A Rare Case of Chronic Myeloid Leukemia with t(3;9;22) 3-way Translocation

Introduction/Objective

Chronic Myeloid Leukemia (CML) is a myeloproliferative neoplasm originating from malignant clonal proliferation of a pluripotent hematopoietic stem cell. CML is characterized by a reciprocal translocation between chromosomes 9 and 22, t(9;22)(q34;q11), that gives rise to an abnormal chromosome 22 called the Philadelphia (Ph) chromosome. The translocation results in the formation of a chimeric BCR-ABL1 fusion gene, which is the molecular hallmark of the disease. However, 5-10% of CML patients present with additional chromosomal abnormalities which is often considered a sign of clonal evolution, genetic instability, and is generally thought to portend a poor prognosis.

Methods

We present a case of CML with a rare 3- way translocation, t(3;9;22)(q21;q34;q11.2), who achieved a major molecular response on imatinib for 18 months. A review of the literature and Mitelman database search is presented focusing on the prognostic implications of this 3 way translocation in the era of tyrosine kinase inhibitors starting in 2001 till now.

Results

Twenty seven cases were reported, but the patient therapeutic response to imatinib and clinical outcome were only reported in 11 cases. Nine cases achieved a cytogenetic remission while the remaining two cases had an adverse outcome.

Conclusion

Taken in conjunction with the favorable outcome in our patient, we suggest that t(3;9;22) is not an adverse prognostic factor in the era of tyrosine kinase inhibitors.

Programa de formación de ayudantes de investigación: conocimiento y satisfacción de los estudiantes

<strong>Introducción</strong><span>: La inserción de estudiantes de pregrado en actividades de investigación es relevante para fomentar la crítica y aplicación de resultados de investigación. La formación de ayudantes de investigación se plantea como una alternativa válida para que los alumnos se expongan, experimenten y participen activamente en el proceso de investigación.</span><br /><strong>Objetivo</strong><span>: Identificar el nivel de conocimiento y grado de satisfacción de los estudiantes después de  participar en un programa de formación de ayudantes de investigación. </span><em>Método</em><span>: Estudio de pre y post test en 20 estudiantes de pregrado de Enfermería. Se evaluó el conocimiento alcanzado y la satisfacción de los estudiantes con el  programa de formación, el cual considera  tres módulos de aprendizaje distribuidos en 180 horas cronológicas.</span><br /><strong>Resultados</strong><span>: El conocimiento de los estudiantes incrementó significativamente con el programa, no se relacionó con el conocimiento que el alumno trae al inicio del mismo, así como tampoco con el semestre que cursa. El grado de satisfacción fue en el 100% de los alumnos muy satisfecho.</span><br /><strong>Discusión</strong><em>:</em><span> Este artículo reporta un programa de formación de ayudantes de investigación que es posible ser replicado en otras realidades, que incrementa el conocimiento, con un alto grado de satisfacción en los estudiantes. La duración del programa podría considerarse una debilidad.</span><br /><strong>Conclusión</strong><em>:</em><span> La participación de estudiantes de pregrado en un programa de formación de ayudantes de investigación, puede considerarse una estrategia para involucrar a alumnos en investigación, y que valoren su aporte en la disciplina de enfermería.</span>

Impact of cognitive impairment, depression, disease activity, and disease damage on quality of life in women with systemic lupus erythematosus

OBJECTIVES

To define the relative role of cognitive impairment, depression, disease activity, and disease damage in the decreased health-related quality of life (HRQoL) frequently observed in systemic lupus erythematosus (SLE) patients.

METHOD

We studied 101 Chilean female SLE patients and applied the 12-item Medical Outcomes Study (MOS) Short Form Health Survey version 2 (SF-12v2) to assess HRQoL and the Cambridge Neuropsychological Test Automated Battery (CANTAB) to assess cognitive function. Analysis of covariance (ANCOVA) models included demographic and disease-related factors and cognitive function tests of sustained attention, memory, and executive function.

RESULTS

All measures of HRQoL were lower in the 101 female SLE patients compared to the women from the Chilean general population. HRQoL was associated with the following factors: (i) depression symptoms, which were detrimental to all components of the physical and mental HRQoL scores; (ii) executive dysfunction (spatial planning), which was associated with lower scores on role limitations due to physical health problems and emotional problems, and general health perceptions; (iii) higher activity and organ damage were deleterious to role physical, bodily pain, and physical summary scores; and (iv) higher damage also impacted physical function. Impairments in sustained attention and memory did not decrease the HRQoL.

CONCLUSIONS

Our results highlight the relevance of executive dysfunction to poor physical and mental health components of HRQoL in SLE together with depression, while disease activity and disease damage are associated with lower HRQoL physical components. The need for cognitive function evaluation and rehabilitation in SLE is indicated.

Increased prevalence of Mycoplasma pneumoniae serological positivity in Chilean young children

BACKGROUND

Mycoplasma pneumoniae is a frequent cause of respiratory infections in school children and adolescents. Epidemiological suspicion is important, since there are no specific symptoms or signs to help in diagnosing infection caused by this agent.

OBJECTIVE

To determine the variation in prevalence over the last 10 years of M. pneumoniae IgM seropositivity according to age, particularly in pre-schoolers.

METHOD

The results of M. pneumoniae IgM serological testing between January 2004 and December 2013 were analysed. Variables such as gender and month and year of sample processing were studied according to age groups (<5, 5-18, 19-50, 51-70 and >70 years of age).

RESULTS

Of a total of 20,020 serological samples, 31.9% proved positive for M. pneumoniae. All age groups showed increases in percentage seropositivity over the last 10 years, although the most significant increase corresponded to the 5-18 years group (from 15.8% to 54%), followed by children <5 years of age (from 8.6% to 30%). Seropositivity was significantly higher in women in all age groups, except in those over 50 years of age.

CONCLUSION

Children under five years of age were the group with the second highest increase in seropositivity.

Effect of foods and Mediterranean diet during pregnancy and first years of life on wheezing, rhinitis and dermatitis in preschoolers

BACKGROUND

There is a conflictive position if some foods and Mediterranean diet (MedDiet) consumed by the mother during pregnancy and by the child during the first years of life can be protective for current wheezing, rhinitis and dermatitis at preschool age.

METHODS

Questionnaires of epidemiological factors and food intake by the mother during pregnancy and later by the child were filled in by parents in two surveys at two different time points (1.5 yrs and 4 yrs of life) in 1000 preschoolers.

RESULTS

The prevalences of current wheezing, rhinitis and dermatitis were 18.8%, 10.4%, and 17.2%, respectively. After multiple logistic analysis children who were low fruit consumers (never/occasionally) and high fast-food consumers (≥3 times/week) had a higher risk for current wheezing; while intermediate consumption of meat (1 or 2 times/week) and low of pasta by mothers in pregnancy were protected. For current rhinitis, low fruit consumer children were at higher risk; while those consuming meat <3 times/week were protected. For current dermatitis, high fast food consumption by mothers in pregnancy; and low or high consumption of fruit, and high of potatoes in children were associated to higher prevalence. Children consuming fast food >1 times/week were protected for dermatitis. MedDiet adherence by mother and child did not remain a protective factor for any outcome.

CONCLUSION

Low consumption of fruits and high of meat by the child, and high consumption of potatoes and pasta by the mother had a negative effect on wheezing, rhinitis or dermatitis; while fast food consumption was inconsistent.

Many respiratory viruses have temporal association with meningococcal disease

BACKGROUND

Previous ecological studies have shown a temporal and spatial association between influenza epidemics and meningococcal disease (MNG); however, none have examined more than two respiratory viruses.

METHODS

Data were obtained in Chile between 2000 and 2005 on confirmed cases of MNG and all confirmed cases of respiratory viruses (influenza A and B; parainfluenza; adenovirus; and respiratory syncytial virus [RSV]). Both variables were divided by epidemiological weeks, age range, and regions. Models of transference functions were run for rates of MNG.

RESULTS

In this period, 1022 reported cases of MNG and 34,737 cases of respiratory virus were identified (25,137 RSV; 4300 parainfluenza; 2527 influenza-A; 356 influenza-B; and 2417 adenovirus). RSV was the major independent virus temporally associated to MNG (it appears one week before MNG), followed by parainfluenza, influenza-B, adenovirus, and influenza-A.

CONCLUSIONS

The rate of MNG in Chile is temporally associated to all of the respiratory viruses studied, but with variability according age range, and regions.

Methacholine challenge test by wheezing and oxygen saturation in preschool children with asthma

Methacholine challenge test (MCT) performed with spirometry is a commonly used test to evaluate bronchial hyperreactivity (BHR) in children. However, preschoolers do not usually collaborate.

OBJECTIVES

To assess the usefulness of MCT through clinical evaluation (wheezing auscultation and decreased pulse arterial oxygen saturation [SpO2]) in recurrent wheezing preschoolers with asthma, in comparison to healthy controls.

METHODS

We performed the MCT (modified Cockroft method) on healthy and on asthmatic preschoolers. The end point was determined by the presence of wheezing in the chest and/or tracheal auscultation (PCw) and/or a decrease in SpO2 of ≥5 from the baseline value (PCSpO2). Maximal methacholine concentration was 8 mg/ml.

RESULTS

The study population comprised 65 children: 32 healthy and 33 asthmatic children. There were no differences in demographic characteristics between the groups. The median methacholine doses for PCw and for PCSpO2 were significantly lower among asthmatic than healthy children: 0.5 mg/ml (0.25-0.5 mg/ml) vs. 2 mg/ml (1-4 mg/ml), respectively, p<0.001; and 0.25 mg/ml (0.25-0.5 mg/ml) and 2 mg/ml (0.5-4 mg/ml), respectively, p<0.001. The best cut-off point of PCw was observed at a methacholine concentration of 0.5 mg/ml (AUC=0.72 [95% CI=0.66-0.77]), its sensitivity was 91%, specificity 43%, PPV 16% and NPV 98%. For PCSpO2 the best cut-off point was a methacholine concentration of 1 mg/ml (AUC=0.85 [95% CI 0.81-0.89]), with sensitivity of 80%, specificity 74%, PPV 49%, and NPV 92%. There were no adverse reactions.

CONCLUSION

MCT using clinical parameters such as wheezing auscultation and SpO2 measurement could be a useful and safe test to confirm BHR among preschoolers.

[A prolonged capillary refill is predictor of low central venous oxygen saturation]

INTRODUCTION

Educational programs in pediatric life support endorse a capillary refill time>2 s as an indicator of shock. In the emergency room, a barrier to the implementation of an early goal directed therapy, aiming at central venous oxygen saturation (ScvO2)≥70% is the insertion of central venous catheter (CVC).

OBJECTIVE

To establish the predictive value of capillary refill time>2 s to detect ScvO2<70% in children admitted to Intensive Care Units.

PATIENTS AND METHOD

Prospective study. We included 48 children admitted in the first 24 hours in ICU with superior vena cava CVC. Simultaneously, we measured ScvO2 and capillary refill time in the heel of upper extremity or toe.

RESULTS

There were 75 paired measurements ScvO2 (75,9±8,4%) and capillary refill capillary (1,9±1,0 s). We found an inverse correlation between capillary refill time and ScvO2 (r-0,58). The ROC curve analysis revealed an excellent ability for the capillary fill time>2 s to predict ScvO2<70% (AUC 0,94) (95% CI 0,87-0,98).

CONCLUSIONS

A prolonged capillary refill time>2 s, is a predictor of ScvO2<70% in children admitted to ICU, which supports the current recommendations. This finding may be relevant in emergency units where the use of CVC is limited and ScvO2 is not available.

Anti-N-methyl-D-aspartate receptor and anti-ribosomal-P autoantibodies contribute to cognitive dysfunction in systemic lupus erythematosus

Objective

Autoantibodies against N-methyl-D-aspartate receptor (anti-NMDAR) and ribosomal-P (anti-P) antigens are potential pathogenic factors in the frequently observed diffuse brain dysfunctions in patients with systemic lupus erythematosus (SLE). Although studies have been conducted in this area, the role of anti-NMDAR antibodies in SLE cognitive dysfunction remains elusive. Moreover, the specific contribution of anti-P antibodies has not been reported yet. The present study attempts to clarify the contribution of anti-NMDAR and anti-P antibodies to cognitive dysfunction in SLE.

Methods

The Cambridge Neuropsychological Test Automated Battery (CANTAB) was used to assess a wide range of cognitive function areas in 133 Chilean women with SLE. ANCOVA models included autoantibodies, patient and disease features.

Results

Cognitive deficit was found in 20%. Higher SLEDAI-2K scores were associated with impairment in spatial memory and learning abilities, whereas both anti-NMDAR and anti-P antibodies contributed to deficits in attention and spatial planning abilities, which reflect fronto-parietal cortex dysfunctions.

Conclusions

These results reveal an association of active disease together with specific circulating autoantibodies, such as anti-NMDAR and anti-P, with cognitive dysfunction in SLE patients.

Systemic lupus erythematosus impairs memory cognitive tests not affected by depression

Objective

Our aim was to assess the contribution of depression to cognitive impairment in patients with systemic lupus erythematosus (SLE).

Methods

Clinical features, education, age, and Hospital Anxiety and Depression Scale (HADS) were evaluated in 82 patients with SLE and 22 healthy controls, all Chilean women. The Cambridge Neuropsychological Test Automated Battery (CANTAB eclipseTM) assessing attention, spatial memory, and learning and executive function domains was applied. Cognitive deficit definition: a cut-off for definite impairment was defined as a score below -2 standard deviations in at least one outcome measure in two or more domains. ANCOVA with stepwise selection evaluated influences of health status (SLE or control), age, education, and HADS depression and anxiety scores on cognitive outcomes. To avoid overfitting, a shrinkage method was performed. Also, adjusted p-values for multiple comparisons were obtained.

Results

Cognitive deficit affected 16 (20%) patients, and no controls ( p = 0.039). Median HADS depression score in SLE patients was 6 (range 0–19) and in controls was 0 (0–19), p < 0.001). ANCOVA and shrinkage models showed that worse cognitive performance in sustained attention and spatial working memory tests was explained by the presence of SLE but not depression, whereas depression only affected a measure of executive function (I/ED Stages completed).

Conclusion

Depression has a limited role in cognitive impairment in SLE. Impairments in sustained attention and spatial working memory are distinctly influenced by yet-unknown disease-intrinsic factors.

Reproducibility and performance of one or two samples of salivary cortisol in the diagnosis of Cushing's syndrome using an automated immunoassay system

The purpose of this article is to evaluate the variability and reproducibility of late night salivary cortisol (LNSC) using electrochemiluminescence immunoassay (ECLIA) and compare the accuracy of one or two samples in diagnosis of Cushing's syndrome (CS). We prospectively included 64 healthy volunteers (HV), 35 patients with clinically suspected CS (S), and 26 patients with confirmed CS. Nine patients in the CS group had 24-h urinary free cortisol (UFC) less than two times the upper limit of normal (mild CS). UFC and two consecutive LNSC (LNSC1, LNSC2) were collected at home. All patients in the S group had normal UFC and low-dose dexamethasone suppression test. No differences were found between the HV and S groups in UFC, LNSC1, and LNSC2. Intra-individual variability between the two samples of LNSC was 22% in HV (1.6-91%), 32% in the S group (1.6-144%), and 51% (1.6-156%) in the CS group. Variability was higher in CS patients than those in the HV (P < 0.001) and S groups (P = 0.05). The AUC of LNSC1 was 0.945 (IC 95% 0.880-1.004); when considering the highest LNSC, the AUC was 0.980 (IC 95% 0.954-1.007) (P < 0.01). We found 23% of discordant LNSC in the S group and 11% in the CS group. Three patients with CS had only one elevated LNSC, all of them with mild CS. Our results suggest that LNSC is variable, and reproducibility is affected in both CS and S patients. We found significant improvements in the diagnostic accuracy of the LNSC measurement by obtaining two samples.

S4D-SRCRB, a soluble member of the group B scavenger receptor cysteine-rich superfamily, binds to both endogenous and exogenous structures (172.8)

Human S4D-SRCRB is a soluble member of the Scavenger Receptor Cysteine-Rich Superfamily (SRCR-SF), and is composed of four group B SRCR domains separated by Pro-, Ser- and Thr-rich polypeptides, which are o-glycosilated. Northern blot analysis indicated that S4D-SRCRB is expressed as two major mRNA species: one of 2,8 kb, with a restricted tissue expression pattern (mainly kidney, placenta and HepG2 cell line), and another of 1,5 kb, with a broader distribution. To gain insight on the function of this molecule, we produced and affinity purified a recombinant form of this protein fused to a HA tag (rhS4D-HA) using an episomal expression system (pCep/Pu) in HEK 293-EBNA cells. Similarly to other members of the SRCR-SF (S5D-SRCRB, CD6 and DMBT1), rhS4D-HA binds to the surface of bacteria (both gram-positive and -negative) and fungi (both saprophytic and pathogenic), and this is mediated through recognition of lipotheicoic acid (LTA) or lipopolysaccharide (LPS), and lineal glucans, respectively. Interestingly, rhS4D-HA increased the secretion of IL-8 of HepG2 when exposed to bacterial cell wall components. Moreover, rhS4D-HA also binds to some (fibronectin and laminin) but not all (collagen) extracellular matrix proteins. Taken together the data suggest that S4D-SRCRB behaves as a dual-specific receptor for non-self and self-structures, likely playing a role in the innate defence and homeostasis of epithelial surfaces.

11β-hydroxysteroid dehydrogenase type 2 polymorphisms and activity in a Chilean essential hypertensive and normotensive cohort

BACKGROUND

11β-hydroxysteroid dehydrogenase type 2 enzyme (11β-HSD2) inactivates cortisol (F) to cortisone (E); its impairment is associated with hypertension. We reported that 15.7% of the Chilean essential hypertensives possessed a high F/E ratio suggesting a partial deficit in 11β-HSD2 activity. It has been reported that the G534A(Glu178/Glu) polymorphism in the HSD11B2 gene is associated with hypertension. Investigate the frequency of the G534A polymorphism and its correlation with the glucocorticoid profile in Chilean essential hypertensive and normotensive subjects.

METHODS

Essential hypertensive outpatients (n = 232) and normotensive subjects (n = 74) were recruited. A change in the AluI restriction enzyme digest pattern, caused by the presence of the G534A polymorphism, was utilized to screen DNA isolated from leukocytes within the cohort before confirmation by sequencing. Plasma renin activity (PRA), serum aldosterone, F, and E were measured by radioimmunoassay. Urinary tetrahydrocortisol (THF), 5α-tetrahydrocortisol (5α-THF), and tetrahydrocortisone (THE) were measured by gas chromatography-mass spectrometry.

RESULTS

G534A polymorphism frequency was similar between hypertensive patients (19 of 232; 8.2%) and normotensive subjects (7 of 74; 9.5%). When categorized by presence or absence of the G534A polymorphism, no significant differences in the serum F/E ratio or other measured biochemical variables were detected. Despite a previous report that the G534A polymorphism is associated with a neighboring C468A (Thr156/Thr) polymorphism, analysis within our cohort showed that only one patient in each group presented with this double polymorphism.

CONCLUSIONS

We report the frequency of the G534A polymorphism in the Spanish-Amerindian population. No correlation was detected between this polymorphism and the presence of hypertension and biochemical parameters in this Chilean cohort.

Crystal structure of the third extracellular domain of CD5 reveals the fold of a group B scavenger cysteine-rich receptor domain

Scavenger receptor cysteine-rich (SRCR) domains are ancient protein modules widely found among cell surface and secreted proteins of the innate and adaptive immune system, where they mediate ligand binding. We have solved the crystal structure at 2.2 A of resolution of the SRCR CD5 domain III, a human lymphocyte receptor involved in the modulation of antigen specific receptor-mediated T cell activation and differentiation signals. The first structure of a member of a group B SRCR domain reveals the fold of this ancient protein module into a central core formed by two antiparallel beta-sheets and one alpha-helix, illustrating the conserved core at the protein level of genes coding for group A and B members of the SRCR superfamily. The novel SRCR group B structure permits the interpretation of site-directed mutagenesis data on the binding of activated leukocyte cell adhesion molecule (ALCAM/CD166) binding to CD6, a closely related lymphocyte receptor homologue to CD5.

The Scavenger Receptor Cysteine-Rich (SRCR) domain: an ancient and highly conserved protein module of the innate immune system

The Scavenger Receptor Cysteine-Rich (SRCR) domain is an ancient and highly conserved protein module of ~100-110 amino acids, which defines a superfamily (SRCR-SF) of either soluble or membrane-bound receptors expressed by hematopoietic and nonhematopoietic cells, at either embryonic or adult stages. The existence of two types of SRCR domains allows the division of the SRCR-SF into two groups. Members of group A contain SRCR domains with 6 cysteine residues and are encoded by two exons, whereas those of group B usually contain 8 cysteines and are encoded by a single exon. Group A members usually present as multidomain mosaic proteins containing single SRCR domains associated to other functional domains, such as enzymatic (protease) domains or collagenous regions. On the contrary, group B members generally present as proteins exclusively composed of tandem repeats of SRCR domains, with or without the presence of CUB and ZP domains thought to be involved in oligomerization but never associated to protease domains. Representatives of either group are found in different animal species, from low invertebrates (sponges) to high vertebrates (mammals). Although no unifying function has been defined for SRCR-SF members, accumulated data, together with the high degree of structural and phylogenetic conservation of SRCR domains indicates that they might subserve basic homeostatic functions, including innate immune defense.

Biochemical characterization of recombinant and circulating human Spalpha

Human Spalpha is a soluble protein expressed by macrophages present in lymphoid tissues (spleen, lymph node, thymus, and bone marrow), for which little functional and structural information is available. It belongs to the group B of the scavenger receptor cysteine-rich superfamily (SRCR-SF) that includes the lymphocyte surface receptors CD5 and CD6 among others. Spalpha is able to bind to different cells of the immune system (monocytes and lymphocytes), which suggests that it may play an important role in the regulation of this system. To study Spalpha, an episomal mammalian expression system (pCEP-Pu/HEK 293-EBNA) was used to produce a recombinant form (rSpalpha) that was utilized for biochemical studies and for the generation of specific hybridomas. Four monoclonal antibodies were selected for their reactivity against rSpalpha by Western blot, immunoprecipitation, and enzyme-linked immunosorbent assays. The monoclonal antibodies recognized three different epitopes on Spalpha. The monoclonal antibodies revealed the existence of two Spalpha isoforms of 38 and 40 kDa, resulting from different sialic acid content. They also showed that Spalpha is a relatively abundant serum protein (60 micro g/ml) that mostly circulates in association with other serum proteins. Accordingly, rSpalpha allowed affinity chromatography isolation of polyclonal and monoclonal immunoglobulin M (IgM). These data indicate that Spalpha is a circulating protein that may play a role in the homeostasis of IgM antibodies.

Cloning of S4D-SRCRB, a new soluble member of the group B scavenger receptor cysteine-rich family (SRCR-SF) mapping to human chromosome 7q11.23

The scavenger receptor cysteine-rich superfamily (SRCR-SF) is a highly conserved group of membrane and/or secreted proteins related to the innate and adaptive immune system. Here, we report the cloning of the gene encoding human S4D-SRCRB, a novel soluble member of the SRCR-SF, which is composed of four group B SRCR domains separated by Pro-, Ser- and Thr-rich polypeptides. The longest cDNA sequence found is 2,806 bp in length and encodes a mature protein of 528 aa, with a predicted molecular mass of M(r) 55,600. The S4D-SRCRB gene is located at Chromosome 7q11.23, telomeric to the Williams-Beuren syndrome deletion. It extends over 20 kb and consists of 11 exons, with each SRCR domain being encoded by a single exon. Northern blot analysis indicated that S4D-SRCRB has a broad tissue distribution and is expressed as two major mRNA species: one of 2.8 kb, with a restricted tissue expression pattern (mainly kidney and placenta), and another of 1.5 kb, with a broader distribution. A similar mRNA expression pattern was observed during the analysis of several tumor cell lines. The highest degree of similarity found between S4D-SRCRB and other group B SRCR-SF members was with human DMBT1 (a mosaic protein composed of fourteen SRCR domains, which is involved in innate defense and epithelia polarization) and chicken 18-B (a turpentine-induced soluble acute-phase protein composed of four SRCR domains). Our data indicate that S4D-SRCRB constitutes a novel SRCR-SF member, which could be involved in basic homeostatic functions such as innate host defense.

High circulating levels of soluble scavenger receptors (sCD5 and sCD6) in patients with primary Sjögren's syndrome

OBJECTIVE

To determine the existence of circulating levels of soluble scavenger receptors (sCD5 and sCD6) in patients with primary Sjögren's syndrome (SS), and to analyse the correlation with clinical and immunological features of SS.

METHODS

Ninety consecutive patients with primary SS were studied. All patients fulfilled four or more of the European diagnostic criteria for SS. sCD5 and sCD6 levels were determined using a specific enzyme-linked immunosorbent assay (ELISA) developed in our laboratory.

RESULTS

Detectable levels of sCD5 were found in 39 (43%) SS patients. The mean+/-standard error values of sCD5 were 3.5+/-0.5 ng/ml for patients with SS and 1.9+/-0.1 ng/ml for healthy blood donors (P<0.001). We found higher levels of sCD5 in patients with hypocomplementaemia (6.5 vs 3.5 ng/ml, P=0.03) and cryoglobulinaemia (6.9 vs 2.6 ng/ml, P=0.001). On the other hand, detectable levels of sCD6 were found in 60 (67%) SS patients. The mean+/-standard error values of sCD6 were 25.5+/-7.8 ng/ml in SS patients and 5.27+/-1.40 ng/ml in healthy blood donors (P=0.01). When the sCD6 levels were compared according to the presence or absence of immunological features, patients with cryoglobulinaemia showed higher levels of circulating sCD6 (77.3 vs 17 ng/ml, P=0.01) than those without cryoglobulinaemia.

CONCLUSION

Patients with primary SS showed higher levels of circulating sCD5 and sCD6 when compared with controls. Moreover, the existence of some immunological features (hypocomplementaemia and cryoglobulinaemia) was associated with high levels of both soluble scavenger receptors. These facts may reflect an enhanced lymphocytic activation in patients with primary SS.

CD5 signal transduction: positive or negative modulation of antigen receptor signaling

The CD5 lymphocyte surface glycoprotein is a coreceptor involved in the modulation of antigen-specific receptor-mediated activation and differentiation signals. Although first considered a costimulatory molecule in mature peripheral T cells, recent studies of CD5-/- mice have opened the possibility that CD5 may also mediate inhibitory signals that attenuate TCR/CD3- and BCR-mediated triggering in thymocytes and a subgroup of B cells (B-1a cells), respectively. The ultimate molecular basis for these differential modulatory properties of CD5, depending on the context of lymphocyte subset and differentiation stage, are presently unknown and are an issue of current intensive investigation. Here, we review recent reports, both contradictory and complementary, focused on CD5-mediated molecular intracellular signaling events that could provide the basis for its immunomodulatory properties.

Residues Y429 and Y463 of the human CD5 are targeted by protein tyrosine kinases

The human CD5 lymphocyte cell surface co-receptor modulates activation and differentiation responses mediated by the antigen-specific receptor of T and B cells. CD5 is phosphorylated following lymphocyte activation; however, the exact sites and kinases involved are yet to be determined. Jurkat T cell transfectants expressing tyrosine-mutated CD5 molecules have been used to show that residues Y429 and Y463 are targeted in vivo by protein tyrosine kinases following cell stimulation with anti-CD3 mAb or pervanadate. This is in agreement with data from direct in vitro kinase assays using purified recombinant Lck and Fyn protein tyrosine kinases. The analysis of Lck- and CD3-deficient Jurkat cells shows that tyrosine phosphorylation of CD5 requires Lck activity. We propose that T cell activation mediates CD5 tyrosine phosphorylation at residues Y429 and Y463 mainly through the activation of Lck.

Identification of a novel single-nucleotide polymorphism (Val554Ile) and definition of eight common alleles for human IL4RA exon 11

The interleukin (IL)-4 receptor alpha chain gene (IL4RA) is a polymorphic gene which is reportedly involved in the development of atopy. Of the 14 single-nucleotide polymorphisms (SNP) reported to date in the coding region of IL4RA, 11 are positioned to exon 11. This big exon encodes more than two thirds of the mature protein, including most of the cytoplasmic region. Here we report the identification of a new IL4RA SNP at the first nucleotide of codon 554 (GTA --> ATA) in exon 11, leading to an amino acid substitution from Val to Ile (V554I). Furthermore, we present complete nucleotide sequence data for eight common alleles resulting from combinations of 9 out of the 12 SNP at IL4RA exon 11. Homo- or heterozygous combinations of these eight alleles accounted for all the IL4RA exon 11 genotypes found in Caucasian individuals from our geographical area.

Fluorides in the new millennium

Water fluoridation is known to be the most successful public health measure of the 20th century. More than half a century later, we are still reaping the benefits of fluoridation. We now know that the most important mechanism of fluoride action occurs through daily low-dose exposures. The battle between demineralization and remineralization occurs constantly, and fluoride shifts the balance to the latter. This dynamic, daily process far supersedes the pre-eruptive fluoride incorporation in importance. Fluoride, however, is now available in a variety of very different forms, useful in waging the war on caries. Nevertheless, opponents of this therapeutic agent maintain that its widespread use should be curtailed. Although the benefits of fluoride can no longer be disputed, fluoride supplementation must be supported and approached with consideration of total fluoride exposure.

Role of two conserved cytoplasmic threonine residues (T410 and T412) in CD5 signaling

CD5 is a transmembrane coreceptor that modulates activation and differentiation signals mediated by the Ag-specific receptor present on both T and B1a lymphocytes. CD5 lacks intrinsic catalytic activity, and its immunomodulatory properties result from intracellular interactions mediated by the CD5 cytoplasmic tail. The nature of these interactions is currently a matter of investigation. Here, we present a selective mutagenesis analysis of two conserved threonine residues (T410 and T412) located at the membrane-proximal cytoplasmic region of CD5. These residues are contained within consensus phosphorylation motifs for protein kinase C and are shown here to be critical for in vivo protein kinase C-mediated phosphorylation of CD5. Functional studies revealed that the integrity of T410 and T412 is also critical for CD5-mediated phosphatidylcholine-specific phospholipase C (PC-PLC) activation and phorbol ester-mediated inhibition of Ab-induced internalization of CD5. These results strongly argue in favor of a role for T410 and T412 in the signaling mediated by CD5.

Genomic organization of the human CD5 gene

CD5 is a member of the family of receptors which contain extracellular domains homologous to the type I macrophage scavenger receptor cysteine-rich (SRCR) domain. Here, we compare the exon/intron organization of the human CD5 gene with its mouse homologue, as well as with the human CD6 gene, the closest related member of the SRCR superfamily. The human CD5 gene spans about 24.5 kb and consists of at least 11 exons. These exons are conserved in size, number, and structure in the mouse CD5 homologue. No evidence for the biallelic polymorphism reported in the mouse could be found among a population of 100 individuals of different ethnic origins. The human CD5 gene maps to the Chromosome (Chr) 11q12.2 region, 82 kb downstream from the human CD6 gene, in a head-to-tail orientation, a situation which recalls that reported at mouse Chr 19. The exon/intron organization of the human CD5 and CD6 genes was very similar, differing in the size of intron 1 and the number of exons coding for their cytoplasmic regions. While several isoforms, resulting from alternative splicing of the cytoplasmic exons, have been reported for CD6, we only found evidence of a cytoplasmic tailless CD5 isoform. The conserved structure of the CD5 and CD6 loci, both in mouse and human genomes, supports the notion that the two genes may have evolved from duplication of a primordial gene. The existence of a gene complex for the SRCR superfamily on human Chr 11q (and mouse Chr 19) still remains to be disclosed.

Identification of a natural soluble form of human CD5

CD5 is a 67 kDa type I glycoprotein which belongs to the Scavenger Receptor Cysteine-Rich (SRCR) family of receptors. This family includes either cell-surface (e.g. CD6) or secreted (e.g. Spalpha) proteins implicated in the development of the immune system and the regulation of immune responses. In this study, we purified and characterised a circulating natural soluble CD5 form (nsCD5) which is indistinguishable (in apparent molecular mass, glycosylation pattern, and antibody reactivity) from a recombinant soluble CD5 form (rsCD5) composed of the three extracellular SCRC domains. The nsCD5 is a N-glycosylated 52 kDa molecule present in normal human serum and in supernatants of in vitro phorbol ester- and CD3-stimulated peripheral blood mononuclear cells. The nsCD5 concentration in sera from healthy donors is relatively low (median 1.75 ng/ml, rn=166) and is similar to that found in sera from patients suffering of various autoimmune (systemic lupus erythematosus, primary Sjogren syndrome, rheumatoid arthritis) and non-autoimmune (chronic renal failure, B-cell chronic lymphocytic leukemia) disorders. In vitro experiments indicate that nsCD5 is released by proteolytic cleavage of the membrane form. These results represent the first evidence of proteolytic release of a transmembrane SRCR family member following cell activation.

Relevance of individual CD5 extracellular domains on antibody recognition, glycosylation and co-mitogenic signalling

CD5 is a type I glycoprotein which modulates T- and B-cell receptor-mediated signals and is expressed by thymocytes, mature T cells and a subset of mature B cells. The extracellular region of CD5 is composed of three scavenger receptor cysteine-rich domains (D1, D2, D3) for which only limited functional and structural data are available. Using cell transfectants expressing ectodomain-deficient CD5 molecules or CD5 immunoglobulin fusion proteins, we analysed individual CD5 domains with respect to monoclonal antibody binding specificity, glycosylation, and co-mitogenic signalling. Our results show the presence of N-linked oligosaccharides on D1 and D2, but not on D3. D1, the most amino-terminal domain, is predicted to be the most appropriately placed domain for an interaction with a ligand. This domain is recognised by a large panel of well characterised CD5 mAbs, reflecting its higher immunogenicity. In an attempt to develop mAbs with specificity for the more conserved membrane-proximal domains, we generated a unique mAb, named 83-C4, whose binding mapped to D3. Co-stimulatory studies revealed no significant differences between anti-D1 and anti-D3 mAbs. The high interspecies conservation of D3 implies a conserved role of this domain in CD5 function and the 83-C4 mAb promises to be a valuable tool in exploring this.

Interaction of recombinant and natural soluble CD5 forms with an alternative cell surface ligand

CD5, a member of the scavenger receptor cysteine-rich (SRCR) receptor family, plays a role in the thymocyte maturation, T cell activation and T cell-antigen-presenting cell interactions. To date only CD5 ligands (CD5L) compatible with a T-B co-stimulatory role have been described (CD72, gp40-80 and IgV(H) framework region) so the existence of alternative CD5L involved in other aspects of T cell biology warrants further exploration. Here we characterize the cell binding properties of a recombinant soluble human CD5 extracellular domain glycoprotein (rsCD5). In contrast to previously characterized ligands, this molecule binds to a broadly distributed cell surface receptor expressed on monocytes, lymphocytes and various cell lines of lymphoid, myelomonocytic and epithelial origin. The cell binding of rsCD5 is divalent cation independent and inhibited by high molar concentrations of certain monosaccharides. Both human CD5 Ig fusion proteins and a natural soluble CD5 form (present in human serum and resulting from proteolytic cleavage following lymphocyte activation) reproduce the cell binding pattern of rsCD5 and block its binding in a competitive form. The involvement of the most N-terminal CD5 SRCR domains (D1 and D2) in binding is deduced from competition cell binding assays with CD5 Ig fusion proteins. These results imply a novel CD5/CD5L interaction model recalling some aspects of the interaction of CD6 with activated leukocyte cell adhesion molecule (ALCAM).

Signaling Through CD5 Involves Acidic Sphingomyelinase, Protein Kinase C-ζ, Mitogen-Activated Protein Kinase Kinase, and c-Jun NH2-Terminal Kinase

The CD5 lymphocyte surface glycoprotein is a coreceptor involved in the modulation of Ag-specific receptor-mediated activation and differentiation signals. The molecular basis for its modulatory properties is not yet well understood. In the present study we describe early biochemical events triggered by CD5 stimulation, which include the phosphatidylcholine-specific phospholipase C (PC-PLC)-dependent activation of acidic sphingomyelinase (A-SMase) in normal and lymphoblastoid T and B cells. The functional coupling of PC-PLC and A-SMase is demonstrated by the abrogation of A-SMase activation by 1) xanthogenate tricyclodecan-9-yl (D609), a selective inhibitor of PC-PLC, and 2) replacement of several C-terminal serine residues (S458, S459, and S461) present in the cytoplasmic tail of CD5 that are known to be critical for PC-PLC activation. Additionally, we demonstrate that activation of protein kinase C-ζ (PKC-ζ) and members of the mitogen-activated protein kinase (MAPK) cascade (MAPK kinase and c-Jun NH2-terminal kinase), but not the NF-κB, are downstream events of the CD5 signaling pathway. A-SMase, PKC-ζ, and MAPK family members are key mediators of cell responses as diverse as proliferation, differentiation, and growth arrest and may contribute to CD5-mediated modulation of TCR or BCR signaling.

Signaling through CD5 involves acidic sphingomyelinase, protein kinase C-zeta, mitogen-activated protein kinase kinase, and c-Jun NH2-terminal kinase

The CD5 lymphocyte surface glycoprotein is a coreceptor involved in the modulation of Ag-specific receptor-mediated activation and differentiation signals. The molecular basis for its modulatory properties is not yet well understood. In the present study we describe early biochemical events triggered by CD5 stimulation, which include the phosphatidylcholine-specific phospholipase C (PC-PLC)-dependent activation of acidic sphingomyelinase (A-SMase) in normal and lymphoblastoid T and B cells. The functional coupling of PC-PLC and A-SMase is demonstrated by the abrogation of A-SMase activation by 1) xanthogenate tricyclodecan-9-yl (D609), a selective inhibitor of PC-PLC, and 2) replacement of several C-terminal serine residues (S458, S459, and S461) present in the cytoplasmic tail of CD5 that are known to be critical for PC-PLC activation. Additionally, we demonstrate that activation of protein kinase C-zeta (PKC-zeta) and members of the mitogen-activated protein kinase (MAPK) cascade (MAPK kinase and c-Jun NH2-terminal kinase), but not the NF-kappaB, are downstream events of the CD5 signaling pathway. A-SMase, PKC-zeta, and MAPK family members are key mediators of cell responses as diverse as proliferation, differentiation, and growth arrest and may contribute to CD5-mediated modulation of TCR or BCR signaling.

Human CD5 Signaling and Constitutive Phosphorylation of C-Terminal Serine Residues by Casein Kinase II

CD5 is a lymphocyte surface glycoprotein with a long cytoplasmic domain suitable for phosphorylation and signal transduction, which is involved in the modulation of Ag-specific receptor-mediated activation and differentiation signals. In this study, we use Jurkat T cell transfectants of CD5 cytoplasmic tail mutants to reveal phosphorylation sites relevant to signal transduction. Our results show that casein kinase II (CKII) is responsible for the constitutive phosphorylation of CD5 molecules at a cluster of three serine residues located at the extreme C terminus (S458, S459, and S461). Furthermore, the yeast two-hybrid system demonstrates the specific association between the C-terminal regions of the CD5 cytoplasmic tail and the regulatory β subunit of CKII. We demonstrate that CKII associates with and phosphorylates the C-terminal region of CD5, a conserved domain known to be relevant for the generation of second lipid messengers, and thereby enables at least one component of its signaling funcion.

Human CD5 signaling and constitutive phosphorylation of C-terminal serine residues by casein kinase II

CD5 is a lymphocyte surface glycoprotein with a long cytoplasmic domain suitable for phosphorylation and signal transduction, which is involved in the modulation of Ag-specific receptor-mediated activation and differentiation signals. In this study, we use Jurkat T cell transfectants of CD5 cytoplasmic tail mutants to reveal phosphorylation sites relevant to signal transduction. Our results show that casein kinase II (CKII) is responsible for the constitutive phosphorylation of CD5 molecules at a cluster of three serine residues located at the extreme C terminus (S458, S459, and S461). Furthermore, the yeast two-hybrid system demonstrates the specific association between the C-terminal regions of the CD5 cytoplasmic tail and the regulatory beta subunit of CKII. We demonstrate that CKII associates with and phosphorylates the C-terminal region of CD5, a conserved domain known to be relevant for the generation of second lipid messengers, and thereby enables at least one component of its signaling function.

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