Polymorphonuclear Chemotaxis Research Articles

Bronchiectasis: A pulmonary disease with systemic consequences.

Bronchiectasis: A pulmonary disease with systemic consequences.

The atypical antipsychotic clozapine selectively inhibits interleukin 8 (IL-8)-induced neutrophil chemotaxis

Clozapine is the most effective antipsychotic to date, but its benefits are counterbalanced by the risk of severe hematological effects. In this study, we analyzed whether clozapine inhibits polymorphonuclear (PMN) leukocyte chemotaxis. We found that clozapine, within the therapeutic concentration range, potently and selectively inhibits PMN chemotaxis induced by interleukin 8 (IL-8), a chemokine inducing neutrophil migration. The effect was not due to its action at dopamine, serotonin and muscarinic receptors, or to a direct antagonism to IL-8 receptors. Furthermore, clozapine did not inhibit PMN chemotaxis by its presumed toxic mechanism. In fact, after an overnight incubation in cell culture, the drug did not increase the physiological PMN apoptosis. An interference of clozapine with the autocrine release of leukotriene B4 (LTB4), a secondary chemoattractant secreted by neutrophils in response to the primary chemoattractant IL-8, was hypothesized. In agreement with this hypothesis, clozapine attenuated the IL-8-induced release of LTB4 in PMNs. A series of experiments with an antagonist of the LTB4 receptor, U75302, and an inhibitor of LTB4 synthesis, zileuton, provided support to this conjecture. Intriguingly MK-571, an inhibitor of the multi-drug resistance protein MRP4, playing a pivotal role in effluxing LTB4, completely blocked PMN chemotaxis induced by IL-8, but gave conflicting results when tested for its ability to reduce LTB4 release, increasing LTB4 efflux by itself but reducing the release when in combination with IL-8. The reduction of PMN chemotaxis due to clozapine could predispose patients to infections. Whether this effect is a prelude to clozapine agranulocytosis requires further investigation.

Reducing the risk of infection in end-stage kidney failure patients treated by dialysis.

After cardiovascular causes, infectious diseases are the next most common cause of death for dialysis patients. The Japanese Society for Dialysis Therapy reported an increased standardized mortality of 7.5-fold [95% confidence limits (CI) 7.3–7.6] for infectious diseases between 2008 and 2009 compared with the general Japanese population. The increased mortality rates for dialysis patients were greatest for sepsis, followed in descending order by peritonitis, influenza, tuberculosis and pneumonia [1]. Patients with chronic kidney disease are more susceptible to some infections, as the azotaemic state alters innate immunity, with reports of reduced monocyte Toll-like receptor 4 expression [2], reduced B-lymphocyte cell populations [3] and impaired polymorphonuclear chemotaxis and phagocytosis [4]. It has also been proposed that changes in the gastrointestinal microbiota, and increased intestinal permeability to endotoxin, lead to a persistent activation of the innate immune system, resulting in the induction of immuneregulatory mediators which then suppress both innate and adaptive immunity [5]. Additionally, immune responses may also be impaired by poor nutritional status, malnutrition and vitamin D deficiency [6]. For many years, it has been recognized that haemodialysis and peritoneal dialysis (PD) patients have a reduced response to vaccination, in terms of developing seroprotective antibody levels, to a number of the commonly available vaccines including hepatitis B, pneumococcus, influenza A H1N1 and tetanus toxoid [7]. The risk of mortality with chest infections in the chronic dialysis patient has been reported to be 14- to 16-fold higher than that for the general population, with >50% of lower respiratory tract infections caused by Streptococcus pneumoniae [8]. Lower respiratory tract infections have additionally been reported to increase the relative risk for cardiovascular events by 3.02 (95% CI: 2.87–3.02) in dialysis patients with pneumonia [9]. Most haemodialysis patients gain fluid between dialysis sessions [10], and this increase in extracellular volume includes lung water. As such, lung water content is increased even in healthy haemodialysis outpatients without any respiratory symptoms prior to dialysis [11]. Whereas it was readily established that the mouth and upper airway are extensively colonized by bacteria, it is only relatively recently that it has been recognized that the lung is also normally colonized. The average person inhales 8000 L of air each day, containing 10 4 –10 6 bacterial cells per cubic metre. The internal surface area of the lung is some 30 times that of the skin and the lung microbiome is determined by the balance between microbial immigration, elimination and the relative growth rates of different bacteria [12]. The proportion of resident to transient microbes remains to be determined in healthy subjects, and it remains to be established how chronic kidney disease and dialysis affect the lung microbiome. Surfactant in the distal alveoli has bacteriostatic activity against some bacterial species, and it is unknown whether this bacteriostatic activity is impaired in dialysis patients. Similarly, other changes in innate and adaptive immunity will affect the risk for pulmonary infections. The lung microbiome is altered by hypoxia [12], and increased water lung content in the dialysis patient will increase hypoxia in dependent areas of the lung. As such these changes may help explain the increased risk of pulmonary infections in dialysis patients. This risk for pulmonary infections appears to be much greater for haemodialysis patients, and although this may be related to greater changes in lung water content during the dialysis week compared with PD patients, haemodialysis patients additionally often travel together to and from dialysis centres and wait together at the start and end of dialysis sessions increasing the risk of respiratory pathogen transmission, whereas PD is a home-based therapy. Inflammatory changes in the lung have been shown to lead to changes in other organs, the so-called organ ‘cross talk’, and the combination of pulmonary inflammation and increased lung water may account for the increased cardiovascular events reported [9]. To reduce the risk IN FOCUS

Proteomic Analysis of Intraluminal Thrombus Highlights Complement Activation in Human Abdominal Aortic Aneurysms

To identify proteins related to intraluminal thrombus biological activities that could help to find novel pathological mechanisms and therapeutic targets for human abdominal aortic aneurysm (AAA). Tissue-conditioned media from patients with AAA were analyzed by a mass spectrometry-based strategy using liquid chromatography coupled to tandem mass spectrometry. Global pathway analysis by Ingenuity software highlighted the presence of several circulating proteins, among them were proteins from the complement system. Complement C3 concentration and activation were assessed in plasma from AAA patients (small AAA, AAA diameter=3-5 cm and large AAA, AAA diameter >5 cm), showing decreased C3 levels and activation in large AAA patients. No association of a combination of single-nucleotide polymorphisms in complement genes between large and small AAA patients was observed. Intense extracellular C3 inmunostaining, along with C9, was observed in AAA thrombus. Analysis of C3 in AAA tissue homogenates and tissue-conditioned media showed increased levels of C3 in AAA thrombus, as well as proteolytic fragments (C3a/C3c/C3dg), suggesting its local deposition and activation. Finally, the functional role of local complement activation in polymorphonuclear (PMN) cell activation was tested, showing that C3 blockade by anti-C3 antibody was able to decrease thrombus-induced neutrophil chemotaxis and reactive oxygen species production. A decrease of systemic C3 concentration and activity in the later stages of AAA associated with local complement retention, consumption, and proteolysis in the thrombus could induce PMN chemotaxis and activation, playing a detrimental role in AAA progression.

852 Under Agarose Migration Assay - a Method to Study Graded Chemotactic Activity of Leukocytes in Newborn Infants

Background: Preterm newborn infants are at risk of developing chronic inflammation and tissue injury in their lungs and CNS due to prolonged and exaggerated accumulation of leukocytes.Aim: To study migration of leukocytes from newborn infants with a modified under agarose cell migration assay.Methods: Blood was collected from healthy adults (n=9) and from healthy, term newborn infants (umbilical cord; caesarean section; spinal anaesthesia; n=9). Isolated leukocytes were added to outer wells and chemoattractants to central wells. Gels were incubated for 2 hours whereby only polymorphonuclear (PMN) leukocytes migrated. Dose responses of intermediate (n=4; IL-8) and end-target (n=5; fMLP) chemoattractants were tested on PMN.Results: Similar dose response curves of PMN migration to gradients of IL-8 and fMLP were observed in newborn infants as in adults, but with less PMN migrating with newborns than with adults. The PMN leukocyte migration per distance in newborns was 80% of adults with IL-8, and >90% of adults with fMLP. There was a high linear correlation between the number of PMN and the distance of migration irrespective of chemoattractant studied (IL-8: r=0.85 and r=0.65 respectively for newborns and adults; p< 0.001 for both) (fMLP: r=0.76 and r=0.87; p< 0.001). The pattern of migration differed between fMLP and IL-8.Conclusion: Similar graded chemotaxis of PMN was observed with under agarose cell migration assay in newborn infants as in adults, making this an attractive method for functional clinical studies of leukocytes in newborn infants during different stages of maturity and disease.

Épidémiologie des isolats d'hémocultures: expérience d'un service d'hématologie clinique

Cancer chemotherapy is responsible for infections by decreasing the phagocytosis and chemotaxis of polymorphonuclear. We conducted a retrospective analysis during the period from 18/10/2006 to 21/05/2008, on all bacteria isolated from blood cultures performed in the department of clinical hematology at the hospital military instruction Mohamed V. One hundred and sixty two blood isolates were selected; Gram positive cocci (CGP) accounted for 60.34% and Gram negative bacilli (GNB) for 24.14%. Coagulase negative staphylococci (SNA) and S. aureus presented a resistance to methicilline respectively 54.55% and 22.22%. Prevalence of Gram positive cocci is consistent with the results of the EORTC (International Antimicrobial Therapy Cooperative Group). Analysis of resistance patterns of all species, except for staphylococci, showed phenotypes essentially community, sometimes wild. In conclusion probabilistic antibiotic treatement of bacteraemia in the haematology department should focus among other staphylococci resistant to methicilline.

The Role of C5a in the Mobilization of Hematopoietic Stem/Progenitor Cells

Abstract The complement system, a vital component of the immune system, has been shown to play a role in hematopoietic stem/progenitor cell (HSPC) trafficking. C3a is known to be important in the retention of HSPC in the bone marrow (BM) as C3a-deficient mice are good mobilizers, and C5a is important in the mobilization of HSPC because C5a-deficient mice are poor mobilizers (Stem Cells2007; 25: 3093). Further, granulocyte-colony stimulating factor (G-CSF) activates the complement system via the classical pathway, down-regulates stromal-derived factor (SDF)-1 in BM stromal cells and decreases expression of its receptor, CXCR4, in myeloid cells. In this work investigated the mechanism of C5a involvement in HSPC mobilization. Using RT-PCR and FACS we examined the expression of the C5a receptor (CD88) on mobilized peripheral blood (PB) and steady-state PB HSPC and mature white blood cells, and in vitro-expanded myeloid, erythroid, and megakaryocytic progenitor cells. We found that CD88, like the G-CSF receptor, is not expressed on BM, PB or cord blood HSPC (CD34+ cells); during CD34+ cell differentiation the expression of CD88 increases in myelocytic and megakaryocytic progenitors; and the percentage of monocytes and polymorphonuclear (PMN) cells expressing CD88 is significantly higher in mobilized than in steady-state PB. Examing the function of C5a (using flow cytometry) we found that, unlike C3a, C5a decreases CXCR4 expression in a dose-dependent manner in monocytes and PMN, but not in lymphocytes; and this effect was not seen when anti-C5a antibody was added. Interestingly, we found that G-CSF down-regulation of CXCR4 expression on PMN was partially restored by anti-C5a antibody, suggesting that the mobilizing effects of G-CSF are at least in part due to the action of C5a. Moreover, chemotaxis of PMN towards SDF-1 (chemotaxis assay) increased when these cells were stimulated with C3a but decreased with both C5a and G-CSF, reflecting the CXCR4 expression status of these cells after stimulation. We also examined the effect of C5a on matrix metalloproteinase (MMP) secretion in BM leukocytes and found that, like G-CSF, C5a increased MMP-9 and MMP-2 secretion into media (zymography). Since the SDF-1/CXCR4 axis plays an integral role in the retention of HSPC in the BM, we conclude that C5a promotes mobilization by disrupting this axis, as well as increasing MMP-9 and MMP-2 secretion by BM leukocytes, thereby allowing egress of HSPC into the PB.

Inflammatory and Hemodynamic Changes in the Cerebral Microcirculation of Aged Rats after Global Cerebral Ischemia and Reperfusion

Effects of aging on inflammation and blood flow in the brain are unclear. Young (three to six months) and aged (19-22 months) male Brown Norway Fisher rats were used to compare (i) leukocyte function in nonischemic conditions and (ii) leukocyte function and hemodynamic changes after ischemia-reperfusion (I-R). In nonischemic studies, polymorphonuclear (PMN) CD11b expression and reactive oxygen species (ROS) production were measured with flow cytometry and PMN chemotaxis was measured with a Boyden chamber (+/-fMLP). In I-R studies, ischemia was induced by bilateral carotid artery occlusion and hypotension (20 minutes). During early reperfusion (30 minutes), leukocyte adhesion and rolling and blood-shear rates were measured using fluorescence microscopy. During late reperfusion (48 hours), mortality, neurological function, and leukocyte infiltration were measured. Stimulated PMN chemotaxis was increased in nonischemic aged rats (p < 0.05). In early reperfusion, there was a significant increase in leukocyte rolling and adhesion in the cerebral microcirculation and a significant decrease in shear rate in aged rats, compared to the young (p < 0.05). During late reperfusion, neurologic function was worse in aged vs. young rats (p < 0.05). These findings suggest that increased intravascular PMN adhesion and vascular dysfunction may contribute to poor neurologic outcome after cerebral I-R in the aged brain.

LPS Responsiveness and Neutrophil Chemotaxis In Vivo Require PMN MMP-8 Activity

We identify matrix metalloproteinase (MMP)-8, the polymorphonuclear (PMN) leukocyte collagenase, as a critical mediator initiating lipopolysaccharide (LPS)-responsiveness in vivo. PMN infiltration towards LPS is abrogated in Mmp8-null mice. MMP-8 cleaves LPS-induced CXC chemokine (LIX) at Ser4∼Val5 and Lys79∼Arg80. LIX bioactivity is increased upon N-terminal cleavage, enhancing intracellular calcium mobilization and chemotaxis upon binding its cognate receptor, CXCR2. As there is no difference in PMN chemotaxis in Mmp8-null mice compared with wild-type mice towards synthetic analogues of MMP-8-cleaved LIX, MMP-8 is not essential for extravasation or cell migration in collagenous matrices in vivo. However, with biochemical redundancy between MMPs 1, 2, 9, and 13, which also cleave LIX at position 4∼5, it was surprising to observe such a markedly reduced PMN infiltration towards LPS and LIX in Mmp8-/- mice. This lack of physiological redundancy in vivo identifies MMP-8 as a key mediator in the regulation of innate immunity. Comparable results were found with CXCL8/IL-8 and CXCL5/ENA-78, the human orthologues of LIX. MMP-8 cleaves CXCL8 at Arg5-Ser6 and at Val7-Leu8 in CXCL5 to activate respective chemokines. Hence, rather than collagen, these PMN chemoattractants are important MMP-8 substrates in vivo; PMN-derived MMP-8 cleaves and activates LIX to execute an in cis PMN-controlled feed-forward mechanism to orchestrate the initial inflammatory response and promote LPS responsiveness in tissue.

Spantide I Decreases Type I Cytokines, Enhances IL-10, and Reduces Corneal Perforation in Susceptible Mice afterPseudomonas aeruginosaInfection

To determine the effects of blocking substance P (SP) interactions with its major receptor (NK1-R) using the antagonist spantide I in susceptible mice infected with Pseudomonas aeruginosa. Immunohistochemistry and enzyme immunosorbent assay (EIA) tested levels of SP in the cornea of B6 and BALB/c mice. B6 mice were treated with spantide, and after infection, slit lamp examination; clinical score; bacterial counts; and myeloperoxidase (MPO), RT-PCR, ELISA, and polymorphonuclear (PMN) cell chemotaxis assays were performed. SP corneal levels were significantly elevated constitutively and after infection in the B6 more than in BALB/c mice. Spantide treatment of B6 mice significantly decreased the number of perforated corneas, bacterial counts, and PMNs. mRNA levels for type I cytokines (e.g., IFN-gamma) as well as MIP-2, IL-6, TNF-alpha, and IL-1beta (mRNA and protein) also were significantly reduced after spantide treatment. The type II cytokine IL-10 (mRNA and protein) was elevated, whereas TGF-beta mRNA levels were unchanged after spantide treatment. PMN chemotaxis was induced by SP and other neuropeptides in vitro, but was not affected by spantide I. mRNA for neurokinin-1-receptor-1 (NK-1R) was detected in the normal and infected corneas and on macrophages (Mphis), but not on PMNs (unstimulated or stimulated with endotoxin [LPS]). Spantide treatment of Mphis reduced IL-1beta after LPS+SP treatment but not after either alone. The SP antagonist Spantide provides a novel approach to reduce type 1 and enhance the type 2 cytokine IL-10 in the infected cornea of B6 mice, leading to a significant reduction in corneal perforation and improved disease outcome.

Subacute necrotising fasciitis in type 2 diabetes mellitus

Patients with diabetes mellitus are more prone to infection, especially if the glycaemic control is poor. Hyperglycaemia can cause various abnormalities such as impaired polymorphonuclear chemotaxis, abnormal phagocytosis, reduced IgG or IgA levels, complement deficiency (e.g. low C4), abnormal intracellular killing and deficient cell-mediated immunity. It is also recognised that infection can predispose to diabetic ketoacidosis (DKA). Necrotising fasciitis (NF) is an unusual but life-threatening soft tissue infection. NF is a rare cause of DKA. We describe such a case and review NF with regard to both its acute and sub-acute presentations.

2-Arylpropionic CXC Chemokine Receptor 1 (CXCR1) Ligands as Novel Noncompetitive CXCL8 Inhibitors

The CXC chemokine CXCL8/IL-8 plays a major role in the activation and recruitment of polymorphonuclear (PMN) cells at inflammatory sites. CXCL8 activates PMNs by binding the seven-transmembrane (7-TM) G-protein-coupled receptors CXC chemokine receptor 1 (CXCR1) and CXC chemokine receptor 2 (CXCR2). (R)-Ketoprofen (1) was previously reported to be a potent and specific noncompetitive inhibitor of CXCL8-induced human PMNs chemotaxis. We report here molecular modeling studies showing a putative interaction site of 1 in the TM region of CXCR1. The binding model was confirmed by alanine scanning mutagenesis and photoaffinity labeling experiments. The molecular model driven medicinal chemistry optimization of 1 led to a new class of potent and specific inhibitors of CXCL8 biological activity. Among these, repertaxin (13) was selected as a clinical candidate drug for prevention of post-ischemia reperfusion injury.

Alteration of chemoattractant receptor expression regulates human neutrophil chemotaxis in vivo.

To elucidate the mechanisms that regulate human neutrophil delivery in vivo, as well as the mechanisms that lead to observed reduction in polymorphonuclear (PMN) delivery to remote sites in septic patients. Alterations in human PMN chemoattractant receptor expression and chemotactic function in vivo were evaluated in two distinct experiments: exudate PMNs (PMNs that have undergone transmigration to skin window blisters in controls) and septic PMNs (circulating PMNs from septic patients in the intensive care unit) were both separately compared with control circulating PMNs. Exudate PMNs displayed increased C5a receptors and C5a chemotaxis, and reduced interleukin-8 receptors (both IL-8 RA and IL-8 RB) and IL-8 chemotaxis. Septic PMNs displayed reduced C5a and IL-8 receptors and decreased C5a chemotaxis but no change in IL-8 chemotaxis. IL-8 but not C5a receptor gene expression decreased in parallel to receptor alteration. These results suggest that change in PMN chemoattractant receptor expression serves to regulate PMN chemotaxis in vivo; that exudate PMN chemotaxis depends more on C5a than IL-8; and that diminished chemoattractant receptors and chemotaxis in septic PMNs may explain decreased PMN delivery in these patients.

In vitro Effects of Meropenem and Imipenem/Cilastatin on Some Functions of Human Natural Effector Cells

Meropenem, a new carbapenem antibiotic, was assessed to evaluate its effects on some functional parameters of human polymorphonuclear (PMN) and natural killer (NK) cells in comparison with imipenem/cilastatin. Both drugs significantly inhibited PMN phagocytosis and chemotaxis at concentrations of 2,000 and 4,000 μg/ml. They affected PMN microbicidal activity, evaluated against Candida albicans, only at 4,000 μg/ml. A study of the effects of both drugs on peripheral NK populations and the human NK line (NK-92) showed that even at 4,000 μg/ml there was no effect on antitumor activity. These data indicate that meropenem can reduce some PMN antimicrobial functions only at very high concentrations like imipenem/cilastatin, whereas no concentration influenced NK activity.

Pathophysiologic effects of uremic retention solutes.

The uremic syndrome can be defined as a deterioration of biochemical and physiologic functions, in parallel with the progression of renal failure, resulting in complex and variable symptomatology (1-3). The compounds that accumulate in the uremic blood and tissues during the development of end-stage renal disease (ESRD), directly or indirectly due to a deficient renal clearance, are called uremic retention solutes. These retention solutes may modify biochemical or physiologic func- tions; if they do so, they contribute to the uremic syndrome. Only a few solutes have an established role as uremic toxins. According to Bergstrom, apart from inorganic compounds, urea, oxalic acid, parathyroid hormone (PTH), and b2-micro- globulin conform to the most strict definition of uremic toxins (4). However, this does not preclude a potential toxic role for various other retention solutes (5). The following factors, which are not always considered, might affect uremic solute concentration and their impact on biologic functions. (1) In addition to classical sources of ure- mic solutes such as dietary protein breakdown, alternative sources such as environment, herbal medicines, or psychedelic drugs may play a role in uremic toxicity. (2) Many solutes with toxic capacity enter the body through the intestine. Changes in the composition of intestinal flora, or changes in intestinal production and absorption, might alter their serum concentra- tion. (3) Some uremic solutes interfere with functions that directly affect the biochemical action of other solutes: the expression of PTH receptors, the response to 1,25(OH)2 vita- min D3, as well as the protein binding and breakdown of several other solutes. (4) Most uremic patients are prescribed a host of drugs. Interference of drugs with protein binding and/or tubular secretion of uremic solutes will influence their biologic effect. (5) Lipophilic compounds may be responsible at least in part for functional alterations in uremia. ( 6) The impact of residual renal function on uremic solute retention should not be neglected. (7) The main strategy that has been used up to now to decrease uremic solute concentration is dialysis, but dialysis is nonspecific and removes essential compounds as well. (8) Uremic solutes accumulate not only in the plasma but also in the cells, where most of the biologic activity is exerted. Re- moval of intracellular compounds during dialysis through the cell membrane may be hampered, resulting in multicompart- mental kinetics and inadequate detoxification. It is of note that lower morbidity and mortality are observed in patients submit- ted to long dialysis sessions (6,7). Compounds may be cleared more efficiently with continuous or long-lasting low efficiency strategies, because removal is more gradual. Our views on the uremic syndrome and several uremic solutes have changed substantially during the last decade. Therefore, it was thought timely to summarize the present state of knowledge about the biochemical, physiologic, and/or clin- ical impact of those compounds that have been subjected to relatively thorough evaluation during these last 10 years. Spe- cific attention was also paid to generation and removal pat- terns.

Disease-modifying antirheumatic drugs. Potential effects in older patients.

Disease-modifying antirheumatic drugs (DMARDs) are frequently used in rheumatoid arthritis. A number of physiological changes occur in the elderly which may modify the use of these medications. The most commonly used DMARDs are antimalarial drugs (particularly hydroxychloroquine), sulfasalazine and methotrexate. The principal mechanism of action of the antimalarials relates to the fact that they change intracellular pH, which downregulates numerous immune functions. Hydroxychloroquine is metabolised to 3 metabolites and has a very low clearance. It is moderately effective in dosages up to 6.4 mg/kg/day. While it is not the most effective of the DMARDs, it is the least toxic. Sulfasalazine is a prodrug which is enzymatically split in the bowel to form sulfapyridine (the principal active metabolite) and 5-aminosalicylic acid. The metabolism of sulfasalazine is complex and, to some extent, genetically determined. The mechanism of action of the drug is not well understood, but involves decreased production of cytokines and decreased proliferative response of lymphocytes. It may slow the rate of bony damage associated with rheumatoid arthritis. Nearly 50% of the patients who are prescribed sulfasalazine continue to receive the drug for up to 4 years. Sulfasalazine is not as well tolerated as hydroxychloroquine. Gastrointestinal toxicity, in particular, seems to be a problem in elderly patients taking this medication. Methotrexate is presently the most popular of the DMARDs for the treatment of rheumatoid arthritis. Methotrexate inhibits dihydrofolate reductase and adenosine release and has a secondary effect on cytokines and polymorphonuclear chemotaxis. It is highly metabolised within cells and remains there for prolonged periods. Up to 70% of patients who are prescribed methotrexate continue treatment for 5 years. Methotrexate treatment is associated with gastrointestinal, hepatic, cutaneous and, possibly, pulmonary adverse effects. The use of azathioprine, penicillamine and gold compounds is briefly reviewed in this article. Elderly patients have an increased incidence of rashes when using penicillamine, relative to young patients. There are no age-related differences in the efficacy and tolerability of azathioprine or gold therapy. The poor absorption and renal toxicity associated with cyclosporin, the new 'salvage' therapy in rheumatoid arthritis, make it generally unsuitable for use in the elderly, except under specialists' supervision.

Effect of antimicrobial agents on chemotaxis of polymorphonuclear leukocytes.

The effect of antimicrobial agents on polymorphonuclear (PMN) chemotaxis was investigated. No significant effect was obtained in vitro with penicillins, cephems, macrolides, aminoglycosides or quinolones by the agarose plate method. However, chemotaxis was inhibited at 100 micrograms/ml or less of minocycline and doxycycline. The inhibitory effect on chemotaxis is considered to be due to chelation of Ca-ions by minocycline or doxycycline. The chelation reduced the concentrations of Ca-ions in the PMNs. The chemotactic index of minocycline increased when CaCl2 or A23187 were given in combination. Our findings indicate that a small number of the short lamellipodia were observed in PMNs preincubated with minocycline or doxycycline and these two agents affected the movement of PMNs morphologically.

In vitro effects of Fasciola hepatica on the main functions of polymorphonuclear leukocytes: Chemotaxis and free radical generation induced by phagocytosis

The effects of adult fluke excretions-secretions (ES) on two major functions of circulating bovine polymorphonuclear (PMN) cells were investigated. Under agarose, PMN chemotaxis was not affected by the ES. ES preincubated with PMN for 15, 30 or 60 min at 37 degrees C, before a chemoluminescence assay, inhibited phagocytosis and/or free radical generation in a dose and time dependent manner.

In VitroEffects of Brodimoprim on Human Polymorphonuclear Leukocyte Functions. Preliminary Results

The in vitro effects of brodimoprim and trimethoprim on the functions of human polymorphonuclear (PMN) leukocytes have been studied comparatively evaluating chemotaxis, phagocytosis and production of superoxide anion. No significant effects of both diaminopyrimidines on chemotaxis and phagocytic activity of PMNs have been observed while both brodimoprim and trimethoprim enhanced the oxidative burst. A synergistic activity between the host immune system and the direct antimicrobial action of brodimoprim may occur while using this diaminopyrimidine in vivo.

In vitro inhibition of interleukin-2-induced defective polymorphonuclear chemotaxis by TNF inhibitor.

Patients undergoing immunotherapy with interleukin-2 experience multiple side effects and are highly susceptible to bacteremia. In a previous study, we confirmed that a profound deficiency of neutrophil chemotaxis is induced by interleukin-2 therapy. Migration in response to N-formyl-methionyl-leucyl-phenylalanine (FMLP), being normal before therapy, was markedly impaired after the first cycle and further decreased after the third cycle of treatment. A direct effect of interleukin-2 on neutrophil chemotaxis is controversial. However, peripheral blood cells exposed to interleukin-2 secrete secondary cytokines. In particular, the release of tumor necrosis factor after interleukin-2 injection has been proposed as an important regulatory mechanisms. When testing random migration and chemotaxis of neutrophils from normal subjects after incubation with the serum from treated patients, we found that this serum induced a defective chemotaxis similar to that of neutrophils from interleukin-2-treated patients. In order to assess the influence of tumor necrosis factor, we tested the effect of anti-tumor necrosis factor-alpha antibody on the chemotactic response of cells after incubation with the serum, and we observed a dose-dependent reduction of neutrophil chemotaxis deficiency. These data suggest that TNF is counteracting the neutrophil chemotactic deficiency observed during IL-2 treatment.