Blocking IL-6 signaling prevents astrocyte-induced neurodegeneration in an iPSC-based model of Parkinson's disease

Parkinson's disease (PD) is a neurodegenerative disease associated with progressive death of midbrain dopamine (DAn) neurons in the substantia nigra (SN). Since it has been proposed that patients with PD exhibit an overall proinflammatory state, and since astrocytes are key mediators of the inflammation response in the brain, here we sought to address whether astrocyte-mediated inflammatory signaling could contribute to PD neuropathology. For this purpose, we generated astrocytes from induced pluripotent stem cells (iPSCs) representing patients with PD and healthy controls. Transcriptomic analyses identified a unique inflammatory gene expression signature in PD astrocytes compared with controls. In particular, the proinflammatory cytokine IL-6 was found to be highly expressed and released by PD astrocytes and was found to induce toxicity in DAn. Mechanistically, neuronal cell death was mediated by IL-6 receptor (IL-6R) expressed in human PD neurons, leading to downstream activation of STAT3. Blockage of IL-6R by the addition of the FDA-approved anti-IL-6R antibody, Tocilizumab, prevented PD neuronal death. SN neurons overexpressing IL-6R and reactive astrocytes expressing IL-6 were detected in postmortem brain tissue of patients at early stages of PD. Our findings highlight the potential role of astrocyte-mediated inflammatory signaling in neuronal loss in PD and pave the way for the design of future therapeutics.

iPSC-Based Modeling of Variable Clinical Presentation in Hypertrophic Cardiomyopathy

BACKGROUND

Hypertrophic cardiomyopathy (HCM) is the most common inherited cardiac disease and a frequent cause of heart failure and sudden cardiac death. Our understanding of the genetic bases and pathogenic mechanisms underlying HCM has improved significantly in the recent past, but the combined effect of various pathogenic gene variants and the influence of genetic modifiers in disease manifestation are very poorly understood. Here, we set out to investigate genotype-phenotype relationships in 2 siblings with an extensive family history of HCM, both carrying a pathogenic truncating variant in the MYBPC3 gene (p.Lys600Asnfs*2), but who exhibited highly divergent clinical manifestations.

METHODS

We used a combination of induced pluripotent stem cell (iPSC)-based disease modeling and CRISPR (clustered regularly interspersed short palindromic repeats)/Cas9 (CRISPR-associated protein 9)-mediated genome editing to generate patient-specific cardiomyocytes (iPSC-CMs) and isogenic controls lacking the pathogenic MYBPC3 variant.

RESULTS

Mutant iPSC-CMs developed impaired mitochondrial bioenergetics, which was dependent on the presence of the mutation. Moreover, we could detect altered excitation-contraction coupling in iPSC-CMs from the severely affected individual. The pathogenic MYBPC3 variant was found to be necessary, but not sufficient, to induce iPSC-CM hyperexcitability, suggesting the presence of additional genetic modifiers. Whole-exome sequencing of the mutant carriers identified a variant of unknown significance in the MYH7 gene (p.Ile1927Phe) uniquely present in the individual with severe HCM. We finally assessed the pathogenicity of this variant of unknown significance by functionally evaluating iPSC-CMs after editing the variant.

CONCLUSIONS

Our results indicate that the p.Ile1927Phe variant of unknown significance in MYH7 can be considered as a modifier of HCM expressivity when found in combination with truncating variants in MYBPC3. Overall, our studies show that iPSC-based modeling of clinically discordant subjects provides a unique platform to functionally assess the effect of genetic modifiers.

Generation of two heterozygous GATA2 CRISPR/Cas9-edited iPSC lines, R398W and R396Q, for modeling GATA2 deficiency

Germline heterozygous GATA2 mutations underlie a complex disorder characterized by bone marrow failure, immunodeficiency and high risk to develop myelodysplastic syndrome (MDS) and acute myeloid leukemia (AML). Our understanding about GATA2 deficiency is limited due to the lack of relevant disease models. Here we generated high quality human induced pluripotent stem cell (iPSC) lines carrying two of the most recurrent germline GATA2 mutations (R389W and R396Q) associated with MDS, using CRISPR/Cas9. These hiPSCs represent an in vitro model to study the molecular and cellular mechanisms underlying GATA2 deficiency, when differentiated into blood progenitors.

Patient-specific iPSC-derived cellular models of LGMDR1

Limb-girdle muscular dystrophy recessive 1 (LGMDR1) represents one of the most common types of LGMD in the population, where patients develop a progressive muscle degeneration. The disease is caused by mutations in calpain 3 gene, with over 500 mutations reported to date. However, the molecular events that lead to muscle wasting are not clear, nor the reasons for the great clinical variability among patients, and this has so far hindered the development of effective therapies. Here we generate human induced pluripotent stem cells (iPSCs) from skin fibroblasts of 2 healthy controls and 4 LGMDR1 patients with different mutations. The generated lines were able to differentiate into myogenic progenitors and myotubes in vitro and in vivo, upon a transient PAX7 overexpressing protocol. Thus, we have generated myogenic cellular models of LGMDR1 that harbor different CAPN3 mutations within a human genetic background, and which do not derive from muscular biopsies. These models will allow us to investigate disease mechanisms and test therapies. Despite the variability found among iPSC lines that was unrelated to CAPN3 mutations, we found that patient-derived myogenic progenitors and myotubes express lower levels of DMD, which codes a key protein in satellite cell regulation and myotube maturation.

Patient-Specific iPSC-Derived Astrocytes Contribute to Non-Cell-Autonomous Neurodegeneration in Parkinson's Disease

Parkinson's disease (PD) is associated with the degeneration of ventral midbrain dopaminergic neurons (vmDAns) and the accumulation of toxic α-synuclein. A non-cell-autonomous contribution, in particular of astrocytes, during PD pathogenesis has been suggested by observational studies, but remains to be experimentally tested. Here, we generated induced pluripotent stem cell-derived astrocytes and neurons from familial mutant LRRK2 G2019S PD patients and healthy individuals. Upon co-culture on top of PD astrocytes, control vmDAns displayed morphological signs of neurodegeneration and abnormal, astrocyte-derived α-synuclein accumulation. Conversely, control astrocytes partially prevented the appearance of disease-related phenotypes in PD vmDAns. We additionally identified dysfunctional chaperone-mediated autophagy (CMA), impaired macroautophagy, and progressive α-synuclein accumulation in PD astrocytes. Finally, chemical enhancement of CMA protected PD astrocytes and vmDAns via the clearance of α-synuclein accumulation. Our findings unveil a crucial non-cell-autonomous contribution of astrocytes during PD pathogenesis, and open the path to exploring novel therapeutic strategies aimed at blocking the pathogenic cross talk between neurons and glial cells.

Patient-Specific iPSC-Derived Endothelial Cells Provide Long-Term Phenotypic Correction of Hemophilia A

We generated patient-specific disease-free induced pluripotent stem cells (iPSCs) from peripheral blood CD34+ cells and differentiated them into functional endothelial cells (ECs) secreting factor VIII (FVIII) for gene and cell therapy approaches to cure hemophilia A (HA), an X-linked bleeding disorder caused by F8 mutations. iPSCs were transduced with a lentiviral vector carrying FVIII transgene driven by an endothelial-specific promoter (VEC) and differentiated into bona fide ECs using an optimized protocol. FVIII-expressing ECs were intraportally transplanted in monocrotaline-conditioned non-obese diabetic (NOD) severe combined immune-deficient (scid)-IL2rγ null HA mice generating a chimeric liver with functional human ECs. Transplanted cells engrafted and proliferated in the liver along sinusoids, in the long term showed stable therapeutic FVIII activity (6%). These results demonstrate that the hemophilic phenotype can be rescued by transplantation of ECs derived from HA FVIII-corrected iPSCs, confirming the feasibility of cell-reprogramming strategy in patient-derived cells as an approach for HA gene and cell therapy.

iPS Cell Cultures from a Gerstmann-Sträussler-Scheinker Patient with the Y218N PRNP Mutation Recapitulate tau Pathology

Gerstmann-Sträussler-Scheinker (GSS) syndrome is a fatal autosomal dominant neurodegenerative prionopathy clinically characterized by ataxia, spastic paraparesis, extrapyramidal signs and dementia. In some GSS familiar cases carrying point mutations in the PRNP gene, patients also showed comorbid tauopathy leading to mixed pathologies. In this study we developed an induced pluripotent stem (iPS) cell model derived from fibroblasts of a GSS patient harboring the Y218N PRNP mutation, as well as an age-matched healthy control. This particular PRNP mutation is unique with very few described cases. One of the cases presented neurofibrillary degeneration with relevant Tau hyperphosphorylation. Y218N iPS-derived cultures showed relevant astrogliosis, increased phospho-Tau, altered microtubule-associated transport and cell death. However, they failed to generate proteinase K-resistant prion. In this study we set out to test, for the first time, whether iPS cell-derived neurons could be used to investigate the appearance of disease-related phenotypes (i.e, tauopathy) identified in the GSS patient.

Advanced cell-based modeling of the royal disease: characterization of the mutated F9 mRNA

Essentials The Royal disease (RD) is a form of hemophilia B predicted to be caused by a splicing mutation. We generated an iPSC-based model of the disease allowing mechanistic studies at the RNA level. F9 mRNA analysis in iPSC-derived hepatocyte-like cells showed the predicted abnormal splicing. Mutated F9 mRNA level was very low but we also found traces of wild type transcripts.

SUMMARY

Background The royal disease is a form of hemophilia B (HB) that affected many descendants of Queen Victoria in the 19th and 20th centuries. It was found to be caused by the mutation F9 c.278-3A>G. Objective To generate a physiological cell model of the disease and to study F9 expression at the RNA level. Methods Using fibroblasts from skin biopsies of a previously identified hemophilic patient bearing the F9 c.278-3A>G mutation and his mother, we generated induced pluripotent stem cells (iPSCs). Both the patient's and mother's iPSCs were differentiated into hepatocyte-like cells (HLCs) and their F9 mRNA was analyzed using next-generation sequencing (NGS). Results and Conclusion We demonstrated the previously predicted aberrant splicing of the F9 transcript as a result of an intronic nucleotide substitution leading to a frameshift and the generation of a premature termination codon (PTC). The F9 mRNA level in the patient's HLCs was significantly reduced compared with that of his mother, suggesting that mutated transcripts undergo nonsense-mediated decay (NMD), a cellular mechanism that degrades PTC-containing mRNAs. We also detected small proportions of correctly spliced transcripts in the patient's HLCs, which, combined with genetic variability in splicing and NMD machineries, could partially explain some clinical variability among affected members of the European royal families who had lifespans above the average. This work allowed the demonstration of the pathologic consequences of an intronic mutation in the F9 gene and represents the first bona fide cellular model of HB allowing the study of rare mutations at the RNA level.

Diminished expression of complement regulatory proteins (CD55 and CD59) in lymphocytes from systemic lupus erythematosus patients with lymphopenia

CD55 and CD59 are glycophosphatidylinositol-anchored proteins with complement inhibitory properties. Lymphopenia in systemic lupus erythematosus (SLE) has been associated with autoantibodies targeting nuclear antigens. The aim of this study was to evaluate the surface density of CD55 and CD59 in T and B lymphocytes from patients with SLE and lymphopenia and its possible correlation with the presence of common SLE autoantibodies. Flow cytometric analyses were performed on CD55 and CD59 stained CD3 and CD19 cells from 40 SLE patients, 30 with lymphopenia and 10 without it, and 25 healthy controls. Autoantibodies were detected in the sera by enzyme linked immunosorbent assay. The mean fluorescence intensity of CD55 and CD59 in T and B cells was significantly diminished in SLE patients with lymphopenia when compared with healthy subjects. Interestingly, the opposite was found in T and B cells from non-lymphopenic SLE patients. Although there was no correlation between CD55 and CD59 surface density and the presence of any specificity of the autoantibodies tested, higher titres of anti-dsDNA, anti-SM and anti-ribosomal p antibodies were significantly associated with lymphopenia. The deficiency of CD55 and CD59 expression may play a role in the pathophysiology of lymphopenia, most likely by increasing the susceptibility of cells to complement mediated cytolysis.

Activity and High-Order Effective Connectivity Alterations in Sanfilippo C Patient-Specific Neuronal Networks

Induced pluripotent stem cell (iPSC) technology has been successfully used to recapitulate phenotypic traits of several human diseases in vitro. Patient-specific iPSC-based disease models are also expected to reveal early functional phenotypes, although this remains to be proved. Here, we generated iPSC lines from two patients with Sanfilippo type C syndrome, a lysosomal storage disorder with inheritable progressive neurodegeneration. Mature neurons obtained from patient-specific iPSC lines recapitulated the main known phenotypes of the disease, not present in genetically corrected patient-specific iPSC-derived cultures. Moreover, neuronal networks organized in vitro from mature patient-derived neurons showed early defects in neuronal activity, network-wide degradation, and altered effective connectivity. Our findings establish the importance of iPSC-based technology to identify early functional phenotypes, which can in turn shed light on the pathological mechanisms occurring in Sanfilippo syndrome. This technology also has the potential to provide valuable readouts to screen compounds, which can prevent the onset of neurodegeneration.

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Fibroblasts from two Sanfilippo C patients were reprogrammed to obtain iPSCs

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iPSCs were successfully differentiated to neural cells that mimic the disease

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Networks of patients’ neurons show altered activity and connectivity

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Early functional phenotypes are prevented in gene-corrected patients’ neurons

Disease-specific phenotypes in dopamine neurons from human iPS-based models of genetic and sporadic Parkinson's disease

Induced pluripotent stem cells (iPSC) offer an unprecedented opportunity to model human disease in relevant cell types, but it is unclear whether they could successfully model age-related diseases such as Parkinson's disease (PD). Here, we generated iPSC lines from seven patients with idiopathic PD (ID-PD), four patients with familial PD associated to the G2019S mutation in the Leucine-Rich Repeat Kinase 2 (LRRK2) gene (LRRK2-PD) and four age- and sex-matched healthy individuals (Ctrl). Over long-time culture, dopaminergic neurons (DAn) differentiated from either ID-PD- or LRRK2-PD-iPSC showed morphological alterations, including reduced numbers of neurites and neurite arborization, as well as accumulation of autophagic vacuoles, which were not evident in DAn differentiated from Ctrl-iPSC. Further induction of autophagy and/or inhibition of lysosomal proteolysis greatly exacerbated the DAn morphological alterations, indicating autophagic compromise in DAn from ID-PD- and LRRK2-PD-iPSC, which we demonstrate occurs at the level of autophagosome clearance. Our study provides an iPSC-based in vitro model that captures the patients' genetic complexity and allows investigation of the pathogenesis of both sporadic and familial PD cases in a disease-relevant cell type.

A protocol describing the genetic correction of somatic human cells and subsequent generation of iPS cells

The generation of patient-specific induced pluripotent stem cells (iPSCs) offers unprecedented opportunities for modeling and treating human disease. In combination with gene therapy, the iPSC technology can be used to generate disease-free progenitor cells of potential interest for autologous cell therapy. We explain a protocol for the reproducible generation of genetically corrected iPSCs starting from the skin biopsies of Fanconi anemia patients using retroviral transduction with OCT4, SOX2 and KLF4. Before reprogramming, the fibroblasts and/or keratinocytes of the patients are genetically corrected with lentiviruses expressing FANCA. The same approach may be used for other diseases susceptible to gene therapy correction. Genetically corrected, characterized lines of patient-specific iPSCs can be obtained in 4-5 months.

Reprogramming of human fibroblasts to induced pluripotent stem cells under xeno-free conditions

The availability of induced pluripotent stem cells (iPSCs) has created extraordinary opportunities for modeling and perhaps treating human disease. However, all reprogramming protocols used to date involve the use of products of animal origin. Here, we set out to develop a protocol to generate and maintain human iPSC that would be entirely devoid of xenobiotics. We first developed a xeno-free cell culture media that supported the long-term propagation of human embryonic stem cells (hESCs) to a similar extent as conventional media containing animal origin products or commercially available xeno-free medium. We also derived primary cultures of human dermal fibroblasts under strict xeno-free conditions (XF-HFF), and we show that they can be used as both the cell source for iPSC generation as well as autologous feeder cells to support their growth. We also replaced other reagents of animal origin (trypsin, gelatin, matrigel) with their recombinant equivalents. Finally, we used vesicular stomatitis virus G-pseudotyped retroviral particles expressing a polycistronic construct encoding Oct4, Sox2, Klf4, and GFP to reprogram XF-HFF cells under xeno-free conditions. A total of 10 xeno-free human iPSC lines were generated, which could be continuously passaged in xeno-free conditions and maintained characteristics indistinguishable from hESCs, including colony morphology and growth behavior, expression of pluripotency-associated markers, and pluripotent differentiation ability in vitro and in teratoma assays. Overall, the results presented here demonstrate that human iPSCs can be generated and maintained under strict xeno-free conditions and provide a path to good manufacturing practice (GMP) applicability that should facilitate the clinical translation of iPSC-based therapies.

Quantitative and qualitative normal regulatory T cells are not capable of inducing suppression in SLE patients due to T-cell resistance

Previous reports have suggested that regulatory T cells (Treg) are abnormal in patients with systemic lupus erythematosus (SLE). In the present work, we quantified CD4+FOXP3+ Treg cells in patients with SLE and found no quantitative alterations. However, we found a clear defect in suppression assays. Surprisingly, SLE-derived Treg cells exhibited a normal phenotype and functional capacity. Conversely, SLE-derived CD4+CD25(-) effector T cells resisted suppression by autologous and allogeneic regulatory cells. Our findings strongly suggest that the defect in T-cell suppression observed in SLE is because of effector cell resistance and not because of an abnormal regulatory function.

Lupus nephritis remission, albeit with positive anti-doping test

A 39-year-old woman developed systemic lupus erythematosus with nephropathy after a holiday in Jamaica. She was prescribed with prednisone, azathioprine and aspirin. As she was obsessed with aesthetic procedures, she decided not to take the prescription. Instead, she took her bodybuilding trainer's advice of one intramuscular injection of stanozolol for 10 weeks in order to increase her gluteus area. One week after finishing the latter regimen, there was no disease activity. Whether lupus remission in this patient was spontaneous or a consequence of stanozolol administration will remain a riddle for this fortunate outcome.

Interleukin-6 and chemokines in the neuropsychiatric manifestations of systemic lupus erythematosus

OBJECTIVE

To define the cytokine and chemokine profile in cerebrospinal fluid (CSF) from patients with neuropsychiatric systemic lupus erythematosus (NPSLE).

METHODS

Forty-two SLE patients who had been hospitalized because of NP manifestations were studied. Patients were evaluated at hospitalization and 6 months later; a CSF sample was obtained at each evaluation. As controls, CSF from 6 SLE patients with septic meningitis, 16 SLE patients with no history of NP manifestations (non-NPSLE), and 25 patients with nonautoimmune diseases were also studied. Soluble molecules, including cytokines (interleukin-2 [IL-2], IL-4, IL-6, IL-10, tumor necrosis factor alpha [TNFalpha], and interferon-gamma [IFNgamma]) and chemokines (monocyte chemotactic protein 1 [MCP-1], RANTES, IL-8, monokine induced by IFNgamma [MIG], and interferon-gamma-inducible 10-kd protein [IP-10]), were measured with the use of cytometric bead array kits.

RESULTS

CSF levels of the following molecules were significantly increased in NPSLE patients as compared with non-NPSLE and nonautoimmune diseases control patients, respectively: IL-6 (32.7 versus 3.0 and 2.96 pg/ml), IL-8 (102.8 versus 29.97 and 19.7 pg/ml), IP-10 (888.2 versus 329.7 [P not significant] and 133.6 pg/ml), RANTES (3.8 versus 2.5 and 2.2 pg/ml), MCP-1 (401.7 versus 257.9 [P not significant] and 136.9 pg/ml), and MIG (35.4 versus 11.4 and 3.5 pg/ml). Low levels of IL-2, IL-4, IL-10, TNFalpha, and IFNgamma were found in all groups. All cytokines and chemokines, except TNFalpha, were significantly higher among the SLE patients with septic meningitis than among the NPSLE patients. Six months later and in the absence of NP manifestations, all elevated molecule levels, except RANTES, in patients with NPSLE had decreased significantly, and no differences were noted between the NPSLE and non-NPSLE groups.

CONCLUSION

A central nervous system response composed of IL-6 and chemokines, but not Th1/Th2 cytokines, is associated with NP manifestations in SLE patients.

Human leukocyte antigen class I, class II, and tumor necrosis factor-alpha polymorphisms in a healthy elder Mexican Mestizo population

Background

There is strong evidence that an individual's genetic background is an important predisposing factor to longevity. In the present study we analysed the frequency of HLA class I, class II, as well as the TNF-α -308 polymorphism that may be related to an increased life span in Mexican Mestizo healthy elders.

Results

HLA typing was performed by polymerase chain reaction sequence specific oligonucleotide (PCR SSO) reverse dot blot. The TNF-α -308 polymorphism was assessed by PCR restriction fragment length polymorphism. A significant increased frequency of HLA-DRB1*11 was found in elderly women whereas this allele was not present in elderly males. The TNF2 allele was also increased in the elder group when compared to young controls. The frequencies of the remaining alleles tested were not statistically different among groups.

Conclusion

These data suggest an ethnicity independent tendency of HLA-DRB1*11 in elder females to increase life span and a possible role of the TNF2 allele with the successful remodelling of senescent immune system.

The gut: beyond immunology

The immune system is characterized by the ability to distinguish self from non-self. The intestinal immune system bears this latter property but, furthermore, it must discriminate among nutritious and beneficial substances from toxic or harmful ones. Considering that the gut has to be colonized by commensal bacteria participating in digestion as well as in the control of pathogen microorganisms, it is not surprising that mucosal surfaces are the largest and probably the most exquisitely specialized immune system's compartment. This means that not only innate and adaptive immunity are present, but further, particular structures, cells, and mechanisms such as physical barrriers, epithelia, Peyer's patches, M cells among others, which together are involved in the dynamic control of the homeostasis between gut and its flora. The present review deals with some popular conceptions about the digestive system with particular emphasis on the gut's immunology.

P-glycoprotein in autoimmune diseases

Multidrug resistance-1 (MDR-1) is characterized by overfunction of P-glycoprotein (P-gp), a pump molecule that decreases intracellular drug concentration by effluxing them from the intracellular space. Broad ranges of structurally unrelated compounds are transported by P-gp, including antineoplastic agents, HIV protease inhibitors, prednisone, gold salts, methotrexate, colchicine as well as several antibiotics. In contrast, many other compounds such as calcium channel blockers (verapamil) and immunosupressors (cyclosporine-A) are able to inhibit P-gp function. The P-gp role in therapeutic failures has been extensively studied in cancer; however, there is little information regarding MDR-1 phenotype in autoimmune disorders. It has been reported that an increased number of lymphocytes are able to extrude P-gp substrates in rheumatoid arthritis, immune thrombocytopenic purpura and systemic lupus erythematosus, the patients with poor response to treatment being the ones that exhibit the highest values. This may be due, at least in part, to a simultaneous long-term usage of several drugs that induce P-gp function. Since abnormally activated cell compartments characterize autoimmune diseases, it is possible that those cells are the ones that exhibit drug resistance. The study of drug resistance mechanisms in autoimmunity may be helpful for the optimization of the current therapeutic schemes through their combination with low doses of P-gp inhibitors.

Lupus Nephritis Outcome With and Without Renal Biopsy

BACKGROUND

: Renal biopsy is an important tool in devising an adequate treatment plan for lupus nephritis. However, it is not always possible to perform a biopsy, and in many cases, treatment must rely exclusively on clinical data.

OBJECTIVE

: The aim of this study was to compare the 5-year course of patients treated without a biopsy with another group with histologic evidence of diffuse proliferative glomerulonephritis (DPGN).

METHODS

: The no-biopsy group consisted of 30 patients with lupus with strong clinical and laboratory suspicion of proliferative glomerulonephritis in whom a renal biopsy was unavailable either because of medical contraindication or the patient's refusal. The biopsy group included 30 patients undergoing biopsy and a histologic diagnosis of DPGN. Patients were followed from the onset of nephritis and at 18, 36, and 60 months.

RESULTS

: At onset, the no-biopsy group showed lower C3 levels and higher proteinuria, although both groups showed evident deterioration of the renal function. No significant differences were found in treatment, outcome, survival, renal function tests, or in the development of kidney failure.

CONCLUSIONS

: Proliferative glomerulonephritis deserves prompt diagnosis and treatment. This study demonstrates that experience in the management of lupus nephropathy, together with clinical and laboratory data, are often enough information to adequately treat proliferative glomerulonephritis even in the absence of a renal biopsy.

Multidrug resistance-1 (MDR-1) in autoimmune disorders IV. P-glycoprotein overfunction in lymphocytes from myasthenia gravis patients

Multidrug resistance (MDR) mechanisms have been widely studied in cancer. Among them, P-glycoprotein (P-gp) overfunction has been associated with resistance to several antineoplastic agents. The physiological role of P-gp involves hormone and metabolite secretion, bacterial product detoxification, and transport of several drugs to the extracellular space, thus inhibiting their toxic or therapeutic effects. The study of MDR-1 in diseases of autoimmune origin has just recently emerged. Corticosteroids remain the mainstay therapy for autoimmune diseases. As prednisone (PDN) is transported by P-gp, the aim of this study was to evaluate the P-gp function in lymphocytes from myasthenia gravis (MG) patients. Thirty MG patients and 25 healthy controls were studied. Peripheral blood mononuclear cells were isolated by gradient centrifugation and incubated with daunorubicin (DNR) (a fluorescent drug extruded by P-gp). Functional activity of P-gp was analyzed by flow cytometry. Results were expressed as percentage of gated lymphocytes able to efflux DNR. Overall, MG patients showed increased numbers of lymphocytes with functional P-gp activity when compared with controls (x = 4.92 +/- 5.26% vs. x = 0.7 +/- 0.48%, respectively) (P < 0.0001). When patients were classified as responders (n = 21) or refractory (n = 9) to treatment, the latter group exhibited higher values of functional P-gp (x = 10.18 +/- 6.39%) when compared to the responder group (x = 2.66 +/- 2.45%) (P = 0.0076). These data suggest, on the one hand, that drug resistance may be induced by long-term treatment or by high PDN doses and, on the other, emphasize the need for the study of P-gp antagonists in order to improve the current therapeutical schemes for the treatment of MG.

Effect of rapamycin on cytokine profile in kidney transplant recipients treated with triple drug therapy

The aim of this study was to explore differences in the cytokine profile among de novo kidney transplant recipients treated with either Rapamycin (Rapa) + cyclosporine (CsA) + prednisone (P) or CsA + azathioprine (Aza) + P.

PATIENTS AND METHODS

Among the 13 adult kidney transplant recipients studied, seven received Rapa + CsA + P while the remaining six received CsA + Aza + P with their living donors serving as controls (n = 13). Spontaneous production of IL-2, IFNgamma, IL-10, and TGF-beta were measured by ELISA in supernatants from 24-hour cultured unstimulated peripheral blood mononuclear cell (PBMC) at time zero (the day before the transplant), and at 3 and 6 months posttransplant. Cytokines were also measured 1 month after CsA withdrawal in the Rapa + CsA + P group.

RESULTS

From time zero to the end of the study, IL-2, IFNgamma, and IL-10 were present at low or undetectable levels in all three groups. TGF-beta tended to increase in supernatants from patients under Rapa + CsA + P at 6 months posttransplant and at 1 month after CsA withdrawal without correlation to Rapa blood levels. TGF-beta remained stable throughout the study period for patients included in the CsA + Aza + P group. There was no difference in this cytokine level between these study groups at any given time.

CONCLUSIONS

This study showed no differences in the spontaneous cytokine profiles evaluated in patients treated with both therapeutic schemes.

Class I and class II MHC polymorphisms in Mexican patients with Behçet’s disease

Behçet's disease is a multi-system inflammatory disorder of unknown etiology. The disease is more prevalent in Eastern Mediterranean countries and Japan where there is a linkage to HLA-B51. Mexican Mestizos are suitable subjects for studying the role of ethnicity in the susceptibility to Behçet's disease. High-resolution HLA class I and class II typing was performed by polymerase chain reaction sequence-specific oligonucleotide (PCR-SSO) reverse dot blot and PCR-single-strand polymorphism in 32 patients with Behçet's disease and 99 healthy ethnically-matched controls. A significant increased frequency of HLA-B(*)44 (P = 0.02; OR = 2.78; CI 95% = 1.1-7.7), HLA-B(*)52 (P = 0.02; OR = 5.33; CI 95% = 1.07-29.1), and HLA-B(*)56 (P = 0.003; OR = 4.19; CI 95% = 3.37-5.21) as well as HLA-DRB1(*)01 and HLA-DRB1(*)13 (p = 0.007; OR = 3.36; CI 95% = 1.22-9.27) was found in Mexican patients with Behçet's disease when compared to controls. The low frequency of native markers in Mexican Mestizo patients with Behçet's disease suggests that genetic admixture between Eastern Mediterraneans and Orientals with Amerindians is a recent event that increased the risk of developing Behçet's disease in the Mexican population.

In vivo IL-10 and TGF-beta production by PBMC from long-term kidney transplant recipients with excellent graft function: a possible feedback mechanism participating in immunological stability

BACKGROUND

Interleukin-10 (IL-10) and transforming growth factor-beta (TGF-beta) are Th2-derived multifunctional cytokines that exhibit potent immunoregulatory and anti-inflammatory properties which might prolong graft survival. The aim of this study was to explore whether spontaneous production of IL-10 and TGF-beta by blood mononuclear cells correlates with excellent long-term graft function.

METHODS

A cross-sectional study was carried out in 32 kidney transplant recipients, without albuminuria, treated with azathioprine and prednisone. Spontaneous IL-10 and TGF-beta were measured by enzyme-linked immunosorbent assay in supernatants from 24 h cultured unstimulated peripheral blood mononuclear cells. Both cytokines were also determined in 10 healthy kidney donors.

RESULTS

There was no correlation between IL-10 or TGF-beta with any variable tested, namely age, SCr, histocompatibility, and post-transplant follow-up. In vivo IL-10 production displayed a statistical trend to be higher in transplant recipients than in controls (362.3 +/- 465, range 12.5-1929.3 pg/ml, and 189 +/- 170, range 4.17-485.7 pg/ml, respectively; p = 0.08), whereas no difference was observed in TGF-beta among the same groups (134.7 +/- 79.2, range 68-421 pg/ml, and 121.4 +/- 25.8, range 75-151 pg/ml, respectively). Interestingly, a statistically significant inverse correlation was observed between IL-10 and TGF-beta in kidney transplant recipients (p = 0.03).

CONCLUSIONS

The higher IL-10 production observed in long-term kidney transplant recipients supports the notion that this cytokine contributes in decreasing allogenic immune responses and allows prolongation of allograft survival. The balance between TGF-beta and IL-10 may be of paramount importance in graft acceptance.

Immunoregulatory defects in patients with systemic lupus erythematosus in clinical remission

Little is known about the immune system of patients with systemic lupus erythematosus (SLE) during periods of silent disease. To address this issue we analysed lymphoid populations andcytokine production of mononuclear cells obtained from SLE patients in remission. We studied 43 patients with inactive disease, 10 with active disease and 30 controls. Remission was defined as at least 1 year during which lack of clinical disease activity permitted withdrawal of all treatment. Remission length ranged from 1 to 30 years. Flow cytometry and ELISA were used to study lymphoid populations (CD4, CD8 and CD19) and cytokine production (IL-2, 4, 10, 12 and 18). Patients with short remission periods (up to 15 years) exhibited an increased percentage of B cells; production of IL-2, IL-10 and IL-12 was decreased; production of IL-18 was increased. Interestingly, patients from groups with long time of inactive disease had corrected most alterations, but had an impaired IL-18 expression. IL-12 production correlated strongly with the length of the remission period (r = 0.7565). The immune system of patients with inactive lupus has partially corrected the disturbances present during disease activity. This is accomplished gradually, sometimes until counter-regulatory alterations are developed. This may allow patients to remain without disease activity.

CD8+ chronic lymphocytic leukemia: an extensive characterization of a bizarre hybrid neoplasia

Atypical chronic lymphocytic leukemia (CLL) expressing the CD8 antigen have a frequency of less than 0.5% of all cases, however, they are not yet been fully characterized. Herein a CD8+ CLL case was extensively studied. Besides the classical CLL antigen expression, an unusual presence of surface markers such as CD11c, CD56, and CD154 was observed. Moreover, gene expression of chemokine receptors belonging to the CCR family were clearly evidenced as well as mRNA for both, Th1 and Th2 cytokines. Likewise, granzyme A, B and perforin gene expression, cytotoxic T cell or NK enzymes were found. The intricate profile of membrane molecules and gene expression suggest that it could be favorable, rather than deletereous, for the maintainance of the neoplastic process.

Deficiency of red cell bound CD55 and CD59 in patients with systemic lupus erythematosus

CD55 and CD59 are glycosylphosphatidylinositol-anchored proteins with complement inhibitory properties. Autoimmune hemolytic anemia (AIHA) has been associated with antiphospholipid antibodies (APLA). The aim of this study was to evaluate the presence of APLA and its possible correlation with diminished CD55 and CD59 in red blood cells from patients with primary AIHA or secondary to systemic lupus erythematosus (SLE). Flow cytometric analyses were performed on CD55 and CD59 stained erythrocytes from 24 patients (primary AIHA, n=8; AIHA plus SLE, n=11; and SLE without AIHA, n=5) and 20 healthy controls. Antibodies to several phospholipids were detected in the sera by ELISA. Most patients with AIHA plus SLE and few with primary AIHA showed deficiency of either or both CD55 and CD59 expression and was not associated to the presence of APLA, while SLE patients exhibited a normal expression of these molecules. Although our findings showed CD55 and CD59 deficiency in primary or secondary AIHA, it appears that this defect plays a facilitator rather than a triggering role for the hemolytic process. Additionally, a role of anti-phospholipid antibodies as causative of this acquired defect is questionable.

Multidrug resistance-1 (MDR-1) in autoimmune disorders III: increased P-glycoprotein activity in lymphocytes from immune thrombocytopenic purpura patients

OBJECTIVE

P-glycoprotein (P-gp) expression has been widely observed in normal and neoplastic cells. The physiologic role of P-gp involves hormone and metabolite secretion, bacterial product detoxification, and transport of several drugs to the extracellular space. Multidrug resistance-1 is characterized by drug extrusion through P-gp, reducing the intracellular levels of drugs and diminishing their pharmacological effects. Treatment of immune thrombocytopenic purpura (ITP) includes agents that are substrates of P-gp; hence, the objective of this study was to analyze the functional activity of P-gp in lymphocytes from patients with ITP.

PATIENTS AND METHODS

30 ITP patients (9 refractory, 5 dependent, 14 responders to treatment, and 2 with stable disease) and 25 healthy controls were studied. Peripheral blood mononuclear cells were isolated by gradient centrifugation and incubated with daunorubicin (a fluorescent drug extruded by P-gp). Functional activity of P-gp was analyzed by flow cytometry. Results were expressed as the percentage of lymphocytes able to extrude daunorubicin.

RESULTS

ITP patients showed an increased number of lymphocytes with P-gp activity (mean=12.3%+/-16%) when compared to controls (mean=0.87%+/-0.72%) (p<0.05). P-gp function was higher in the refractory group (median=9.4%) than in the treatment-dependent (median=5.4%), responder (median=6.4%), and stable disease (median=5.2%) groups, although no statistical differences were found among them.

CONCLUSION

Enhanced P-gp activity in ITP may be related to an unfavorable clinical outcome and poor response to treatment. Furthermore, P-gp function might affect therapeutic requirements for disease control.

Weekly dose of leflunomide for the treatment of refractory rheumatoid arthritis: an open pilot comparative study

AIMS

To assess the therapeutic effect of leflunomide in weekly dose of 100 mg in patients with refractory rheumatoid arthritis.

MATERIAL AND METHODS

Sixteen patients were included (18-72 years, disease duration 2-32 years). Eight patients received a weekly dose of 100 mg of leflunomide and 8 the conventional dose. Current treatment was not modified. All patients underwent a monthly evaluation for one year, applying the 1995 ACR preliminary definition of improvement in rheumatoid arthritis.

RESULTS

After 2 months, the group treated with the conventional leflunomide dose evidenced a remarkable improvement (7/8 patients achieving ACR 20), while the group receiving the weekly dose, the improvement was not as clearly evident (3/8 patients achieving ACR 20). By the fourth to sixth month, the response was comparable on both groups (6/6 and 6/8 patients achieving ACR 50 in the daily and weekly dose, respectively) and prevailed through the end of the study. There were no statistical differences between groups at any evaluation. Side effects made itself clear in 6 patients in the daily leflunomide group, and 2 patients withdrawn leflunomide because severe gastrointestinal symptoms and hepatotoxicity, respectively. In the group of weekly leflunomide 2 patients presented side effects which disappeared spontaneously.

CONCLUSION

The use of leflunomide in a weekly dose of 100 mg proved to have similar therapeutic benefit as that of the conventional scheme and might represent a new option for the treatment of refractory rheumatoid arthritis patients.

Bacterial DNA in synovial fluid cells of patients with juvenile onset spondyloarthropathies

OBJECTIVE

To identify bacterial DNA in synovial fluid cells of patients with active juvenile onset spondyloarthropathy (SpA).

METHODS

The main group of study constituted 22 patients with juvenile onset SpA. In addition, five patients with adult onset SpA and nine with rheumatoid arthritis (RA) were studied. Polymerase chain reaction (PCR) with either genus- or species-specific primers was performed on synovial fluid cells to detect DNA sequences of Chlamydia trachomatis, Yersinia enterocolitica, Salmonella sp., Shigella sp., Campylobacter sp. and Mycobacterium tuberculosis. The presence of antibacterial antibodies in sera and synovial fluid was also determined by enzyme-linked immunoassay.

RESULTS

The synovial fluid of nine patients with juvenile onset SpA, three with adult onset SpA and one with RA contained bacterial DNA. Five juvenile onset SpA samples had DNA of one single bacterium; two juvenile onset SpA and three adult onset SpA had DNA of two bacteria and two juvenile onset SpA had DNA of three bacteria. Overall, Salmonella sp. DNA was detected in seven synovial fluid samples, Shigella sp., Campylobacter sp. and M. tuberculosis were found in four samples each, and C. trachomatis was found in two. The bacterial DNA findings correlated with neither diagnosis nor disease duration. One RA synovial fluid had DNA of Campylobacter sp. Neither serum nor synovial fluid antibacterial antibodies correlated with DNA findings or clinical diagnosis.

CONCLUSION

In this study, single and several combinations of bacterial DNA were identified in the synovial fluid of patients with long-term undifferentiated and definite juvenile onset SpA and adult onset SpA. Of relevance is that bacterial DNA corresponds to bacteria producing endemic disease in our population.

Innate immune mechanisms in the pathogenesis of systemic lupus erythematosus (SLE)

Immune imbalance in SLE increases the susceptibility to infectious diseases. The aim of this study was to analyze several mechanisms related to non-specific immunity in this autoimmune disorder. We studied in vivo CD11b expression, phagocytosis, and chemotaxis in polymorphonuclear cells (PMN) from SLE patients. All tests were also performed under hrIL-8 stimulating conditions and analyzed by flow cytometry. Intracellular leucocyte (monocytes and PMN) enzyme activity was evaluated using specific substrates for cathepsin B and D, collagenase, and oxidative burst by flow cytoenzymology. An exaggerated in vivo CD11b expression was observed on PMN from SLE patients without noticeably in vitro effect upon hrIL-8. Similarly both, phagocytosis and chemotaxis were diminished and showed no response to hrIL-8 stimulation. The opposite was found in PMN from controls. Intracellular enzyme activity was comparable between groups as far as cathepsin B and D are concerned. A tendency of decreased oxidative-burst induction was noted in monocytes and PMN from SLE patients, whereas collagenase activity was found clearly increased in both leucocyte subpopulations. Our results may represent a deficient ability of the innate immune mechanisms for the clearance of infectious agents, immune complexes, satisfactory resolution of inflammatory processes and tissue repair in SLE.

Innate immune response mechanisms in non-insulin dependent diabetes mellitus patients assessed by flow cytoenzymology

It is well known that infections in patients with diabetes mellitus are more severe, although there is controversy for increased susceptibility to them. Non-specific immune response mechanisms could be related to defense and/or susceptibility to pathogens. The aim of this study was to investigate the activity of several enzymes involved in the primary host defense mechanisms in non-insulin dependent diabetes mellitus (NIDDM). Twenty NIDDM females with a mean HbA(1c) level of 8.19% were included. No patient had clinical evidence of infection. As controls 20 healthy females were studied. The enzymes tested were dipeptidyl-peptidase I (DPP-I), cathepsin B and D, NADPH oxidase and superoxide dismutase (oxidative burst) and collagenase. Isolated leukocytes were incubated with the specific substrates in pyrogen free conditions. The intracellular enzyme activity was analyzed by flow cytometry. Collagenase enzymatic activity was similar in the three leukocyte subpopulations studied. Oxidative burst induction in monocytes was comparable between both groups. Enzyme activity of cathepsin B and D in all cell subsets, oxidative burst in PMN cells, and DPP-I in lymphocytes and monocytes from patients, was higher than those from healthy females (P<0.05). Overall, our findings demonstrate an enhanced functional status of several intracellular leukocyte enzymes in NIDDM. Furthermore, the increased oxidative burst induction and the consequent production of free radicals, may contribute to vascular complications. Other mechanisms - either from the non-specific or specific immune response - deserve investigation to establish if diabetic patients are more susceptible to infectious diseases.

Clinical and biologic effects of anti-interleukin-10 monoclonal antibody administration in systemic lupus erythematosus

OBJECTIVE

To evaluate the safety and clinical efficacy of administering an anti-interleukin-10 (anti-IL-10) monoclonal antibody (mAb) to systemic lupus erythematosus (SLE) patients with active and steroid-dependent disease. In addition, we sought to assess the effects of in vivo IL-10 neutralization on biologic markers of SLE.

METHODS

Treatment consisted of 20 mg/day intravenous administration of an anti-IL-10 murine mAb (B-N10) for 21 consecutive days, with a followup period of 6 months. Six patients were studied.

RESULTS

Treatment was safe and well tolerated. All patients developed antibodies against B-N10. Cutaneous lesions and joint symptoms improved in all patients beginning during B-N10 administration and continuing to month 6. The SLE Disease Activity Index decreased from a mean +/- SEM of 8.83+/-0.91 on day 1 to 3.67+/-0.67 on day 21 (P = 0.001), 1.50+/-0.84 at month 2, and 1.33+/-0.80 at month 6 (P<0.001). At the end of followup, the disease was clinically inactive in 5 of the 6 patients. Prednisone administration was decreased from a mean +/- SEM of 27.9+/-5.7 mg/day on day 1 to 9.6+/-2.0 mg/day at month 6 (P<0.005). Activity of immune and endothelial cells rapidly decreased, as assessed by the early evolution of several biologic markers.

CONCLUSION

This is the first report of IL-10 antagonist administration to humans. The study shows the involvement of IL-10 in the pathogenesis of SLE, and indicates that the use of IL-10 antagonists may be beneficial in the management of refractory SLE.

Multidrug resistance-1 (MDR-1) in rheumatic autoimmune disorders. Part II: Increased P-glycoprotein activity in lymphocytes from systemic lupus erythematosus patients might affect steroid requirements for disease control

BACKGROUND

Over-expression of the membrane glycoprotein called P-glycoprotein has been widely observed in a variety of both normal and neoplastic cells. P-glycoprotein is a pump molecule that transports hydrophobic drugs (including steroids) and toxins outside the cells, thus inhibiting their therapeutic or toxic effects. The gene encoding P-glycoprotein is named multidrug resistance-1 (MDR-1).

OBJECTIVE

To evaluate the functional activity of P-glycoprotein in lymphocytes and monocytes from patients with systemic lupus erythematosus.

METHODS

30 systemic lupus erythematosus patients and 20 healthy controls were studied. Peripheral blood mononuclear cells isolated by gradient centrifugation were incubated in the presence of daunorubicin (a fluorescent drug extruded by P-glycoprotein) at 37 degrees C or 4 degrees C for 30 min. P-glycoprotein activity was then analyzed using flow cytometry. Results were expressed as the percentage of lymphocytes or monocytes with high P-glycoprotein activity (i.e., low fluorescence).

RESULTS

Mean fluorescence values for lymphocytes and monocytes were comparable between patients and healthy controls. However, because our method allowed to measure P-glycoprotein function at the single-cell level, we were able to show that the mean percentage of lymphocytes with high P-glycoprotein activity was increased in the patients (11.51% +/- 14.3%) as compared to the healthy controls (0.71% +/- 0.57%) (P < 0.05). Moreover, P-glycoprotein activity was lower in the patients in clinical remission than in those with active disease.

CONCLUSIONS

Our results suggest that P-glycoprotein function might affect glucocorticoid requirements in systemic lupus erythematosus.

Multidrug resistance-1 (MDR-1) in rheumatic autoimmune disorders. Part I: Increased P-glycoprotein activity in lymphocytes from rheumatoid arthritis patients might influence disease outcome

BACKGROUND

Multidrug resistance (MDR) is characterized by overexpression of P-glycoprotein, a pump molecule that decreases intracellular drug concentrations by increasing drug efflux from cells.

OBJECTIVE

To look for correlations between clinical status and P-glycoprotein activity and/or TNF-alpha mRNA levels in patients with rheumatoid arthritis.

METHODS

Sixteen patients were studied. Based on response to therapy, eight were refractory and eight nonrefractory to treatment. Findings were compared to those in 24 healthy controls. Flow cytometry was used to evaluate P-glycoprotein activity in peripheral blood mononuclear cells isolated by gradient centrifugation and incubated with the P-glycoprotein substrate daunorubicin. TNF-alpha mRNA levels were determined using quantitative PCR.

RESULTS

Patients with rheumatoid arthritis showed an increased number of lymphocytes with high P-glycoprotein activity (p = 0.0001) as compared to the normal controls. P-glycoprotein activity was higher in the refractory than in the non-refractory patient subgroup (p = 0.006). Also, TNF-alpha mRNA levels were markedly higher in the refractory subgroup than in the nonrefractory subgroup, and were undetectable in the normal controls.

CONCLUSIONS

Enhanced P-glycoprotein activity may be closely related to an unfavorable clinical course and a poor response to treatment. Increased TNF-alpha expression and chronic exposure to various drugs, including glucocorticoids, may contribute to increase P-glycoprotein activity. Both high P-glycoprotein activity and excessive amounts of TNF-alpha seem associated with poor outcome in rheumatoid arthritis.

Possible role of interleukin-10 in autoantibody production and in the fate of human cord blood CD5+ B lymphocytes

Mononuclear cell subsets in 25 human umbilical cord blood samples and 10 healthy adults were studied. We found a decreased percentage of CD3+ cells, CD8+ cells and gammadelta T cells in cord blood compared with blood from healthy adults. The CD16+56+ and CD19+CD5+ phenotypes were overexpressed in cord blood. We then measured spontaneous gene expression and the production of interleukin-10 in mononuclear cells from cord blood and adult subjects. Although we found no difference between cord blood cells and those from healthy adults, a tendency towards spontaneous interleukin-10 production was observed in cord blood. Phorbol 12-myristate 13-acetate stimulation revealed that, among lymphocytes, cord blood B cells are the main cellular source of interleukin-10. Finally, we found no evidence of augmented spontaneous apoptosis but an increased bcl-2 gene expression in non-T cells from cord blood. Interleukin-10 might protect CD19+CD5+ B cells from apoptosis by inducing bcl-2 and promoting autoantibody production in this B-cell subpopulation.

Increased collagenase and dipeptidyl peptidase I activity in leucocytes from healthy elderly people

The incidence of infectious diseases increases with ageing. The enzymatic activity of leucocytes may have a relevant role in the morbidity and mortality due to infections in the elderly. In this study we have compared the activity of enzymes involved in the inflammatory response in leucocytes from young and elderly women. A total of 35 healthy females was studied, 20 volunteers aged 78-98 years (mean 89.1 years) and 15 young controls aged 19-34 years (mean 26 years). All of them were in good clinical condition, without any acute or chronic disease. Intracellular enzyme activity was analysed by flow cytometry in leucocytes from young and elderly women. The enzyme substrates employed were for oxidative burst, L-aminopeptidase, collagenase, cathepsin B, C, D and, G and dipeptidyl peptidase I. The intracellular enzyme activity assessed by flow cytometry in leucocytes from young and elderly women was similar, as far as oxidative burst, L-aminopeptidase, cathepsin B, C, D and G are concerned. An increased collagenase activity was detected in granulocytes from elders. The mean fluorescence channels for this enzyme corresponded to 86 +/- 23 and 60 +/- 15 in cells from elders and controls, respectively (P = 0.01224). An increased dipeptidyl peptidase I activity was detected in lymphocytes from elderly women. The corresponding values for this enzyme in elders and the young were 65.9 +/- 43.3 and 17.3 +/- 5, respectively (P = 0. 0036). The proper functional activity of intracellular enzymes involved in inflammatory responses is likely to be determinant for successful ageing.

Differential oncogene and TNF-alpha mRNA expression in bone marrow cells from systemic lupus erythematosus patients

The aim of the study was to investigate the bone marrow expression of genes involved in cell growth and apoptosis in patients with systemic lupus erythematosus (SLE). Spontaneous expression of bcl-2, bax, c-myc. c-fos, c-jun, p53, Fas and tumour necrosis factor (TNF)-alpha by bone marrow cells was measured using either semiquantitative or quantitative reverse transcription polymerase chain reaction in SLE patients (n = 8) and in eight normal control subjects. The expression of bcl-2 was found to be higher in SLE patients than in controls. Bone marrow cells from SLE patients showed significant down-regulation of bax, c-myc, c-fos and p53 (P < or = 0.05), as compared to normal controls. In both SLE patients and controls the expression of c-jun and Fas was very low or undetectable. Finally, TNF-alpha gene expression was higher in bone marrow samples from SLE patients than in those of controls (P= 0.01). The abnormal expression of genes regulating cell growth and apoptosis in bone marrow cells from SLE patients may help explain the presence of autoreactive cells in secondary lymphoid organs and peripheral blood of SLE patients.

Role of IL-10 in the abnormalities of early cell activation events of lymphocytes from patients with systemic lupus erythematosus

Lymphocytes from patients with systemic lupus erythematosus (SLE) exhibit abnormalities in early cell activation events as well as increased production of IL-10. We explored the possible role of IL-10 on defective cell activation events of SLE lymphocytes and first studied the in vitro effect of IL-10 on peripheral blood mononuclear cells (PBMNC) from healthy subjects. After 5 days of culture in the presence of exogenous IL-10, these cells demonstrated abnormal expression of CD69 as well as high intracellular pH and defective activation of the Na+/H+ anti-porter by PMA. We then investigated the effect of IL-10 blockade on PBMNC from SLE patients. SLE PBMNC cultured for 5 days with a blocking anti-IL-10 monoclonal antibody (mAb) partially corrected abnormalities in CD69 expression and intracellular pH; however, in 1/5 patients studied, no significant positive effect was observed. The effect of the anti-IL-10 mAb was apparently not related to protection against activation-induced cell death. We conclude that IL-10 in normal PBMNC induce some of the defects in early cell activation events seen in SLE lymphocytes. Accordingly, the blockade of IL-10 partially corrects these abnormalities in SLE cells. Our data further support the importance of IL-10 in immune dysfunction seen in SLE.