Search PubMed⌕ Search

Biomedical subjects

D Roos

Publications and source records attributed to D Roos.

At least 73 records · Page 4Linked to original sources

Influence of peroperative lavage solutions on peritoneal defence mechanisms in vitro.

OBJECTIVE: To find out the in vitro reaction of mesothelial cells and polymorphonuclear leucocytes (PMN) to incubation with seven commonly-used lavage solutions. DESIGN: Experimental study. SETTING: Laboratories, The Netherlands. MATERIAL: Cultured human peritoneal mesothelial cells and isolated PMN. INTERVENTION: Incubation of cells with clinically used lavage solutions (sodium chloride, Hartmann's solution, povidone-iodine, Dakin's solution, taurolidine, chlorhexidine, and hydrogen peroxide). MAIN OUTCOME MEASURES: Activation of monolayers of mesothelial cells and PMN measured by release of oxygen free radicals (chemiluminescence) and interleukin (IL)-8 concentrations and toxic effects measured by morphology, release of lactate dehydrogenase, failure of the restriction of the passage of inulin, and incorporation of propidium iodide. RESULTS: All solutions activated and killed mesothelial cells and PMN to some extent; the more concentrated the solution the greater the effect on these cells. CONCLUSION: Lavage solutions both poison and stimulate mesothelial cells and neutrophils, and some solutions are more potent than others.

Anti-Infective Agents, Local↗

Osteolymphoma (primary bone lymphoma): an Australian review of 70 cases. Australasian Radiation Oncology Lymphoma Group (AROLG).

BACKGROUND: To examine prognostic factors, treatment outcomes and design future studies for Osteolymphoma (OL)--also known as primary bone lymphoma. METHODS: Between 1979 and 1993, 70 patients with OL were treated in nine Australian centres. The effect of patient-, tumour-, and treatment-related factors on local control, distant disease-free survival and overall survival were assessed by multivariate analysis. RESULTS: Most patients (94%) received radiotherapy (RT) (median dose 40 Gy) and 56% received chemotherapy. Multifocal disease was present in 20% of patients. The five year rates of overall survival and local control were 59% and 82%. Although there was a trend towards better results with the addition of chemotherapy, on multivariate analysis, there were no factors identified which appeared to impact upon overall and disease-free survival. Among the distant recurrences, there was a high proportion in bone (33%). Six patients suffered pathological fractures after treatment. CONCLUSION: High rates of local control were achieved by RT, but the overall survival remains relatively poor, worse than nodal lymphoma. The natural history of the disease suggests that OL may be a distinct entity, different to nodal lymphomas, so the results of clinical trials in nodal lymphoma may not be relevant to OL. Prospective studies could define the outcome of combined modality therapy and set a benchmark for testing further proposals, as well as improving our knowledge of the clinical features of OL.

Adult↗

Vascular-endothelial-cadherin modulates endothelial monolayer permeability.

Vascular endothelial (VE)-cadherin is the endothelium-specific member of the cadherin family of homotypic cell adhesion molecules. VE-cadherin, but not the cell adhesion molecule platelet/endothelial cell adhesion molecule (PECAM-1), markedly colocalizes with actin stress fibers at cell-cell junctions between human umbilical vein endothelial cells. Inhibition of VE-cadherin-mediated, but not PECAM-1-mediated, adhesion induced reorganization of the actin cytoskeleton, loss of junctional VE-cadherin staining and loss of cell-cell adhesion. In functional assays, inhibition of VE-cadherin caused increased monolayer permeability and enhanced neutrophil transendothelial migration. In a complementary set of experiments, modulation of the actin cytoskeleton was found to strongly affect VE-cadherin distribution. Brief stimulation of the beta2-adrenergic receptor with isoproterenol induced a loss of actin stress fibers resulting in a linear, rather than 'jagged', VE-cadherin distribution. The concomitant, isoproterenol-induced, reduction in monolayer permeability was alleviated by a VE-cadherin-blocking antibody. Finally, cytoskeletal reorganization resulting from the inactivation of p21Rho caused a diffuse localization of VE-cadherin, which was accompanied by reduced cell-cell adhesion. Together, these data show that monolayer permeability and neutrophil transendothelial migration are modulated by VE-cadherin-mediated cell-cell adhesion, which is in turn controlled by the dynamics of the actin cytoskeleton.

Actins↗

Hb Nijkerk: a new mutation at codons 138/139 of the beta-globin gene inducing severe hemolytic anemia in a Dutch girl.

We describe a new structural mutant of the beta-globin chain in a 17-year-old Dutch Caucasian girl. The mutant is associated with a severe pathology as a consequence of hyper-instability of the hemoglobin tetramer. The proband, whose parents had no history of hemolysis, was admitted to the hospital at 5 months of age with hemolytic anemia and splenomegaly. No indications for autoimmune defects or enzymopathies were found. Repeated hemoglobin electrophoresis on cellulose acetate revealed no abnormalities. At the age of 17 years, a minor abnormal band of less than 1% was detected on starch gel electrophoresis, migrating slightly faster than Hb A2. Sequencing of the beta-globin gene revealed heterozygosity for a 4 bp deletion (GCTA) in combination with a 1 bp insertion (T) at codons 138/139. This event eliminates two amino acids (Ala-Asn) and introduces a new residue (Tyr). We discuss the hematological and the pathophysiological consequences of this mutant, which is fully expressed as a gene product, and apparently assembled into unstable tetramers that precipitate shortly after.

Acute Disease↗

Reactive oxygen species are required for the phagocytosis of myelin by macrophages.

Reactive oxygen species (ROS) are thought to be involved in the pathogenesis of multiple sclerosis (MS) and experimental allergic encephalomyelitis (EAE). In this study we showed that the phagocytosis of myelin by macrophages triggers the production of ROS. We also demonstrated that ROS play a crucial role in the myelin phagocytosis. Blocking the ROS production with NADPH oxidase inhibitors (100 microM DPI or 10 mM Apocynin) essentially prevented the phagocytosis of myelin. Furthermore, scavenging of ROS with catalase (H2O2) or mannitol (OH-) decreased the phagocytosis of myelin by macrophages, whereas superoxide dismutase (O2-) did not show this effect. In addition, Lipoic acid (LA), a non-specific scavenger of ROS, also decreased the phagocytosis of myelin by macrophages. In our results, we demonstrate for the first time that ROS appear to play a regulatory role in the phagocytosis of myelin.

Animals↗

Nicotinamide-adenine dinucleotide phosphate oxidase assembly and activation in EBV-transformed B lymphoblastoid cell lines of normal and chronic granulomatous disease patients.

This paper deals with the mechanisms of activation of NADPH oxidase investigated using EBV-transformed human B lymphoblastoid cell lines (B cells) from normal subjects and from patients affected by X-linked chronic granulomatous disease (CGD). The results reported are as follows. 1) In normal B cells, the NADPH oxidase components p67phox, p40phox, p22phox, and gp91phox were less expressed than in polymorphonuclear neutrophils. 2) In normal B cells stimulated with PMA, p47phox, p67phox, and p40phox translocated to the membranes as occurs in polymorphonuclear neutrophils. 3) In CGD, B cells expressing p22phox in the absence of gp91phox, p47phox, p67phox, and p40phox did not translocate to the membranes after stimulation with PMA. 4) In PMA-stimulated B cells from an X91+ CGD patient in which p22phox was normally expressed and gp91phox was present but lacked five amino acids, translocation of p47phox to the membranes was unaffected, but p67phox and p40phox were poorly translocated, and the production of O2- was greatly reduced with respect to that by normal B cells. Taken together, these findings indicate that 1) a low expression of some NADPH oxidase components may represent the molecular basis of the low production of O2- in B lymphocytes; 2) the cytosolic components of NADPH oxidase cannot bind to p22phox on the membranes in the absence of gp91phox; 3) p47phox can translocate to the membranes independently of p67phox and p40phox; and 4) gp91phox may have a role in mediating and/or stabilizing the binding of p67phox and p40phox to the membranes of activated cells.

B-Lymphocytes↗

Triple role of platelet-activating factor in eosinophil migration across monolayers of lung epithelial cells: eosinophil chemoattractant and priming agent and epithelial cell activator.

Infiltration of eosinophils into the lung lumen is a hallmark of allergic asthmatic inflammation. To reach the lung lumen, eosinophils must migrate across the vascular endothelium, through the interstitial matrix, and across the lung epithelium. The regulation of this process is obscure. In this study, we investigated the migration of human eosinophils across confluent monolayers of either human lung H292 epithelial cells or primary human bronchial epithelial cells. Established eosinophil chemoattractants (IL-8, RANTES, platelet-activating factor (PAF), leukotriene B4, and complement fragment 5a (C5a)) or activation of the epithelial cells with IL-1beta induced little eosinophil transmigration (<7% in 2 h). In contrast, addition of PAF in combination with C5a induced extensive (>20%) transepithelial migration of unprimed and IL-5-primed eosinophils. Eosinophil migration assessed in a Boyden chamber assay, i.e., without an epithelial monolayer, was only slightly increased upon addition of PAF and C5a. Preincubation of eosinophils with the PAF receptor antagonist WEB 2086 only inhibited migration of unprimed eosinophils toward PAF and C5a, whereas preincubation of epithelial cells with WEB 2086 abolished migration of both IL-5-primed and unprimed eosinophils. This latter result indicated the presence of PAF receptors on epithelial cells. Indeed, addition of PAF to epithelial cells induced an increase in cytosolic free Ca2+, which was blocked by the PAF receptor antagonists WEB 2086 and TCV-309. Our results show that PAF induces permissive changes in epithelial cells, and that PAF acts as a chemoattractant and priming agent for the eosinophils.

Adjuvants, Immunologic↗

PU.1 as an essential activator for the expression of gp91(phox) gene in human peripheral neutrophils, monocytes, and B lymphocytes.

We have reported a deficiency of a 91-kDa glycoprotein component of the phagocyte NADPH oxidase (gp91(phox)) in neutrophils, monocytes, and B lymphocytes of a patient with X chromosome-linked chronic granulomatous disease. Sequence analysis of his gp91(phox) gene revealed a single-base mutation (C --> T) at position -53. Electrophoresis mobility-shift assays showed that both PU.1 and hematopoietic-associated factor 1 (HAF-1) bound to the inverted PU.1 consensus sequence centered at position -53 of the gp91(phox) promoter, and the mutation at position -53 strongly inhibited the binding of both factors. It was also indicated that a mutation at position -50 strongly inhibited PU.1 binding but hardly inhibited HAF-1 binding, and a mutation at position -56 had an opposite binding specificity for these factors. In transient expression assay using HEL cells, which express PU.1 and HAF-1, the mutations at positions -53 and -50 significantly reduced the gp91(phox) promoter activity; however, the mutation at position -56 did not affect the promoter activity. In transient cotransfection study, PU.1 dramatically activated the gp91(phox) promoter in Jurkat T cells, which originally contained HAF-1 but not PU.1. In addition, the single-base mutation (C --> T) at position -52 that was identified in a patient with chronic granulomatous disease inhibited the binding of PU.1 to the promoter. We therefore conclude that PU.1 is an essential activator for the expression of gp91(phox) gene in human neutrophils, monocytes, and B lymphocytes.

B-Lymphocytes↗

Clinical value of soluble IgG Fc receptor type III in plasma from patients with chronic idiopathic neutropenia.

Previous studies have shown that the plasma level of soluble IgG Fc receptor type III (sFcgammaRIII) is a measure of the total body neutrophil mass. The aim of this study was to determine whether the plasma level sFcgammaRIII is associated with the risk of contracting bacterial infections in patients with neutropenia. We collected blood from 66 patients suffering from acquired idiopathic neutropenia, whose blood was sent to our laboratory for diagnostic evaluation of neutropenia (neutrophil count <1,500 cells/microL). Soluble FcgammaRIII levels were measured in plasma. Genotype distibutions of FcgammaR polymorphisms were determined. Clinical data were obtained from the patient files. Patients were assessed as to whether or not they had suffered from a bacterial infection 3 months before to 3 months after a single sFcgammaRIII measurement. In addition, longitudinal data were obtained from 21 patients. Of the 66 neutropenic patients who were included, 15 had suffered from a bacterial infection in the period 3 months before to 3 months after sFcgammaRIII measurement. The age and sex distribution was equal among the groups with and without infections, as were the genotype frequencies of neutrophil FcgammaR polymorphisms. Both neutrophil count and plasma level sFcgammaRIII were significantly lower in the patient group with infections, compared with the noninfected group (P = .03 and P < .0001, respectively). No infections were reported for patients who had plasma sFcgammaRIII levels above 100 arbitrary units (AU; normal value, 30 to 200). After matching each infected patient with two noninfected patients having the same neutrophil count, sFcgammaRIII plasma levels remained significantly lower in the group with infections (P = . 0001). For the patients who were followed in time, no infections were reported when sFcgammaRIII levels were above 100 AU. In conclusion, our population of patients with chronic idiopathic neutropenia with plasma sFcgammaRIII levels above 100 AU did not show an increased risk of contracting bacterial infections.

Adolescent↗

Human eosinophils express, relative to other circulating leukocytes, large amounts of secretory 14-kD phospholipase A2.

Human eosinophils perform several functions dependent on phospholipase A2 (PLA2) activity, most notably the synthesis of platelet-activating factor (PAF) and leukotriene C4 (LTC4). Several forms of PLA2 have been identified in mammalian cells. In the present study, the 14-kD, secretory form of PLA2 was detected in human eosinophils by immunocytochemical staining with the specific monoclonal antibody (MoAb) 4A1. In contrast, preparations of neutrophils, monocytes, lymphocytes, and basophils did not show detectable staining. With two MoAbs in a sandwich enzyme-linked immunosorbent assay (ELISA), large amounts of sPLA2 were detected in lysates of eosinophils, that were 20-fold to 100-fold higher than in the other circulating leukocytes (ie, neutrophils, basophils, monocytes, and lymphocytes). In addition, with a commercially available sPLA2 activity assay kit, we were able to show high activity of sPLA2 in human eosinophils relative to neutrophils. Investigations at the ultrastructural level showed that sPLA2 in eosinophils is mainly located in specific granules. Immunoelectron microscopy also visualized sPLA2 within phagosomes after addition of opsonized particles to the eosinophils. However, sPLA2 was not detected in the cell-free supernatants of activated eosinophils, in contrast to eosinophil-cationic protein (ECP), which colocalizes with sPLA2 in resting eosinophils. These findings warrant further studies into the role of sPLA2 in eosinophil function.

Basophils↗

Fc gamma RIIIB gene duplication: evidence for presence and expression of three distinct Fc gamma RIIIB genes in NA(1+,2+)SH(+) individuals.

Recently, a new alloantigen on IgG Fc receptor type IIIb (Fc gamma RIIIb), SH, was described (Bux et al, Blood 89:1027, 1997). We identified three healthy individuals whose neutrophils reacted positively with the SH antiserum. The neutrophil antigen (NA) phenotype of all three donors was NA(1+,2+). Analysis of genomic DNA showed that the three donors were positive for the described SH-encoding mutation in the NA2-Fc gamma RIIIB gene, 266C-->A. However, NA(1,2) genotyping and nucleotide sequencing of an NA2-specific fragment amplified from the genomic DNA fragment showed that these individuals carried three Fc gamma RIIIB genes, namely, NA1-Fc gamma RIIIB, NA2-Fc gamma RIIIB, and SH-Fc gamma RIIIB, encoding NA1-Fc gamma RIIIb, NA2-Fc gamma RIIIb, and SH-Fc gamma RIIIb, respectively. Southern blot analysis confirmed these findings. Furthermore, all three transcripts were isolated from neutrophil mRNA. To investigate whether the presence of three Fc gamma RIIIB genes resulted in a higher membrane expression of Fc gamma RIIIb, we measured the reactivity of neutrophils from NA(1+,2+)SH(+) individuals with a panel of CD16 monoclonal antibodies (MoAbs) in comparison with neutrophils from NA(1+,2+)SH(-) controls. Reactivity of four different anti-pan-Fc gamma RIII MoAbs and NA2-specific MoAb GRM1 was higher with SH(+) neutrophils compared with controls, whereas that of NA1-specific MoAbs was similar, which is in concordance with the results from the genomic analysis. We observed that reactivity with NA2-specific CD16 MoAb PEN1 was sixfold higher in SH(+) individuals compared with controls. Apparently, the 60Ala-->Asp substitution in SH-Fc gamma RIIIb influences the epitope recognized by PEN1. In conclusion, we identified three NA(1+,2+)SH(+) individuals carrying three Fc gamma RIIIB genes and observed a clear gene-dosage effect on the level of expression of neutrophil Fc gamma RIIIb.

Adult↗

Somatic triple mosaicism in a carrier of X-linked chronic granulomatous disease.

The X-linked form of chronic granulomatous disease (CGD) is caused by mutations in the CYBB gene, which encodes the 91-kD subunit of the flavocytochrome b558, a component of the superoxide-generating nicotinamide adenine dinucleotide phosphate (NADPH) oxidase in phagocytic leukocytes. Mutations in this gene are very heterogeneous and often unique for one family. Here we report on a family with two patients (brothers), one with a 3-kb deletion comprising exon 5 and the other with a 3.5-kb deletion comprising exons 6 and 7 of the CYBB gene. Sequence analysis of polymerase chain reaction (PCR)-amplified genomic DNA proved these deletions to be overlapping for 35 bp. Analysis by restriction fragment length polymorphism of genomic DNA from the mother's leukocytes showed her to be a carrier of both deletions in addition to the normal CYBB sequence. This triple somatic mosaicism was confirmed with PCR-amplified genomic and complementary DNA. The presence of the normal CYBB gene in the mother was also proven by the finding of normal superoxide-generating neutrophils in addition to cells lacking this ability. Triple X syndrome was excluded. These findings suggest that the mutations are the result of an event in early embryogenesis of the mother, possibly involving a mechanism like sister chromatid exchange.

Adolescent↗

The Fc gammaRIIIA-158F allele is a risk factor for systemic lupus erythematosus.

OBJECTIVE: To study whether the Fc gammaRIIIA-158V/F polymorphism, which affects IgG binding affinity, is a risk factor for systemic lupus erythematosus (SLE). METHODS: We genotyped a group of 70 Caucasian SLE patients for all known Fc gammaR polymorphisms. Of this group, 45 patients (64%) had nephritis. In 35 patients, this diagnosis was confirmed by renal biopsy. RESULTS: In the total group of 70 SLE patients, the frequency of the Fc gammaRIIIA-158F allele was 0.74, versus 0.57 in healthy controls (P = 0.003). The genotype distribution of the Fc gammaRIIIA-158V/F polymorphism was also significantly different from that of the control population (P = 0.004). The distribution of the other Fc gammaR polymorphisms--Fc gammaRIIA-131R/H, Fc gammaRIIIB-NA(1,2), and Fc gammaRIIIA-48L/R/H--was similar in SLE patients and controls. CONCLUSION: In our group of SLE patients, only the distribution of the alleles of the Fc gammaRIIIA-158V/F polymorphism was significantly different from that in the control group. This might indicate that macrophage expression of the Fc gammaRIIIA-158F isoform is involved in the disturbed clearance of immune complexes in patients with SLE.

Alleles↗

The molecular basis of chronic granulomatous disease.

CGD is a rare inherited immunodeficiency syndrome, caused by the phagocytes' inability to produce (sufficient) reactive oxygen metabolites. This dysfunction is due to a defect in the NADPH oxidase, the enzyme responsible for the production of superoxide. It is composed of several subunits, two of which, gp91phox and p22phox, form the membrane-bound cytochrome b558, while its three cytosolic components, p47phox, p67phox and p40phox, have to translocate to the membrane upon activation. This is a tightly and intricately controlled process that involves, among others, several low-molecular weight GTP-binding proteins. Gp91phox is encoded on the X-chromosome and p22phox, p47phox and p67phox on different autosomal chromosomes, and a defect in one of these components leads to CGD. This explains the variable mode of inheritance seen in this syndrome. Clinically CGD manifests itself typically already at a very young age with recurrent and serious infections, most often caused by catalase-positive pathogens. Modern treatment options, including prophylaxis with trimethoprim-sulfamethoxazole and rIFN-gamma as well as early and aggressive anti-infection therapy, have improved the prognosis of this disease dramatically. CGD, as a very well-characterized inherited affection of the hematopoietic stem cells, is predestined to be among the first diseases to profit from the advances in cutting-edge therapeutics, such as gene therapy and in utero stem cell transplantation.

Animals↗

Are serum human chorionic gonadotropin clearance curves of use in monitoring methotrexate treatment in cervical pregnancy?

OBJECTIVE: To describe the monitoring of an unsuccessful case of methotrexate treatment of cervical pregnancy. DESIGN: Case report. SETTING: University hospital. PATIENT(S): A 27-year-old woman, gravida 3, para 1, with a vital cervical pregnancy. INTERVENTION(S): Feticide and methotrexate administered both locally and systemically. MAIN OUTCOME MEASURE(S): Treatment success, defined as elimination of the cervical pregnancy with preservation of the uterus. RESULT(S): Despite reassuringly declining serum hCG concentrations, several episodes of severe vaginal bleeding demanded transfusions of 19 U of packed cells, two angiographic embolizations that were complicated by septicemia, and a balloon catheter tamponade followed by a third angiographic embolization. Ultimately, a hysterectomy was necessary because of uncontrollable vaginal bleeding. CONCLUSION(S): This case report shows that serum hCG monitoring was not helpful in the detection of impending treatment failure. Currently, no guidelines are available to clinicians for predicting treatment failure of methotrexate in patients with cervical pregnancy. Serum hCG clearance curves do enable the timely detection of inadequately declining serum hCG concentrations, for which additional methotrexate can be administered.

Adult↗

Degranulation of human basophils by picomolar concentrations of IL-3, IL-5, or granulocyte-macrophage colony-stimulating factor.

In most secretory cells, an increase in the cytosolic free Ca2+ concentration ([Ca2+]i) is associated with the exocytosis response. In this study we have evaluated the effect of thapsigargin on histamine release from purified (70% to 97% pure) human basophils of nonallergic donors. Thapsigargin (2 micromol/L), by inhibiting the uptake of Ca2+ in the stores of the endoplasmic reticulum, leads within 1 minute to a gradual increase in [Ca2+]i in human basophils. Incubation of basophils with thapsigargin by itself induced only a very small release of histamine (5.6% +/- 1.8%). However, under suboptimal conditions of stimulation with other agonists, preincubation of basophils with thapsigargin significantly enhanced histamine release. Most strikingly, addition of thapsigargin made basophils extremely sensitive for histamine release induced by IL-3 (maximum histamine release, 71% +/- 7%), IL-5 (maximum histamine release, 43% +/- 8%), or granulocyte-macrophage colony-stimulating factor (GM-CSF) (maximum histamine release, 57% +/- 10%). These cytokines by themselves did not induce histamine release in purified basophils. The effect of thapsigargin was mimicked to a limited extent by addition of platelet-activating factor. We conclude that depletion of the Ca2+ stores may be a critical event in the activation of receptor-mediated histamine release in human basophils.

Basophil Degranulation Test↗

Acute effects of therapeutic irradiation for prostatic carcinoma on anorectal function.

AIM: The incidence of anorectal symptoms after radiotherapy (RTH) for localised pelvic malignant disease is unclear. In addition, the effects of pelvic irradiation on both anorectal motility and sensory function are poorly defined. A prospective study was therefore performed on 35 patients (55-82 years of age) with localised prostatic carcinoma before and four to six weeks after RTH to assess its effects on anorectal function. METHODS: Anorectal symptoms were assessed by questionnaire. Anorectal pressures at rest and in response to voluntary squeeze, rectal distension, and increases in intra-abdominal pressure were evaluated with perfused sleeve side hole manometry. Rectal sensation was tested during graded balloon distension. Rectal compliance was calculated by the pressure-volume relation obtained during the testing of rectal sensation. Ultrasound was used to determine anal sphincter structure and integrity. RESULTS: RTH had no effect on anal sphincter morphology. The frequency of defecation increased after RTH (7 (3-21) v 10 (3-56) bowel actions a week; p < 0.01). After RTH, 16 patients had faecal urgency and eight faecal incontinence, compared with five and one respectively before RTH (p < 0.01 for each). Basal and squeeze sleeve recorded pressures were reduced after RTH (54 (3) v 49 (3) mm Hg (p < 0.05) and 111 (8) v 102 (8) mm Hg (p < 0.01), before and after RTH respectively; means (SEM)). Rectal compliance was reduced after RTH (1.2 v 1.4 mm Hg/ml, p < 0.05). After RTH, threshold volumes for perception of rectal distension were lower in the 16 patients who either experienced faecal urgency for the first time (13 patients) or reported worsening of this symptom (three patients) compared with the remaining patients (34 (4) v 48 (5) ml respectively, p < 0.05). CONCLUSION: Faecal incontinence (23%) is a common problem four to six weeks after RTH for prostatic carcinoma and is associated with minor reductions in anal sphincter pressures. The high prevalence of faecal urgency in patients after RTH may be related to alterations in rectal perception of stool.

Aged↗

Leukocyte adhesion deficiency type 1 (LAD-1)/variant. A novel immunodeficiency syndrome characterized by dysfunctional beta2 integrins.

Leukocyte adhesion deficiency (LAD) is characterized by the inability of leukocytes, in particular neutrophilic granulocytes, to emigrate from the bloodstream towards sites of inflammation. Infectious foci are nonpurulent and may eventually become necrotic because of abnormal wound healing. LAD-1 is characterized by the absence of the beta2 integrins (CD11/CD18) on leukocytes. When expression is completely absent, patients often die within the first year. However, low levels of beta2 expression may result in a milder clinical picture of recurrent infection, which offers a better prognosis. In this paper, we describe the in vivo and in vitro findings on a patient with clinical features of a mild LAD-1 disorder, i.e., suffering from bacterial infections without apparent pus formation in the presence of a striking granulocytosis, showing no delayed-type hypersensitivity reaction upon skin testing, no specific antibody generation, but normal in vitro T cell proliferation responses after immunization. Expression levels of CD11/CD18 proteins were completely normal, but leukocyte activation did not result in CD11/ CD18 activation and high-avidity ligand-binding. In vitro chemotaxis and endothelial transmigration of the neutrophils as well as leukocyte aggregation responses were almost absent. On the other hand, beta1 and beta3 integrin-mediated adhesion functions were completely normal. During follow-up, a bleeding tendency related to decreased beta3 activation became clinically apparent, different from previously described cellular adhesion molecule variants. Therefore, this is the first well-documented case of a clinical combined immunodeficiency syndrome that results from nonfunctional CD11/CD18 molecules, and thus designated LAD-1/ variant.

Antigens, CD↗