Christoph Duba

Dendritic cells generated from blood precursors of chronic myelogenous leukemia patients carry the Philadelphia translocation and can induce a CML-specific primary cytotoxic T-cell response.

Dendritic cells (DC) are professional antigen‐presenting cells specialized in the initiation of primary immune responses. We were interested to know whether mature DC can be grown in vitro from peripheral blood mononuclear cells (PBMC) of patients with chronic myelogenous leukemia (CML), and whether they carry the Philadelphia (Ph) translocation. Using a method recently described, DC were generated from PBMC precursors of 12 patients with CML using GM‐CSF, IL‐4, and monocyte‐conditioned medium. DC exhibited the typical morphology with thin cytoplasmatic processes and expressed high levels of MHC class II, CD86, and CD83 typical for mature DC. After sorting with the monoclonal antibody CD83, a cell population of more than 95% CD83 positive cells was obtained. The presence of the Ph translocation was analyzed in these cells, in PBMC, lymphoblastoid cell lines (LCL), and in phytohemagglutinin (PHA)‐induced T blasts from the same patients by fluorescence in situ hybridization (FISH). In contrast to all other cells analyzed, the vast majority of DC (95.9 ± 0.7%) displayed the Ph translocation, irrespective of disease stage or therapy. PBMC were predominantly positive for the Ph chromosome (67.6 ± 7.3%), whereas only 11.4 ± 1% of the B cells and 4.4 ± 1.1% of the PHA blasts carried the Ph translocation. Using such leukemic DC as antigen‐presenting cells, a primary CML‐directed cytotoxic immune response in vitro was obtained, as shown by the specific recognition of Ph chromosome positive cells. We conclude that DC can be generated from blood progenitors of CML patients in vitro and exhibit, to a large extent, the Ph translocation. Such DC, which in a preliminary experiment have been able to induce a primary CML‐directed cytotoxic immune response in vitro, might be ideal candidates for adoptive immunotherapy either by direct transfer of DC for in vivo generation of a T‐cell response or by in vitro generation of CML‐specific cytotoxic autologous or HLA‐matched normal T‐cell clones for use in vivo. Genes Chromosomes Cancer 20:215–223, 1997.

The gene for the Lp(a)-specific glycoprotein is closely linked to the gene for plasminogen on chromosome 6

SummaryWe have studied the segregation of the Lp(a) glycoprotein phenotypes and of the plasminogen (PLG) polymorphism in three two-generation families. The inheritance of the Lp(a) gene was followed using the Lp(a) glycoprotein size polymorphism and that of the plasminogen gene, using protein and DNA polymorphisms. In the three families studied, no recombination was observed in 18 meioses. The lod score for linkage between the Lp(a) glycoprotein locus and the plasminogen locus in these families is greater than 5.0 at a recombination fraction of θ=0. Our results show that the structural gene for the Lp(a) glycoprotein is closely linked to the gene for plasminogen on chromosome 6.

Interferon-alpha-2C and LD ara-C for the treatment of patients with CML: Results of the austrian multicenter phase II study

Small pilot studies of patients with CML have reported on encouraging response rates after treatment with interferon-alpha (IFNalpha) in combination with low-dose cytosine arabinoside (LD ara-C). We therefore initiated a multi-center phase II trial in order to investigate the efficacy and tolerability of this combination in newly diagnosed patients with Ph-positive chronic myelogenous leukemia (CML). Eighty-four patients were treated with IFN-alpha-2c at daily subcutaneous doses of 3.5 MU and LD ara-C added subcutaneously for 10 days every month at a dose of 10 mg/m2, following an initial reduction of WBC to less than 20 x 10(9)/l with hydroxyurea (HU). Within a median observation period of 28 (5-59) months the patients received a median of 7 (1-35) IFNalpha and LD ara-C cycles. Treatment was stopped due to side effects in 16 cases (19%) and to primary or secondary treatment failure in 38 cases (45%). In 45 patients (54%) complete hematological response (CHR) was achieved; in 39 patients (46%) cytogenetic responses including 15 (18%) complete cytogenetic responses (CHR) were observed. Median duration of cytogenetic responses was 15 months. Relapses were seen in 8/15 patients (53%) with complete cytogenetic remission (CCR), in 3/6 patients (50%) with partial cytogenetic response and in 9/18 patients (50%) with minor cytogenetic response. In conclusion, the combination of IFNalpha and LD ara-C resulted in encouraging rates of hematological and cytogenetic responses in patients with CML with low to moderate toxicity.

Mapping of the human protein kinase C-θ (PRKCQ) gene locus to the short arm of chromosome 10 (10p15) by FISH ☆

Members of the protein kinase C (PKC) family of serine/threonine kinases play critical roles in the regulation of cellular differentiation and proliferation of diverse cell types. In an attempt to find PKC isoforms that are involved in growth control and/or activation of T lymphocytes, we have used a human peripheral blood lymphocyte-derived cDNA library to identify a novel PKC isoform, termed PKC-{theta}. The human PKC-{theta} cDNA (human gene symbol PRKCQ) was characterized and found to encode an {approximately} 80-kDa protein, expressed predominantly in lymphoid tissues and hematopoietic cell lines, in particular T cells. A murine homolog gene derived from skin cDNA library was found to be expressed predominantly in skeletal muscle. Molecular cloning and biochemical studies identified PKC enzymes as members of a distinct family that constitutes, at the gene level, nine mammalian members, i.e., {alpha}, {beta}, {gamma}, {delta}, {epsilon}, {zeta}, {theta}, and {lambda}, of which three have already been assigned to individual human chromosomes. Thus, PKC-{alpha} was mapped to H17q22-q24, PKC-{Beta} to H16p12-q11.1, and PKC-{gamma} to H19q13.4. The chromosomal location of other members is yet unknown. 13 refs., 1 fig.

A randomized study comparing interferon (IFNα) plus low-dose cytarabine and interferon plus hydroxyurea (HU) in early chronic-phase chronic myeloid leukemia (CML)

This multicenter randomized phase III study was designed to compare the efficacy and toxicity of IFN alpha-2c (3.5 MU/d) in combination with either araC (10 mg/m(2) d1-10) or hydroxyurea (HU: 25 mg/kg per day) in newly diagnosed CML patients. A total of 114 patients were randomized. Following a median observation period of 36 (range 1-73) months the major cytogenetic response rates were 25 and 27% and the 4-year survival probabilities 62.5 and 63% for the araC and HU group, respectively. While the overall toxicity profile was comparable between both groups, patients in the HU arm exhibited a slightly higher degree of WHO grades 3 and 4 non-hematological toxicities.

Interferon alpha-2c therapy of patients with chronic myelogenous leukemia: long-term results of a multicenter phase-II study

Abstract In a prospective multicenter phase-II trial 80 patients with Philadelphia (Ph)-positive chronic myelogenous leukemia (CML) were treated with recombinant interferon (IFN)α-2c, administered subcutaneously at an absolute dose of 3.5 megaunits (MU)/day. Complete hematological remission was achieved in 29 (39%) and partial hematological remission in 26 (35%) of the 74 patients evaluable for response. Major cytogenetic responses were observed in ten (13%) and minor cytogenetic responses in 11 patients (15%). Median duration of cytogenetic response was 33 months (range, 2–90); relapses were seen in all of the 11 patients with minor and in three of the ten patients with major cytogenetic responses. Median survival estimates for pretreated (n=19) and untreated (n=58) patients were 51 months (95% confidence interval [CI], 30–72) and 77 months (95% CI, 43–111), and the survival probabilities at 5 years were 45% and 54% for the two groups, respectively. Hematological response after 3 months of treatment demonstrated a clear-cut discriminative capacity with 5-year survival probabilities of 100%, 67% and 24% for patients achieving CHR (n=6), PHR (n=34), and less than PHR (n=35), respectively. Landmark analysis at 12, 18, and 24 months after start of IFN therapy and an analysis treating time to cytogenetic response as a time-dependent covariate showed that cytogenetic response was associated with longer survival. The impact of a low-dose IFN regimen on survival in CML patients is unclear and requires further clarification by randomized clinical trials. Early hematological and cytogenetic response to IFN-α treatment identifies patients with a favorable long-term prognosis.

Interferon-α for the treatment of elderly patients with chronic myeloid leukaemia

The present retrospective analysis is based on data of 213 patients with chronic myeloid leukaemia (CML). They were treated with interferon (IFN)a-2C (Berofor ® ) at daily doses of 3.5 MU subcutaneously (s.c.), alone or in combination with low-dose ara-C or hydroxyurea, according to four consecutive studies of the Austrian CML Study Group. Comparisons were made between 41 patients aged ]60 years and 172 younger patients. The elderly patients (median: 64 years; range: 60‐73) showed similar pretreatment characteristics compared with the younger group, but included a higher percentage of Sokal Stage three (51 vs 20%). Median observation periods were similar (38 vs 39 months), whereas the duration of IFNa treatment was shorter in the elderly group (median 57 vs 42 weeks). The rate of overall haematological responses (73 vs 78%) and complete haematological response (44 vs 54%), was similar in both cohorts. Differences seen in partial (5 vs 12%) and complete cytogenetic response (10 vs 13%), were not statistically significant, but a tendency in favour of the younger cohort had to be noted. Summing up, in elderly patients acceptable rates of haematological and cytogentic response can be expected after treatment with IFNa alone or in combination with LD ara-C or HU.

Treatment of patients with advanced chronic myelogenous leukemia with interferon-alpha-2b and continuous oral cytarabine ocfosfate (YNK01): a pilot study

The efficacy of continuous oral cytarabine ocfosfate (YNK01) (300 mg/day) in combination with interferon alpha (IFNalpha, 5x10(6) IU/day) was evaluated in patients with advanced chronic myelogenous leukemia, who previously failed to respond to IFNalpha-based therapies. Dose escalations up to 900 mg YNK01 were allowed in patients who failed to respond. In view of our results, four patients developed a complete hematological response after YNK01 was started. Among those who initially responded to YNK01, one complete cytogenetic response was achieved 18 months later. Although the data are preliminary, this is the first study showing that continuous administration of YNK01 along with IFNalpha is effective in patients with advanced chronic myelogenous leukemia.

Treatment of 11 patients with chronic myelogenous leukemia with interferon-alpha-2C and low-dose cytosine arabinoside.

Patients with Philadelphia (Ph) chromosome-positive chronic myelogenous leukemia (CML) and on interferon (IFN)-alpha-2c treatment for at least two months were entered in the present pilot study. IFN-alpha treatment was maintained identically and cytosine arabinoside (Ara-C) was added at monthly cycles of 10 mg/m2/day for ten days subcutaneously. In the case of a leukocyte nadir above 10 G/l, the Ara-C dose was increased to 20 mg/m2/day for 10 days per month. Ten of the eleven patients entered in this study were evaluable for toxicity and response. They received a total of 87 IFN-alpha/Ara-C cycles (3-14/patient). Five patients received 1-5 cycles with Ara-C dose intensification to 20 mg/m2/day. The following gastrointestinal and hematological toxicities were attributable to Ara-C, as they had not been observed in these patients during the preceding IFN-alpha monotherapy period. Gastrointestinal side effects consisted of nausea grade 1 (n = 5) and diarrhea grade 2 (n = 1). Hematotoxicity was observed in eight patients, grade 1 in five patients and grades 2, 3 and 4 in one of the patients each. Both episodes of grades 3 and 4 toxicity were seen during dose escalation to 20 mg/m2. Small cytogenetic responses (4-14%) were observed in 3 patients and a larger one (50%) in one patient, hematological improvement or stable disease in an additional three patients. These preliminary data suggest that the combination of IFN-alpha and low-dose Ara-C is active in inducing cytogenetic responses in CML patients at an acceptable rate of toxicity and therefore warrant further investigation.

Dose escalation of ara-C may improve response rates in a subgroup of chronic myeloid leukemia patients with poor response to interferon-α and low-dose ara-C

The present analysis was performed to evaluate the impact of cytosine arabinoside (ara-C) dose escalation on hematological and cytogenetic responses in patients with chronic myelogenous leukemia (CML) who failed to respond to low-dose ara-C (LD ara-C) at a dose of 10 mg/m″/d over 10 days per month and interferon-α (IFNα, 3.5 MU/d). Following the same administration schedule, dose escalation of ara-C to 15 and 20 mg/m2/d 1–10 was performed in 36 of 119 patients (30%) due to inadequate hematological response and/or disease progression. As a result, improvement of hematological and cytogenetic responses was achieved in 22 (61%) and nine (25%) patients, respectively. Escalated ara-C dose levels were usually well tolerated, although some patients experienced deterioration of preexisting side effects. Our results support the critical role of ara-C dose towards a better disease control in CML.