nan Halie

CONTINUOUS-INFUSION OF CEFTAZIDIME IN FEBRILE NEUTROPENIC PATIENTS WITH ACUTE MYELOID-LEUKEMIA

Twelve febrile patients with severe neutropenia, who had undergone aggressive chemotherapy for acute myeloid leukemia, were treated empirically with a continuous infusion of ceftazidime 100 mg/kg/day after a 500 mg loading dose, in order to study the pharmacokinetics of ceftazidime after continuous infusion and to examine the clinical applicability of continuous infusion in this patient population. Three patients had a slight decrease in renal function. All patients attained a steady-state ceftazidime serum level of >20 µg/ml within 180 to 240 min, which was considered effective against most pathogens in neutropenic patients. The median volume of distribution for the patient group was 29.1 I, the elimination half-life was 2.5 h and the clearance of ceftazidime was 7.7 l/h. A subnormal kidney function influenced half-lives and clearance (but not volume of distribution), as expected. When precautions were taken to avoid known interactions between ceftazidime and other compounds to be infused simultaneously, continuous infusion of ceftazidime was applicable for treatment of neutropenic patients without major side effects.

The effect of cyclosporine on haematological parameters in patients with paroxysmal nocturnal haemoglobinuria

Four patients with paroxysmal nocturnal haemoglobinuria (PNH) were treated with cyclosporine. The treatment with cyclosporine was based on the hypothesis that immune-mediated bone-marrow damage is the common pathogenetic mechanism of aplasia and PNH, with lack of GPI-linked ligands for an immune attack (i.e. LFA-3, CD58) rendering PNH cells a growth advantage over other bone marrow cells. In the first patient, presenting with a mixed AA/PNH syndrome, a gradual recovery from aplasia was seen after prolonged treatment with cyclosporine. In a second patient, with a mixed AA/PNH syndrome, no haematological improvement was noted during cyclosporine administration, but this patient became transfusion-independent with increasing neutrophil and platelet counts after a course of ATG in combination with androgen therapy. Both these patients showed an increment in the proportion of neutrophils with normal expression of GPI-linked proteins concurrently with the improvement of haematological characteristics. In the two other patients, presenting with typical PNH, cyclosporine treatment did not result in any change in haematological characteristics, nor in PNH parameters. No significant change in haemolytic parameters was seen in any of the patients. It is concluded that immunosuppressive therapy may be of benefit in patients with a mixed AA/PNH syndrome. This effect became apparent after prolonged treatment with cyclosporine in one patient, and after a subsequent course of ATG with concomitant androgen therapy in another.

Differential regulation of M‐CSF and IL‐6 gene expression in monocytic cells

Summary Using the human monocytic cell line Mono Mac 6 we studied the involvement of Ca2+, protein kinase A (PKA), and protein kinase C (PKC) dependent pathways in the regulation of M‐CSF and IL‐6 gene expression. The results demonstrate that on activation with the calcium ionophore A23187 both M‐CSF and IL‐6 mRNA are induced after 3 and 6 h respectively. Co‐stimulation with A23187 plus PMA resulted in an up‐regulation of M‐CSF mRNA and a downregulation of IL‐6 mRNA. Conversely co‐stimulation with A23187 plus DBcAMP resulted in a down‐regulation of M‐CSF mRNA and an up‐regulation of IL‐6 mRNA.

Interleukin-4 prevents the induction of G-CSF mRNA in human adherent monocytes in response to endotoxin and IL-1 stimulation

Human recombinant interleukin‐4 (IL‐4) was studied for its effects on the expression of granulocyte‐colony stimulating factor (G‐CSF) mRNA in human adherent monocytes in the absence and presence of endotoxin and interleukin 1 (IL‐1), IL‐4 (15 ng/ml) did not induce G‐CSF transcripts in monocytes but suppressed the endotoxin‐induced G‐CSF expression when added simultaneously. Sequential treatment of monocytes with IL‐4 followed by endotoxin suppressed G‐CSF mRNA induction totally. This effect was independent of the presence of fetal bovine serum but dependent of the IL‐4 dose. Comparable results were obtained with IL‐1, IL‐1 (50 U/ml) induced G‐CSF expression in human adherent monocytes which could be counteracted by IL‐4 pretreatment. In addition, it was shown that the induction of G‐CSF mRNA by the calcium‐ionophore A23187 or by c‐AMP elevating agents could be blocked by IL‐4. These suppressive effects of IL‐4 were not related to changes in the half‐life of G‐CSF mRNA and were independent of protein synthesis. Finally it was demonstrated that IL‐4 had comparable effects on the G‐CSF secretion of endotoxin and IL‐1 stimulated human monocytes by using a murine bone marrow assay. These results indicate that IL‐4 down‐regulates the expression of G‐CSF gene and secretion of proteins in human activated monocytes.

INTERLEUKIN-4 SUPPRESSES THE INTERLEUKIN-3 DEPENDENT ERYTHROID COLONY FORMATION FROM NORMAL HUMAN BONE-MARROW CELLS

Human recombinant interleukin 4 (IL‐4) was studied for its effects on the erythroid burst forming unit (BFU‐E) from human bone marrow cells. IL‐4 alone neither supports nor suppresses the erythropoietin (Epo)‐dependent colony formation. Different results were obtained when IL‐4 was combined with interleukin‐3 (IL‐3) in the presence of Epo. IL‐4 suppressed the IL‐3 supported erythroid colony formation in all cases (an increase of 58 ± 8% with IL‐3 versus an increase of 14 ± 7% with IL‐3 plus IL‐4, n= 8). This antagonizing effect was dependent on the continuous presence of IL‐4 in the culture medium, but was independent of adherent cells. B‐, T‐cells, or the presence of serum in the culture medium. Finally, the effects of IL‐4 and IL‐3 were studied on the ‘Epo‐independent’BFU‐E by adding Epo on day 3. A decline of the IL‐3 supported BFU‐E was observed in the presence of IL‐4 but the degree of reduction was equivalent to the results obtained when Epo was supplied at day 0. These findings indicate that IL‐4 acts as suppressive growth factor for the IL‐3 supported erythroid colony formation from human bone marrow cells.

The effects of IL-1 and IL-4 on the Epo-independent erythroid progenitor in polycythaemia vera

Summary. Human recombinant interleukin‐1 (IL‐1) was studied for its effects on the erythroid progenitors from normal subjects and from patients with polycythaemia vera (PV). No supportive effect of IL‐1 was noticed on the normal erythropoietin (Epo) dependent, erythroid burst‐forming unit (BFU‐E) using peripheral blood or bone marrow. In contrast, the Epo‐independent BFU‐E from peripheral blood of PV patients could be stimulated significantly. This enhancing effect of IL‐1 was not only observed with unsorted but also with sorted CD34+ cells. In addition, it was shown that IL‐1 indirectly stimulated the Epo‐independent BFU‐E because anti‐GM‐CSF could abrogate the supportive effects of IL‐1. In contrast to the Epo‐independent BFU‐E, the Epo‐dependent erythroid colony formation from PV patients could not be augmented by IL‐1. Finally, we studied the effects of IL‐4 on the Epo‐independent BFU‐E, because IL‐4 can affect the erythroid colony formation and modulate the effects of IL‐1. IL‐4 suppressed the Epo‐independent BFU‐E. This effect could be counteracted by the addition of IL‐1 to the culture medium. However, the suppressive effect of IL‐4 was not related to a decline in spontaneous release of IL‐1, because an anti‐IL‐1 antibody did not modify the spontaneous erythroid colony formation. These data indicate that IL‐1 and IL‐4 exert separate influences on the Epo‐independent erythroid colony formation in PV.

Lymphocytes with parallel tubular structures: Morphologically a distinctive subpopulation

SummaryPeripheral blood lymphocytes were fractionated in T, B and Null cell enriched subsets by means of sheep red blood cell rosette (ESRBC) sedimentation and nylon wool adherence. The ultrastructural features of these subpopulations were investigated.The T cell fraction in which the sheep erythrocytes were removed from the ESRBC rosette-forming cells (ESRBC-RFC) by lysis with ammonium chloride, consisted mainly of two morphologically distinctive subsets. The majority of the cells (80%) displayed a smooth surface membrane and had a high nuclear to cytoplasmic ratio with few cytoplasmic organelles. The other cell type (18%) had a relatively rough surface membrane, a low nuclear to cytoplasmic ratio, often an indented nucleus and numerous cytoplasmic organelles such as characteristic amorphous granules and sometimes parallel tubular structures (p.t.s.). If the T cells were obtained after mechanical vibration of the ESRBC-RFC, the majority of these cells appeared morphologically identical to this latter cell type.Cells with p.t.s. and amorphous granules were also demonstrated within the Null and B cell enriched fractions (50% and 25% repectively), though in the B cell enriched fraction this cell type is probably due to a contamination of Null cells.Previous observations had already demonstrated that these cells in the three fractions represent the Fcγ receptor-bearing lymphocytes.The similarities suggest that the Fcγ receptor-bearing and p.t.s. containing lymphocytes form a morphologically distinct subpopulation.

Parallel Tubular Structures in T, B and Null Lymphocyte Subpopulations

T, B and Null lymphocyte-enriched subpopulations were isolated by means of sheep red blood cell (E SRBC) sedimentation and nylon wool adherence. In these subsets the proportion of Fc receptor-bearing cells was determined by the antibody-coated human and ox erythrocyte rosette assays (EA Hu and Ox). In the T-cell fraction the proportion of Fc-bearing lymphocytes was dependent on the procedure by which the sheep erythrocytes were removed from the E SRBC rosette-forming cells. Mechanical vibration resulted in considerably higher percentages of EA rosette-forming cells (EA-RFC) than osmotic shock or lysis with ammonium chloride. In all three procedures the number of EA Hu-RFC was slightly higher than the number of EA Ox-RFC. In the B-cell fraction the proportion of EA Ox-RFC was higher than that of EA Hu-RFC, mean values 43 and 33%, respectively. In the Null cell fraction the reversed was seen: mean values 54% EA Hu-RFC and 45% EA Ox-RFC. In all three lymphocyte fractions the majority of the EA-RFC contained parallel tubular structures and/or associated amorphous granules. Non-Fc receptor-bearing lymphocytes only occasionally showed parallel tubular structures or the amorphous granules.

LYMPHOCYTE SUB-POPULATIONS IN LYMPHOPROLIFERATIVE DISEASES - PARALLEL TUBULAR STRUCTURES IN FC RECEPTOR-BEARING LYMPHOCYTES

In analogy with the data of Henkart and Henkart for normal persons, lymphocytes with parallel tubular structures (PTS or the macrotubular bundle) of patients with Hodgkin’s disease were all found to b

PARALLEL TUBULAR STRUCTURES IN LYMPHOCYTES .2. CORRELATION WITH CELLULAR IMMUNITY AND CYTOMEGALOVIRUS AND EPSTEIN-BARR VIRUS-ANTIBODIES IN HODGKINS-DISEASE

The increased incidence of parallel tubular structures in lymphocytes of patients with Hodgkins disease was investigated for a correlation with either impairment of cellular immunity (measured by DNCB-skin test and PHA-induced lymphocyte stimulation in vitro) or an increase of antibodies against cytomegalovirus or Epstein-Barr virus. No correlations were found. Statistical analysis revealed antibody titers especially in the group of patients with high percentages of lymphocytes containing the tubular inclusions. This probably reflects only the connection between these findings and the progression of the disease. The nature and function of the parallel tubular structures have to be investigated further. In Hodgkins disease they may have significance for the understanding of an alteration in lymphocyte function and morphology.