FcγRI-Mediated Activation of Human Mast Cells Promotes Survival and Induction of the Pro-survival Gene Bfl-1

Activation of mast cells through either FcɛRI or FcγRI leads to release of mediators contributing to the inflammatory response. One of the biologic characteristics of mast cells in allergic pathology is that these cells have the capacity to recover and regranulate after aggregation of FcɛRI. We have previously demonstrated that the pro-survival protein A1/Bfl-1 is required for mast cells to survive IgE-mediated activation. In the present study, we have investigated whether human mast cells show similar induction of bfl-1 and activation-induced survival after aggregation of FcγRI. Human cord blood-derived mast cells were activated by aggregation of either FcɛRI or FcγRI, and activation-induced survival and induction of bfl-1 was measured. We found that aggregation of FcγRI-induced expression of bf-1 and caused a comparable activation-induced mast cell survival as FcɛRI does. These data suggests that activation through Fc-receptors contribute to mast cell survival during antibody-dependent mast cell mediated inflammatory responses.     

Effect of anti-IgE antibodies on IgE binding to CD23

Human sera contain anti-IgE autoantibodies. Using a human B lymphoblastoid cell line (Wil-2WT cells) and monoclonal murine anti-IgE antibodies (BSW17 and Le27) we investigated a possible role of such anti-IgE antibodies. A 100-fold excess of monoclonal anti-IgE antibodies inhibited binding of 125I labeled IgE to Fc epsilon RII on Wil-2WT cells. Further, both monoclonal anti-IgE antibodies dissociated surface bound IgE from Fc epsilon RII on Wil-2WT cells. However, BSW17 which does not trigger histamine release from human leucocytes, was much more effective in dissociating Fc epsilon RII bound IgE than Le27 which triggers histamine release. These results may suggest that naturally occurring IgG anti-IgE antibodies are able to inhibit binding of IgE to its receptor.     

The antinociception induced by \-endorphin administered intrathecally is mediated by the activation of μ and κ-opioid receptors in the rat

The antinociception induced by -endorphin given supraspinally has been previously demonstrated to be mediated by the stimulation of 603.gif" alt="epsiv" align="BASELINE" BORDER="0">-, but not -, - or -opioid receptors in rats and mice. The present study was designed to determine what types of opioid receptors in the spinal cord are involved in the antinociception induced by intrathecally (i.t.) administered -endorphin. Antinociception was assessed by the tailflick test in male Sprague-Dawley rats. CTOP (0.9–6.6 nmol), a selective -opioid receptor antagonist, or nor-BNI(13.6–95.3 nmol), a selective -opioid receptor antagonist, given i.t. dose-dependently reversed i.t. administered -endorphin-induced inhibition of the tail-flick response. On the other hand, naltrindole (6.6–44.4 nmol), a selective -opioid receptor antagonist, or -endorphin (1–27) (1–6.7 nmol), a selective 603.gif" alt="epsiv" align="BASELINE" BORDER="0">-opioid receptor antagonist given i.t., did not antagonize the inhibition of the tail-flick response induced by i.t. administered -endorphin. The results are consistent with the previous study in mice [Tseng LF and Collins KA (1992) Eur J Pharmacol 214: 59–65] that the antinociception induced by -endorphin given i.t. is mediated by the stimulation of - and -, but not - and 603.gif" alt="epsiv" align="BASELINE" BORDER="0">-opioid receptors.Abbreviations i.t. Intrathecal - CTOP D-Phe-Cys-Tyr-D-Try-Orn-Thr-Pen-Thr-NH₂ - nor-BNI Norbinaltorphimine     

A phase 1/2 trial of ublituximab,a novel anti‐CD20 monoclonal antibody,in patients with B‐cell non‐Hodgkin lymphoma or chronic lymphocytic leukaemia previously exposed to rituximab

This phase 1/2 study evaluated the safety, pharmacokinetic behavior and anti‐tumour activity of ublituximab, a unique type I, chimeric, glycoengineered anti‐CD 20 monoclonal antibody, in rituximab‐relapsed or ‐refractory patients with B‐cell non‐Hodgkin lymphoma (B‐NHL ) or chronic lymphocytic leukaemia (CLL ). Induction therapy (doses of 450–1200 mg) consisted of 4 weekly infusions in cycle 1 for NHL and 3 weekly infusions in cycles 1 and 2 for CLL . Patients received ublituximab maintenance monthly during cycles 3–5, then once every 3 months for up to 2 years. Enrolled patients with B‐NHL (n  = 27) and CLL (n  = 8) had a median of 3 prior therapies. No dose‐limiting toxicities or unexpected adverse events (AE s) occurred. The most common AE s were infusion‐related reactions (40%; grade 3/4, 0%); fatigue (37%; grade 3/4, 3%); pyrexia (29%; grade 3/4, 0%); and diarrhoea (26%; grade 3/4, 0%). Common haematological AE s were neutropenia (14%; grade 3/4, 14%) and anaemia (11%; grade 3/4, 6%). The overall response rate for evaluable patients (n  = 31) was 45% (13% complete responses, 32% partial responses). Median duration of response and progression‐free survival were 9·2 months and 7·7 months, respectively. Ublituximab was well‐tolerated and efficacious in a heterogeneous and highly rituximab‐pre‐treated patient population.     

Co-cultivation of mast cells and FcɛRIα+ dendritic-like cells from human hip bone marrow

BACKGROUND: Mast cells contribute to the pathogenesis of asthma and allergy through the release of a plethora of pro-inflammatory mediators and cytokines. Their study is hampered by the difficult access to human tissue samples. Human mast cells have been cultured from CD34+ progenitors in the bone marrow of normal volunteers following iliac crest bone marrow biopsy but this is invasive. Hip bone marrow could provide a more convenient less invasive source of mast cell progenitors. OBJECTIVE: To characterize mast cells cultured from human bone marrow obtained at routine hip surgery. METHODS: Mononuclear cells were isolated from the bone marrow reamings of patients undergoing routine hip replacement surgery and were cultured with recombinant stem cell factor (SCF), IL-6 and IL-10. Cell surface markers were examined using flow cytometry, protease expression monitored using immunohistochemistry, histamine measured by radioenzymic assay, Ca2+ responses analysed using ratiometric Ca2+ imaging, and ion currents recorded via the patch-clamp technique. RESULTS: Mast cells were absent at baseline, but accounted for 65 +/- 7% of cells after 8-12 weeks of culture, equating to a mean 0.6 +/- 0.14 x 10(6) mast cells per culture. Fifty-three percent of tryptase+ cells also contained chymase. The remaining cells comprised a population of large CD1a+ HLA-DR+ and Fc epsilon RI alpha+ cells, most likely dendritic cells. All mast cells expressed CD117 and the high-affinity IgE receptor alpha-chain (Fc epsilon RI alpha) constitutively, and developed a Ca2+ response following IgE-dependent activation. These cells exhibited 7.8 +/- 2.9% net IgE-dependent histamine release, and demonstrated a similar ion channel profile to human lung mast cells. In particular, the intermediate conductance Ca(2+)-activated K+ channel opened following IgE-dependent activation. CONCLUSIONS: Mast cells grown from human hip marrow provide a rich non-invasive source of functionally mature mast cells. In addition, this culture system may be useful for the generation of Fc epsilon RI alpha+ dendritic cells.     

Results of Transplantation of Kidneys Procured From Donors After Brain Death Aged 60 Years and Older

Objective

To analyze results of transplantation of kidneys procured from donors after brain death aged 60 years and older (hereafter denoted by “≥60”) compared to kidneys procured from donors after brain death aged 40–59 years (hereafter denoted by “40–59”) in medium-term follow-up period, and to assess factors that affect recipient and kidney graft survival.

Potential of circulatory procalcitonin as a biomarker reflecting inflammation among South Indian diabetic foot ulcers

Objective

Diabetic foot ulcer (DFU), the major complication associated with diabetes mellitus, has been shown to precede amputation in up to 90% of cases. Recent data reveal that procalcitonin (PCT) is a valid marker for the diagnosis of bacterial infections compared with traditional markers like white blood cell count, C-reactive protein levels, and erythrocyte sedimentation rate in DFU patients. Furthermore, cytokines are proposed to act as modulators and mediators for the expression and release of PCT into the circulation. Hence, this preliminary study was conducted to evaluate the diagnostic accuracy of PCT compared with other traditional markers and to predict the association of PCT plasma levels with inflammatory cytokines and clinical parameters of incident diabetes among South Indian DFU subjects.

Multiple approaches to the reduction of dental fear

Participant modeling, symbolic modeling, and graduated exposure were compared with each other and with two control treatments for effectiveness in reducing fear of dentistry in 33 adults who had avoided dental treatment for from 1 to 10 yr. Assessment of in-chair psychological responsiveness and overt behavior showed no significant pre-post change for any group although all of them reported significant reduction in state anxiety and expected pain. During the 24 months following treatment, from 50 to 87.5% of the subjects were able to return to regular dental care with the highest “return” rate appearing in the participant modeling condition.     

Direct evidence that FK506 inhibition of FcεRI-mediated exocytosis from RBL mast cells involves calcineurin

Abstract Fc εRI-mediated exocytosis of preformed mediators from mast cells and basophils (e.g. histamine, serotonin, beta-hexosaminidase) is sensitive to the immunosuppressants cyclosporin A and FK506 (IC ₅₀ 200 and 4 n M , respectively) but not rapamycin. The mechanism of inhibition does not appear to involve tyrosine phosphorylation, hydrolysis of inositol phosphates or calcium flux. Here we report experiments using a molecular approach to assess the role of calcineurin, a serine/threonine phosphatase thought to be the primary pharmacological target of these drugs. Calcineurin’s activity requires association of its catalytic (A) subunit with an intrinsic regulatory (B) subunit. We hypothesized that calcineurin-sensitive signalling events should be affected by the depletion of calcineurin B subunits, thereby reducing the number of active A:B complexes. We therefore transfected rat basophilic leukemia (RBL) cells with an inhibitory (dominant negative) form of the calcineurin A subunit, which binds the calcineurin B subunit with high affinity but does not possess catalytic activity (B subunit knock-out, BKO). In these transfected cells, the dose-response curve for the inhibition of FcεRI-mediated exocytosis by FK506 was shifted to the left, indicating an increased drug sensitivity of BKO-transfected cells. We conclude that FK506 inhibition of FcεRI-mediated exocytosis in mast cells specifically targets calcineurin activity. Received: 3 September 1997