Immune responses are regulated by opposing positive and negative signals triggered by the interaction of activating and inhibitory cell surface receptors with their ligands. Here, we describe novel paired activating and inhibitory immunoglobulin-like receptors, designated myeloid-associated immunoglobulin-like receptor (MAIR) I and MAIR-II, whose extracellular domains are highly conserved by each other. MAIR-I, expressed on the majority of myeloid cells, including macrophages, granulocytes, mast cells, and dendritic cells, contains the tyrosine-based sorting motif and the immunoreceptor tyrosine-based inhibitory motif-like sequences in the cytoplasmic domain and mediates endocytosis of the receptor and inhibition of IgE-mediated degranulation from mast cells. On the other hand, MAIR-II, expressed on subsets of peritoneal macrophages and B cells, associates with the immunoreceptor tyrosine-based activation motif-bearing adaptor DAP12 and stimulates proinflammatory cytokines and chemokine secretions from macrophages. Thus, MAIR-I and MAIR-II play important regulatory roles in cell signaling and immune responses.

Summary. Background:  Eltrombopag is an oral, non‐peptide thrombopoietin receptor agonist that has shown efficacy and safety in chronic immune thrombocytopenia (ITP). However, ethnic differences in eltrombopag exposure have been reported: area under the curve exposure to eltrombopag was 87% greater among ITP patients of East Asian descent than among ITP patients of non‐East Asian ITP descent. Objectives:  To evaluate the efficacy and safety of eltrombopag by using, in Japanese ITP patients, lower starting (12.5 mg) and maximum (50 mg) doses of eltrombopag than the standard starting (50 mg) and maximum (75 mg) doses approved in the USA and Europe. Patients:  We examined 23 Japanese patients with previously treated chronic ITP with a platelet count of < 30 000 μL−1 in a multicenter study comprising a randomized, double‐blind, placebo‐controlled phase for 6‐week evaluation (15 eltrombopag, and eight placebo) and an open‐label phase for 6‐month evaluation (23 eltrombopag). Results and Conclusions:  The response rate (platelet count of ≥ 50 000 μL−1) at week 6 of the 6‐week double‐blind phase was 60% in eltrombopag‐treated patients and 0% in placebo‐treated patients. Ten of 23 patients (43.5%) responded for ≥ 75% of predefined assessment visits during the 6‐month open‐label phase. Notably, 22% (5/23) of patients responded to 12.5 mg of eltrombopag, which was administered within the first 3 weeks of eltrombopag treatment. Bleeding decreased with eltrombopag treatment as compared with baseline. Eltrombopag was generally well tolerated; one patient experienced a transient ischemic attack on day 9. Eltrombopag (12.5–50 mg) is effective for the management of Japanese patients with chronic ITP (NCT00540423).

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The online version of this article has a Supplementary Appendix. BackgroundPatients with acute myeloid leukemia who are treated with conventional chemotherapy still have a substantial risk of relapse; the prognostic factors and optimal treatments after relapse have not been fully established. We, therefore, retrospectively analyzed data from patients with acute myeloid leukemia who had achieved first complete remission to assess their prognosis after first relapse. Design and MethodsClinical data were collected from 70 institutions across the country on adult patients who were diagnosed with acute myeloid leukemia and who had achieved a first complete remission after one or two courses of induction chemotherapy. ResultsAmong the 1,535 patients who were treated with chemotherapy alone, 1,015 relapsed. Half of them subsequently achieved a second complete remission. The overall survival was 30% at 3 years after relapse. Multivariate analysis showed that achievement of second complete remission, salvage allogeneic hematopoietic cell transplantation, and a relapse-free interval of 1 year or longer were independent prognostic factors. The outcome after allogeneic transplantation in second complete remission was comparable to that after transplantation in first complete remission. Patients with acute myeloid leukemia and cytogenetic risk factors other than inv(16) or t(8;21) had a significantly worse outcome when they did not undergo salvage transplantation even when they achieved second complete remission. ConclusionsWe found that both the achievement of second complete remission and the application of salvage transplantation were crucial for improving the prognosis of patients with acute myeloid leukemia in first relapse. Our results indicate that the optimal treatment strategy after first relapse may differ according to the cytogenetic risk.Key words: acute myeloid leukemia, allogeneic hematopoietic cell transplantation, first relapse, second remission, cytogenetic risk. 2010;95(11):1857-1864. doi:10.3324/haematol.2010 This is an open-access paper. Citation: Kurosawa S, Yamaguchi T, Miyawaki S, Uchida N, Sakura T, Kanamori H, Usuki K, Yamashita T, Okoshi Y, Shibayama H, Nakamae H, Mawatari M, Hatanaka K, Sunami K, Shimoyama M, Fujishima N, Maeda Y, Miura I, Takaue Y, and Fukuda T. Prognostic factors and outcomes of adult patients with acute myeloid leukemia after first relapse. Haematologica Prognostic factors and outcomes of adult patients with acute myeloid leukemia after first relapse

After cecal ligation and puncture, mice lacking the phosphatidylserine receptor CD300a on mast cells show more neutrophil recruitment to the peritoneal cavity, improved bacterial clearance, and extended survival.

Certain activating immune receptors expressed on myeloid cells noncovalently associate with either DAP12 or FcεRIγ (FcRγ chain), the ITAM-bearing transmembrane adapter proteins. An activating receptor, myeloid-associated Ig-like receptor (MAIR) II, is expressed on a subset of B cells and macrophages in the spleen and peritoneal cavity of mice and associates with DAP12 in these cells. However, we demonstrate here that cross-linking MAIR-II with mAb induced secretion of a significant amount of the inflammatory cytokines TNF-α and IL-6 from DAP12−/− as well as wild-type (WT) peritoneal macrophages. We show that MAIR-II associates with not only DAP12 but also FcRγ chain homodimers in peritoneal macrophages. LPS enhanced the FcRγ chain expression and FcRγ chain-dependent cell surface expression of MAIR-II and had additive effects on MAIR-II-mediated inflammatory cytokine secretion from peritoneal macrophages. The lysine residue in the transmembrane region of MAIR-II was involved in the association with FcRγ chain as well as DAP12. Our findings present the first case of an activating receptor that uses either DAP12 or FcRγ chain as a signaling adapter. The FcRγ chain may provide cooperation with and/or compensation for DAP12 in MAIR-II-mediated inflammatory responses by peritoneal macrophages.

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The results suggest a guideline for plasma glucose monitoring during CHOP chemotherapy in patients with no history of DM.