Miguel Cuchacovich

Prostate Cancer Cell Proliferation In vitro Is Modulated by Antibodies against Glucose-Regulated Protein 78 Isolated from Patient Serum

Circulating autoantibodies against the glucose-regulated protein of 78 kDa (GRP78) are present at high levels in prostate cancer patients and are a biomarker of aggressive tumor behavior. We purified the anti-GRP78 IgGs and examined their effect on 1-LN, PC-3, DU145, and LnCap human prostate cancer cells. We also evaluated its effects on the breast cancer MDA-MB231 and melanoma DM413 cell lines. The anti-GRP78 antibody binds only to cells expressing GRP78 on the surface, to a site also recognized by its physiologic agonist, activated alpha(2)-macroglobulin (alpha(2)M*). This antibody is completely specific for a peptide, including the primary amino acid sequence CNVKSDKSC, which contains a tertiary structural motif mimicking an epitope in GRP78. Tertiary structural analysis suggested the linear GRP78 primary amino acid sequence LIGRTWNDPSVQQDIKFL (Leu(98)-Leu(115)) as the putative binding site, containing the tertiary structual arrangement described above, which was confirmed experimentally. The anti-GRP78 antibodies from prostate cancer patients recognize almost exclusively this epitope. We produced animal antibodies against both these peptides, and they are able to mimic the effects of the human antibody. Our experiments also suggest this epitope as highly immunogenic, thereby explaining the specificity of the immune response against this epitope in GRP78, observed in humans. Using 1-LN cells as a model, we show that anti-GRP78 IgG purified from the sera of these patients mimics the proproliferative effects induced by alpha(2)M* via the common receptor, GRP78. Furthermore, increasing concentrations of human anti-GRP78 IgG show a dose-dependent protective effect on apoptosis induced by tumor necrosis factor alpha.

Effect of interleukin‐6 receptor blockade on the balance between regulatory T cells and T helper type 17 cells in rheumatoid arthritis patients

A new paradigm has emerged relating the pathogenesis of rheumatoid arthritis (RA), focused on the balance between T helper type 17 cells and regulatory T cells (Tregs). In humans, both subpopulations depend on transforming growth factor (TGF)‐β for their induction, but in the presence of inflammatory cytokines, such as interleukin (IL)‐6, the generation of Th17 is favoured. Tocilizumab is a therapeutic antibody targeting the IL‐6 receptor (IL‐6R), which has demonstrated encouraging results in RA. The aim of this study was to evaluate the effect of tocilizumab on Th1 cells, Th17 cells, IL‐17 and interferon (IFN)‐γ double secretors Th17/Th1 cells, and Tregs in RA patients. Eight RA patients received tocilizumab monthly for 24 weeks and blood samples were obtained every 8 weeks to study T cell populations by flow cytometry. The frequency of Th17 cells, Th1 cells and Th17/Th1 cells was evaluated in peripheral blood mononuclear cells (PBMCs) activated in vitro with a polyclonal stimulus. Tregs were identified by their expression of forkhead box protein 3 (FoxP3) and CD25 by direct staining of PBMCs. Although no changes were detected in the frequency of Th1 or Th17 cells, the percentages of peripheral Tregs increased after therapy. In addition, the infrequent Th17/Th1 subpopulation showed a significant increment in tocilizumab‐treated patients. In conclusion, tocilizumab was able to skew the balance between Th17 cells and Tregs towards a more protective status, which may contribute to the clinical improvement observed in RA patients.

Tumour necrosis factor-α (tnf-α) levels and influence of -308 TNF-α promoter polymorphism on the responsiveness to infliximab in patients with rheumatoid arthritis

Objective: To investigate the influence of −308 tumour necrosis factor‐α (TNF‐α) promoter polymorphism and circulating TNF‐α levels in the clinical response to the infliximab treatment in patients with rheumatoid arthritis (RA). Methods: One hundred and thirty‐two RA patients were genotyped for TNF‐α promoter by polymerase‐chain reaction restriction fragment‐length polymorphism (PCR‐RFLP) analysis. Ten patients with the −308 TNF‐α gene promoter genotype G/A, and 10 with the G/G genotype were selected and received 3 mg/kg of infliximab at Weeks 0, 2, 6, and 14. Results: Both groups showed a significant improvement with treatment in all variables studied. Total mean TNF‐α levels increased significantly with respect to basal levels in most of patients after treatment [probability (p)=0.04]. Only patients from G/A showed a statistically significant correlation between ACR 50 and the increase of TNF‐α levels (p<0.03). Conclusion: A relationship was detected between ACR criteria of improvement and increased circulating TNF‐α levels in RA patients subjected to anti‐TNF‐α therapy.

B cells from rheumatoid arthritis patients show important alterations in the expression of CD86 and FcγRIIb, which are modulated by anti-tumor necrosis factor therapy

IntroductionSeveral molecules help preserve peripheral B cell tolerance, but when altered, they may predispose to autoimmunity. This work studied the expression of the costimulatory molecule CD86 and the inhibitory receptor for IgG immune complexes FcγRIIb (CD32b), on B cells from rheumatoid arthritis (RA) patients, and the influence of anti-tumor necrosis factor (TNF) therapy.MethodsPeripheral B cells from 18 RA patients and 13 healthy donors were characterized using flow cytometry. Eleven patients who underwent a six-month adalimumab therapy were further assessed for phenotypic changes on their B cells.ResultsRA patients exhibited a high percentage of naïve and memory B cells expressing CD86. In contrast, expression of FcγRIIb was significantly reduced on RA memory B cells and plasmablasts as compared to healthy donors, probably due to downregulation of this receptor when differentiating from naïve to memory cells. These alterations on FcγRIIb were associated with high levels of anti-citrullinated vimentin autoantibodies. In addition, treatment with adalimumab normalized the expression of CD86 on memory B cells and reduced the expression of FcγRIIb, mainly on naïve B cells.ConclusionsOur findings show that peripheral B cells from RA patients have an altered expression of key molecules, such as CD86 and FcγRIIb. Because this latter receptor is required for feedback inhibition, a deficient expression might contribute to humoral autoimmune responses. Furthermore, these molecules are likely to be influenced by inflammatory factors, since they were modulated by TNF inhibition.

Comparison of the Clinical Efficacy of Two Different Immunosuppressive Regimens in Patients with Chronic Vogt-Koyanagi-Harada Disease

Purpose: To prospectively compare 2 immunosupressive regimens in patients with active Vogt-Koyanagi-Harada disease in spite of systemic glucocorticoid treatment. Methods: Forty-four patients were diagnosed between 1998 and 2005. Twenty-one developed chronic intraocular inflammation in spite of glucocorticoid treatment and were randomized to receive either prednisone and azathioprine (AZA) (n = 12) or prednisone and cyclosporine (CyA) (n = 9). Results: In the AZA group Tyndall score decreased from 1.21 ± 1.10 to 0.29 ± 0.62 (p < .01), and visual acuity (LogMAR) improved from 0.32 ± 0.35 to 0.09 ± 0.16 (p < .001). In the CyA group Tyndall score decreased from 1.67 ± 1.08 to 0.16 ± 0.51 (p < .001), and visual acuity improved from 0.41 ± 0.40 to 0.25 ± 0.42 (p < .001). Patients in the AZA group needed a significantly higher average prednisone dose and total cumulative dose than those in the CyA group, p < .01 for each comparison. Conclusions: Both regimens showed a good clinical efficacy, but CyA seems to be a better glucocorticoid-sparing agent than AZA.

Antibodies against the voltage-dependent anion channel (VDAC) and its protective ligand hexokinase I in children with autism

Autistic children show elevated serum levels of autoantibodies to several proteins essential for the function of normal brains. The voltage-dependent anion channel (VDAC) and hexokinase-I, a VDAC protective ligand, were identified as targets of this autoimmunity in autistic children. These autoantibodies were purified using immunoaffinity chromatographic techniques. Both antibodies induce apoptosis of cultured human neuroblastoma cells. Because VDAC and hexokinase-I are essential for brain protection from ischemic damage, the presence of these autoantibodies suggests a possible causal role in the neurologic pathogenesis of autism.

Infliximab can induce a prolonged clinical remission and a decrease in thyroid hormonal requirements in a patient with SAPHO syndrome and hypothyroidism

SAPHO syndrome is a rare entity that compromises the skeletal system (arthritis–osteitis) and is associated with various dermatological conditions such as palmoplantaris pustulosis (PPP) and acne. We present the case of a 39-year-old man with invalidating arthritis derived from a SAPHO syndrome and hypothyroidism (after radioiodine treatment for a Graves’ disease). Due to the severity and refractoriness of his disease, we decided to use infliximab. He showed a prompt and prolonged response of his joint and cutaneous manifestations after three doses of a tumor necrosis factor alpha (TNF-α) blocker. Interestingly, he also decreased his levothyroxine requirements after TNF-α blockade therapy.

Leflunomide decreases joint erosions and induces reparative changes in a patient with psoriatic arthritis

We read with great interest the article by Scott and colleagues,1 in which they report radiological improvement or halting of disease progression with leflunomide treatment in a group of patients with rheumatoid arthritis (RA). Leflunomide has also been reported to be effective in some studies including a small group of patients with psoriatic arthritis (PsA), but radiological evolution was not evaluated.2,3 We report the case of a patient with PsA who had clinical remission and radiological amelioration after a year with leflunomide treatment. To our knowledge, this is the first evidence that leflunomide may induce reparative changes such as filling of a bone cyst in a patient with PsA. A 37 year old white man presented in August 1997 with a history of pain in the left wrist, right ankle, and both feet during the previous three months. His past history and physical examination were unremarkable except for synovitis in the painful joints and a single well demarcated erythematous hyperkeratotic plaque on the trunk. A dermatologist was consulted and psoriasis vulgaris was confirmed …

Analysis of autoantibodies to plasminogen in the serum of patients with rheumatoid arthritis

Sera from patients with rheumatoid arthritis containing high titers of anti-streptokinase antibodies were found to contain anti-plasminogen antibodies of the IgG and IgA classes. High titers of anti-plasminogen autoantibodies of the IgA class were also found in sera from patients with systemic lupus erythematosus and Sjögren syndrome. Studies of the immune response to thrombolytic therapy with streptokinase in patients with no prior history of autoimmune disease suggest a strong correlation between streptokinase administration and the appearance of autoantibodies to plasminogen of the IgA class. The IgA anti-plasminogen autoantibody is specific for an epitope in a region of plasminogen which binds streptokinase and the IgG autoantibody reacts with an epitope in the C-terminal region corresponding to the catalytic domain of the plasminogen zymogen. Our findings suggest a different origin for the two classes of antiplasminogen immunoglobulins in rheumatoid arthritis patients. Since plasminogen binding to rheumatoid synovial fibroblasts is enhanced, the high titers of both classes of anti-plasminogen autoantibodies may add to the localization and perpetuation of the immune response. We suggest that plasminogen may be a target of the immune response in autoimmune disease.

Eficacia del infliximab en pacientes con síndrome de Behçet portadores de úveo-retinitis grave

The efficacy and safety of repeated administration of infliximabwas evaluated in five patients (two men, three women) with Behcet syndrome accompanied bysevere uveoretinitis. Ocular and extra ocular inflammation was suppressed in all patientsduring the observation period without any serious adverse reactions. The results in thesepatients suggests that TNF-