Leflunomide derivative FK778 inhibits production of antibodies in an experimental model of alloreactive T-B cell interaction

OBJECTIVES

The contribution of humoral immune response in allograft and xenograft rejection has been clearly demonstrated in recent years. For this reason, inhibition of alloantibody production has become essential in managing transplanted patients. Here, we assessed the effects of the leflunomide derivative FK778 (FK778) in the control of antibody production resulting from semiallogeneic cognate T-B-cell interactions.

MATERIALS AND METHODS

BALB/c mice were tolerized at birth with semiallogeneic spleen cells from (BALB/c X C57BL/6) F1 mice, with or without overexpression of human bcl-2 transgene in B cells. These tolerized mice were treated with different dosages of FK778, either from birth, or from the third week of age, when autoantibody production was detected. The production of autoantibodies, used as markers of semiallogeneic cognate T-B - cell interactions, was evaluated at different time points during drug administration or after the interruption of treatment.

RESULTS

FK778 treatment started at birth inhibited the production of semiallogeneic-driven antibodies in a dose-dependent manner. In addition, FK778 also reduced the levels of preformed circulating autoantibodies in adult mice, although the dosage required was 4 times higher than that used in neonates. However, the levels of IgG antibodies in these tolerized mice increased after FK778 withdrawal, indicating that FK778 failed to induce tolerance to semiallogeneic host CD4+ Th2 and/or donor B cells.

CONCLUSIONS

Our results demonstrate the efficacy of FK778 in the control of antibody production resulting from semiallogeneic cognate T-B - cell interactions.

TNF‐α promoter gene polymorphisms in Spanish children with persistent oligoarticular and systemic‐onset juvenile idiopathic arthritis

OBJECTIVE

To explore the possible association/s of the first reported tumour necrosis factor (TNF-alphaTNF-) alpha promoter gene polymorphisms -308, -238, -376 and -163 (G-->A) with systemic (SoJIA) and oligoarticular subtypes of juvenile idiopathic arthritis (JIA); and to test the association between these polymorphisms and the class I/class II HLA alleles in our population.

METHODS

The patient group comprised 29 oligoarticular and 26 systemic Caucasian Spanish children with JIA; 68 healthy volunteers from the same ethnic group and geographical region served as controls. HLA alleles were determined using low-resolution polymerase chain reaction (PCR). TNF-alpha promoter gene polymorphisms were screened using PCR denaturing gradient gel electrophoresis (PCR-DGGE), followed, if positive, by restriction fragment length polymorphism (RFLP) analysis for identification.

RESULTS

No statistical association was found between the four polymorphisms studied and JIA. However, the -308 G-->A polymorphism (TNF A2) tended to be more frequent in patients with SoJIA than in the oligoarticular group. TNF A2 was strongly associated with the extended haplotype A1B8DR3 (p = 0.003), and the tandem polymorphism -238/-376 in the presence of B18 and DR3.

CONCLUSION

The TNF A2 allele was more frequent in SoJIA than in the oligoarticular group. TNF A2 can help to create a more inflammatory milieu in this JIA subtype, in combination with other polymorphisms involved in regulatory sequences of key molecules in the inflammatory response. The association of the -308 and -238/-376 polymorphisms with specific alleles of the HLA is reconfirmed.

Tarsitis as an initial manifestation of juvenile spondyloarthropathy

OBJECTIVE

The aim of this study was to determine the frequency of tarsitis as one of the first symptoms of juvenile spondyloarthropathy (JSpA) and to analyze whether patients with tarsitis at onset differ from those without it.

METHODS

A retrospective chart review was performed, from January 1996 to September 2007, at a paediatric rheumatology unit of a tertiary university hospital.

RESULTS

Tarsitis was detected in one-third of the children diagnosed with JSpA. They had fever and received antibiotics due to a suspected infection more frequently than those without tarsitis. Inflammatory low back pain was extremely unusual among these patients.

CONCLUSION

There were some differences between children diagnosed with JSpA initially affected with tarsitis and those without it. Patients with tarsitis as one of the first symptoms were often misdiagnosed as soft tissue infections.

[Contribution of animal models to the study and treatment of systemic autoimmune disease]

Animal models of autoimmune diseases, either spontaneous or induced, have been very useful tools to investigate the mechanisms involved in the pathogenesis of human autoimmune diseases as well as in the design of new therapeutic strategies for their treatment. The development of biotechnology and molecular biology resulted in the production of transgenic animals overexpressing or lacking a given protein. As a result of this technology, a great number of animal models of human diseases have been developed in recent years. A further evolution in transgenic methodology allows the selective control of gene expression in a particular organ or tissue at desired time points during embryonic or postnatal development. In the present article the authors discuss the advantages and inconveniences of animal models and describe the most frequently employed models in the study of 4 rheumatologic syndromes with an autoimmune origin: rheumatoid arthritis, systemic lupus erythematosus, scleroderma, and spondiloarthritis.

Evolution of Drug use After Enforcing a Protocol in a Medium Stay Unit. Results Four Years Later

Aims:

Comorbidity between drug misuse and mental disorders affects negatively in the prognosis of psychistric illness, so it’s important to guarantee drug abstinence at least during hospitalization. This is even more significant in a medium stay unit because patients are more serious and resistant to treatment.

In February 2003, a multidisciplinary group was formed to evaluate the situation of drug use in a psychiatric hospital and a drug screening protocol was then created.

We evaluate if with the protocol, drug use decreases during hospitalization in a medium stay unit in a psychiatric hospital.

Methods:

We first compared drug use (positive results in urine samples) from 2000 to 2002 (before protocol: urine samples collected when there’s drug misuse suspicion) with the period after the protocol was enforced (from 2003 to 2006). Afterwards, we analyzed if drug use during hospitalization continues decreasing in 2007.

In the protocol urine samples are collected when there’s a past misuse history, consumption suspicion, randomly and every time they leave for home.

Results:

It is proved that drug use decreases during hospitalization since the new protocol came into force. Drug use continues reducing since the enforcement of the drug screening protocol.

Conclusion:

The introduction and exhaustive completion of a protocol designed to decrease drug misuse in a psychiatric hospitalization unit, provokes a high reduction of drug use, and each year, the reduction of drug misuse is higher. So we think it’s convenient to generalize this kind of measures.

Efficacy of a Drug Screening Protocol

Aims:

Comorbidity between drug misuse and mental disorders affects negatively in the prognosis of psychiatric illness, so it’s important to guarantee drug abstinence during hospitalization.

The Hospital of Zamudio contains short and medium stay units. Patients are referred to medium stay units when disorders are more serious or the symptoms are resistant to treatment.

In February 2003, a multidisciplinary group was formed to evaluate the situation of drug use in a psychiatric hospital and a drug screening protocol was then created.

We evaluate if the enforcement of the protocol, has decreased drug use during hospitalization.

Methods:

It’s compared, retrospectively, drug use (positive results in urine samples) since the screening drug protocol was enforced (2003) to 2007. Urine samples are collected when there’s a past misuse history, consumption suspicion, randomly and every time the patient leave for home. It’s also compared the differences between short and medium stay units.

Results:

It’s proved that drug use decreases during hospitalization since the new protocol came into force in a medium stay unit. This drug protocol is not useful in a short stay unit.

Conclusions:

The introduction and completion of this protocol provokes a high reduction of drug use in a medium stay unit. This design seems not to be adequate to short stay units. Probably, collecting urine samples when patients came into a short unit gives false positive results because these patients don’t come from other hospitalization units as in the case of medium stay unit.

Differences Between Patients of a Medium Stay Unit Depending on the Derivation Unit

Aims:

The medium stay unit of the hospital of Zamudio is a psychiatric hospitalization unit where serious patients are admitted, specially those with psychotic and affective disorders. The complexity of the pathology extends the average stay of hospitalization with an average of 60 days to improve.

There are 2 derivation units from which medium stay takes patients:

•

Methods:

It is analyzed, retrospecitvely, the profile of patients in a medium stay unit comparing the derivation unit they come from in 2007.

Results and conlusions:

There are no statistically significant differences in the number of patients derived from the diverse units.

The sociodemographic and administrative profile of the patients is similar in both groups: a single middle aged (between 45-50 years old) that is hospitalized knowlingly (63%). The average stay at hospital is 55 days.

Attending to the clinical profile we concluded that patients derived from the Hospital of Zamudio suffer from Bipolar disorder as main diagnosis. The rest of disorders remain similar comparing both units.

Biological and phylogenetic characterization of virulent Newcastle disease virus circulating in Mexico

In 2002-2003, velogenic Newcastle Disease Virus outbreaks, closely related to the Mexican isolates, were confirmed in the United States (U.S.) in southern California, Arizona, Nevada, and Texas. In this report, virulent NDVs isolated in Mexico between 1998 and 2006 were subjected to biologic characterization, using standard pathogenicity tests, and to phylogenetic analysis. Chicken embryo mean death time (MDT) test results ranged from 39.7 to 61.5 hours, and intracerebral pathogenicity index (ICPI) values were between 1.59 and 1.94, compared to a possible maximum value of 2.0. These isolates showed a dibasic amino acid motif at the fusion protein cleavage site sequence required for host systemic replication. Phylogenetic analysis indicated that the Mexican virulent NDVs belong to the class II, genotype V viruses and can be clearly divided in two groups as follows: isolates from 1998 to 2001 with close epidemiologic relationship with the latest U.S. NDV outbreaks, and phylogenetically distinct viruses, isolated from 2004 to 2006, which showed higher virulence. The assessment of the evolution of viruses from Mexico and other neighboring countries will aid in the U.S surveillance efforts for early detection of highly virulent NDV.

Prevention of murine lupus disease in (NZBxNZW)F1 mice by sirolimus treatment

Sirolimus is a new immunosuppressive drug used to avoid allograft rejection. The immunosuppressive effect of sirolimus is due to inhibition of the mammalian target of rapamycin, necessary for the proliferation and clonal expansion of activated T-cells. Because T-cells play a central role in the pathogenesis of autoimmune disease developed in (NZBxNZW)F1 mice, we evaluated the therapeutic use of sirolimus in such mice. (NZBxNZW)F1 female mice received 1mg/kg/day of sirolimus from 12 to 37 weeks of age. The development of autoimmune disease was evaluated by measuring the serum levels of auto-antibodies (autoAbs) and their immunoglobulin isotypes, prevalence of glomerulonephritis and mortality rates. Sirolimus directly inhibited production of autoAbs, glomerular deposits of immunoglobulins and development of proteinuria; also the survival of these mice was prolonged. Our results demonstrate the beneficial effects of sirolimus in preventing the development of lupus disease in (NZBxNZW)F1 female mice.

Increased Goodpasture antigen-binding protein expression induces type IV collagen disorganization and deposit of immunoglobulin A in glomerular basement membrane

Increased expression of Goodpasture antigen-binding protein (GPBP), a protein that binds and phosphorylates basement membrane collagen, has been associated with immune complex-mediated pathogenesis. However, recent reports have questioned this biological function and proposed that GPBP serves as a cytosolic ceramide transporter (CERT(L)). Thus, the role of GPBP in vivo remains unknown. New Zealand White (NZW) mice are considered healthy animals although they convey a genetic predisposition for immune complex-mediated glomerulonephritis. Here we show that NZW mice developed age-dependent lupus-prone autoimmune response and immune complex-mediated glomerulonephritis characterized by elevated GPBP, glomerular basement membrane (GBM) collagen disorganization and expansion, and deposits of IgA on disrupted GBM. Transgenic overexpression of human GPBP (hGPBP) in non-lupus-prone mice triggered similar glomerular abnormalities including deposits of IgA on a capillary GBM that underwent dissociation, in the absence of an evident autoimmune response. We provide in vivo evidence that GPBP regulates GBM collagen organization and its elevated expression causes dissociation and subsequent accumulation of IgA on the GBM. Finally, we describe a previously unrecognized pathogenic mechanism that may be relevant in human primary immune complex-mediated glomerulonephritis.

CD4+CD25+ T cell-dependent inhibition of autoimmunity in transgenic mice overexpressing human Bcl-2 in T lymphocytes

Regulation of lymphocyte survival is essential for the maintenance of lymphoid homeostasis preventing the development of autoimmune diseases. Recently, we described a systemic lupus erythematosus associated with an IgA nephropathy in autoimmune-prone (NZW x C57BL/6)F(1) overexpressing human Bcl-2 (hBcl-2) in B cells (transgenic (Tg) 1). In the present study, we analyze in detail a second line of hBcl-2 Tg mice overexpressing the transgene in all B cells and in a fraction of CD4(+) and CD8(+) T cells (Tg2). We demonstrate here that the overexpression of hBcl-2 in T cells observed in Tg2 mice is associated with a resistance to the development of lupus disease and collagen type II-induced arthritis in both (NZW x C57BL/6)F(1) and (DBA/1 x C57BL/6)F(1) Tg2 mice, respectively. The disease-protective effect observed in autoimmune-prone Tg2 mice is accompanied by an increase of peripheral CD4(+)CD25(+) hBcl-2(+) regulatory T cells (T(regs)), expressing glucocorticoid-induced TNFR, CTLA-4, and FoxP3. Furthermore, the in vivo depletion of CD4(+)CD25(+) T(regs) in (DBA/1 x C57BL/6)F(1) Tg2 mice promotes the development of a severe collagen type II-induced arthritis. Taken together, our results indicate that the overexpression of hBcl-2 in CD4(+) T cells alters the homeostatic mechanisms controlling the number of CD4(+)CD25(+) T(regs) resulting in the inhibition of autoimmune diseases.

Calcineurin inhibitors, but not rapamycin, reduce percentages of CD4+CD25+FOXP3+ regulatory T cells in renal transplant recipients

BACKGROUND

Immunosuppression in renal transplantation, although manageable in the short-term, is a major hurdle for long-term graft survival. Recently, increased frequencies of CD4CD25 regulatory T cells (Tregs) have been described as an additional mechanism that induces alloimmune tolerance.

METHODS

We assessed 64 renal transplant recipients with stable renal function for at least one year. Patients were divided into two groups according to the immunosuppression they were receiving at the moment of the study: one consisted of patients receiving rapamycin (Rapa) but not calcineurin inhibitors (CNI), and the other group received CNI but not Rapa. The Rapa group was further divided into three subgroups according to their previous experience with CNI: CNI-free, CNI withdrawal, and CNI conversion. Frequencies of blood Tregs were studied by flow cytometry after staining with monoclonal antibodies specific for different markers of Tregs.

RESULTS

Frequencies of CD4 T cells with regulatory phenotype and function were significantly decreased in peripheral blood of renal transplant patients receiving CNI compared with those receiving Rapa. This effect was independent of an early exposure to CNI because the CNI-free patients in the Rapa group showed similar frequencies of Tregs to the CNI withdrawal and CNI conversion groups.

CONCLUSIONS

CNI, but not Rapa, induce a decrease of circulating Tregs in stable renal transplant recipients. Thus, Rapa might be further explored in strategies using preservation of Tregs for transplant tolerance. Furthermore, quantification of blood Tregs may be a suitable tool to identify renal transplant recipients who may be candidates for reduced immunosuppression.

Cyclosporine A in juvenile idiopathic arthritis. Results of the PRCSG/PRINTO phase IV post marketing surveillance study

OBJECTIVE

To investigate the clinical use patterns, clinical effect and safety of cyclosporine A (CSA) in juvenile idiopathic arthritis (JIA) in the setting of routine clinical care.

METHODS

An open-ended, phase IV post marketing surveillance study was conducted among members of the Pediatric Rheumatology Collaborative Study Group (PRCSG) and of the Paediatric Rheumatology International Trials Organisation (PRINTO) to identify patients with polyarticular course JIA who had received CSA during the course of their disease.

RESULTS

A total of 329 patients, half of whom had systemic JIA, were collected in 21 countries. Data were collected during 1240 routine clinic visits. CSA was started at a mean of 5.8 years after disease onset and was given at a mean dose of 3.4 mg/kg/day. The drug was administered in combination with MTX in 61% and along with prednisone in 65% of the patients who were still receiving CSA. Among patients who were still receiving CSA therapy at the last reported visit, remission was documented in 9% of the patients, whereas in 61% of the patients the disease activity was rated as moderate or severe. The most frequent reason for discontinuation of CSA was insufficient therapeutic effect (61% of the patients); only 10% of the patients stopped CSA because of remission. In 17% of the patients, side effects of therapy was given as the primary reason for discontinuation.

CONCLUSION

This survey suggests that CSA may have a less favourable efficacy profile than MTX and etanercept, whereas the frequency of side effects may be similar. The exact place of CSA in the treatment of JIA can only be established via controlled clinical trial.

The Escherichia coli heat-labile enterotoxin induces apoptosis of immature lymphocytesin vivo via a glucocorticoid-dependent pathway

Escherichia coli heat-labile enterotoxin (LT) exhibits a broad range of immunomodulatory activities, including the induction of lymphocyte-programmed cell death. However, the nature of the lymphoid populations sensitive to LT-induced apoptosis and the mechanisms used by this toxin to promote such activity are still unclear. In this study, we demonstrate that LT induces in mice a rapid increase in the levels of circulating corticosterone, resulting in a dramatic induction of cell death of immature CD4+CD8+, B220+IgM- and IgM+IgD- T and B cell progenitors, respectively. Apoptosis of these cell populations is similar to that reported after experimental treatment with corticosteroids, it is inhibited by mifepristone, a glucocorticoid receptor antagonist, and does not occur in adrenalectomized animals. These results clearly indicate that endogenous glucocorticoids are the mediators of the LT-induced cell death, which involves Bcl-2-dependent apoptotic pathways. The LT-mediated programmed cell death requires systemic exposure and the enzymatic activity of LT, since a mutant devoid of any enzymatic activity have no pro-apoptotic effect at any dose tested.

Organochlorine compounds in liver and concentrations of vitellogenin and 17beta-estradiol in plasma of sea bass fed with a commercial or with a natural diet

Results from previous experiments directed to determine the effect of different nutritional factors or the effect of xenobiotics on hormonal control of reproduction, lead to the hypothesis that hormonal perturbations repeatedly observed in sea bass (Dicentrarchus labrax) broodstock feeding commercial diets could have been caused by the presence of aryl hydrocarbon receptor (AhR) ligands, such as dioxins, furans and polychlorinated biphenyls (PCBs) in the diet. To evaluate this hypothesis, dioxins and related compounds were analysed in liver of female sea bass fed with a commercial or with a natural diet consisting of trash fish (bogue, Boops boops), and concentrations of vitellogenin (VTG) and 17beta-estradiol (E2) were determined in plasma obtained previously in monthly samplings of these animals. As observed in other experiments, females fed with a commercial diet exhibited lower VTG and higher E2 plasma levels than females fed with the natural diet. In liver, sea bass fed with the commercial diet exhibited a profile clearly dominated by high-chlorinated dioxins while in fish fed with the natural diet this profile was dominated by low chlorinated furans. However, typical AhR ligands, such as 2,3,7,8-tetrachlorodibenzo-p-dioxin showed no differences between groups or, as is the case of planar PCBs, showed higher concentrations in the liver of fish fed with the natural diet. These results do not permit to explain the observed hormonal alterations by a possible antiestrogenic effect caused by dioxins and related compounds.

Identification from a positional scanning peptoid library of in vivo active compounds that neutralize bacterial endotoxins

Two peptoids that neutralize the Gram-negative lipopolysaccharide (LPS) were identified from the screening of a positional scanning library. The evaluation of the in vivo activity of these compounds in an endoxemia murine model is also reported. These peptoids did not neutralize lipid A, i.e., the hydrophobic toxic component of LPS. This fact suggests that they do not have access to the micellar core and that they should bind to the hydrophilic carbohydrate portion of LPS.

A new role for BMP5 during limb development acting through the synergic activation of Smad and MAPK pathways

In an attempt to identify new genes implicated in the control of programmed cell death during limb development, we have generated a cDNA library from the regressing interdigital tissue of chicken embryos. We have analyzed 804 sequences from this library and identified 23 genes involved in apoptosis in different models. One of the genes that came up in the screening was the Bone Morphogenetic Protein family member, Bmp5, that has not been previously involved in the control of apoptosis during limb development. In agreement with a possible role in the control of cell death, Bmp5 exhibited a regulated pattern of expression in the interdigital tissue. Transcripts of Bmp5 and BMP5 protein were abundant within the cytoplasm of the fragmenting apoptotic interdigital cells in a way suggesting that delivery of BMPs into the tissue is potentiated during apoptosis. Gain-of-function experiments demonstrated that BMP5 has the same effect as other interdigital BMPs inducing apoptosis in the undifferentiated mesoderm and growth in the prechondrogenic mesenchyme. We have characterized both Smad proteins and MAPK p38 as intracellular effectors for the action of BMPs in the developing limb autopod. Activation of Smad signaling involves the receptor-regulated genes Smad1 and -8, and the inhibitory Smad6, and results in both the upregulation of gene transcription and protein phosphorylation with subsequent nuclear translocation. MAPK p38 is also quickly phosphorylated after BMP stimulation in the limb mesoderm. Treatment with the inhibitor of p38, SB203580, revealed that there are interdigital genes induced by BMPs in a p38-dependent manner (DKK, Snail and FGFr3), and genes induced in a p38-independent manner (BAMBI, Msx2 and Smads). Together, our results suggest that Smad and MAPK pathways act synergistically in the BMP pathway controlling limb development.

Lymphoproliferative disorders in paediatric rheumatic diseases. A report of two cases

Lymphoproliferative disorders (LPD) are reported with a much lower frequency in children with rheumatic diseases than in their adult counterparts. We describe 2 patients who developed a lymphoma during the course of the disease. The first is a 16-year-old girl diagnosed with systemic juvenile idiopathic arthritis 6 years before who developed a mucosa-associated lymphoid tissue (MALT) lymphoma. The second report involves a boy diagnosed with systemic lupus erythematosus at 9 years of age who developed a Hodgkin's lymphoma 9 years after the disease onset. In spite of the low frequency of LPD in children with rheumatic diseases, these processes do occur.