. We conclude that flow cytometry is of great help in confirming CNS leukaemia and eliminating other conditions. Therefore, leukaemic patients can benefit from double cytological and flow cytometric CSF studies.

Expression of functional granulocyte colony-stimulating factor receptors on human B-lymphocytic leukemia cells

We analyzed the expression of cell surface antigens and granulocyte colony-stimulating factor (G-CSF) receptors using flow cytometry, the expression of G-CSF mRNA receptor, using reverse transcription (RT)-PCR, and tested the effect of G-CSF on leukemia colony formation. A total of 14 lymphocytic leukemia patients were examined, seven with acute lymphocytic leukemia (ALL), two with adult T-cell leukemia (ATL), two with B-chronic lymphocytic leukemia (CLL), two with chronic myelocytic leukemia in lymphoid blastic crisis (CML-LBC), and one with plasma cell leukemia (PCL). The presence of G-CSF receptors was demonstrated in 4/14 (29%) patients, two with ALL, one with CLL, and one with CML-LBC, and was associated with stimulation of leukemia clonogenic cell growth by G-CSF. In addition, all four positive leukemia cell types expressed typical B-cell antigens. Our results indicated that G-CSF receptors are expressed on some portion of B-lymphoid leukemia and that their receptors are functional as growth stimulators.

Impact of cryopreservation on B cell chronic lymphocytic leukaemia phenotype

BACKGROUND AND OBJECTIVES

Freezing is a practical approach for cell preservation for retrospective studies. The aim of this work was to check the cryopreservation impact on B cell chronic lymphocytic leukaemia phenotype.

MATERIAL AND METHODS

Blood samples from 15 CLL patients were analyzed freshly and after freezing at -196 degrees C, without separation, and thawing. Results were compared by Student's paired t-test.

RESULTS

The phenotype of fresh CLL cells was as follows: CD19+, CD5+, faint CD20, CD23+/-, weak CD22 and sIg, CD37+, HLA-DR+, FMC7-. After cryopreservation, the percentage of CD5 and CD23 positive cells decreased, whereas HLA-DR positive cells increased moderately. The CLL Matutes's score was modified in 6 cases out of 15 (40%).

CONCLUSION

Cryopreservation modifies B cell chronic lymphocytic leukaemia phenotype, by decreasing CD5 and CD23 expression.

[B cell acute lymphocytic leukemia with marked leukocytosis and t(3;15)(q27;q2?2)]

We report on a 16-year-old boy with B cell acute lymphocytic leukemia presenting marked leukocytosis (388,000/microliter) and resistance to multidrug chemotherapy. Karyotypical analysis revealed a novel t(3;15)(q27;q2?2) chromosomal abnormality. Because 3q27 is known to be a locus of the bcl-6 gene, which is frequently involved in B cell malignancies, molecular biological analyses were performed. Although no rearrangement was detected in 5 genes including bcl-6 on 3q27 and 2 genes on 15q2, reverse transcriptase-polymerase chain reaction procedures detected relatively strong mRNA expression of the bcl-6, smrp, dvl3, and tpml genes. These results indicate that immature leukemic cells with CD10 and CD34 positivity and rearrangement of the T cell receptor beta gene may coexist with relatively mature subpopulations that are positive for CD19 and CD20 surface markers, bcl-6 expression, and rearrangement of the gene for immunoglobulin kappa.

Similar characteristics of the CDR3 of V(H)1-69/DP-10 rearrangements in normal human peripheral blood and chronic lymphocytic leukaemia B cells

The variable heavy chain (V(H)) gene segment V(H)1-69/DP-10 has been shown to be over-represented in B-cell chronic lymphocytic leukaemia (CLL). Because of certain similar characteristics of their complementarity determining region 3 (CDR3), including preferential utilization of J(H)6 elements and an extended length, it has been suggested that antigenic stimulation might be involved in leukaemogenesis. Utilizing single-cell PCR to amplify and sequence genomic DNA from individual normal human peripheral blood B cells, we have obtained 7/421 productively and 1/69 nonproductively rearranged V(H) genes that used V(H)1-69/DP-10. All productive rearrangements were unmutated, used J(H)6 and had an average CDR3 length similar to that previously found in V(H)1-69/DP-10-expressing CLL cells. These results suggest that CLL may arise from B cells commonly found in the peripheral B-cell repertoire and do not represent expansion of a unique subset of specific antigen-reactive B cells.

Autoimmune haemolysis in patients with B-CLL treated with chlorodeoxyadenosine (CDA)

We have treated 19 B-chronic lymphocytic leukaemia (B-CLL) patients with CDA (Leustat, Janssen-Cilag). Four patients developed severe autoimmune haemolytic anaemia, and 2 of these had severe reticulocytopenia due to red cell aplasia/hypoplasia. Two patients died as a complication of the haemolysis one during the primary episode, with a clinical course suggestive of transfusion associated graft-versus-host disease (taGVHD), and one following a relapse of haemolysis. The onset of haemolysis occurs within 4 cycles of CDA therapy and is temporally related to the T-lymphocyte nadir induced by CDA. The presence of a positive DAT prior to therapy in 3 of 4 patients developing haemolysis suggests that the CDA induced T-lymphocytopenia may exacerbate the tendency of certain CLL patients to autoimmune haemolysis.

Pharmacological and biochemical strategies to increase the accumulation of arabinofuranosylguanine triphosphatein primary human leukemia cells

Purine nucleoside phosphorylase deficiency leads to a dGTP-mediated T-lymphopenia, suggesting that an analogue of deoxyguanosine would be selectively effective in T-cell disease. 9-beta-D-Arabinofuranosylguanine (ara-G) is relatively resistant to hydrolysis by purine nucleoside phosphorylase and selectively toxic to T cells, but its low solubility has prevented its use in the clinic. 2-Amino-6-methoxy-arabinofuranosylpurine (GW506U) serves as the water-soluble prodrug for ara-G. A Phase I trial in patients with refractory hematological malignancies demonstrated that the clinical responses to this agent were directly related to the peak levels of ara-G 5'-triphosphate (ara-GTP) in target cells. The aim of the present study was to develop and test strategies to increase intracellular accumulation of ara-GTP in primary human leukemia cells of myeloid and B-lymphoid origin. Three strategies were tested. First, incubations with 100 microM ara-G for 4 h produced a linear median accumulation rate of 19 microM/h (range, 2-45 microM/h; n = 15) in lymphoid leukemia cells and 16 microM/h (range, 0.5-41 microM/h; n = 11) in myeloid leukemia cells. Saturation of ara-GTP accumulation was achieved only after 6-8 h exposure in both lymphoid and myeloid leukemia cells, suggesting a rationale for prolonged infusion. Second, a dose-dependent increase in ara-GTP accumulation was observed with incubations of 10-300 microM ara-G for 3 h. Hence, dosing regimens that achieve high plasma levels of ara-G during therapy may increase cellular levels of ara-GTP. Finally, a biochemical modulation approach using in vitro incubation of leukemia cells with 10 microM 9-beta-D-arabinofuranosyl-2-fluoroadenine for 3 h, followed by either 50 or 100 microM ara-G for 4 h, resulted in a statistically significant median 1.3-fold (range, 1.1-9.0-fold; P = 0.034) and 1. 8-fold (range, 0.9-10.6 fold; P = 0.018) increase in ara-GTP compared to cells incubated with ara-G alone. Extension of these studies to ex vivo incubations confirmed our in vitro findings. These strategies will be used in the design of clinical protocols to increase ara-GTP accumulation in leukemia cells during therapy.

Monitoring minimal residual disease in peripheral blood in B-lineage acute lymphoblastic leukaemia

The use of peripheral blood rather than marrow has potential advantages for monitoring minimal residual disease during the treatment of leukaemia. To determine the feasibility of using blood, we used a sensitive polymerase chain reaction method to quantify leukaemia in the blood and marrow in 35 paired samples from 15 children during induction treatment. Leukaemic cells in the blood ranged from 1.1 x 10(-2) to < 9.4 x 10(-7) leukaemic cells/total cells, corresponding to 1.3 x 10(7) to < 2 x 10(3) leukaemic cells/l. In 15 paired samples, leukaemia could be quantified in both tissues and in 20 paired samples, leukaemia was not detected in one or both tissues so that only upper level limits could be set. In the former 15 pairs, the level of leukaemia in peripheral blood was directly proportional to that in marrow but was a mean of 11.7-fold lower. Leukaemia in blood was detected in 10/12 pairs in which the level in marrow was > 10(-4), but in only two of 13 pairs in which the level in marrow was < 10(-5). Patients studied at multiple time-points showed parallel declines in the number of leukaemic cells in both tissues. The results showed that leukaemia could be monitored in peripheral blood during induction therapy, and quantitative considerations based on the results suggest that monitoring of blood during post-induction therapy may be of value in detecting molecular relapse.

[Thrombocytosis in patients with non-Hodgkin's lymphomas and Hodgkin's disease]

Secondary thrombocytosis appears in patients with various neoplastic and autoaggressive diseases and infections. Thrombocytosis occurrence among 358 patients with NHL and 46 with HD treated at the Department of Haematology of CMKP (Postgraduate Training Centre) and Warsaw Medical School in 1986-1993 is here presented. The 11 patients (3%) among the ones with NHL and the 11 (24%) with HD showed thrombocytosis. Much more frequently the increased thrombocyte count could have been found in patients with low grade T-cell lymphomas (14%) and in patients with Hodgkin's disease. The patients with chronic B-cell lymphocytic leukemia (1%) showed thrombocytosis in very few cases. Thrombocyte count in patients with NHL was not high (mean-596.0 x 10(9)/L median-558.0 x 10(9)/L) which was similar as in those with HD (mean-601.0 x 10(9)/L median-558.0 x 10(9)/L).

Analysis of blood T-cell cytokine expression in B-chronic lymphocytic leukaemia: evidence for increased levels of cytoplasmic IL-4 in resting and activated CD8 T cells

The cytoplasmic cytokines of purified blood T cells (CD4/CD8) in B-CLL patients (n = 5) and controls (n = 5) were evaluated by flow cytometry. The mean levels of cytoplasmic IL-4 were significantly elevated in resting and activated B-CLL CD8 cells compared to control CD8 cells. IL-4 cytoplasmic levels were comparable for resting B-CLL and control CD4 cells but greater for B-CLL activated CD4 cells. The mean fluorescence intensity of B-CLL CD8 cytoplasmic IL-4 was 4-5-fold greater, indicating higher IL-4 density per CLL CD8 than control CD8 cells. Both CLL CD4 and CD8 cells post-activation had higher levels of cells double positive for cytoplasmic IL-4 and interferon. These data indicate that freshly isolated CD8 and CD4 blood T cells from B-CLL patients have significantly elevated (above control) levels of commitment to expression of IL-4. Since IL-4 has an important modulatory impact on CLL and normal B cells, this observation has implications regarding the biology of B-CLL.

Circulating levels of soluble CD23 reflect clinical and biological features of leukemic B-cell chronic lymphoproliferative disorders

One hundred and twenty-four sera from patients with various leukemic B-cell chronic lymphoproliferative diseases were investigated at diagnosis by ELISA for their soluble CD23 content. Immunophenotyping was carried out in all patients, and in a selected subset the mean number of membrane-bound CD23 molecules per cell was also investigated. Seventy-three patients had typical B chronic lymphocytic leukemia, 41 leukemic B-cell disorders with atypical morphological and/or immunophenotypic features, 5 had low-grade follicular cell lymphoma in the leukemic phase, and 5 had splenic lymphoma with villous lymphocytes. Soluble CD23 levels were significantly higher than in normal sera (mean +/- SD: typical B chronic lymphocytic leukemia 3,650 +/- 4,654 U/ml, atypical B chronic lymphocytic leukemia 3,440 +/- 4,671 U/ml, follicular cell lymphoma 3,200 +/- 1,511 U/ml, splenic lymphoma with villous lymphocytes 8,236 +/- 7,294 U/ml, controls 137 +/- 128 U/ml; P < 0.001). More advanced Rai's stages were related to higher soluble CD23 levels (P < 0.01), both in typical and atypical B chronic lymphocytic leukemias, the highest levels and the best correlation with the absolute number of circulating CD19+ cells (r = 0.50) being observed in the typical form. The number of membrane-bound CD23 molecules per cell was significantly higher in typical than in atypical B chronic lymphocytic leukemias (mean number 156,727 +/- 94,668 vs. 12,010 +/- 10,643, P < 0.001). Our data suggest that soluble CD23 levels correlate with the clinical and biological features of leukemic B-cell lymphoproliferative disorders.

B-cell prolymphocytic leukemia expressing discordant myeloid-associated antigens in simultaneous specimens from bone marrow and peripheral blood

The case of a 73-year-old man with B-cell prolymphocytic leukemia (PLL) and rapid clinical demise is reported. Flow cytometric immunophenotyping results of specimens obtained from the patient demonstrated a monoclonal CD5 positive B-cell population with myeloid-associated marker expression, which was discordant: CD15 and CD11b were expressed in bone marrow leukemic cells, whereas peripheral blood leukemic cells showed virtually no expression of these markers. Discordant immunophenotyping results between bone marrow and peripheral blood cells have been reported recently. Additionally, investigators have associated expression of CD13 and CD11b by chronic B-cell lymphoid leukemias with a more aggressive clinical course and shorter survival. Expression of these myeloid-associated antigens by B-cell prolymphocytes in PLL has not been widely reported. Cytogenetic analysis revealed a karyotype of 46,XY/?44,XYdel(1q),del (3p), whereas molecular genetic studies demonstrated immunoglobulin gene rearrangements in both heavy and light chain regions. Cytochemical staining for PAS (periodic acid-Schiff), nonspecific esterase and methyl-green-pyronin was positive in leukemic cells.

Identification of soluble APO-1 in supernatants of human B- and T-cell lines and increased serum levels in B- and T-cell leukemias

The cell-surface protein APO-1 is a member of the nerve growth factor (NGF)/tumor necrosis factor (TNF) receptor superfamily. APO-1 mediates apoptosis in susceptible cells upon stimulation with the monoclonal antibody anti-APO-1 or upon binding of its natural ligand. Soluble receptors had previously been identified for most members of the NGF/TNF receptor superfamily. Recently, a soluble form of APO-1 (sAPO-1) was described. We established a sandwich enzyme-linked immunosorbent assay to detect sAPO-1 in culture supernatants of human cell lines and in human sera. sAPO-1 was found in culture supernatants of different human B- and T-cell lines. Molecular weights of sAPO-1 and membrane APO-1 were similar. In addition, in comparison to healthy donors, sera from patients with different high- and low-grade malignant B- and T-cell leukemias and lymphomas contained increased levels of sAPO-1. These findings may have implications for the growth of leukemias and the diagnostic monitoring of individual patients.

Cytogenetic heterogeneity in t(11;19) acute leukemia: clinical, hematological and cytogenetic analyses of 48 patients--updated published cases and 16 new observations

We report on 16 cases of t(11;19) acute leukemia and review data of published observations: altogether updated data of 48 patients are analyzed. Four hematological groups could be distinguished: (i) 13 cases of acute lymphoblastic leukemia (ALL) of B lineage, mostly CD19+; (ii) eight cases of biphenotypic leukemia: CD19+ (most often) ALL but with simultaneous or inducible expression of differentiation marker of monocytic lineage. The B lineage and biphenotypic leukemias were predominantly found in female infants; (iii) four cases of T-ALL in children; and (iv) 23 acute non-lymphocytic leukemia (ANLL) cases generally of M4 or M5 subtype, predominantly in males. Cytogenetically, at least two subtypes were observed with possibly an identical breakpoint on 11q23 but discrete breakpoints on 19p: lymphoid, biphenotypic, and most congenital myeloid cases showed a distal breakpoint on 19p13 producing 11q- and 19p+ derivatives, while most older myeloid cases showed 11q+ and 19p- derivatives as a result of a more proximal breakpoint on 19p12 or p13.1. The latter type was clearly detected using R bands but barely visible using Q or G bands while the other translocation was easy to detect with G bands but could be missed with R bands. The white blood cell count is usually high in these t(11;19) acute leukemias and prognosis is poor, except for T-ALL cases.

Autoantibody activity and V gene usage by B-cell malignancies

Autoreactive B cells account for a substantial part of the B-cell repertoire. They frequently secrete polyspecific natural autoantibodies, which probably bind with low affinity to the different antigens they recognize and which express germinal genes. The role of this pre-immune repertoire still remains to be defined but it has been suggested that it participates in the elimination of cell breakdown products, serves as a first barrier of defense or acts as a template upon which antigen driven selection and somatic recombinations could induce the emergence of high affinity induced antibodies. The present study, reviews the evidence favouring the idea that this autoreactive B-cell repertoire, which expresses a restricted set of V genes, frequently undergoes malignant transformation. This evidence arises from the study of the autoantibody activity and V gene usage in three different models of B-cell malignancies namely monoclonal immunoglobulins; chronic lymphocytic leukemia; and follicular non-Hodgkin's lymphomas.

Molecular investigation of the cytokines produced by normal and malignant B lymphocytes

Different normal and malignant human B-cell populations were studied with a twofold aim: to define which cytokines are produced in vivo, and to assess the relationship between cytokine production and kinetic state. To analyse normal B-cells representative of different stages of activation and proliferation in vivo, we purified germinal centre (GC)-B blasts and mantle B (M-B) cells from tonsils. To compare malignant B lymphocytes with their closest normal equivalent cells, we separated malignant CD5+B lymphocytes from the peripheral blood of patients with B-chronic lymphocytic leukemia (B-CLL) and normal CD5+B lymphocytes from cord blood. The expression of interleukins (IL) IL-1 alpha, IL-1 beta, tumour necrosis factor alpha (TNF-alpha), transforming growth factor beta (TGF-beta), IL-2, IL-4, and IL-6 genes was analysed using Northern and Western blotting techniques. TNF-alpha mRNA is produced by resting (M-B) and actively proliferating (GC-B) normal B lymphocytes. TGF-beta mRNA is present at high levels in resting normal M-B cells, while the transcript levels are lower in proliferating GC-B and in activated CD5+B lymphocytes. IL-2 production is limited to the actively proliferating GC-B blasts, IL-1 beta and IL-6 to resting M-B cells. The cytokine production profile of CD5+ malignant B-CLL cells differs from that of their putative normal counterparts and is more like the profile of M-B cells, since B-CLL cells produce IL-1 beta, TNF-alpha, TGF-beta, and IL-6. These observations lead to the following conclusions: among normal B lymphocyte populations, resting M-B lymphocytes are the most active cytokine producers, and B-CLL malignant B cells reflect the production pattern of normal resting B lymphocytes.

The technicon H6000 analyzer discriminates chronic lymphocytic leukemia from other B-cell leukemias through automatic assessment of large unstained cells

The separation of chronic lymphocytic leukemia of B-cell origin from other chronic B-cell leukemias is subjective, being largely based on the morphologic features of the lymphoid cells in the peripheral blood. The percentage of large unstained cells determined with a Technicon H6000 analyzer (an automated blood cell differential analyzer, Technicon Instruments Corp, Tarrytown, NY) was used as a cell volume variable in an investigation of 70 cases of chronic lymphocytic leukemia of B-cell origin and of other chronic B-cell leukemias. The significant degree of correlation between the percentage of large unstained cells and morphoimmunophenotypic diagnosis, although obtained for a relatively small number of cases, suggests that this method of cell volume analysis can be used to improve diagnostic reproducibility in chronic B-cell leukemia.

The basic study on kappa-lambda imaging by delta-curve for the detection of a monoclonal B-cell population in the peripheral blood

Recently, kappa-lambda analysis with the "D" value was developed by Ault to detect a minor population of malignant B cells in peripheral blood. This analysis is based on the Kolmogorov-Smirnov test, and the D value is calculated by a flowcytometer and a computer. We have recently devised a more sensitive parameter for the kappa-lambda analysis than the D value called the delta-curve (delta c); the delta c applies the same principle as that of the D value. Mixing experiments with kappa-type and lambda-type chronic lymphocytic leukemia cells revealed that the delta c could not only detect a minor population of malignant kappa-B cells, but also that of malignant lambda-B cells using more sensitivity than the D value. A total of 49 blood samples obtained from 27 patients with various B-cell malignancies were investigated. D values were abnormal in 37% of all samples, while abnormal patterns of the delta c were recognized in 71%. On the other hand, 59% of samples obtained from the patients with B-cell lymphoma in aleukemic phase showed abnormal delta c, whereas D values exceeded the upper limit of the normal value in only 15% of the samples. It was suggested that the delta c could detect 3% to 7% of malignant B cells that were mixed with a population of normal lymphocytes.