Novel therapeutic approach to improve hematopoiesis in low risk MDS by targeting MDSCs with the Fc-engineered CD33 antibody BI 836858.

We recently reported that the accumulation of myeloid-derived suppressor cells (MDSC), defined as CD33+HLA-DR-Lin-, has a direct role in the pathogenesis of myelodysplastic syndrome (MDS). In particular, CD33 is strongly expressed in MDSC isolated from patients with MDS where it has an important role in MDSC-mediated hematopoietic suppressive function through its activation by S100A9. Therefore, we tested whether blocking this interaction with a fully human, Fc-engineered monoclonal antibody against CD33 (BI 836858) suppresses CD33-mediated signal transduction and improves the bone marrow microenvironment in MDS. We observed that BI 836858 can reduce MDSC by antibody-dependent cellular cytotoxicity, which correlated with increases in granule mobilization and cell death. BI 836858 can also block CD33 downstream signaling preventing immune-suppressive cytokine secretion, which correlates with a significant increase in the formation of CFU-GM and BFU-E colonies. Activation of the CD33 pathway can cause reactive oxygen species (ROS)-induced genomic instability but BI 836858 reduced both ROS and the levels of double strand breaks and adducts (measured by comet assay and γH2AX). This work provides the ground for the development of a novel group of therapies for MDS aimed at MDSC and their disease-promoting properties with the goal of improving hematopoiesis in patients.

Lenalidomide promotes p53 degradation by inhibiting MDM2 auto-ubiquitination in myelodysplastic syndrome with chromosome 5q deletion.

Allelic deletion of the RPS14 gene is a key effector of the hypoplastic anemia in patients with myelodysplastic syndrome (MDS) and chromosome 5q deletion (del(5q)). Disruption of ribosome integrity liberates free ribosomal proteins to bind to and trigger degradation of mouse double minute 2 protein (MDM2), with consequent p53 transactivation. Herein we show that p53 is overexpressed in erythroid precursors of primary bone marrow del(5q) MDS specimens accompanied by reduced cellular MDM2. More importantly, we show that lenalidomide (Len) acts to stabilize MDM2, thereby accelerating p53 degradation. Biochemical and molecular analyses showed that Len inhibits the haplodeficient protein phosphatase 2A catalytic domain alpha (PP2Acα) phosphatase resulting in hyperphosphorylation of inhibitory serine-166 and serine-186 residues on MDM2, and displaces binding of RPS14 to suppress MDM2 autoubiquitination whereas PP2Acα overexpression promotes drug resistance. Bone marrow specimens from del(5q) MDS patients resistant to Len overexpressed PP2Acα accompanied by restored accumulation of p53 in erythroid precursors. Our findings indicate that Len restores MDM2 functionality in the 5q- syndrome to overcome p53 activation in response to nucleolar stress, and therefore may warrant investigation in other disorders of ribosomal biogenesis.

Flow cytometric detection of anti-AB antibody titers in blood group O recipients of blood group A2 donor kidneys.

AIM: ABO-incompatible kidney transplantation has been accepted for end-stage renal failure patients who have no ready opportunity for a deceased or living donor. Antibody titration for ABO-incompatible renal transplantation is not only difficult but also lacks conformity among laboratories. Herein we analyzed 20 living related renal transplant couples to detect recipient anti-A2 antibody using flow cytometric analysis. MATERIALS AND METHODS: Patients were admitted to our center for renal transplantation between January 1999 and December 2010. All but four of them had undergone a previous renal transplantation from an ABO-compatible donor but experienced graft failure. All donor blood groups were subtyped by our blood bank using a lectin-based dilution assay. To detect recipient anti-A2 antibody titers we used a tube hemagglutination method. A/B antibody titer analysis by flow cytometry incubated serially diluted serum samples with donor erythrocytes. Each analysis was repeated three times over a 2-week period using an older and the last sera simultaneously. RESULTS: The 13 male and 7 female patients showed our overall mean age of 32 ± 12 years. All patients had panel-reactive antibody levels below 15%. The level of flow cytometric antibody titers did not vary upon repeated analysis (P = .01). When compared with the tube method there was a discrepancy of the level at which the antibody titer became negative. DISCUSSION: Flow cytometric antibody titration is a practical and rapid technique to determine the amount of anti-A2 antibody in renal recipients.

What do patients really know about cardiopulmonary rehabilitation: a cross-sectional survey study.

BACKGROUND: Although it is known that cardiopulmonary rehabilitation (CPR) reduces mortality and morbidity, it is not widely implemented as is in Turkey. One factor might be lack of demand since the levels of knowledge and awareness among patients who are eligible for CPR seem to be insufficient. AIM: It is aimed to investigate the level of awareness and knowledge of CPR among patients with cardiopulmonary problems. DESIGN: Cross-sectional survey study. SETTING: Outpatient. METHODS: Knowledge regarding CPR was assessed by questionnaires given to 690 patients recruited in seven university hospitals and six training and research hospitals in which either comprehensive or limited CPR services are available. POPULATION: Patients who have cardiopulmonary problems RESULTS: Of the patients, 34.7% were given information on CPR by healthcare staff, and 25.3% reported that their source of information was physicians. Although 49.9% of the patients knew that they needed to exercise for their cardiac/pulmonary problems, only 23.4% and 32.1% of those were aware that fast walking and climbing stairs, respectively, would not pose a risk to their cardiac/pulmonary health. The majority of the patients believed that activities of daily living, which comprise the most important component of exercise-based CPR, were harmful for their cardiopulmonary health. We found that 31.1% of the patients exercised regularly. During their stay at the hospital, certain kinds of exercises were suggested to 62.7% of the patients, and 34.7% of these patients performed various exercises. Of the patients who were given detailed information on cardiopulmonary rehabilitation, 69% stated that they would be willing to participate in a similar program. CONCLUSION: Although nearly half of the patients stated that they needed CR, it was observed that the ratio of patients who had true knowledge of CPR was low among patients. It is imperative to furnish patients with information on CPR, both in the field of PMR and throughout Turkey, and to put more effort into running those services effectively. Furthermore, we should make an effort to increase the level of liaison between patients and physicians and other healthcare professionals who participate in the treatment of cardiac/pulmonary patients.

Influence of serum and soluble CD25 (sCD25) on regulatory and effector T-cell function in hepatocellular carcinoma.

Our previous studies showed that high levels of soluble CD25 (sCD25) in the serum of patients with hepatocellular carcinoma (HCC) correlated with blunted effector T-cells (Teff) responses, tumour burden and poor survival. Understanding the interactions between Teff, CD4+CD25+ regulatory T cells (Treg) and soluble factors can identify novel therapeutic targets. In this study, we characterize the mechanisms by which HCC serum and sCD25 mediate suppression of Teff and evaluate the effect of sCD25 on the suppression assays with normal healthy control cells (NHC) at a 1:1 Treg to Teff cell ratio to determine whether sCD25 has any impact on Treg suppression. HCC serum and sCD25 suppressed Teff proliferation and downregulated CD25 expression on HCC Teff in a dose-dependent fashion with sCD25 doses above 3000 pg/ml. Treg from HCC and cirrhosis patients suppressed proliferation of target CD4+CD25- Teff in serum-free medium (SFM). HCC Treg showed a higher degree of suppression than cirrhosis-derived Treg. In contrast, Treg from NHC did not suppress target Teff in SFM. However, isolated Treg from all three study subjects (HCC, cirrhosis and NHC) suppressed CD4+CD25- Teff in serum conditions or in the presence of sCD25 in the range 6000-12,000 pg/ml. In conclusion, downregulation of CD25 cell surface expression on Teff is part of the overall suppressive mechanism of sCD25 and HCC serum on Teff responses. The observed sCD25 and HCC serum-mediated suppression is further influenced via novel immune-inhibitory interaction between CD4+CD25+ Treg and sCD25.

Hepatitis C virus modulates human monocyte-derived dendritic cells.

This study is to examine the monocyte-derived dendritic cell (DC) response to hepatitis C virus (HCV) in a cell culture system. Adherence-derived DCs were incubated with various titres of JFH-1 (HCV genotype 2a), generated from transfected Huh 7.5 cells or co-incubated with Newcastle disease virus (NDV). Infection and the type 1 interferon (IFN) response were assessed by real-time reverse transcriptase-polymerase chain reaction, morphology by light microscopy and immunophenotype by flow cytometry. Our data demonstrated no viral replication or particle release from DC after HCV infection. Morphologically, monocytes showed a tendency to shift to immature DCs when cultured with HCV, when compared with control monocytes. This shift was confirmed by flow cytometry and appeared to be related to viral titres. There was also an increase in immature DC numbers. HCV infection induced IFNß expression in DCs, and the amount seemed to be inversely correlated with viral titres indicating that HCV has the capacity to negatively regulate such cells. However, IFNα does not appear to be affected by direct contact with the virus. A strong IFNß signal induced by NDV in DC was substantially diminished by HCV. HCV negatively affects the maturation of DCs and suppresses the type 1 IFN response of DC. Our results suggest a mechanism of viral evasion of host immunity.

Sacroiliitis and polyneuropathy during isotretinoin treatment.

Isotretinoin, a medication for acne, has been reported to cause a variety of side effects on the musculoskeletal system. We present a case of sacroiliitis (a relatively uncommon feature) and sensorimotor demyelinating polyneuropathy, which has been reported previously in only a few cases during isotretinoin therapy. Clinical symptoms were improved after the withdrawal of isotretinoin and the follow-up electrophysiological study performed 2 years after the initial diagnosis of polyneuropathy showed mild improvement. Dermatologists are advised to be alert to symptoms of polyneuropathy and sacroiliitis during treatment with isotretinoin.

Comparison of serum IL-1 beta, sIL-2R, IL-6, and TNF-alpha levels with disease activity parameters in ankylosing spondylitis.

Ankylosing spondylitis (AS) is a chronic, inflammatory, rheumatological disease affecting primarily the sacroiliac joint and vertebral column, with an etiology that remains obscure. Cytokines are soluble proteins that have specific roles in inflammatory response, arranging the interaction between cells of the immune system both in natural and specific immune reactions. This study was planned to evaluate the relation between the level of cytokines and the clinical and laboratory findings of patients with AS compared to healthy subjects. In this study, we demonstrated increased serum levels of soluble interleukin-2 receptor (sIL-2R), Interleukin-6 (IL-6), and tumor necrosis factor-alpha (TNF-alpha) in patients with AS compared with healthy subjects. Only IL-1 beta levels were not increased in AS patients. We found a correlation between C-reactive protein and IL-6 levels and between erythrocyte sedimentation rate and sIL-2R, IL-6 and TNF-alpha levels. Only the sIL-2R level was correlated with Bath AS Metrology Index and Bath AS Functional Index. We suggest that sIL-2R, IL-6, and TNF-alpha may have a role in the pathogenesis of AS and that their serum levels can be used as disease activity parameters and tools for diagnosis.

Dynamic postural balance in ankylosing spondylitis patients.

OBJECTIVES: In this study, our objectives were to investigate whether patients with ankylosing spondylitis (AS) have a poorer dynamic balance than normal subjects, and to study the relationship between balance and posture. METHODS: Seventy patients (57 men, 13 women) with AS and 35 (31 men, 4 women) controls matched for age, weight, height and body mass index were tested using the Biodex Stability System. Anteroposterior (AP), mediolateral (ML) and overall (OA) indices were obtained with bilateral stance at platform stabilities of 8 and 4. Subjects were tested with 'eyes open' at all times. Correlation analyses were performed between stability indices (OA, AP, ML) and disease duration, cervical rotation (CR), tragus to wall distance (TWD), lumbar side flexion (LSF), lumbar flexion (LF), intermalleolar distance (IMD) and Bath Ankylosing Spondylitis Metrology Index (BASMI) total score. RESULTS: No significant difference was found between the AS patients and healthy subjects with respect to all three stability indices at levels 4 and 8. A positive correlation was found only between ML stability index and TWD at level 8 (r, 0.249; P = 0.038). No other positive correlation was detected between stability indices and CR, TWD, LSF, LF, IMD, total BASMI score and disease duration. CONCLUSIONS: AS has no negative effect on postural stability. The only clinically significant association was found between dynamic postural balance and TWD.