Impact of lack of knowledge on risk perception and protective practices of home nurses handling antineoplastic drugs

Introduction: Health care workers handling antineoplastic drugs (ADs) are at risk of carcinogenic, mutagenic and reproductive toxic risks (CMR). The aim of this study was to assess the impact of the lack of knowledge (K) on risk perception (P) and on protective practices (PP) related to the handling of home-based chemotherapy (HC) by home nurses. Methods: This study was conducted in Normandy among home nurses. A questionnaire was developed to explore the K, P and PP related to handling ADs by home nurses working with four different providers from two hospitals. Results: Among the 28 home nurses included, 25.93% had received initial training on the specific treatment of ADs, 48.15% scored below average on risk management K, 52.00% scored below average on personal PP. Conclusion: This study reveals the importance of adapted and regular training on the handling of ADs. It will help develop a climate of safety and reinforce adherence to wearing personal protective equipment to protect health care workers from contamination.

UHPLC-MS/MS method for the quantification of ultra-traces of irinotecan and its metabolites in red blood cells and plasma to detect caregivers' contamination

The occupational exposure of caregivers to antineoplastic agents has been demonstrated since 1979. Since the early 1990s, numerous studies from several countries have demonstrated the contamination of care facilities by antineoplastic drugs. As it is easier to sample, most contamination measurements in workers are carried out in urine sample. The distribution and elimination half-lives of irinotecan suggest that blood can be considered as better than urine for the biomonitoring of a potential contamination of healthcare workers. We describe here the development and the validation of a UHPLC-MS/MS method to simultaneously quantify irinotecan, and two of its main metabolites, APC and SN-38, at ultra-trace levels in plasma and red blood cells (RBC). This method has been applied to blood samples collected from several healthcare services in a French comprehensive cancer center. The results demonstrate that the method is sensitive enough to identify a contamination of healthcare workers by irinotecan and SN-38 at very low concentrations. Moreover, the results show that analysis of RBC is of great interest and complementary to that of serum.

Perception, knowledge, practices and training regarding the risk of exposure to antineoplastic drugs in three French compounding units

INTRODUCTION

Healthcare workers are exposed to hazardous drugs such as antineoplastic drugs, which have potential carcinogenic, mutagenic and teratogenic effects. Protective measures must be taken after appropriate staff training to handle antineoplastic drugs in a safe way. The objective was to assess perception, knowledge, practices and training regarding the risk of exposure of healthcare workers in three French compounding units.

METHODS

This descriptive study was based on a questionnaire made of 33 questions divided into five sections related to the handling of antineoplastic drugs: perception of the risks, knowledge of the risks, protection practices, specific training and general questions.

RESULTS

Among the 39 participants, over half considered their overall risk of exposure to antineoplastic drugs not being very low. Inhalation was known to 69.2% of them as possible route of contamination. The breakroom was identified by 28.9% of them as a place of contamination. The procedure in case of accidental exposure to antineoplastic drugs was known by 69.2%, but only half could explain it. Only 38.5% said they changed their gloves every 30 min as recommended. Barely half said that they had been trained specifically for the handling of antineoplastic drugs during an initial training. Over half wished to be informed, trained and aware of the proper handling of antineoplastic drugs.

CONCLUSION

Although some of these results are encouraging, specifically when compared to the other settings where antineoplastic drugs are handled, there is still room for improvement. Efforts to build an adapted and impactful training program must pursue.

CLINICAL TRIAL REGISTRATION

Study CONTACT, ref. 19-504.

Knowledge and practices about safe handling regarding the risk of exposure to antineoplastic drugs for caregivers in compounding units and in operating rooms performing HIPEC/PIPAC

INTRODUCTION

Ever since the late 1970s, occupational exposure associated with the handling of antineoplastic drugs (ADs) in the healthcare environment has been highlighted and demonstrated. Contamination was detected in both operating rooms (OR) and compounding units (CU), where healthcare workers handle and are exposed to ADs in different ways. In the OR, the risk of exposure is higher and the staff receives less training in handling ADs than in the CU. This study aimed to assess and compare knowledge and practices about the safe handling of ADs by caregivers working in these two locations, namely the CU and OR.

METHODS

Two questionnaires (one each for the OR and CU) were created by two investigator pharmacists and were completed during a personal interview of 20 min. The questions were related to the following topics: training, knowledge about occupational exposure and questions related to protective practices. A scoring system was implemented to assess the knowledge and practices of each participant.

RESULTS

In total, 38 caregivers working in the OR and 39 in the CU were included in our study. Significantly more CU staff had specific initial training (p < 0.001) and ongoing training (p < 0.001) in handling ADs. Concerning the knowledge score, OR caregivers had a significantly lower median score for contamination routes (p < 0.001), contamination surfaces (p < 0.001), existing procedures (p < 0.001) and total knowledge (p < 0.001) than CU caregivers. Concerning protective handling practices of ADs, the two locations had nonsignificantly different median scores (p = 0.892).

CONCLUSION

This study suggests that there is still room for improvement in terms of knowledge and protection practices when handling ADs. An appropriate and tailored training program should be developed and provided to all caregivers who handle or come in contact with ADs.Clinical trial registrationStudy CONTACT, ref. 19-504.

Perception, knowledge, and handling practice regarding the risk of exposure to antineoplastic drugs in oncology day hospitalization units and compounding unit staff

BACKGROUND

Antineoplastic drug exposure is a major problem in regard to caregivers' health. The aim of the present study was to assess the perception, knowledge, and handling practices of all occupation level categories of two oncology day hospitalization units and two compounding units regarding the risk of exposure to antineoplastic drugs.

METHODS

This descriptive study, performed through face-to-face interviews, concurrently assessed the perception, knowledge, and handling practices of antineoplastic drugs in five different job categories in four different settings. This work was part of a larger comprehensive project examining surface and blood contamination. Different scores were assigned to evaluate responses to a questionnaire about the perception, knowledge, and handling practices of healthcare workers, a risk global score including a risk perception score, and education/knowledge and handling practices scores.

RESULTS

In the survey, continuous training was associated with the global risk score (p = 0.03), particularly with the handling practices risk score (p = 0.01). Job category was also significantly associated with the global risk score (p < 0.001), particularly with the handling practices risk score (p < 0.001) and the education/knowledge score (p < 0.001). Pharmacy technicians had the highest score regarding risk perception (71.4%), indicating a higher perception of risk, and had a lower score regarding handling practices (25.0%) as well as a lower score (15.7%) regarding risk knowledge. Nurses and physicians had a high score (50%) regarding the risk of handling practices and a score of 57.1% regarding risk perception, indicating an increased perception of safety. Auxiliary caregivers had the highest global score (43.5%) and a score of 30.0% regarding handling practices.

CONCLUSIONS

This study identified significant differences among healthcare workers depending on job categories in the antineoplastic drug handling practices and in the knowledge of the risks associated with occupational exposure to antineoplastic drugs. These differences were particularly important between trained and untrained participants, revealing the importance of implementing a continuous training program.

Perception, knowledge and protective practices for surgical staff handling antineoplastic drugs during HIPEC and PIPAC

Objectives

Two surgical techniques used for peritoneal metastasis involve a risk of exposure to antineoplastic drugs (ADs): hyperthermic intraperitoneal chemotherapy (HIPEC) and pressurized intraperitoneal aerosol chemotherapy (PIPAC). The objective of this study was to assess the differences in perception, training, and knowledge of the risks as well as in the protection practices and occupational exposures of all worker categories.

Methods

This descriptive study, led in two hospitals from two distant French regions, was performed through a face-to-face interview and assessed the perception, knowledge and handling practices of ADs by a questionnaire consisting of 52 questions.

Results

Fifty-one professionals participated in this survey. A total of 29.4% (n=15) professionals were afraid to handle ADs. Very few workers have been trained on handling ADs during initial training dedicated to all caregiver (5.9%; n=3). HIPEC is considered to involve a higher risk of exposure to ADs than PIPAC (81.6% (n=31) vs. 57.9% (n=22), respectively, p=0.022, agreement 65.8%). Protective equipment is considered to be less suitable for HIPEC than for PIPAC (29% (n=11) vs. 10.5% (n=4), respectively, p=0.016, agreement 81.6%). Concerning the potential AD contamination location, the participants identified a significant difference between these two practices. During HIPEC, 15.7% (n=6) of caregivers indicated that they had negative symptoms perceived in their practice vs. 2.6% (n=1) during PIPAC.

Conclusions

This study shows that perception, knowledge and protection practices are different between HIPEC and PIPAC. It also shows a difference between the worker categories. In view of the difficulties in making operating room staff available, the related training programmes must have an adapted format.

Impact of low- and high-risk operators handling irinotecan on the blood contamination of health care workers in oncology day care units

INTRODUCTION

Health care workers handling antineoplastic drugs (ADs) are at risk of mutagenicity and adverse reproductive effects. Despite protective equipment and AD handling guidelines, AD levels are still detected in caregivers in oncology units. This study attempted to assess blood contamination by irinotecan and its metabolites in all health care workers in oncology day hospital units according to activities specific to each employment category.

METHODS

The study was performed at two different hospitals: a university hospital and a comprehensive cancer centre. Forty-four participants were categorized according to their daily activity as a high-risk operator (29 nurses/ward aides and 5 cleaning staff) and a low-risk operator (7 doctors and 3 secretaries). The collected blood samples were subjected to UHPLC-MS/MS. The plasma and red blood cell (RBC) levels of irinotecan and its metabolites (SN-38; APC) were determined using a validated analytical method detection test.

RESULTS

Two hundred sixty-four assay results were collected (132 plasma results and 132 RBC results). The comparison between low- and high-risk operator-contaminated workers was not significant (18.33% positive results in low-risk operators vs. 25.98% positive results in high-risk operators; P = 0.22). This homogeneity showed overall contamination within the unit. Positive results were obtained in 21.43% of physicians, 11.11% of secretaries, 25.86% of nurses/ward aides and 26.67% of cleaning staff. These results could be explained by the lack or failure of personal and collective protective equipment. A lack of protection and inadequate decontamination procedures can result in surface contamination.

CONCLUSIONS

This study evaluated blood contamination with irinotecan and its metabolites in health care workers from day hospital care units. Among the 24.24% of contaminations observed in care units, the difference between low- and high-risk operator contamination was not significant (P = 0.22). The impact on blood contamination found is the same between low- and high-risk caregivers. This implies that the protective precautions associated with the handling of anticancer drugs must therefore be followed by all staff, including those believed to be at low risk of exposure.

Blood contamination of the pharmaceutical staff by irinotecan and its two major metabolites inside and outside a compounding unit

BACKGROUND

Caregivers in healthcare settings are exposed to a risk of antineoplastic drug contamination which can lead to adverse health effects. Biological monitoring is necessary to estimate the actual level of exposure of these workers. This study was conducted with the aim of assessing blood contamination levels by irinotecan and its metabolites of pharmaceutical staff operating inside and outside a compounding unit.

METHODS

The study took place within the pharmaceutical unit of a French comprehensive cancer centre. Blood samples were collected from the pharmacy workers operating inside and outside the compounding unit, and analysed by UHPLC-MS/MS. Plasma and red blood cell irinotecan and its metabolites (SN-38; APC) were determined with a validated analytical method detection test.

RESULTS

A total of 17/78 (21.8%) plasma and red blood cell-based assays were found to be contaminated among staff. Overall, the total number of positive assays was significantly higher for staff members working outside the compounding unit than for workers working inside it (P = 0.022), with respectively 5/42 (11.9%) and 12/36 (33.3%) positive assays. For plasma dosages, the "outside" group had a significantly higher number of positive assays (P = 0.014). For red blood cell-based assays, no significant difference was found (P = 0.309).

CONCLUSIONS

This study reveals that pharmaceutical staff serving in health care settings are exposed to a risk of antineoplastic drug contamination, not only inside the compounding room but also in adjacent rooms. The results would help to raise awareness and potentially establish protective measures for caregivers working in areas close to the compounding room as well.

Does equipment change impact blood contamination with irinotecan and its two major metabolites in a centralized cytotoxic pharmacy unit?

Background

Antineoplastic drugs exposure is a major problem for caregivers’ health. The aim of this study is to assess blood contamination with irinotecan and its two metabolites in a centralized pharmacy unit for cytotoxic drug preparations workers before and after protective equipment changes.

Methods

The study took place in a university hospital centralized pharmacy unit for cytotoxic drug and was performed in two parts, before (Round 1: R1) and after equipment changes (Round 2: R2). Collection of pharmacy staff blood samples was performed in UHPLC-MS/MS. Plasma and red blood cell irinotecan and its metabolites (SN38; APC) were determined with a validated analytical method detection test.

Results

A total of 15/36 (41.6%) assays were positive in R1 and 16/72 (22.2%) in R2 with a significant decrease between periods ( P =  0.035). For plasma dosages, no difference between the two periods was found ( P =  0.71); respectively 4/18 (22.2%) assays were positive in R1 and 6/36 (16.6%) in R2. For red blood cells dosages, a significant decrease between periods was found ( P =  0.01); respectively 11/18 (61%) were positive in R1 and 10/36 (27.8%) in R2.

Conclusions

These dosages make it possible to have the very first evaluation for plasma and red blood cell contamination with irinotecan and its metabolites in the context of equipment changes, both at individual and collective levels. This work would help to protect health workers from the potential risks represented by these molecules, especially by revealing a contamination of workers in order to objectify the results of exposure.

[A multidisciplinary collaboration for the benefit of patients]

A study focusing on therapeutic education sessions for patients with psoriasis receiving subcutaneous biotherapy was carried out in a dermatology department of a university hospital. To meet the needs identified by the research, multi-professional collaboration around a therapeutic patient education approach resulted in the creation and implementation of specific information tools and the organisation of training sessions for the nurses. A subsequent survey showed a 100% satisfaction rate among patients and nurses.

Appropriate use of antifungals: impact of an antifungal stewardship program on the clinical outcome of candidaemia in a French University Hospital

OBJECTIVES

The objective of this study was to compare clinical outcomes of patients with candidaemia before and after implementation of an antifungal stewardship program (AFSP).

METHODS

This study included all consecutive cases of candidaemia identified from January 2012 to December 2015 in a French University Hospital. Data were collected retrospectively for a period of 2 years before implementation of the AFSP, and prospectively for 2 years after. All cases were reviewed by a multidisciplinary panel of experts including infectiologists, a microbiologist and pharmacists to have a complete follow-up of patients.

RESULTS

33 and 37 patients were finally included in the first and second period, respectively. The sites of entry of the candidaemia cases studied were as follows: intraabdominal in 29 cases (41.4%), central venous catheter 21 (30.0%), other or unknown: 20 (28.6%). Infectiologist consultations increased from 36.4 to 86.5% between the two periods with a significative impact on daily blood cultures which were more frequently performed in the second period (p = 0.04), and the use of echinocandins which was more frequent in the second period (97.1% of cases vs 78.8%, p = 0.03). The 3-month mortality rate declined from 36.4% in the first period to 27.0% in the second period (p = 0.4).

CONCLUSIONS

Despite the insufficient number of candidaemia cases and the presence of other unmodifiable risk factors of mortality which did not allow us to show a significant effect on the 3-month mortality, AFSP had a significant effect on daily blood cultures and echinocandin use as first-line therapy.

Chronic vascular rejection: histologic comparison between two murine experimental models

BACKGROUND

We previously developed an experimental model to study chronic vascular rejection (CVR) in mice, the orthotopic aortic allograft. More recently we performed human arterial grafts into SCID/Beige mice reconstituted with human spleen cells. We report herein the differences in CVR lesions.

MATERIAL AND METHODS

In the first model, recipient mice were C57BL/6 (H-2b), and donor mice were DBA/2 (H-2d). In the second model, terminal branches of the human superior mesenteric artery were transplanted into SCID/Beige mice in the infrarenal aorta. Human immune reconstitution was achieved by a single intraperitoneal injection of 30 x 10(6) human spleen cells. The presence of human lymphocytes and IgG was verified weekly. In both models, the vascular grafts were inserted in the infrarenal aortic position using the sleeve technique. The transplanted mice were sacrificed at 35 days after the operation. The grafts were analyzed by histology and morphometry. The mean intimal thickening was calculated based on transverse sections at 0.1-mm intervals.

RESULTS

Typical CVR lesions developed with neointimal thickening, T-cell infiltration, and smooth muscle cell (SMC) proliferation in both models. In the mouse aortic model, disappearance of SMC in the media was noted in contrast to human arterial transplants, where the media remained intact.

CONCLUSION

Other groups have noted that arteries conserve their media in clinical organ transplants. From this point of view, the lesions in the second experimental model (human arteries) better reflect the pathology of CVR in clinical transplantation than the murine aortic transplant model.

Use of human mesenteric arteries to study chronic vascular rejection in SCID/beige mice reconstituted with human spleen cells

We wanted to establish a preclinical model of chronic vascular rejection (CVR) by transplanting small arteries from the mesentery of cadaveric organ donors by the rapid "sleeve" technique into SCID/beige mice reconstituted with human allogeneic spleen cells. After institutional authorization and with informed consent from relatives, we obtained tissues and cells from cadaveric organ donors. A piece of mesentery was recovered from the donor and kept in buffered solution at 4 degrees C until use. After dissection of the mesentery, small arteries of suitable size were transplanted in place of the infrarenal aorta of the mice. Cells for the immunological reconstitution of the mice were spleen cells from the same or other organ donors. Twenty-three suitable arterial segments were obtained from the mesentery of three cadaveric donors. Ten of the mice received 3 x 10(7) human spleen cells intraperitoneally 1 week after the arterial graft and they all showed circulating human CD3+ and CD19+ cells 2 weeks after injection. The mice were sacrificed 5 weeks after the arterial graft. SCID/beige mice reconstituted with allogeneic spleen cells showed a typical CVR, whereas mice that received no cells had a normal vascular anatomy. We believe our model is well suited for the study of treatment of CVR under human allograft conditions.

Human immune reconstitution with spleen cells in SCID/Beige mice

BACKGROUND

We developed an original experimental model to study chronic vascular rejection (CVR) consisting of a graft of human mesenteric artery followed by human immune reconstitution into CB.17 SCID/Beige mice. Human immune reconstitution achieved after human PBMC injection has often been variable and incomplete. The aim of this work was to develop an alternative method to achieve a complete, functional human immune reconstitution.

METHOD

After institutional authorizations, spleen cells were recovered from cadaveric organ donors. Single intraperitoneal injections of various doses of spleen cells were made into 70 CB.17 SCID/Beige mice. Reconstitution of the human immune system was monitored by flow cytometry (circulating human cells) and ELISA (human IgG). Colonization of murine lymphoid organs by human cells was studied by immunohistochemistry and flow cytometry. Evaluation of the immune function consisted of examination of CVR lesions in human arterial grafts. The animals were humanely killed at day 28.

RESULTS

After injection of 30 to 40 x 10(6) spleen cells, the mice showed significant human CD3(+), CD19(+), and CD56(+) populations in peripheral blood. The mean human cells levels were, respectively, 8.2% +/- 5.4%, 2.9% +/- 1.2%, and 5.3% +/- 5.1%. Murine spleen and mesenteric lymph nodes were colonized by human T and B cells, while the murine thymus was only colonized by human T cells. Human IgG was detected in murine serum (65.9 +/- 63.3 mg/L) and typical CVR lesions were observed within the allogeneic grafts.

CONCLUSION

Intraperitoneal injection of 30 to 40 x 10(6) human spleen cells into CB.17 SCID/Beige mice induces complete and functional human immune reconstitution allowing the study of CVR under human allogeneic conditions.

Chlamydia pneumoniae induces interleukin-10 production that down-regulates major histocompatibility complex class I expression

Recently, it was demonstrated that CD8(+) T cells are important for the response against Chlamydia pneumoniae. By use of the human monocytic cell line U937 and human monocytes taken from peripheral blood, we investigated the effect of infection on various molecules critical for CD8(+) T cell function. A strong secretion of interleukin (IL)-10 by infected cells was observed, together with an inhibited expression of major histocompatibility complex (MHC) class I antigens, but without significant alteration of tumor growth factor-beta secretion or MHC class II expression. Recombinant IL-10 added to uninfected U937 cells decreased the expression of MHC class I, whereas blocking antibodies to IL-10 and its receptor abolished the C. pneumoniae-induced inhibition of MHC class I expression. Analysis of our data provides evidence that IL-10 secretion induced by C. pneumoniae infection of monocytic cells down-regulates the expression of MHC class I molecules and thereby might reduce the presentation of bacterial epitopes by MHC. This would decrease the ability of CD8(+) T cells to eliminate infected cells.

[Clinical and bacteriologic response to irrigation with a chlorhexidine solution in the treatment of periodontal pockets]

Most of parodontal diseases have a bacterial aetiology. Their episodic and asynchronic evolution differs from site to site. The "in situs" antimicrobian used in the parodontal bags reduces the systemic administration. Various antibiotics or antiseptics slow liberation systems were experimented. Two patients suffering from advanced parodontitis were treated after radicular scraping by subgingival irrigation with a syringe filled with chlorhexidine. Each patient presented at last four parodontal bags more or less six millimetres (6 mm) deep. The following clinical parameters were noted: Patch index, bleeding index, bag depth. A bacteriological analysis was realized at the beginning and of the treatment. Controls were made at D60. Results showed a significant improvement of clinical parameters. It seems that the chlorhexidine irrigation improves the parodontal treatment efficiency.

N-linked oligosaccharides can protect target cells from the lysis mediated by NK cells but not by cytotoxic T lymphocytes: role of NKG2-A

We have previously shown that glycophorin A (GPA), inserted by electropulsation into the membrane of K562 cells, protected them from natural killer (NK) cell-mediated cytotoxicity and the unique N-linked oligosaccharide of GPA was essential for resistance to occur. The present study demonstrates that the protection level conferred by GPA is similar to the resistance induced by HLA-Cw3 expressed by transfected K562 cells. A monoclonal antibody against NKG2-A, an NK inhibitory receptor interacting with HLA class I antigens and belonging to the C-type lectin receptor, was able to restore the ability of NK cells to lyse K562 cells expressing HLA-Cw3 at the cell membrane but not electroinserted-GPA, suggesting that the N-linked oligosaccharide of GPA cannot be a ligand for NKG2-A. GPA was then electroinserted into the membrane of two lymphoblastoid B-cell lines: one was sensitive to NK cell-mediated lysis, the other was susceptible to cytotoxic CD8+ T-lymphocyte (CTL)-mediated cytotoxicity. The electroinserted GPA protected the target cells from NK-mediated cytotoxicity, whereas it did not modify the cell susceptibility to lysis by CTL. Endoglycosidase F treatment abolished the resistance towards NK cell-mediated lysis, suggesting that N-linked glycans could inhibit mechanisms used by NK cells to exert their cytotoxic function in agreement with our previous results.

Oxidized low density lipoproteins induce apoptosis in PHA-activated peripheral blood mononuclear cells and in the Jurkat T-cell line

Oxidized low density lipoproteins (oxLDLs) and activated T lymphocytes are present in early atherosclerotic plaques. It has been shown that oxLDLs are cytotoxic to cultured vascular cells but their possible toxic action on T lymphocytes has not been described. Peripheral blood lymphocytes from healthy individuals were stimulated in vitro with the polyclonal activator phytohemagglutinin and treated with various doses of native and mildly oxidized LDLs. Low doses of oxLDLs inhibited cell growth and DNA synthesis after 48 h culture and at 200 microg apoB/ml we observed a loss of cell viability. Dead cells did not exhibit significant increase of alteration of membrane integrity (i.e., necrosis) but showed chromatin fragmentation evaluated by DNA staining with 4', 6-diamidino-2-phenylindole and propidium iodide. This fragmentation increased with TBARS and hydroperoxide levels. The expression of early apoptosis marker Apo2.7 rose among the CD3(+) T-cell population. In addition, morphological analysis showed apoptotic features (cell shrinking, nucleus condensation, and fragmentation). Study of phosphatidylserine expression using Annexin V confirmed that oxLDLs induced apoptosis in activated lymphocytes. In the Jurkat T-cell line cultured with oxLDLs, apoptotic morphological changes (condensation and nucleus fragmentation) were observed and they were accompanied by DNA fragmentation visualized by propidium iodide staining and electrophoresis showing apoptotic ladder. These results demonstrate that mildly oxidized LDLs induce apoptosis in a part of activated and proliferating T cells. T-lymphocyte apoptosis induction in atherosclerotic lesions might contribute to the development of an inappropriate local T cell response.

Mildly oxidized low-density lipoproteins decrease early production of interleukin 2 and nuclear factor kappaB binding to DNA in activated T-lymphocytes

Activated T-lymphocytes are found early in atherosclerosis lesions, but little is known about their role. Oxidized low-density lipoproteins (oxLDLs) are considered to be involved in the pathogenesis of the lesions, and we have previously demonstrated that oxLDLs inhibit not only interleukin (IL)-2-receptor expression on the surface of in vitro-activated T-lymphocytes but also their proliferation. We have now investigated the effect of oxLDLs on blast differentiation, on IL-2 synthesis and on the activation of the nuclear factor kappaB (NF-kappaB) system in activated lymphocytes. Mildly oxLDLs (50 and 100 microgram/ml) decreased the number of lymphoblasts and the level of IL-2 concentration in the culture supernatants after activation of lymphocytes by phytohaemagglutinin and PMA+ionomycin. The inhibition of IL-2 production was observed in the CD3(+) T-lymphocyte cytoplasm as early as 4 h after activation by PMA+ionomycin. The study of NF-kappaB showed that oxLDLs led to a decrease of activation-induced p65/p50 NF-kappaB heterodimer binding to DNA, whereas the presence of the constitutive nuclear form of p50 dimer was unchanged. This was correlated with an unchanged level of the active form of the cytosolic inhibitor protein IkappaB-alpha. Taken together, these observations suggest that the immunosuppressive effect of oxLDLs might operate via a dysregulation of the T-lymphocyte activation mechanisms.

Mildly oxidized low-density lipoproteins suppress the proliferation of activated CD4+ T-lymphocytes and their interleukin 2 receptor expression in vitro

Activated T-lymphocytes are present in early atherosclerotic lesions where they may interact with oxidized low-density lipoproteins (oxLDLs). In this study the non-specific effect of oxLDLs on the activation of T-cells in vitro was investigated. LDLs were oxidized by UV irradiation and characterized by a low level of lipid peroxidation and only slight apolipoprotein B modification. Peripheral blood lymphocytes from normal individuals were stimulated in vitro with the polyclonal activator phytohaemagglutinin in the presence of various doses of LDLs and oxLDLs. LDLs enhanced the proliferation of peripheral blood lymphocytes at doses up to 100 microg/ml but were inhibitory at 200 microg/ml, whereas low doses of oxLDLs (over 10 microg/ml) inhibited the proliferation. OxLDLs also inhibited the proliferative responses of an alloreactive CD4+ T-cell line immortalized by Herpes virus saimiri and an influenza haemagglutinin-specific CD4+ T-cell clone. Viability tests using Trypan Blue exclusion or expression of Apo2.7, an apoptosis marker, did not indicate any significant cell death at doses up to 100 microg/ml oxLDL. At this concentration, cell-cycle analysis showed an accumulation of cells at the G1/S interface in the CD4+ cell clone, without significant DNA fragmentation. The expression of the activation antigen CD25 on T-lymphocytes (on phytohaemagglutinin-activated T-cells and on CD4+ T-cell clone), requisite to the commitment of activated T-cells from G1 phase to S phase, was also inhibited by oxLDLs whereas expression of other activation antigens such as CD69 and HLA-DR was unchanged. In conclusion, these data show that mildly oxidized LDLs inhibit the proliferation and CD25 expression of activated T-lymphocytes and suggest that oxLDLs may slow down the T-cell response in atherosclerotic lesions.

Nucleosome-dependent escape of tumor cells from natural-killer-mediated lysis: nucleosomes are taken up by target cells and act at a postconjugation level

Our previous data suggested that chromatin fragments released from dead cells into the extracellular medium could be involved in the impairment of natural-killer (NK)-mediated cytotoxicity reported in cancer patients. In the present study, an inhibition of the NK-mediated lysis was obtained in vitro by nucleosome addition to different tumor target cells, independently of their sensitivity to NK-mediated lysis. We observed a rapid endocytosis and degradation of nucleosomes by K562 tumor target cells and (although to a much lesser extent) a binding to a subpopulation of lymphocytes. Nucleosomes impaired neither the conjugation step nor the expression of adhesion molecules at the effector (CD11a, CD18, CD2) or target (CD54, CD58) cell surface. On the contrary, flow-cytometry analysis of the conjugation suggested that nucleosomes might stabilize the conjugates. Investigations of the killing process showed that nucleosomes decreased the NK cytotoxic potential without modifying Ca2+-dependent lethal-hit-delivery kinetics. The cytotoxic potential was not restored by increasing the available magnesium and calcium concentrations in the extracellular medium. Taken together, the results suggest that the inhibition of NK-mediated lysis by nucleosomes may result from alterations of the NK mechanism at the postconjugation level and after lethal-hit delivery. Hence, the inhibition could involve a delay in the recycling of effector cells, or a resistance of tumor target cells to NK cells.

Glycophorin A protects K562 cells from natural killer cell attack. Role of oligosaccharides

Glycophorin A is a protein with an abundant glycosylation (60% carbohydrate by weight), and studies have suggested that resistance of target cells to natural killing may be correlated with the level of glycophorin A expression. To assess the role of glycophorin A and of its carbohydrates in sensitivity to lysis by natural killer (NK) cells, the glycoprotein was inserted into the membrane of K562 target cells using electropulsation. Peripheral blood lymphocytes were used as effector cells. When glycophorin A was inserted into the membrane, the level of resistance to NK cell attack increased with the number of glycophorin A molecules electroinserted. The resistance to lysis was not due to a defect in target cell-effector cell binding. Electroassociation of glycophorin A did not cause a decrease in the expression of either "positive signals" for NK cells (such as CD71, CD15, and CD32 antigens) or cellular adhesion molecules (CD18, CD29, CD54, and CD58). Furthermore, electroinsertion of glycophorin A did not trigger any "negative signals," such as class I HLA antigen expression. Finally, it was shown that the sialic acid and O-linked oligosaccharides of glycophorin A did not play any role in its effect against NK cells. Conversely, the unique N-linked oligosaccharide was shown to be essential for resistance to occur.

Study of LDL and acetylated LDL endocytosis by mononuclear cells in HIV infection

Activated lymphocytes have a high level of low density lipoprotein (LDL) uptake as compared to resting lymphocytes, whereas scavenger receptors for acetylated LDL (Ac-LDL) are expressed on limited number of immune cells, i.e., monocytes/macrophages. The endocytosis of LDL and Ac-LDL by mononuclear cells was studied during in vitro and in vivo HIV infection, in order to use LDL and Ac-LDL as carriers of antiviral and/or immunomodulatory drugs towards lymphocytes and monocytes. The uptake of LDL and Ac-LDL was analyzed by cytofluorimetry. LDL endocytosis in PHA/IL2-activated lymphocytes was higher than in resting lymphocytes. In vitro HIV infection of PHA/IL2-activated lymphocytes did not alter the high LDL endocytosis in lymphocytes. CD4+ and CD8+ cells. In a group of 12 symptomatic patients there was no alteration of LDL endocytosis in lymphocytes, CD4 and CD8 lymphocytes. In another group of 23 individuals, the Ac-LDL endocytosis mediated by CD14+ monocytes was unaltered in asymptomatic patients (n = 6) and in some symptomatic patients (n = 6, CD14+ cells > 100/mm3). On the contrary, in other symptomatic patients (n = 11, CD14+ cells < 100/mm3), the number of Ac-LDL+ CD14+ cells decreased, whereas their efficiency of Ac-LDL endocytosis increased as compared to those of other HIV+ patients. In conclusion, the use of lipoproteins as carriers to increase the drug delivery to CD4+ lymphocytes and to CD14+ monocytes can be envisaged, since: (i) the LDL endocytosis was not impaired in CD4 lymphocytes of HIV+ patients, and (ii) the Ac-LDL uptake by monocytes was altered only in some patients of stage IV.

Evidence for a dual effect of acebutolol, a beta blocker, on the mouse humoral immune response

Acebutolol induces transient polyclonal B cell activation in C57B1/6 mice but down-modulates the spontaneous polyclonal activation of NZBxNZW lupus mice. The immunomodulatory effects of this beta-blocker were studied in C57l/6 mice injected with LPS or immunized with sheep red blood cells. The effect of acebutolol on the polyclonal activation of lymphocytes induced by LPS was also investigated in heterozygous and nu/nu C57BL/6 mice. Finally, the direct effect of acebutolol on spleen cells was studied in vitro. Acebutolol treatment for 15 days (50mg/kg/day) inhibited the polyclonal activation of lymphocytes induced by LPS in C57BL/6 and in C57BI/6 nu/nu mice, but increased the humoral response to sheep red blood cells in C57Bl/6 mice. Moreover, spleen cells from C57Bl/6 mice treated for 15 days with acebutolol showed an increased number of CD5+ and CD4+ lymphocytes, as well as an increased reactivity to concanavalin A but not to LPS. In vitro, acebutolol at 10(-5)-10(-7) M induced an increased reactivity of spleen cells from naive mice to concanavalin A, whereas it did not affect the B cell responsiveness to LPS. These results indicate that acebutolol modulates both T-cells and non T-cells in the immune system.

LDL and acetyl-LDL inhibit the NK activity and are taken up by CD56+ lymphocytes

The effect of LDL and modified LDL (acetyl-LDL) was studied on human natural killer cell-mediated cytotoxicity against K562 cells. Incubation for 24 h of peripheral blood lymphocytes (PBL) with a high concentration (200 micrograms/ml) of LDL decreased the NK activity in some donors. After acetylation of the LDL protein (apoB), the modified-LDL systematically inhibited the NK function of PBL in a time- and dose-dependent manner. Inhibition mediated by acetyl-LDL (AcLDL) was significantly greater than that of LDL, indicating that the apoB modification can mediate the inhibition of the NK function. AcLDL also inhibited the NK activity of peripheral blood mononuclear cells, suggesting that, under our experimental conditions, monocytes are not efficient enough to protect NK cells against the adverse effects of modified-LDL. With a cytofluorimetric analysis, the internalization of acetyl-LDL by PBL was demonstrated and was only 3-4 times lower than LDL internalization in lymphocytes. It appeared to be time, temperature and dose dependent, saturable and different from the internalization mediated by the known scavenger receptors. Finally, CD14- CD3+ lymphocytes and CD14- CD56+ lymphocytes were able to internalize AcLDL in the same way. Our results suggest that in some in vivo circumstances, when the LDL concentration and/or the modified-LDL/LDL ratio increase in tissues, lipoproteins are internalized by NK cells and also can induce adverse effects on the NK function.

In vitro inhibition of natural-killer-mediated lysis by chromatin fragments

A qualitative impairment of natural killer (NK) function and the presence of circulating DNA have been independently reported in clinical situations such as cancer and lupus. The existence of receptors for chromatin fragments at the leukocyte membrane raised the question of the relation between the presence of chromatin fragments in the extracellular medium and the impairment of NK function. The present study shows that plasmas from patients with metastatic cancer and with pathological DNA concentrations inhibited significantly the NK activity of normal lymphocytes as compared to cancer plasmas with DNA concentrations in the normal range. In vitro, it was demonstrated that chromatin fragments inhibited the NK-mediated cytotoxicity in a dose-dependent manner. Inhibitory concentrations of nucleosomes (2.5-10 micrograms/ml) were lower than those of DNA and histones alone (100 micrograms/ml). Inhibitory effects of nucleosomes, DNA and histones differed also according to the effector population used: nucleosomes were effective whatever the CD56+ cell enrichment of the effector population, while DNA inhibition needed T cells, and histone inhibition probably resulted from a subtoxic effect, prevented by the presence of adherent cells. Finally we found that nucleosomes could inhibit the NK function only when they were present in the extracellular medium. Taken together, these data suggest that the persistence of nucleosomal DNA at sites of cell death or in the blood might be responsible, at least partly, for the NK activity impairment observed in pathological circumstances characterized by a high rate of cell death phenomena such as cancer.

Electropermeabilization mediates a stable insertion of glycophorin A with Chinese hamster ovary cell membranes

Electropulsation allowed us to incorporate glycophorin A, an integral membrane protein, into mammalian nucleated cell membranes (Chinese hamster ovary cells). The induction of stable protein association is effective only when the field intensity is higher than its threshold value, creating membrane permeabilization to small molecules. Under controlled conditions, cell viability was only slightly altered by this treatment. Pulse number and duration controlled both the number of modified cells and incorporated molecules. The phenomena was temperature dependent. An average of 5 x 10(4) molecules/cell was bound. About 80% of cells in the pulsed population were observed to incorporate glycophorin. The protein incorporation was shown to be stable 48 h after electroassociation. Electrically bound proteins were shared between the cells after each division. As enhanced binding is detected if glycophorin is added after the pulses, it is the long-lived alteration of the membrane mediated by the pulses which supports the association.

Electric field-mediated glycophorin insertion in cell membrane is a localized event

Purified soluble glycophorin, an intrinsic protein, can be back 'electroinserted' in the membrane of Chinese hamster ovary cells by submitting the cell/protein mixture to short electric field pulses. Previous studies showed that this complex between pulsed cells and proteins, which is detected only when the cell membrane is electropermeabilized, was very stable. This strongly suggested that the protein was indeed inserted in the membrane. The basic processes involved in this phenomena are studied in the present work. The association is observed at the single cell level by means of videoimmunofluorescence. Electric field-mediated insertion occurs firstly in a limited patch of the cell surface, which size is in agreement with the prediction of Electropermeabilization theory. A free diffusion of the inserted proteins then follows on the cell surface. The diffusion coefficient is computed to be less than 10(-10) cm2/s as observed for transmembranous proteins. This slow process gives an homogeneous distribution of the inserted protein.

In vitro stimulation of polymorphonuclear cell adhesion by ribomunyl and antibiotic + ribomunyl combinations: effects on CD18, CD35 and CD16 expression

Several functions of polymorphonuclear cells (PMNs) require adhesion to occur. Various membrane proteins' functions such as CD18 (beta 2 chain of integrin), CD35 (CR1) and CD16 (F c gamma Receptor III) participate in adhesion. In vivo treatment with Ribomunyl (R), an immunomodulating agent, was shown to enhance adhesion and migration of PMNs. To explore the direct effect of R on PMNs, cells from healthy subjects were treated in vitro with R. A significant increase of PMN adhesion and expression of CD18 and CD35 molecules were observed with 50 and 100 micrograms/ml of R after 2 h incubation. However, R-treatment decreased the PMN reactivity towards anti-CD16 (F c gamma RIII) monoclonal antibody. The effect of R on adhesion and membrane molecule expression was independent of the presence of serum and of polymixin B. Thus, this effect cannot be due to lipopolysaccharide (LPS) contaminants and does not require interactions with serum components. In previous studies, it was shown that in vitro amoxicillin increased some PMN functions whereas josamycin decreased them. The in vitro incubation of PMNs with R and amoxicillin (100 micrograms/ml) potentiated the positive effect of amoxicillin on adhesion and the antibiotic counterbalanced the negative effect of R on CD16 expression. In addition, R compensated the negative effect of josamycin (100 micrograms/ml) on PMN adhesion and on CD18 and CD35 expression. This study indicates: (1) the direct effect of R on PMN adhesion and on expression of molecules involved in adhesive-mediated functions, and (2) the beneficial effect of the association of R with antibiotics which can stimulate PMN activity.

Studies on the susceptibility to NK-mediated lysis and the simultaneous expression of various surface molecules in anthracyclin-treated K562 cells and in four K562 cell clones

Target molecules for NK cells are unknown. Numerous studies have proposed putative target molecules, but have examined their role in the modulation of sensitivity to NK-mediated lysis one independently of each other. We examined the simultaneous expression of various surface molecules and the susceptibility of K562 cells to NK attack. We have previously shown that adriamycin (40 nM) and aclacinomycin (15 nM) can induce, in vitro, an increase of glycophorin A (GPA) on K562 cells, a modulation of transferrin receptor (TfR) and CD15 antigen expression and a significant resistance of cells to NK-mediated lysis. In the present work, Fc gamma receptor II (CD32) expression at the K562 cell membrane was clearly decreased after aclacinomycin-treatment but was unaltered by adriamycin-treatment. Four K562 cell clones were studied. Two clones (F and G) expressed a higher level of CD32 at the membrane (62% and 70% of erythrocyte antibody (EA) rosettes respectively) and two clones (9 and 19) expressed lower a level (18% and 7% EA rosettes respectively) than the original population (43%). The sensitivity to lysis by NK cells was increased in clones F, G and 9 but decreased in clone 19 (without alteration in the binding capacity). Relationships between the sensitivity to NK attack and the levels of simultaneous expression of CD32, TfR, CD15, glycophorin A (GPA) and MHC class I monomorphic antigens were studied. In addition, the presence at the membrane of some cellular adhesion molecules (CD54, CD58, CD29, CD18, CD56) was examined in anthracyclin-treated cells and in the four clones. The difference in the sensitivity of target cells to NK attack is not strictly related to variation of one or other of these molecules. Our previous and present data suggest that the resistance of K562 cells to NK cells may correlate with the level of erythroid maturation at the cell membrane, involving simultaneous variations in expression of several molecules such as a decrease of TfR, CD15 and CD32 and an increase of GPA.

An in vivo model for the experimental selection of drugs able to prevent immune complex glomerulonephritis

Polyclonal activation of lymphocytes and immune complex-mediated glomerular lesions were induced in C57Bl/6 mice by injecting bacterial lipopolysaccharide (LPS) twice a week for 2 weeks. The usefulness of such a model for in vivo evaluation of immunomodulatory and therapeutic effects of drugs, was investigated by treating mice with DIAM4, a cyclophosphazenic compound known to modulate polyclonal activation of lymphocytes and to prevent mouse lupus nephritis. Prevention of LPS-triggered lymphocyte polyclonal activation and glomerular lesions was observed in the DIAM4-treated mice. Such a model can be used conveniently to select compounds effective in the treatment of immune glomerulonephritis.

Comparative effects of fagaronine, adriamycin and aclacinomycin on K562 cell sensitivity to natural-killer-mediated lysis. Lack of agreement between alteration of transferrin receptor and CD15 antigen expressions and induction of resistance to natural killer

Little is known about membrane target antigens for natural killer (NK) cells. Transferrin receptor and CD15 antigen might be two of these target structures. A novel antileukemic alkaloid, fagaronine, is able to induce hemoglobin synthesis in the K562 cell line. Numerous reports suggest relations between the expression of natural killer target structures and the differentiation stage of malignant cells. Effects of fagaronine on the expression of glycophorin A, transferrin receptor and CD15 antigen and susceptibility to NK-mediated lysis have been investigated in K562 cells and compared to those of two anthracyclines (Adriamycin and aclacinomycin A) known to be erythroid-differentiation inducers. When comparing the balance of differentiating effect and toxicity, the dose and time-dependent effects of the drugs, fagaronine and aclacinomycin, are equivalent on K562 cells. In experimental conditions where fagaronine (3500 nM), Adriamycin (40 nM) and aclacinomycin (15 nM) recruit the same percentage of hemoglobin-containing cells (40%-50%), glycophorin A expression increases and transferrin receptor expression decreases. Only Adriamycin treatment decreases CD15 antigen expression. In addition, Adriamycin and aclacinomycin, but not fagaronine, induce resistance to NK-mediated lysis. These data suggest that (a) it is unlikely that CD15 antigen and transferrin receptor, separately considered, can be unique target structures for NK cells; and (b) fagaronine is a potent erythroid inducer which, in our system, has similar effects to aclacinomycin without induced resistance to NK attack.

Quantitative morphological aspects of granulocytic differentiation induced in HL-60 cells by dimethylsulfoxide and retinoic acid

HL-60 cells differentiate to mature granulocytes when cultured with DMSO or retinoic acid. These two drugs can induce different expression of phenotypic or functional properties in these cells. The morphological characteristics of the differentiation sequences elicited by these two drugs have been therefore evaluated by a quantitative cytological analysis technique using a SAMBA 200 cell image processor. The maturation sequences induced by DMSO or retinoic acid differed mainly in nuclear geometry and cytoplasmic granules expression. Multivariate statistical analyses of data reveal that DMSO and retinoic acid elicited granulocytic maturation through two separate morphological pathways which can be individualized as early as 24 hr after differentiation induction. Image processing may therefore offer an interesting tool for studying new drugs with differentiation potential in chemotherapy.

Association of adriamycin-induced resistance to NK-mediated lysis with sialic acid level and immunological reactivity of transferrin receptors and glycophorin A

Adriamycin (ADM) can increase sialic acid content in K 562 cells and reduce their susceptibility to NK-mediated lysis. In this report, hypothetical relationship between this resistance and augmentation in sialylation has been investigated. Variations in the time of exposure to ADM showed that 12 hours were sufficient to cause maximal recruitment of benzidine-positive cells, growth inhibition and resistance to NK-mediated lysis. On the contrary, the membrane sialic acid density seemed stable and 24 hours of drug exposure were necessary to observe a clear rise in sialic acid. Neuraminidase treatment of control and ADM-treated K 562 cells was associated with an obvious enhancement in their susceptibility to NK-mediated lysis which can be explained by an increase in the target-effector binding ability as assessed by a direct conjugate-forming cell assay. However, the neuraminidase treatment did not modify the sensitivity difference to lysis between untreated and ADM-treated cells. As compared to control the reactivity of ADM-treated cells was higher with an antiglycophorin A (GPA) MAb and lower with an antitransferrin receptor (TFR) MAb. Kinetic studies suggested that GPA expression is a better index of ADM-induced resistance to NK-mediated lysis than TFR expression. In addition, neuraminidase treatment showed that TFR and GPA modulations induced by ADM can be correlated with sialylation alterations.

Age related differences in immunocompetence and incidence of mammary adenocarcinoma in murine mammary tumor virus-infected C3H/Bi mice

In breeder C3H/Bi female mice, infected neonatally by murine mammary tumor virus (MTV), the incidence of spontaneous mammary tumors is greater than 95% between 5 and 9 months of age. In young (2-3 months) female the probability for developing a tumor in the next month is negligible, higher than 80% in mice of middle age (5-6 months) but lower than 4% in aged (10-12 months) females. The age-related changes of some immune functions of spleen cells from these tumor free female mice have been evaluated. While the proliferative capacity of cells to Phytohemagglutinin (PHA) increases, the T cell-dependent antibody response against sheep red blood cells (SRBC) and the antibody-dependent cellular cytotoxicity (ADCC) are significantly decreased in 5-6-month-old mice as compared to the young (2-3 months) female mice. The antibody response against SRBC and the mitogenic response to PHA decline markedly in 10-12-month-old mice but the ADCC increases in this group of mice. In addition, assays with monoclonal anti-Lyt-1 and anti-Lyt-2 antibodies indicate that percentage of Lyt 1- 2+ cells (suppressor and cytotoxic T cells) is lower in 10-12-month-old female as compared to 5-6-month-old animals. These results show that the immune alterations observed in 10-12-month-old C3H/Bi mice are not closely associated with an increase in incidence of spontaneous tumors and suggest that a high non-T killer cell activity could protect some of these older C3H/Bi female mice against mammary tumor development.

Evidence for sialidase activity in K 562 cells: inhibition by adriamycin treatment

Sialidase activity has been studied in the human erythroleukemia K 562 cell line grown in vitro. The total sialidase activity was determined using disialoganglioside GD1a and fetuin as exogenous substrates. The enzymatic activity was stimulated by 0.08% Triton X-100 and reached the highest level at pH 4.0. Results obtained showed that gangliosides are hydrolysed more extensively than glycoproteins by K 562 sialidases. This finding could suggest that endogenous gangliosides may be the main source of metabolically available sialic acid in K 562 cell line. After treatment of K 562 cells by Adriamycin (40 nM), a potent anticancer drug, sialidase activity decreased by 40% as compared to control cells. This decrease occurs early during the first day of incubation with Adriamycin. This inhibition of sialidase activity could explain previous results obtained in our laboratory which show an enhanced sialylation of the membrane glycoconjugates after Adriamycin treatment.