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GMP production and testing of Xcellerated T Cells for the treatment of patients with CLL.

BACKGROUND: Pre-clinical studies suggest Xcellerated T Cells have the potential to produce a potent anti-tumor effect, restore broad immune function and reduce the risk of infectious complications in patients with CLL. Unlike other cancer settings, T cells constitute only a small fraction of CLL patients' PBMC. To generate large numbers of Xcellerated T Cells of high purity from CLL patients' PBMC, a reproducible, streamlined and cost-effective good manufacturing process (GMP) is required. METHODS: The 10-L volume Wave Bioreactor-based Xcellerate III Process using Xcyte Dynabeads in a single custom 20-L Cellbag container was adapted, qualified and implemented for GMP operations. RESULTS: For n=17 CLL patients, starting with approximately 1.34 x 10(9) CD3+ T cells at 6.8+/-7.5% purity in the PBMC leukapheresis products, using the 10-L volume Wave Bioreactor-based Xcellerate III Process, it was feasible to manufacture 137.0+/-34.3 x 10(9) Xcellerated T Cells at 98.5+/-1.0% CD3+ T-cell purity. An average 400-fold clearance of malignant B cells was documented during the manufacturing process. The Xcellerated T Cells produced from the Xcellerate III Process exhibited high in vitro biologic activity and have their T-cell receptor repertoire restored to a normal diversity. In-process T-cell activation was reproducibly robust, as measured by increase in cell size, up-regulation of CD25 and CD154 expression and the secretion of IL-2, IFN-gamma and tumor necrosis factor (TNF)-alpha. DISCUSSION: A low-volume, high-yield bioreactor-based process has been developed, qualified and implemented for the reproducible, GMP manufacture of high purity, biologically active Xcellerated T Cells for the treatment of CLL patients in clinical trials.

B-Lymphocytes↗

Generation of DC-based vaccine for therapy of B-CLL patients. Comparison of two methods for enriching monocytic precursors.

BACKGROUND: The generation of Ag-loaded DC under good manufacturing practice (GMP) conditions is logistically challenging and further compounded when the starting precursors need to be purified from B-CLL patients who have overwhelming numbers of circulating B-CLL cells and decreased numbers of monocytes. METHODS: We have previously demonstrated that DC with endocytosed B-CLL apoptotic bodies are powerful stimulators of anti-leukemic T cells. In this study we compared counterflow elutriation and immunomagnetic separation for enriching monocyte precursors, and evaluated the feasibility of generating DC from B-CLL patients and the effects of cryopreservation. RESULTS: Monocyte yield from a single leukapheresis product of a B-CLL patient varied from 1 x 108 to 10 x 108 total cells, from which 40-200 x 106 mature DC could be produced. Adequate numbers of monocytes could not be enriched from one patient with 0.2% monocytes in the leukapheresis product, and the target of 50 x 106 DC was barely achieved in another patient with 0.9% monocytes in the pheresed cells. These results suggested that successful production of DC is dependent on a minimum frequency of 1% CD14(+) monocytes in the leukapheresis product. Cryopreservation of tumor cell-loaded DC yielded a recovery rate of 86+/-4.4% upon thawing, with a total viability of 90+/-2.8%. Most importantly, cryopreserved Ag-loaded DC retained their morphology, phenotype and function. DISCUSSION: The results demonstrate that adequate numbers of functional DC required for clinical therapy can be generated from patients who have >1% of CD14(+) monocytes in the leukapheresis product. Moreover, Ag-loaded DC can be cryopreserved and recovered without significant change in phenotype or function.

Cancer Vaccines↗

Antioxidant enzymes in lymphocytes from normal subjects and patients with chronic lymphocytic leukaemia: increased glutathione peroxidase activity in CLL B lymphocytes.

The activities of several enzymes that protect against oxidative injury were determined in blood lymphocytes from patients with B chronic lymphocytic leukaemia (CLL) and from normal subjects. Similar glutathione reductase (GR), catalase and glucose-6-phosphate dehydrogenase (G6PD) activities were found in normal and CLL lymphocytes. Higher glutathione peroxidase (GP) activity was found in CLL lymphocytes. This activity in CLL B lymphocytes was 2-fold higher than that of normal B lymphocytes, and 3-fold higher than that of T lymphocytes from either source. Several disease processes have been associated with decreased glutathione peroxidase activity. Our finding with CLL B lymphocytes is believed to be the first example of an increased GP activity in a disease. It may reflect either the expansion of a rare type of B cell population or be an expression of the malignant process.

B-Lymphocytes↗

Signal requirements for activation of leukaemic T cells from a chronic lymphocytic leukaemia (T-CLL).

In order to define the signal requirements for leukaemic T cell activation, the proliferation and interleukin-2 (IL-2) production of peripheral lymphocytes from a patient with a HTLV-I-, CD4+, CD45RA+ CD45RO+ CD25- T-CLL were evaluated after the delivery of different stimuli. Unlike resting CD4+ normal T lymphocytes that can be activated only by a two-signal stimulation, T-CLL cells proliferated and released IL-2 in response to a pair of anti-CD2 monoclonal antibodies (MoAbs) or concanavalin A (Con A) in the absence of both accessory cells (AC) and phorbol myristate acetate (PMA). The two stimuli were also able to induce CD25 expression within 12-20 h on the majority of T-CLL cells. A response to anti-CD3 and anti-CD28 MoAbs was detected only in the presence of PMA, similar to that observed in normal resting T lymphocytes matched for phenotype. Both Con A- and CD2-induced proliferation were strongly inhibited by the addition of anti-CD25 MoAb. Furthermore, T-CLL lymphocytes acquired anti-tumour lytic activity after culture in the presence of PMA and ionomycin. We conclude that HTLV1- CD25- T-CLL can be characterized not only by morphological and phenotypical studies but also on the basis of signal requirements for cell activation.

Antibodies, Monoclonal↗

The chemokinetic inhibitory factor (CIF) in serum of CLL patients: correlation with infection propensity and disease activity.

We have recently described the partial purification and characterization of a neutrophil migration inhibitory activity present in serum from patients with chronic lymphocytic leukaemia (CLL). This new lymphokine, the chemokinetic inhibitory factor (CIF), is produced by B-CLL cells. It is a heat-labile glycoprotein of an approximate molecular weight (m. w.) of 30000. In this extended investigation 64/89 CLL-patients had CIF in their serum. CLL serum diluted to a concentration of 0.02% gave significantly decreased chemokinetic activity, suggesting that CIF is potent at very low concentrations. 31/89 patients had increased infection propensity. Significantly more patients with CIF in serum had infections compared to the group with normal susceptibility to infections. The combination of low Ig levels and CIF in serum discriminated even better between the infection-prone and non-infection-prone patients. CIF in serum was not correlated to tumour cell mass - estimated by Rai clinical staging - tumour progression or deoxythymidine kinase, S-TK, an enzyme that may reflect proliferating cells. The existence of this new lymphokine in serum seems to contribute to the increased susceptibility to infections seen in CLL patients.

Adult↗

Nucleoside transporters, bcl-2 and apoptosis in CLL cells exposed to nucleoside analogues in vitro.

The purine nucleoside analogues fludarabine (F1) and chlorodeoxyadenosine (2-CdA) are considered to be cell cycle specific agents which require DNA synthesis for cytotoxicity. However, their efficacy in the treatment of CLL, an indolent lymphoid malignancy suggests additional mechanisms of action. Like cytosine arabinoside (AraC), F1 and 2-CdA gain access to the cell via a specific nucleoside transporter (NST) protein. To investigate the mode of action of these drugs in CLL, we used a fluorescent ligand for the NST (5'-(SAENTA- x8)-fluorescein) and 3-colour flow cytometry to determine NST expression on CD5+/CD19+ B-cells from the peripheral blood (PB) of patients with CLL. NST levels on these cells was found to be not significantly different from normal control lymphocytes (mean = 485 +/- 425) vs. (mean = 553 +/- 178). Exposure to varying concentrations (0, 3 microM and 30 microM) of F1 and 2-CdA, however, resulted in an upregulation of NST (mean = 1552 +/- 775 with 30 microM FL; mean = 3392 +/- 2197 with 30 microM 2-CdA) after 48. "Large" lymphoid cells (not present in normal PB) were found to express significantly more NST (mean = 2540 +/- 2861) and have a higher proliferative capacity than "small" cells (mean = 357 +/- 517 NST/cell). Incubation of CLL cells with F1 (n = 6) and 2-CdA (n = 8) in vitro over 48 h also resulted in an increase in the proportion of cells in S-phase (0 microM = 0.2 + 2 - 0.1; 30 microM FL = 2.4 +/- 2.0; 30 microM 2-CdA = 3.3 +/- 1.3) and a significant increase in morphologically identifiable apoptosis. Apoptosis was confirmed by flow cytometric DNA analysis (0 microM = 13 +/- 8%; 30 microM FL = 40 +/- 20%; 30 microM 2-CdA = 48 +/- 11%). In situ hybridization using a biotinylated cDNA bcl-2 probe demonstrated that bcl-2 mRNA expression was markedly decreased in treated cells after 24 h. These studies have demonstrated that: (1) NST expression on CLL lymphocytes is low; (2) in vitro exposure to the analogues increases both the level of NST expression and the % cells in S-phase; (3) exposure to the analogues downregulates bcl-2 expression and increases apoptosis.

Antigens, CD19↗

Analysis of VH251 gene mutation in chronic lymphocytic leukemia (CLL) and normal B-cell subsets.

B-cell chronic lymphocytic leukemia (CLL) is the malignant, monoclonal equivalent of a human CD5+ B cell. Previous studies have shown that the VH and VL genes rearranged and/or expressed in CLL have low and random mutations. In this study, however, we have found that the rearranged VH251 gene, one of the three-membered VH5 family, has extensive and selective mutations in B-CLL cells. Somatic mutation at the nucleotide level is 6.03%, and there is a high ratio of replacement to silent mutation in CDRs relative to FWRs. CDR1 mutation is particularly prevalent, and interchanges often lead to acquisition of charge. In VH251 rearranged in CD5+ and CD5- cord-blood B cells, adult peripheral-blood B cells and EBV-transformed CD5+ B-cell lines, the somatic mutation levels are much lower (0.45%, 0.93%, and 1.92%, respectively) with concomitantly lower replacement to silent ratios in CDRs relative to FWRs. The extensive and highly selective somatic mutation of VH251 used in CD5+ CLL cells strongly suggests that part of CLL is generated under the influence of antigen selection and stimulation.

B-Lymphocyte Subsets↗

An overview of young CLL patients: a single-centre experience from Turkey.

Chronic lymphocytic leukaemia (CLL) is generally considered to be a disease of the older population. The aim of this retrospective study was to determine whether younger subjects with CLL (< or = 55 years of age) were different from older patients in their clinical features and prognoses. A total of 198 CLL patients registered to the centre were analyzed: 47 (24%) were 55 years of age or younger and 37 who were followed up regularly were included in the study. The male/female ratio was significantly higher in young patients (3.7 vs. 1.51; p = 0.02). More young patients were asymptomatic than old patients at initial presentation (38.3% vs. 28.5%; p > 0.05). The clinical features, laboratory findings, the distribution of both age groups into clinical stages, and the overall response rate to treatment were similar. The median time to follow-up was 62 months. During this period, 14 of the young patients died (48.3%); all were males. The median survival was longer in the young (64.5 vs. 47 months, p > 0.05). The 5-year survival rate of young patients was more than the old (57% vs. 31%), but the 10-year survival rates did not differ between the two groups (7% vs. 8%). The rate of CLL-related death was higher in young patients (71% vs. 59%; p > 0.05). Univariate analysis revealed no prognostic factor which could influence the survival probability of young patients. In this study, the prognostic values of some variables could not be assessed accurately as the number of regularly followed young patients was low and some data were missing. However, it is expected that survival will be longer in young CLL patients, so the search for different curative treatment strategies will continue.

Adult↗

Telomere length and telomerase activity delineate distinctive replicative features of the B-CLL subgroups defined by immunoglobulin V gene mutations.

Patients with B-cell chronic lymphocytic leukemia (B-CLL) segregate into subgroups with very different survival times. Because clinical observations suggest that leukemic cells accumulate at different rates, we measured telomere length and telomerase activity in B-CLL cells to distinguish differences in cellular replication. Our data indicate that the telomeres of B-CLL cells are shorter than telomeres of B cells from healthy subjects, indicating that the leukemic cells have a prolonged proliferative history. Leukemic cells of the immunoglobulin V gene mutation subgroups differ in telomere length and telomerase activity. B lymphocytes from the subgroup with poor outcome and with limited IgV gene mutations have uniformly shorter telomeres and more telomerase activity than those from the subgroup with better outcome and with considerable mutations. Differences in telomere length appear to largely reflect the proliferative histories of precursors of the leukemic cells, although differences in cell division, masked by the action of telomerase, cannot be excluded. These results may provide insight into the stages of maturation and the activation pathways of the cells that give rise to B-CLL. In addition, they reinforce the concept that B-CLL is not simply an accumulative disease of slowly dividing B lymphocytes but possibly one of B cells with extensive proliferative histories.

Antigens, Differentiation, B-Lymphocyte↗

Genome-wide analysis of DNA copy number changes and LOH in CLL using high-density SNP arrays.

Recurrent genomic aberrations are important prognostic parameters in chronic lymphocytic leukemia (CLL). High-resolution 10k and 50k Affymetrix SNP arrays were evaluated as a diagnostic tool for CLL and revealed chromosomal imbalances in 65.6% and 81.5% of 70 consecutive cases, respectively. Among the prognostically important aberrations, the del13q14 was present in 36 (51.4%), trisomy 12 in 9 (12.8%), del11q22 in 9 (12.8%), and del17p13 in 4 cases (5.7%). A prominent clustering of breakpoints on both sides of the MIRN15A/MIRN16-1 genes indicated the presence of recombination hot spots in the 13q14 region. Patients with a monoallelic del13q14 had slower lymphocyte growth kinetics (P=.002) than patients with biallelic deletions. In 4 CLL cases with unmutated VH genes, a common minimal 3.5-Mb gain of 2p16 spanning the REL and BCL11A oncogenes was identified, implicating these genes in the pathogenesis of CLL. Twenty-four large (>10 Mb) copy-neutral regions with loss of heterozygosity were identified in 14 cases. These regions with loss of heterozygosity are not detectable by alternative methods and may harbor novel imprinted genes or loss-of-function alleles that may be important for the pathogenesis of CLL. Genomic profiling with SNP arrays is a convenient and efficient screening method for simultaneous genome-wide detection of chromosomal aberrations.

Adult↗

Intracytoplasmic immunoglobulins in the differential diagnosis of lymphocytic lymphomas of the B-CLL type and immunocytic lymphomas.

One hundred and thirty-three consecutive cases originally classified either as a lymphocytic lymphoma of the B-CLL type or as an immunocytic (IC) lymphoma could be reclassified morphologically and analyzed for the presence of cytoplasmic immunoglobulins (cIg) with the PAP-technique. The morphologic reclassification confirmed the initial diagnosis in most cases, whereas after staining for cIg, the diagnosis was changed in a large number of cases, i.e. from B-CLL to IC, or the reverse, or from IC of the polymorphic subtype (ICp) to 'high-grade' non-Hodgkin lymphoma (NHL). Cases classified as IC were often localized (stage I+II: 22/43) with a long disease-free survival after local radiation therapy, while B-CLL were usually generalized. For patients in stage IV, the prognosis of B-CLL was significantly superior to that of IC, which in turn was superior to the prognosis of cases referred to as 'high-grade' NHL. The difficulties in the morphologic distinction between B-CLL and IC on one hand and between ICp and some 'high-grade' NHL on the other hand, as well as the clinical significance of these distinctions, are discussed.

Adult↗

Ubiquitin-proteasome system and increased sensitivity of B-CLL lymphocytes to apoptotic death activation.

The ubiquitin-proteasome-dependent proteolytic system has been reported to regulate apoptotic cell death in many experimental cell models. We recently found that B-CLL (chronic lymphocytic leukemia) lymphocytes are hypersensitive to apoptotic death activation through specific inhibition of proteasome function by lactacystin. Lactacystin efficiently activates apoptotic death process in B-CLL lymphocytes at doses at which no apoptotic effect can be observed in normal human lymphocytes in which 10-fold higher doses of lactacystin are required to weakly induce apoptosis. This hypersensitivity of B-cell CLL may be a result of an altered ubiquitin pathway and proteasomal proteolysis in these malignant cells, and this alteration could be specific for this malignancy. Together with other published works, these results suggest that lactacystin, though not per se a discriminatory inhibitor of the ubiquitinated protein processing/degradation, can nonetheless be discriminatory in the apoptotic cell response between B-CLL and normal lymphocytes: the property that promises efficacy in clinical trials of B-cell CLL. This hypothesis is documented by the fact that lymphocytes from patients in complete remission become resistant to lactacystin-induced apoptosis as normal lymphocytes do.

Acetylcysteine↗

Tumor suppressor genes and clonal evolution in B-CLL.

This review highlights the genetic alterations that have been detailed in the malignant B-cell clones of patients with B-chronic lymphocytic leukemia (CLL). In particular, the alterations seen in p53 and the retinoblastoma (Rb) genes are reviewed. In addition, the multiplicity of cytogenetic alterations observed at baseline and on sequential analysis are summarized. The cytogenetic and molecular biologic analysis of B-CLL clones has revealed that there is a dynamic array of genetic events which occur within a B-cell clone. This latter data strongly suggests that clonal evolution may occur in B-CLL patients. However the relationship of the clonal instability to the patient's clinical course is still unclear. The relatively frequent detection of multiple tumor suppressor gene alterations in the B-CLL clones offer several interesting clues regarding the transformation event within B-CLL. A model is proposed which attempts to explain the potential contribution and interaction of p53 and Rb gene alterations in a malignant B-cell transformation.

Clone Cells↗

Receptors for Helix pomatia A haemagglutinin on leukaemic lymphocytes from patients with chronic lymphocytic leukaemia (CLL).

Blood lymphocytes from thirteen patients with CLL were studied for surface-bound Ig (SIg), Fc receptors (EA rosettes), receptors for sheep erythrocytes (E rosettes) and receptors for Helix pomatia A haemagglutinin (HP), a carbohydrate-binding protein with specificity for N-acetyl-D-galactosamine and related sugars. Fluorescein-labelled HP binds to subpopulations of human peripheral blood lymphocytes (PBL) treated with neuraminidase. In normal peripheral blood, HP binds to the T-lymphocytes while the majority of the B cells bearing surface-bound immunoglobulin do not have receptors for HP. In untreated CLL, HP binds to 90-100 percent of the neuraminidase-treated PBL. Almost all of the SI-G-POSITIVE CELLS IN CLL patients also have receptors for HP. Two groups of patients were found: in one the total fraction of SIg+ cells was less than or equal to 50 percent and about 30 percent of these lost their Ig during incubation at 37 degrees C. No such loss of SIg was revealed in the remaining patients where total SIg+ fraction was approximately 70 percent. These patients usually had higher blood lymphocyte counts, probably reflecting a more advanced disease. CLL patients in remission with low numbers of leukaemic cells also had low numbers of blood lymphocytes carrying both SIg and HP-receptors. It is concluded that leukaemic cells carry both HP receptors and SIg. Testing of this combination therefore provides a valuable new tool for monitoring patients with CLL.

Aged↗

Deregulation of the ubiquitin system and p53 proteolysis modify the apoptotic response in B-CLL lymphocytes.

We recently reported increased sensitivity of B-cell chronic lymphocytic leukemia (B-CLL) lymphocytes to apoptotic death activation by the proteasome-specific inhibitor lactacystin. Here, we show that only specific-not nonspecific-proteasomal inhibitors can discriminate between malignant and normal lymphocytes in inducing the apoptotic death response. Indeed, lactacystin and its active metabolite clasto-lactacystin beta-lactone induced apoptotic death in CLL but not in normal lymphocytes. This difference was completely abolished when tripeptide aldehydes such as MG132 or LLnL (which can also inhibit calpains) were used as less specific proteasomal inhibitors. Moreover, B-CLL cells exhibited a constitutive altered ubiquitin-proteasome system, including a threefold higher chymotrypsin-like proteasomal activity and high levels of nuclear ubiquitin-conjugated proteins compared with normal lymphocytes. Interestingly, B-CLL cells also displayed altered proteolytic regulation of wild-type p53, an apoptotic factor reported to be a substrate for the ubiquitin-proteasome system. Nuclear wild-type p53 accumulated after lactacystin treatment used at the discriminating concentration in malignant, but not in normal, lymphocytes. In contrast, p53 was stabilized by MG132 or LLnL in malignant and normal cells undergoing apoptosis, indicating that in normal lymphocytes p53 is regulated mainly by calpains and not by the ubiquitin-proteasome system. This work raises the possibility that two different proteolytic pathways controlling p53 stability may be pathologically imbalanced. This could result in modification of apoptosis control, since in CLL-lymphocytes a highly upregulated ubiquitin-proteasome system, which controls p53 stability among other apoptotic factors, was correlated with an increased propensity of these cells to apoptosis triggered by lactacystin.

Acetylcysteine↗

[The interphase fluorescence in situ hybridization (I-FISH) technique in patients with chronic lymphatic leukemia (CLL)].

BACKGROUND: Trisomy 12 was found to be the most frequent chromosomal aberration identified by conventional cytogenetic studies of bone marrow cells and peripheral lymphocytes of patients with CLL. Molecular-cytogenetic techniques which enable examination of dividing and/or non-diving interphase nuclei (I-FISH), proved existence of other chromosomal abnormalities, mainly deletions, which could have in CLL patients relation to the origin, course and prognosis of the disease. METHODS AND RESULTS: During the last two years bone marrow chromosomes of all patients with CLL were examined by G-banding and by I-FISH. The numerical changes of chromosome 12 were followed by centromeric DNA probe in dividing and non-dividing cells. The small deletions were ascertained by locus specific probes for 13q14 (Rb gene), 17p13 (p53 protein) and 11q23 (MLL gene). These genes are responsible for cell division and their function is probably in connection with neoplastic process. It is of interest whether numerical and structural chromosomal rearrangements are primary or secondary changes and what is their impact on etiology of CLL. 93 patients were examined by DNA prove CEP12 and trisomy 12 was found in 24 of them (25.8%), the range of the clone was 2.5-75.5% of the screened cells. Deletion del(13)(q14) was examined by probe D13S319 in 73 patients and proved in 24 of them (32.8%), pathological clone ranged 2.5-80.0% of the cells. Deletion del(17)(p13) was found in 14 patients out of 61 examined by probe LSI p53 (22.9%). The extent of the clone was 2.5-34.0% of examined cells. Deletion 11q23 was not ascertained in any of 11 patients by means of probe LSI 11q23 (MLL). All probes used for FISH were manufactured by VYSIS. CONCLUSIONS: FISH is very sensitive method, suitable for molecular-cytogenetic examination of leukemic patients. With I-FISH the deletion of 13q14 was ascertained as the most frequent chromosomal aberration in series of 73 patients with CLL. We continue to increase the number of patients screened by I-FISH with all eligible DNA probes and start the prospective study on patients with chromosomal pathology. We will correlate the immunophenotype, morphology, clinical course and prognosis with karyotypic findings.

Adult↗

Soluble form of TRAIL, Fas and FasL in the serum of patients with B-CLL.

PURPOSE: Although many studies demonstrated expression of TNF family members in the course of B-CLL, there is a little known about relationships between soluble forms of these proteins. Furthermore, there is no study reported on effects of used therapy on this relation. The present study was designed to asses the relationships between the serum concentrations of sFas, sFasL and sTRAIL in patients with B-CLL regarding their correlation with clinical stage and used therapy. MATERIAL AND METHODS: We studied 40 patients with B-cell chronic lymphocytic leukemia (B-CLL) at diagnosis, before treatment and four weeks after therapy. To measure sFas, sFasL and sTRAIL levels in serum commercially available ELISA kits were used. RESULTS: We found increased concentrations of sFas in sera of all patients with B-CLL before treatment in comparison to the control group. There were no significant differences in concentrations of sFasL and sTRAIL between patients and control group. Increased sFasL concentrations after FC and CC therapy as well as decreased concentrations after 2CdA therapy in comparison to values before treatment were found. The concentrations of sTRAIL after FC and CC therapy were higher than those in patients before treatment. CONCLUSIONS: Results obtained suggest that relationship between sFas, sFasL and sTRAIL in sera of patients with B-CLL before treatment may facilitate the growth B leukemic cells. Changes in these relations after therapy with FC and CC can make a contribution to inhibit B cells growth on the apoptosis way in this patient group.

Antineoplastic Combined Chemotherapy Protocols↗

Exogenous interleukin 2 (IL 2) reconstitutes deficient in vitro T-cell growth of patients with chronic lymphocytic leukemia of B-cell lineage (B-CLL).

Mechanisms of tumor growth are concerned with the possibility that neoplasms are disturbed in their response to growth factors. Interleukin 2 (IL 2) is secreted by activated T-cells and is required for autocrine T-cell growth. Controversy exists as to the functional capacity of T-lymphocytes in patients with B-cell chronic lymphocytic leukemia (CLL). We studied 14 patients with previously untreated, early CLL. Data were compared to 16 healthy individuals. Immunophenotyping showed that T-cells in B-CLL are highly activated as evidenced by HLA-DR and IL 2 receptor expression. Membrane receptors for IL 2 on the patients' T-cells were overexpressed. The T4:T8 ratio was 1.5. T-cells for in vitro studies were isolated by their ability to form E-rosettes with AET and repeated Ficoll density gradient centrifugation. Purified T-cells were grown on semisolid agar and their capability to form colonies investigated using a variety of exogenous stimulants. It was found that patients with CLL showed a pronounced impairment in forming T-cell colonies. However, colony formation was restored to normal by adding exogenous recombinant IL 2, indicating that endogenous IL 2 production of T-cells is deficient. This finding might have implications for the therapeutical use of IL 2 in CLL patients.

Aged↗