Platelet-derived MIF : A novel platelet chemokine with distinct recruitment properties

Objective: Macrophage migration inhibitory factor (MIF) is an inflammatory cytokine with chemokine-like functions that plays a role in several inflammatory diseases including atherosclerosis. We recently demonstrated that in addition to macrophages and endothelial cells, platelets are a source of MIF. However, the functional relevance of platelet-derived MIF and differences to other platelet chemokines are unclear. Here, we sought to define the secretion pattern of platelet MIF and to characterize its functional profile in comparison with known atherogenic platelet chemokines. Methods and results: Applying ELISA, we show that MIF is released from thrombin-stimulated platelets after 2 h, whereas CXCL12 and CXCL4 are secreted within minutes. Applied to platelets, MIF, unlike CXCL12, did not enhance platelet activation as analyzed by platelet aggregation, CD62P exposure and chemokine secretion studies. In contrast, both MIF and CXCL12 attenuated ADP-induced calcium transients in platelets. Transmigration and monocyte flow adhesion assays toward conditioned platelet supernatants together with MIF antibody blockade or supernatants from Mif(-/-) mice suggested that platelet-derived MIF has a stronger chemotactic activity than CXCL12 at its respective optimal secretion interval, and showed that platelet MIF substantially contributes to monocyte adhesion on endothelial layers. Moreover, MIF was found to delay clot retraction. Conclusions: We demonstrate that MIF differs from other platelet-derived chemokines by delayed secretion kinetics and by a distinct autocrine/paracrine modulation potential. Importantly, MIF was found to be a major platelet-derived chemotactic recruitment factor with clot-modulating properties and therefore might be relevant in inflammatory diseases such as atherosclerosis

Expression Analysis of a Highly Adherent and Cytotoxic Small Colony Variant of Pseudomonas aeruginosa Isolated from a Lung of a Patient with Cystic Fibrosis

The heterogeneous environment of the lung of the cystic fibrosis (CF) patient gives rise to Pseudomonas aeruginosa small colony variants (SCVs) with increased antibiotic resistance, autoaggregative growth behavior, and an enhanced ability to form biofilms. In this study, oligonucleotide DNA microarrays were used to perform a genome-wide expression study of autoaggregative and highly adherent P. aeruginosa SCV 20265 isolated from a CF patient's lung in comparison with its clonal wild type and a revertant generated in vitro from the SCV population. Most strikingly, SCV 20265 showed a pronounced upregulation of the type III protein secretion system (TTSS) and the respective effector proteins. This differential expression was shown to be biologically meaningful, as SCV 20265 and other hyperpiliated and autoaggregative SCVs with increased TTSS expression were significantly more cytotoxic for macrophages in vitro and were more virulent in a mouse model of respiratory tract infection than the wild type. The observed cytotoxicity and virulence of SCV 20265 required exsA, an important transcriptional activator of the TTSS. Thus, the prevailing assumption that P. aeruginosa is subject to selection towards reduced cytotoxicity and attenuated virulence during chronic CF lung infection might not apply to all clonal variants

Dosage of high‐dose methotrexate as CNS prophylaxis in DLBCL: A detailed analysis of toxicity and impact on CNS relapse

No abstract available

Timing of high-dose methotrexate CNS prophylaxis in DLBCL: a multicenter international analysis of 1384 patients

Prophylactic high-dose methotrexate (HD-MTX) is often used for diffuse large B-cell lymphoma (DLBCL) patients at high risk of central nervous system (CNS) relapse, despite limited evidence demonstrating efficacy or the optimal delivery method. We conducted a retrospective, international analysis of 1384 patients receiving HD-MTX CNS prophylaxis either intercalated (i-HD-MTX) (n = 749) or at the end (n = 635) of R-CHOP/R-CHOP-like therapy (EOT). There were 78 CNS relapses (3-year rate 5.7%), with no difference between i-HD-MTX and EOT: 5.7% vs 5.8%, P = .98; 3-year difference: 0.04% (-2.0% to 3.1%). Conclusions were unchanged on adjusting for baseline prognostic factors or on 6-month landmark analysis (n = 1253). In patients with a high CNS international prognostic index (n = 600), the 3-year CNS relapse rate was 9.1%, with no difference between i-HD-MTX and EOT. On multivariable analysis, increasing age and renal/adrenal involvement were the only independent risk factors for CNS relapse. Concurrent intrathecal prophylaxis was not associated with a reduction in CNS relapse. R-CHOP delays of ≥7 days were significantly increased with i-HD-MTX vs EOT, with 308 of 1573 (19.6%) i-HD-MTX treatments resulting in a delay to subsequent R-CHOP (median 8 days). Increased risk of delay occurred in older patients when delivery was later than day 10 in the R-CHOP cycle. In summary, we found no evidence that EOT delivery increases CNS relapse risk vs i-HD-MTX. Findings in high-risk subgroups were unchanged. Rates of CNS relapse in this HD-MTX-treated cohort were similar to comparable cohorts receiving infrequent CNS prophylaxis. If HD-MTX is still considered for certain high-risk patients, delivery could be deferred until R-CHOP completion