Rituximab treatment in Myasthenia gravis: an open-label trial

Myasthenia gravis (MG), an antibody (AB)-mediated autoimmune disorder, responds to treatments targeting the humoral response such as intravenous immunoglobulines (IVIG) and plasma exchange treatments (PEX). Rituximab (RTX), a monoclonal anti-CD20 AB that depletes the specific B lymphocyte population should be efficient and is being used for resistant MG patients in small cohorts. Objectives: This is an observational prospective study that aims to determine the efficacy of RTX in MG, the duration of the clinical effect after treatment and the possible sparing effect on other immunosuppressive drugs.Methods: Between January 2009 and December 2010, 8 MG (2 with anti-MUSK AB) patients (62.5% female) with mean age of 41 years (range 24-79 yo), were treated by RTX. The patients treated were those who experienced serious side-effects and/or treatment failure. In three cases the criteria for treatment was the need to spare frequent recurrent plasmapheresis or IGIV treatment. We compared the functional tests before and prospectively after the treatment (schema used for one cure: 2 9 1gr within 15 days interval), the duration of the efficiency (follow-up of 4-24 months) and we repeated the cures based on clinical criteria.Results: Two patients (25%) underwent 3 RTX cures, 2 (25%) underwent 2 cures and the others (50%) one cure. No adverse events were observed. Six patients (75%) showed a clinical response with improvement of the functional scores and reduction of the concomitant immunosuppressive treatments (75% for prednisone, 35% for other immunosuppressive drugs) that persists over a period of 4-9 months. Follow-up of clinical state and lymphocyte count showed an inverse correlation between the CD 19 count and the clinical state of the patients.Conclusion: In this small series of patients RTX treatment shows significant improvement of clinical state of MG refractory to conventional treatment patients, without side-effects reported, even in patients that were retreated. Larger studies should be held to determine if RTX could be an alternative to plasmapheresis and IVIG as second-line treatment in MG.

Functional analysis of different haematopoietic stem cell subsets

RÉSUMÉ : Elucider les bases moléculaires et cellulaires du fonctionnement des cellules souches s'avère crucial dans la compréhension de l'organisation cellulaire au sein des tissus et des organes ainsi que pour le développement de nouvelles stratégies thérapeutiques en médecine régénérative et en oncologie. Les cellules souches adultes les mieux connues sont celles responsables de l'hématopoïèse, les cellules souches hématopoïétiques (CSH). Durant ces dernières années, la recherche a porté une attention particulière à l'isolation prospective de CSH dérivées de la moelle osseuse de souris en utilisant des marqueurs de surface cellulaire ainsi que des propriétés fonctionnelles alléguées. Par la suite, la capacité fonctionnelle des CSH a été vérifiée classiquement par leur transplantation intraveineuse dans des souris réceptrices conditionnées et par l'analyse de leur aptitude à reconstituer le système hématopoïétique à long terme. Des études récentes suggèrent que la transplantation des cellules directement dans la moelle osseuse pourrait non seulement aboutir à une prise de greffe plus rapide et plus efficace, mais pourrait même aider à l'identification de cellules qui ont certes des propriétés intrinsèques de CSH, mais qui n'ont pas la capacité de trouver leur niche au sein de la moelle osseuse et ont donc échoué dans les analyses classiques de reconstitution. Dans cette étude, nous comparons à deux niveaux la fonction de différents sous-groupes de cellules souches de la moelle osseuse, définis par leur phénotype de surface cellulaire. Premièrement, nous étudions leur capacité à reconstituer des souris létalement irradiées après injection soit intraveineuse soit intrafémorale. Deuxièmement, par analyse cytométrique de flux à 8 couleurs, nous comparons leur activité relative de « side population » (SP) par exclusion du colorant fluorescent Hoechst 33342. Nos résultats préliminaires renforcent en effet l'idée que la transplantation intrafémorale aboutit à une greffe plus rapide et plus efficace. Par contre, en utilisant cette approche, nous n'arrivons pas à identifier des cellules capables de prendre greffe spécifiquement quand elles sont injectées en intrafémorale. Finalement, bien qu'une confirmation in vivo soit encore nécessaire, nous suggérons sur la base de nos analyses cytométriques de flux, que les cellules SP Sca1t~és éie~~ CD48t~és bas sont très enrichies en CSH. Ceci permettrait l'isolation ex vivo de CSH de la moelle osseuse de souris par une stratégie à la fois nouvelle et simple. SUMMARY : Elucidating the molecular and cellular bases of stem cell function is crucial for the understanding of cellular organisation within tissues and organs as well as for the development of new therapeutic strategies in regenerative medicine and oncology. The best-known adult stem cells are those responsible for haematopoiesis, the haematopoietic stem cells (HSCs). In recent years, much effort has been put into the prospective isolation of mouse bone marrow (BM)-derived HSCs using cell-surface markers and alleged functional properties. Upon isolation, the functional capacity of putative HSCs has been classically assessed by intravenous transplantation into conditioned recipient mice and analysis of their ability to reconstitute the haematopoietic system at long-term. It has recently been suggested that transplanting the cells directly into the BM might not only result in more rapid and more effective engraftment, but even help to identify cells that have intrinsic HSC properties but lack the ability to home to their BM niche and have thus failed to succeed in classical reconstitution assays. In this study, we compare the function of different BM cell subsets, as defined by their cell surface phenotype, on two levels. Firstly, we assess their ability to reconstitute lethally irradiated mice, when injected either intravenously or intrafemorally. Secondly, using 8-colour flow cytometric analysis, we compare their relative side population (SP) activity by exclusion of the fluorescent dye Hoechst 33342. Our preliminary results indeed reinforce the idea that intrafemoral transplantation results in faster and more effective engraftment, however, using this approach, we are unable to identify cells that are capable of engrafting specifically when injected intrafemorally. Finally, although in vivo confirmation is still required, we propose, based on the results of our flow cytometric analyses, that SP Scat Very h'9h CD48Very'°W cells should be highly enriched for HSCs. This would allow for a simple new strategy for the isolation of mouse BM HSCs ex vivo.

The Smartcanula: a new tool for remote access perfusion in limited access cardiac surgery.

Devices for venous cannulation have seen significant progress over time: the original, rigid steel cannulas have evolved toward flexible plastic cannulas with wire support that prevents kinking, very thin walled wire wound cannulas allowing for percutaneous application, and all sorts of combinations. In contrast to all these rectilinear venous cannula designs, which present the same cross-sectional area over their entire intravascular path, the smartcanula concept of "collapsed insertion and expansion in situ" is the logical next step for venous access. Automatically adjusting cross-sectional area up to a pre-determined diameter or the vessel lumen provides optimal flow and ease of use for both, insertion and removal. Smartcanula performance was assessed in a small series of patients (76 +/- 17 kg) undergoing redo procedures. The calculated target pump flow (2.4 L/min/m2) was 4.42 +/- 61 L/ min. Mean pump flow achieved during cardiopulmonary bypass was 4.84 +/- 87 L/min or 110% of the target. Reduced atrial chatter, kink resistance in situ, and improved blood drainage despite smaller access orifice size, are the most striking advantages of this new device. The benefits of smart cannulation are obvious in remote cannulation for limited access cardiac surgery, but there are many other cannula applications where space is an issue, and that is where smart cannulation is most effective.

Tasosartan, enoltasosartan, and angiotensin II receptor blockade: the confounding role of protein binding.

Tasosartan is a long-acting angiotensin II (AngII) receptor blocker. Its long duration of action has been attributed to its active metabolite enoltasosartan. In this study we evaluated the relative contribution of tasosartan and enoltasosartan to the overall pharmacological effect of tasosartan. AngII receptor blockade effect of single doses of tasosartan (100 mg p.o. and 50 mg i.v) and enoltasosartan (2.5 mg i.v.) were compared in 12 healthy subjects in a randomized, double blind, three-period crossover study using two approaches: the in vivo blood pressure response to exogenous AngII and an ex vivo AngII radioreceptor assay. Tasosartan induced a rapid and sustained blockade of AngII subtype-1 (AT1) receptors. In vivo, tasosartan (p.o. or i.v.) blocked by 80% AT1 receptors 1 to 2 h after drug administration and still had a 40% effect at 32 h. In vitro, the blockade was estimated to be 90% at 2 h and 20% at 32 h. In contrast, the blockade induced by enoltasosartan was markedly delayed and hardly reached 60 to 70% despite the i.v. administration and high plasma levels. In vitro, the AT1 antagonistic effect of enoltasosartan was markedly influenced by the presence of plasma proteins, leading to a decrease in its affinity for the receptor and a slower receptor association rate. The early effect of tasosartan is due mainly to tasosartan itself with little if any contribution of enoltasosartan. The antagonistic effect of enoltasosartan appears later. The delayed in vivo blockade effect observed for enoltasosartan appears to be due to a high and tight protein binding and a slow dissociation process from the carrier.

Single-dose oral amoxicillin or linezolid for prophylaxis of experimental endocarditis due to vancomycin-susceptible and vancomycin-resistant Enterococcus faecalis.

Endocarditis prophylaxis following genitourinary or gastrointestinal procedures targets Enterococcus faecalis. Prophylaxis recommendations advocate oral amoxicillin (2 g in the United States and 3 g in the United Kingdom) in moderate-risk patients and intravenous amoxicillin (2 g) or vancomycin (1 g) plus gentamicin in high-risk patients. While ampicillin-resistant (or amoxicillin-resistant) E. faecalis is still rare, there is a concern that these regimens might fail against vancomycin-resistant and/or aminoglycoside-resistant isolates. The present study tested oral linezolid as an alternative. Rats with catheter-induced aortic vegetations were given prophylaxis simulating human pharmacokinetics of oral amoxicillin (2- to 3-g single dose), oral linezolid (600 mg, single or multiple oral doses every 12 h), or intravenous vancomycin (1-g single dose). Rats were then inoculated with the minimum inoculum infecting 90% of the animals (90% infective dose [ID(90)]) or with 10 times the ID(90) of the vancomycin-susceptible E. faecalis strain JH2-2 or the vancomycin-resistant (VanA phenotype) E. faecalis strain UCN41. Amoxicillin was also tested with two additional vancomycin-susceptible E. faecalis strains, 309 and 1209. Animals were sacrificed 3 days later. All the tested bacteria were susceptible to amoxicillin and gentamicin. Single-dose amoxicillin provided 100% protection against all four isolates at both the ID(90) and 10 times the ID(90). In contrast, linezolid required up to four consecutive doses to provide full protection against the vancomycin-resistant isolate. Vancomycin protected only against the vancomycin-susceptible strain. The high efficacy of single-dose oral amoxicillin suggests that this regimen could be used for prophylaxis in both moderate-risk and high-risk patients without additional aminoglycosides. Linezolid appears to be less reliable, at least against the vancomycin-resistant strain.

Abaisser la pression arterielle: urgent ou pas urgent? [How urgent is it to decrease high blood pressure?]

Severe hypertension represents a frequent problem for the general practitioner. One has to decide if the blood pressure needs to be decreased immediately (hypertensive emergency), or if the blood pressure maybe progressively decreased in a few hours and normalized in a few days (hypertensive crisis). Thus it is crucial to identify on the basis of the clinical history and a careful physical examination, the patients for whom the arterial blood pressure elevation represents an acute danger for organ damage or a vital threat in the absence of immediate blood pressure control. In the case of hypertensive crisis, oral medication is usually sufficient (slow release or GITS nifedipine, nitroglycerin, labetalol, captopril). The hypertensive emergency sometimes requires an oral medication before the admission to the emergency room, then followed by intravenous drug administration (sodium nitroprussiate, nitroglycerin, labetalol).

The efficacy of amoxycillin/clavulanate (Augmentin) in the treatment of severe staphylococcal infections.

The experimental and clinical values of amoxycillin/clavulanate in severe Staphylococcus aureus infections are reviewed. Experimentally, amoxycillin/clavulanate was highly effective in the treatment of acute endocarditis due to methicillin-sensitive isolates of S. aureus (MSSA) in rats. In addition, high doses of amoxycillin/clavulanate also cured experimental endocarditis due to methicillin-resistant strains of S. aureus (MRSA) in the animal model. In the clinical setting, a review of 86 patients with either community- or hospital-acquired bacteraemia due to MSSA showed that intravenous treatment with amoxycillin/clavulanate was adequate for empirical (and apparently also long-term) therapy of such severe infections. However, the retrospective nature of the analysis did not allow assessment of the relative efficacy of amoxycillin/clavulanate as compared with standard anti-staphylococcal drugs, such as flucloxacillin or vancomycin. Further prospective studies are warranted to address this issue. Thus, amoxycillin/clavulanate appears to be a good candidate for empirical treatment of severe infections that may be caused by MSSA. Usage of amoxycillin/clavulanate against MRSA is, however, still experimental and is not currently advocated for the treatment of MRSA infections in humans.

A novel technique using echocardiography to evaluate venous cannula performance perioperatively in CPB cardiac surgery.

OBJECTIVE: Transthoracic echocardiography (TTE) has been used clinically to disobstruct venous drainage cannula and to optimise placement of venous cannulae in the vena cava but it has never been used to evaluate performance capabilities. Also, little progress has been made in venous cannula design in order to optimise venous return to the heart lung machine. We designed a self-expandable Smartcanula (SC) and analysed its performance capability using echocardiography. METHODS: An epicardial echocardiography probe was placed over the SC or control cannula (CTRL) and a Doppler image was obtained. Mean (V(m)) and maximum (V(max)) velocities, flow and diameter were obtained. Also, pressure drop (DeltaP(CPB)) was obtained between the central venous pressure and inlet to venous reservoir. LDH and Free Hb were also compared in 30 patients. Comparison was made between the two groups using the student's t-test with statistical significance established when p<0.05. RESULTS: Age for the SC and CC groups were 61.6+/-17.6 years and 64.6+/-13.1 years, respectively. Weight was 70.3+/-11.6 kg and 72.8+/-14.4 kg, respectively. BSA was 1.80+/-0.2 m(2) and 1.82+/-0.2 m(2), respectively. CPB times were 114+/-53 min and 108+/-44 min, respectively. Cross-clamp time was 59+/-15 min and 76+/-29 min, respectively (p=NS). Free-Hb was 568+/-142 U/l versus 549+/-271 U/l post-CPB for the SC and CC, respectively (p=NS). LDH was 335+/-73 mg/l versus 354+/-116 mg/l for the SC and CC, respectively (p=NS). V(m) was 89+/-10 cm/s (SC) versus 63+/-3 cm/s (CC), V(max) was 139+/-23 cm/s (SC) versus 93+/-11 cm/s (CC) (both p<0.01). DeltaP(CPB) was 30+/-10 mmHg (SC) versus 43+/-13 mmHg (CC) (p<0.05). A Bland-Altman test showed good agreement between the two devices used concerning flow rate calculations between CPB and TTE (bias 300 ml+/-700 ml standard deviation). CONCLUSIONS: This novel Smartcanula design, due to its self-expanding principle, provides superior flow characteristics compared to classic two stage venous cannula used for adult CPB surgery. No detrimental effects were observed concerning blood damage. Echocardiography was effective in analysing venous cannula performance and velocity patterns.

CB1 cannabinoid receptor modulates MDMA acute responses and reinforcement

Background: 3, 4-methylenedioxymethamphetamine (MDMA) is a popular recreational drug widely abused by young people. The endocannabinoid system is involved in the addictive processes induced by different drugs of abuse. However, the role of this system in the pharmacological effects of MDMA has not been yet clarified.Methods: Locomotion, body temperature and anxiogenic-like responses were evaluated after acute MDMA administration in CB1 knockout mice. Additionally, MDMA rewarding properties were investigated in the place conditioning and the intravenous self-administration paradigms. Extracellular levels of DA in the nucleus accumbens were also analyzed after a single administration of MDMA by in vivo microdialysis. Results: Acute MDMA administration increased locomotor activity, body temperature and anxiogenic-like responses in wild type mice, but these responses were lower or abolished in knockout animals. MDMA produced similar conditioned place preference and increased dopamine extracellular levels in the nucleus accumbens in both genotypes. Nevertheless, CB1 knockout mice failed to self-administer MDMA at any of the doses used. Conclusions: These results indicate that CB1 cannabinoid receptors play an important role in the acute prototypical effects of MDMA, and are essential in the acquisition of an operant behavior to self-administer this drug.

L-canavanine, an inhibitor of inducible nitric oxide synthase, improves venous return in endotoxemic rats.

OBJECTIVE: To investigate the hemodynamic effects of L-canavanine (an inhibitor of inducible, but not of constitutive, nitric oxide synthase) in endotoxic shock. DESIGN: Controlled, randomized, experimental study. SETTING: Animal laboratory. SUBJECTS: Wistar rats. INTERVENTIONS: Rats were anesthetized with pentobarbital, and hemodynamically monitored. One hour after an intravenous challenge with 5 mg/kg of Escherichia coli endotoxin, the rats were randomized to receive a continuous infusion of either L-canavanine (20 mg/kg/hr; n = 8) or vehicle only (isotonic saline, n = 11). In all animals, the infusion was given over 5 hrs at a rate of 2 mL/kg/hr. These experiments were repeated in additional rats challenged with isotonic saline instead of endotoxin (sham experiments). MEASUREMENTS AND MAIN RESULTS: Arterial blood pressure, heart rate, thermodilution cardiac output, central venous pressure, mean systemic filling pressure, urine output, arterial blood gases, blood lactate concentration, and hematocrit were measured. In sham experiments, hemodynamic stability was maintained throughout and L-canavanine had no detectable effect. Animals challenged with endotoxin and not treated with L-canavanine developed progressive hypotension and low cardiac output. After 6 hrs of endotoxemia, both central venous pressure and mean systemic filling pressure were significantly below their baseline values, indicating relative hypovolemia as the main determinant of reduced cardiac output. In endotoxemic animals treated with L-canavanine, hypotension was less marked, while cardiac output, central venous pressure, and mean systemic filling pressure were maintained throughout the experiment. L-canavanine had no effect on the time-course of hematocrit. L-canavanine significantly increased urine output and reduced the severity of lactic acidosis. CONCLUSIONS: Six hours after an endotoxin challenge in rats, low cardiac output develops, which appears to be primarily related to relative hypovolemia. L-canavanine, a selective inhibitor of the inducible nitric oxide synthase, increases the mean systemic filling pressure, thereby improving venous return, under these conditions.

Behandlung des akuten Hirninfarktes [Treatment of acute stroke -- an overview]

This paper provides an overview on the actual state of acute therapy in patients with ischemic stroke. The discussion focusses on intravenous and intraarterial thrombolysis, antithrombotic therapy, and the treatment of medical and neurological complications, and therapy recommendations are presented. Finally ongoing studies, particularly those concerning thrombolysis with glycoprotein IIb/IIIa receptor blockers and ultrasound-assisted thrombolysis, are presented.

Bloodstream infections related to totally implantable venous access port: What is the situation in our hospital?

Port-a-Cath© (PAC) are totally implantable devices that offer an easy and long term access to venous circulation. They have been extensively used for intravenous therapy administration and are particularly well suited for chemotherapy in oncologic patients. Previous comparative studies have shown that these devices have the lowest catheter-related bloodstream infection rates among all intravascular access systems. However, bloodstream infection (BSI) still remains a major issue of port use and epidemiology data for PAC-associated BSI (PABSI) rates differ strongly depending on studies. Also, current literature about PABSI risk factors is scarce and sometimes controversial. Such heterogeneity may depend on type of studied population and local factors. Therefore, the aim of this study was to describe local epidemiology and risk factors for PABSI in adult patients in our tertiary- care university hospital. We conducted a retrospective cohort study in order to describe local epidemiology. We also performed a nested case-control study to identify local risk factors of PABSI. We analyzed medical files of adult patients who had a PAC implanted between January 1st, 2008 and December 31st, 2009 and looked for PABSI occurrence before May 1st, 2011 to define cases. Thirty nine PABSI occurred in this population with an attack rate of 5.8%. We estimated an incidence rate of 0.08/1000 PAC-days using the case-control study. PABSI causative agents were mainly Gram positive cocci (62%). We identified three predictive factors of PABSI by multivariate statistical analysis: neutropenia on outcome date (Odds Ratio [OR]: 4.05; 95% confidence interval [CI]:1.05- 15.66; p=0.042), diabetes (OR: 11.53; 95% CI: 1.07-124.70; p=0.044) and having another infection than PABSI on outcome date (OR: 6.35; 95% CI: 1.50-26.86; p=0.012). Patients suffering from acute or renal failure (OR: 4.26; 95% CI: 0.94-19.21; p=0.059) or wearing another invasive device (OR: 2.99; 95%CI:0.96-9.31; p=0.059) did not have a statistically increased risk for developing a PABSI according to classical threshold (p<0.05) but nevertheless remained close to significance. Our study demonstrated that local epidemiology and microbiology of PABSI in our institution was similar to previous reports. A larger prospective study is required to confirm our results or to test preventive measures.

Once-yearly zoledronic acid and days of disability, bed rest, and back pain: randomized, controlled HORIZON Pivotal Fracture Trial.

The objective of this study was to determine the effect of once-yearly zoledronic acid on the number of days of back pain and the number of days of disability (ie, limited activity and bed rest) owing to back pain or fracture in postmenopausal women with osteoporosis. This was a multicenter, randomized, double-blind, placebo-controlled trial in 240 clinical centers in 27 countries. Participants included 7736 postmenopausal women with osteoporosis. Patients were randomized to receive either a single 15-minute intravenous infusion of zoledronic acid (5 mg) or placebo at baseline, 12 months, and 24 months. The main outcome measures were self-reported number of days with back pain and the number of days of limited activity and bed rest owing to back pain or a fracture, and this was assessed every 3 months over a 3-year period. Our results show that although the incidence of back pain was high in both randomized groups, women randomized to zoledronic acid experienced, on average, 18 fewer days of back pain compared with placebo over the course of the trial (p = .0092). The back pain among women randomized to zoledronic acid versus placebo resulted in 11 fewer days of limited activity (p = .0017). In Cox proportional-hazards models, women randomized to zoledronic acid were about 6% less likely to experience 7 or more days of back pain [relative risk (RR) = 0.94, 95% confidence interval (CI) 0.90-0.99] or limited activity owing to back pain (RR = 0.94, 95% CI 0.87-1.00). Women randomized to zoledronic acid were significantly less likely to experience 7 or more bed-rest days owing to a fracture (RR = 0.58, 95% CI 0.47-0.72) and 7 or more limited-activity days owing to a fracture (RR = 0.67, 95% CI 0.58-0.78). Reductions in back pain with zoledronic acid were independent of incident fracture. Our conclusion is that in women with postmenopausal osteoporosis, a once-yearly infusion with zoledronic acid over a 3-year period significantly reduced the number of days that patients reported back pain, limited activity owing to back pain, and limited activity and bed rest owing to a fracture.

BAL9141, a novel extended-spectrum cephalosporin active against methicillin-resistant Staphylococcus aureus in treatment of experimental endocarditis.

The therapeutic efficacy of BAL9141 (formerly Ro 63-9141), a novel cephalosporin with broad in vitro activity that also has activity against methicillin-resistant Staphylococcus aureus (MRSA), was investigated in rats with experimental endocarditis. The test organisms were homogeneously methicillin-resistant S. aureus strain COL transformed with the penicillinase-encoding plasmid pI524 (COL Bla+) and homogeneously methicillin-resistant, penicillinase-producing isolate P8-Hom, selected by serial exposure of parent strain P8 to methicillin. The MICs of BAL9141 for these organisms (2 mg/liter) were low, and BAL9141was bactericidal in time-kill curve studies after 24 h of exposure to either two, four, or eight times the MIC. Rats with experimental endocarditis were treated in a three-arm study with a continuous infusion of BAL5788 (formerly Ro 65-5788), a carbamate prodrug of BAL9141, or with amoxicillin-clavulanate or vancomycin. The rats were administered BAL9141 to obtain steady-state target levels of 20, 10, and 5 mg of per liter or were administered either 1.2 g of amoxicillin-clavulanate (ratio 5:1) every 6 h or 1 g of vancomycin every 12 h at changing flow rates to simulate the pharmacokinetics produced in humans by intermittent intravenous treatment. Treatment was started 12 h after bacterial challenge and lasted for 3 days. BAL9141 was successful in the treatment of experimental endocarditis due to either MRSA isolate COL Bla+ or MRSA isolate P8-Hom at the three targeted steady-state concentrations and sterilized &gt;90% of cardiac vegetations (P &lt; 0.005 versus controls; P &lt; 0.05 versus amoxicillin-clavulanate and vancomycin treatment groups). These promising in vivo results with BAL9141 correlated with the high affinity of the drug for PBP 2a and its stability to penicillinase hydrolysis observed in vitro.

Immunoscintigraphic localization of inflammatory lesions: concept, radiolabelling and in vitro testing of a granulocyte specific antibody.

Current nuclear medicine techniques for the localization of inflammatory processes are based on injection of 111In labelled autologous granulocytes which need to be isolated and radiolabelled in vitro before reinjection. A new technique is presented here that obviates the need for cell isolation by the direct intravenous injection of a granulocyte specific 123I labelled monoclonal antibody. In this publication the basic parameters of the antibody granulocyte interaction are described. Antibody binding does not inhibit vital functions of the granulocytes, such as chemotaxis and superoxide generation. Scatchard analysis of binding data reveals an apparent affinity of the antibody for granulocytes of 6.8 X 10(9) l/mol and approximately 7.1 X 10(4) binding sites per cell. Due to the high specificity of the antibody, the only expected interference is from CEA producing tumors.