Richard Lerner

Rapid adhesive responses of endothelial cells and of neutrophils induced by leukotriene B4 are mediated by leucocytic adhesion protein CD18.

Controversy has existed as to the ability of leukotriene B4(LTB4) to enhance adhesive properties of human neutrophils (PMN) and endothelial cells. We found that LTB4 induced a rapid but transient adhesion of PMN to an albumin‐coated plastic surface and to cultured human umbilical vein endothelial cells (HUVEC). Although the adhesive response of PMN to the chemotactic peptide N‐formyl‐methionyl‐leucyl‐phenylalaninc (fMLP) was longer lasting, peak hyperadherence was of similar magnitude as to LTB4 and was less susceptible to assay conditions. Adherence induced by either LTB4 or fMLP could be abrogated by the monoclonal antibody 60.3, indicating similar dependence on the leucocyte adhesion protein CD18. Lipoxin A did not induce PMN hyperadherenee. Treating HUVEC with LTB4, but not with its omega‐oxidized metabolites 20‐OH‐ and 20‐COOH‐LTB4, lipoxin A, or with IMLP conferred a rapid, dose‐related, enhanced adhesion of PMN. This effect was dependent on CD18 and on divalent cations. It disappeared with prolonged exposure to LTB4, required a metabolically active HUVEC, and was not due to passive binding of LTB4 lo HUVEC. Thus, LTB4 induces a transient expression of hyperadhesiveness in HUVEC as well as in neutrophils, and both effects are dependent on expression of CD18.

Leukotriene B4 induced hyperadhesiveness of endothelial cells for neutrophils

Leukotriene B4 (LTB4) induced a transient state of hyperadhesiveness in cultured human umbilical vein endothelial cells (HUVEC), leading to increased binding of neutrophil granulocytes (PMN). The effect of LTB4 was more rapidly emerging and transient than responses to platelet activating factor (PAF), thrombin and phorbol myristate acetate (PMA). At 0.1 microM of LTB4, it was comparable to hyperadhesiveness induced by 1 U/ml of thrombin, but less than that conferred by 0.1 microM of PAF and PMA. The adherence response to LTB4 was specific since the structural analogue 5S,12S-diHETE, which lacks PMN-stimulating effects, failed to promote HUVEC adhesiveness.

Effects of antirheumatic drugs on adhesiveness of endothelial cells and neutrophils

Because disease-modifying antirheumatic drugs might exert part of their effects on adhesion of polymorphonuclear neutrophils (PMN) to endothelial cells, this being the first step for PMN migration to inflammatory lesions, we evaluated such drug effects in vitro. Gold sodium thiomalate (GSTM) impaired the ability of interleukin 1beta (IL-1beta)-stimulated human umbilical vein endothelial cells (HUVEC) to express E-selectin and to bind PMN but had no effect on the expression of intercellular adhesion molecule 1 (ICAM-1) or on hyperadhesivity of N-formyl-methionyl-leucyl-phenylalanine (fMLP)-stimulated PMN. Auranofin (AF) interacted with HUVEC and PMN adhesiveness but in opposite directions: this drug hampered IL-1beta-induced HUVEC hyperadhesiveness and expression of E-selectin and intercellular adhesion molecule 1, but augmented PMN adherence and CD18 expression. The net effect of auranofin was a reduction of cytokine-driven adhesiveness and enhancement of formylpeptide-induced adhesion. Salazopyrin did not affect HUVEC or PMN adhesiveness or E-selectin and intercellular adhesion molecule 1 expression. Thus, the gold-containing drugs modulated HUVEC and PMN adhesiveness by different mechanisms but ones involving surface adhesion molecules.

Platelet activating factor and leukotriene B4 induce hyperpolarisation of human endothelial cells but depolarization of neutrophils

We studied one expression of cell activation in neutrophils (PMN) and endothelial cells (EC), membrane potential changes [assessed by the fluorescent dye, di-C-O5(3)]. Human neutrophils responded with depolarization after exposure to fMLP, LTB4, A23187, PAF and PMA. In contrast, only PAF and LTB4 induced membrane potential changes in human umbilical vein EC, which responded with increased fluorescence, possibly indicating membrane hyperpolarization. These discordant responses may reflect processes of significance for interactions between EC and PMN.

Lipoxin A4 Induces Neutrophil-Dependent Cytotoxicity for Human Endothelial Cells

The authors have assessed the capacity of neutrophil granulocytes (PMN) to kill cultured human umbilical–vein endothelial cells (HUVEC) in vitro (as release of 51Cr) in response to the recently described double dioxygenation product of arachidonic acid, lipoxin A4 (LXA4). LXA4 conferred a marked cytotoxicity, whereas formyl–methionyl–leucyl–phenylalanine (fMLP) was less potent. The LXA4 and fMLP effects were dose dependent, with a maximum at 100 nM (which caused 2.7–and 2.3–fold increases of 51 Cr release, respectively, relative to buffer–treated controls). The LXA4 and fMLP responses increased with the PMN concentration, depended on the fetal calf serum concentration, incubation temperature and duration and the presence of calcium and magnesium ions.

Corynebacterium Group JK in a Hematological Ward: Infections, Colonization and Environmental Contamination

Because 2 patients with acute leukemia expired in septicemia with multiresistant Corynebacterium group JK (JK) the occurrence and significance of these bacteria in a hematological ward was analysed. During the following year JK was isolated in 6 other patients with acute leukemia, in 5 as a colonizing agent and in 1 as cause of an anorectal abscess. The environmental investigation with cultures from all patients, personnel and rooms in the ward disclosed heavy contamination with JK in 2 isolation rooms housing JK-colonized patients. Contamination with JK in other rooms was very sparse and there were no JK-positive cultures from personnel or other patients in the ward. Repeated environmental cultures taken after the JK-colonized patients left the isolation rooms showed sparse contamination with JK. Thus, JK strains can survive in the environment for a long time.

A pilot study of piperacillin and ciprofloxacin as initial therapy for fever in severely neutropenic leukemia patients

We studied the efficacy of piperacillin and ciprofloxacin as initial parenteral therapy in 41 adult patients with leukemia who developed 47 febrile episodes during severe neutropenia following chemotherapy. 40 patients (98%) survived their febrile episode(s), whereas 1 patient died of infection. When assessed at 72 h after initiation of treatment (early evaluation), 24/47 episodes (51%) had been successfully treated. These 24 favourable responses were seen in 15/24 (63%) microbiologically documented infections and 9/19 (47%) fever of unknown origin (FUO). At the resolution of fever (late evaluation) 46 episodes were evaluable, and 28 (61%) had responded successfully to piperacillin and ciprofloxacin. Successful treatment was most frequently observed in microbiologically defined infections, 18/23 (78%). Three of 5 (60%) Gram-positive, 11/12 (92%) Gram-negative and 1 of 2 mixed bacteremias were successfully treated. In contrast, only 10/19 (53%) FUO and none of 4 clinically defined infections had responded. Thus, this pilot study indicates that piperacillin and ciprofloxacin may be a safe and effective combination for the treatment of febrile episodes in severely neutropenic leukemia patients, which merits further investigation in randomized trials.

Ceftazidime as Initial Therapy in Febrile Patients with Acute Leukemia during Induction Chemotherapy

We studied the efficacy of ceftazidime as initial monotherapy in 82 adult patients with acute leukemia who developed 123 febrile episodes during induction chemotherapy. 88% of the patients survived their febrile episode(s), whereas 10% died of infection. When assessed at 72 h after initiation of treatment (early evaluation), 43/123 episodes (35%) had been successfully treated with ceftazidime. These 43 favourable responses were seen in 15/47 (32%) microbiologically documented infections, 20/46 (43%) clinically defined infections, and 8/30 (27%) fever of unknown origin (FUO). At the resolution of fever (late evaluation) 115 episodes were evaluable, and 48% had responded successfully to ceftazidime. Successful treatment was most frequently observed in FUO, 18/29 (62%). In contrast, only 19/44 (43%) microbiologically documented infections and 18/42 (43%) clinically defined infections were cured during ceftazidime treatment. In bacteremia the response rate was only 8/26 (31%). Thus, this study shows that although ceftazidime can be safely used for initial empirical monotherapy in neutropenic leukemia patients, the need for therapy modification is high and few patients with serious infections are cured with ceftazidime alone.

Bendamustine in combination with high-dose radiotherapy and thalidomide is effective in treatment of multiple myeloma with central nervous system involvement.

To the Editor: Central nervous system (CNS) involvement is found in about 1% of multiple myeloma (MM) patients (1). The reported overall survival for these patients usually does not exceed 6 months. Of the different modes of CNS involvement, leptomeningeal myeloma is thought to have the worst prognosis (2–4). Here, we describe two myeloma patients with leptomeningeal myeloma relapse at 29 and 53 months after diagnosis. Treatment with BTD (bendamustine 70 mg/m on day 1, 2, 14 and 15 in a 4-wk cycle, and thalidomide 100 mg daily and dexamethasone 20 mg on day 1, 2, 3, 4, 14, 15, 16 and 17) and craniospinal irradiation resulted in disappearance of CNS lesions. The regime did not cause any grade 3 haematological or non-haematological toxicity. Survival from CNS involvement was 14 and 11+ months, respectively. Case 1

The Effect of 20‐Trifluoromethyl Leukotriene B4 on Neutrophil Functional Responses

20‐triHuoromelhyl‐lcLikotriene B4 (20CF3LTB4) is a stable derivative of leukotriene B4 (LTB4) that is not subjected to co‐oxidation to less active metabolites. 2OCK3LTB4 was as potent as LTB4 as a chemotactic, adhesion‐promoting and aggregatory agent for human neutrophils, but bad only 11 ± 3% of the ability to induce an Oxidative response. Nonetheless, both compounds were equally efficient in order to confer a rapid and monophasic increment of the concentration of cytosolic calcium. The kinetics of the calcium, aggregatory and chemiluminescent responses to 2OCF3‐LTB4 were similar to that of LTB4. These findings suggest that the insertion of the trifluoromethyl group into the LTB4 molecule causes a shift of the biological activity profile, suggesting that 20CF3LTB4 binds mainly to high affinity LTB4 receptors. Moreover, the similarity of the response kinetics of LTB4 and 20CF3‐ LTB4 suggests that the mechanism for the rapid and transient responses of LTB4 is not due to its w‐oxidation.