Wolfgang Hilbe

T-cell subsets in schizophrenia: a comparison between drug-naive first episode patients and chronic schizophrenic patients

T-cell subsets (CD3+, CD4+, CD8+, NK-cells) and the CD4+/CD8+ ratio were measured in 56 schizophrenic patients admitted to hospital with an acute psychosis. Thirty-five patients with chronic schizophrenia and 21 drug-naive first episode schizophrenic patients were compared with 16 healthy controls. T-cell subsets were quantified in the acute state of the illness (day 0), after 7 days of treatment and at the time of discharge. In the acute state, schizophrenic patients showed higher CD3+ and CD4+ cells (p = 0.05) and a higher CD4/CD8 ratio (p = 0.02) than healthy controls, while NK-cells were lower (p = 0.05). In first episode patients, all T-cell alterations normalized during treatment. In the chronic group the ratio remained high, whereas the initially low number of NK-cells normalized over time. These findings, supporting immune system dysregulation in schizophrenia, are discussed in relation to psychopathology, the stage of illness and effects of medication.

Fluorescence In Situ Hybridization (FISH) on Peripheral Blood Smears for Monitoring Philadelphia Chromosome-Positive Chronic Myeloid Leukemia (CML) During Interferon Treatment: A New Strategy for Remission Assessment

Interferon‐α (IFN‐α) alone or in combination with cytostatic drugs can induce major and durable cytogenetic responses in about 20 to 25% of chronic myeloid leukemia (CML) patients. Since these patients have a significant survival benefit, more frequent follow‐up investigations have become clinically important but require bone marrow (BM) aspirates. The aim of our study was to evaluate interphase fluorescence in situ hybridization (IPF) on peripheral blood (PB) smears as a rapid and reliable method to quantify Ph‐positive myeloid cells. IPF analysis was performed on 49 PB samples from 36 patients in the chronic phase of CML and at different stages of cytogenetic remission. IPF results of 30 PB samples were compared with those from BM aspirates simultaneously obtained from the same patients to evaluate the correlation of Ph‐positive cells. Further, the hypermetaphase FISH (HMF) technique was performed on cultured BM preparations of 31 patients for comparison with IPF results on PB. An excellent correlation was observed between the IPF results obtained on PB and BM samples (r = 0.98, y = x − 0.6, p < 0.0001). The mean difference between HMF from BM, on the one hand, and IPF from PB, on the other hand, was 3.2% (SD = ± 8.4%). Seventy percent of samples were identically classified in one of the four subgroups of cytogenetic response. Thirty percent were classified in neighbouring response groups. We conclude that FISH performed on PB is a rapid and reliable method for assessing the cytogenetic response of CML patients on IFN‐α based therapies, allowing more frequent and less invasive follow‐up investigations although it is not able entirely to replace routine analysis of BM. Genes Chromosomes Cancer 21:90–100, 1998.

Decreased potency of MDR‐modulators under serum conditions determined by a functional assay

Summary. A variety of agents are capable of overcoming P‐glycoprotein‐mediated multidrug resistance (MDR) in vitro. However, the clinical potential of these compounds is often limited due to high plasma protein binding. We compared the efficacy of several MDR‐reversing compounds in serum‐free culture medium and under serum conditions by means of a functional assay. Using flow cytometry the efflux of the fluorescent dye rhodamine 123 (Rhl23) was measured from normal peripheral blood CD8+ T‐lymphocytes which express low levels of P‐glycoprotein. Inhibition of Rhl23 efflux by R‐verapamil, dexnigludipine‐HCl, cyclosporin A, SDZ PSC833 and the protein kinase C (PKC) inhibitor CGP 41251 was determined in serum‐free medium and in serum at concentrations from 0.1 to 50μmol/l. With the exception of SDZ PSC833 all MDR modulators showed an insufficient or suboptimal modulation of P‐glycoprotein under serum conditions at concentrations achievable in vivo. The highest potency under serum conditions demonstrated SDZ PSC833: even at a concentration of 0.5μxmol/1 a sufficient inhibitory effect was observed. Subsequently this approach was applied to patients suffering from B‐cell chronic lymphocytic leukaemia (B‐CLL; n= 3) and acute myeloid leukaemia (AML; n= 2) which were positive in the Rh l23 efflux assay. As for normal CD8+ T‐lymphocytes, much higher drug concentrations were required under serum conditions to effectively inhibit Rhl23 efflux from the leukaemic cells. Thus the interpretation of results of clinical‘modulator’trials should consider the decreased bioavailability of MDR‐reversing agents.

PKC-independent modulation of multidrug resistance in cells with mutant (V185) but not wild-type (G185) p-glycoprotein by bryostatin 1

Bryostatin 1 is a new antitumor agent which modulates the enzyme activity of protein kinase C (PKC, phospholipid-Ca2+-dependent ATP:protein transferase, EC 2.7.1.37). Several reports have suggested that the pumping activity of the multidrug resistance gene 1 (MDR1)-encoded multidrug transporter P-glycoprotein (PGP) is enhanced by a PKC-mediated phosphorylation. It was shown here that bryostatin 1 was a potent modulator of multidrug resistance in two cell lines over-expressing a mutant MDR1-encoded PGP, namely KB-C1 cells and HeLa cells transfected with an MDR1-V185 construct (HeLa-MDR1-V185) in which glycine at position 185 (G185) was substituted for valine (V185). Bryostatin 1 is not able to reverse the resistance of cells over-expressing the wild-type form (G185) of PGP, namely CCRF-ADR5000 cells and HeLa cells transfected with a MDR1-G185 construct (HeLa-MDR1-G185). Treatment of HeLa-MDR1-V185 cells with bryostatin 1 was accompanied by an increase in the intracellular accumulation of rhodamine 123, whereas no such effect could be observed in HeLa-MDR1-G185 cells. HeLa-MDR1-V185 cells expressed the PKC isoforms alpha, delta and zeta. Down-modulation of PKC alpha and delta by 12-O-tetradecanoylphorbol-13-acetate (TPA) did not affect the drug accumulation by bryostatin 1. Bryostatin 1 depleted PKC alpha completely and PKC delta partially. In HeLa-MDR1-V185 cells, short-term exposure to bryostatin 1, which led to a PKC activation, was as efficient in modulating the pumping activity of PGP as long-term exposure leading to PKC depletion. Bryostatin 1 competed with azidopine for binding to PGP in cells expressing the MDR1-V185 and MDR1-G185 forms of PGP. It is concluded that bryostatin 1: i) interacts with both the mutated MDR1-V185 and the wild-type MDR1-G185; ii) reverses multidrug resistance and inhibits drug efflux only in PGP-V185 mutants; and iii) that this effect is not due to an interference of PKC with PGP. For gene therapy, it is important to reverse the specific resistance of a mutant in the presence of a wild-type transporter and vice versa. Our results show that it is possible to reverse a specific mutant PGP.

Reversal of multidrug resistance by the staurosporine derivatives CGP 41251 and CGP 42700

It has been shown previously that the staurosporine derivative CGP 41251, a specific inhibitor of protein kinase C (IC50 = 50 nM), exhibits antitumor activity and reverses mdr1‐mediated multidrug resistance. At present, the compound is evaluated as an anticancer drug in clinical phase I trials. We compared the effects of CGP 41251 with CGP 42700, another staurosporine derivative, which exhibits low protein kinase C inhibiting activity (IC50 = >100 μM). We found that in contrast to CGP 41251, CGP 42700 does not show antiproliferative activity in HeLa and KB cells in tissue culture (up to a concentration of 10 μM). We compared both compounds for their ability to reverse mdr1‐mediated resistance in KB‐C1 and in HeLa‐MDR1 cells (transfected with the mdr1 gene). CGP 42700 is able to reverse mdr1‐mediated resistance to a similar extent as CGP 41251. The intracellular accumulation of rhodamine 123 in KB‐C1 cells following pretreatment with CGP 41251 for 30 min was higher than that following treatment with CGP 42700 if determined in medium without serum. However, quantitation of rhodamine efflux in an ex vivo assay using human CD8+ cells in serum showed that CGP 42700 is more effective in inhibiting the efflux of rhodamine 123 than CGP 41251. We conclude from our results that (1) CGP 42700 is more effective in reversal of multidrug resistance in serum than CGP 41251, indicating that the compound may be useful for treatment of patients, and (2) CGP 42700 does not inhibit protein kinase C and cell proliferation and, therefore, may be less toxic and elicit less side effects in humans than other chemosensitizers. Int. J. Cancer 77:64–69, 1998.© 1998 Wiley‐Liss, Inc.

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.

CYTOKINE PRIMING OF THE GRANULOCYTE RESPIRATORY BURST IN MYELODYSPLASTIC SYNDROMES

Increased susceptibility to infections in patients with myelodysplastic syndromes (MDS) is thought to be due to neutropenia as well as functional abnormalities of neutrophils. In the present study we examined the effect of two different stimulants (fMLP, PMA) and three cytokines (alphaTNF, G-CSF and GM-CSF), both singly and in combination on granulocyte (RB) in 25 MDS patients compared to seven healthy controls. Single fMLP and PMA-stimulation showed similar results for both groups. Preincubation with cytokines enhanced fMLP-stimulated RB in most MDS patients and controls, but in patients to a significantly lesser extent when compared to the control group (p < or = 0,05). Combinations of alphaTNF + GM-CSF and alphaTNF + G-CSF were highly synergistic in priming fMLP-stimulated burst in both groups. But again, as with the single cytokine priming this effect was markedly reduced in MDS patients compared to controls (p < or = 0,05). A specific priming defect for one of the cytokines or a cytokine combination could not be demonstrated. Serum alphaTNF levels were measured in 18 and neutrophil alkaline phosphatase (NAP) index in 23 patients. Results did not correlate with variations of the RB in MDS patients. We conclude that reduced alphaTNF, GM-CSF and G-CSF priming of granulocyte RB is a frequent finding in MDS and may contribute to the enhanced susceptibility to bacterial infections.

T Cells and Natural Killer Cells after Treatment of Hairy Cell Leukaemia with 2-Chlorodeoxyadenosine

We report that continuous suppression of CD4+ lymphocyte subsets does not necessarily lead to an increased rate of infections more than 6 months after treatment of hairy cell leukemia (HCL) with 2-chlorodeoxyadenosine (cladribine; 2-CdA). In a retrospective analysis of 17 consecutive patients with HCL treated with 2-CdA and followed thereafter for an average of 440 days (ranging from 71 to 1,046 days), all lymphocyte subsets significantly decreased after therapy. However, natural killer (NK) cells increased to 203 cells/microliter during the following 4 months, whereas CD3+ and CD4+ T cell subsets did not reach pretreatment values even more than 1 year after 2-CdA therapy. In our study group, 5 opportunistic infections occurred during the first 2 weeks after treatment with 2-CdA, and no severe infections were registered after this early leukopenic phase. A review of the current literature revealed that at least 56 infections occurred in 158 patients repeatedly treated with 2CdA for low-grade lymphoproliferative diseases other than HCL (= 35%). In patients with HCL, the rapid increase of NK cell counts after 6 months might be responsible for reducing the risk of severe infections after the early leukopenic phase despite CD4+ cell suppression.

Cladribine Treatment of a Patient with Hairy Cell Leukemia and Concomitant Multiple Sclerosis

This is the first report on a patient suffering from both multiple sclerosis (MS) and hairy cell leukemia. The patient was first treated with interferon-α. Due to disease progression two courses of cladribine were given resulting in an improvement of the clinical course of both diseases. Interestingly, it was possible to arrest and even ameliorate the progression of MS by administering as little as 30% of the dosage recently recommended for the treatment of this disease.

Treatment of relapsed and refractory acute myelogenous leukaemia with aclacinomycin A (ACA) and etoposide (VP-16)

Ten patients with refractory and relapsed acute myelogenous leukaemia (AML) and one patient with CML in blast crisis were treated with aclacinomycin A (ACA, 60 mg/m2/day for 5 days) and etoposide (VP-16, 100 mg/m2/day for 5 days) and analysed retrospectively. Of 11 patients, seven (63%) achieved an objective response including four CRs (36%). Most impressively, two patients experienced consecutive CRs (second, third, and fourth) following relapses. Only two patients (18%) were primary resistant with persisting leukaemia. In conclusion, the combination of ACA and VP-16 is an active regimen in refractory and relapsed AML with a toxicity comparable with other salvage regimens.