Aharon Kessel

Intravenous immunoglobulin therapy affects T regulatory cells by increasing their suppressive function.

Intravenous Ig therapy (IVIg) is reported to be a useful regimen in treating autoimmune diseases. In this study, we asked whether IVIg (in vitro) could increase the expression of TGF-β, IL-10, and the transcription factor FoxP3 in T regulatory (Treg) cells, and the idea that IVIg could enhance suppressive properties of these cells. CD4+ T cells from 12 healthy individuals were cultured in the presence or absence of IVIg vs human control IgG during 16, 24, and 36 h. Using FACS analysis and gating on CD4+CD25high Treg cells, we assessed the expression of intracellular TGF-β, IL-10, and FoxP3. In addition, the production of TNF-α by stimulated CD4+ T cells alone or in culture with CD25+ by itself or together with IVIg was also assessed. The presence of IVIg with Treg cells in culture significantly increased the intracellular expression of TGF-β (17.7 ± 8.5% vs 29.8 ± 13%; p = 0.02), IL-10 (20.7 ± 4.7% vs 34.2 ± 5.2%; p = 0.008) and FoxP3 (20.8 ± 5.2% vs 33.7 ± 5.9%; p = 0.0006) when compared with cells cultured alone or with control human IgG. The suppressive effect of CD4+CD25+ T cells presented as the decrease of TNF-α production by stimulated CD4+CD25− (effector T cells) was further increased by adding IVIg to cell culture. We hereby demonstrate an additional mechanism by which IVIg could maintain self-tolerance and decrease immune-mediated inflammation.

Clinical and laboratory parameters in predicting chronic urticaria duration: a prospective study of 139 patients

Background:  Despite the disabling nature of chronic urticaria (CU), little is known about the diseases duration or the efficacy of adopting aggressive therapeutic regimens such as cyclosporine A.

Interleukin‐7 receptor α (IL‐7Rα) deficiency: cellular and molecular bases. Analysis of clinical, immunological, and molecular features in 16 novel patients

Summary:  Analysis of gene‐targeted mice and patients with severe combined immunodeficiency due to mutations of the α chain of the interleukin‐7 receptor (IL‐7Rα) has shown important differences between mice and humans in the role played by IL‐7 in lymphoid development. More recently, it has been shown that IL‐7Rα is also shared by the receptor for another cytokine, thymic stromal lymphopoietin (TSLP). In this review, we discuss recent advances in IL‐7‐ and TSLP‐mediated signaling. We also report on the clinical and immunological features of 16 novel patients with IL‐7Rα deficiency and discuss the results of hematopoietic stem cell transplantation.

Low‐dose cyclosporin A in the treatment of severe chronic idiopathic urticaria

In a limited number of severe chronic idiopathic urticaria (CIU) patients, low‐dose cyclosporin A (CsA) treatment was found to be effective. This open study aimed to extend this clinical observation and determine the safety of treatment with CsA. In addition, it aimed to determine the prevalence and characteristics of the autologous serum skin test (AST) in such patients, and whether this test is affected by CsA treatment. Thirty‐five patients who suffered from severe CIU (score 3), and who were followed for 6 months (using a clinical urticaria‐severity score [range 0–3]) were divided into three groups: 19/35 were treated for 3 months with low‐dose CsA, and thereafter followed for an additional 3 months; 6/35 dropped out of protocol treatment; and 10/35 untreated patients (followed for the same period) served as a disease controls. In the treated group, no side‐effects were observed, and by the end of treatment, 13/19 (68%) patients were in full remission (score 0) and the remainder scored 1. In contrast, the 10 CsA‐untreated patients scored 3 for the whole follow‐up period of 6 months. Positive AST was found in 14/35 (40%) of patients, whereas none were detected in 20 healthy control subjects. AST neither correlated with disease activity nor predicted response to treatment. This uncontrolled study shows that low‐dose CsA is effective in treating CIU patients, and can be given safely for 3 months. However, CIU patients requiring initially high doses of glucocorticosteroids and with a long clinical history are less amenable to CsA treatment.

Increased Spontaneous Apoptosis of CD4+CD25+ T Cells in Patients with Active Rheumatoid Arthritis Is Reduced by Infliximab

Abstract: Increased secretion of tumor necrosis factor‐alpha (TNF‐α), along with interleukin‐1 (IL‐1) and interleukin‐6 (IL‐6), is important in the pathogenesis of rheumatoid arthritis (RA). T regulatory CD4+CD25+ cells play a role in maintaining self‐tolerance by downregulating Th1‐induced proinflammation. This function has been found to be altered in active RA, whereas anti‐TNF‐α therapy has been found to improve the suppressive abilities of these cells. Our objectives were to investigate whether T regulatory cells in patients with active RA display a higher sensitivity to spontaneous apoptosis than in normals, and to look into the potential of infliximab (anti‐TNF‐α therapy) to reduce the sensitivity of these cells to spontaneous apoptosis. Seventeen patients suffering from active RA, having failed multiple disease‐modifying antirheumatic drug (DMARD) therapies, were treated with infliximab. Spontaneous apoptosis (as detected by annexin V binding) was determined in all patients and compared with a group of normal individuals at baseline and after three months on infliximab treatment. Peripheral blood mononuclear cells were incubated in 24‐well plates at 1 × 106 cells/mL for 48 hours. Annexin V binding on CD4+CD25+ was assessed using three‐color assay by flow cytometry. Prior to infliximab initiation, spontaneous apoptosis of T regulatory cells from active RA patients was found to be increased in comparison with controls (26 ± 4.2% vs. 19.8 ± 4.8%, respectively; P= 0.01). Three months later (while still on infliximab) spontaneous apoptosis was comparable in the two groups (20.7 ± 5.2% vs. 20.9 ± 3.4%; P 5 0.8). The absolute number of CD4+CD25+ cells/mL in the peripheral blood at baseline was reduced in 11 out of 17 active RA patients when compared with that of the control group (24 ± 7 vs. 32 ± 11, respectively; P= 0.02). Following anti‐TNF‐α therapy, CD4+CD25+ cell counts of patients were equivalent to those of normals. The alteration and reversal in both spontaneous apoptosis and cell count of T regulatory cells was found to correlate with RA disease activity. CD4+CD25+ T regulatory cells display increased proclivity to undergo spontaneous apoptosis in active RA. Alterations in CD4+CD25+ cell apoptosis and cell count were found to correlate with RA disease activity. Reversal of these deviations from normal was documented in association with the beneficial outcome of infliximab therapy.

Regulatory T cells (CD4+CD25brightFoxP3+) expansion in systemic sclerosis correlates with disease activity and severity

BACKGROUND The role and function of T regulatory (Treg) cells have not been fully investigated in patients with systemic sclerosis (SSc). METHODS Ten patients with SSc donated 20ml of peripheral blood. Activity (Valentini) and severity (Medsger) scores for SSc were calculated for all patients. Healthy volunteers (controls) were matched to each patient by gender and age. CD4(+) cells were separated using the MACS system. The numbers of Treg cells were estimated by flow cytometry after staining for CD4, CD25, and FoxP3 and calculated as patient-to-control ratio separately for each experiment. Correlations with activity and severity indices of the disease were performed. Twenty-four-hour production of TGF-beta and IL-10 by activated CD4(+) cells was measured by ELISA in culture supernatants. RESULTS The numbers of Treg cells, expressed as patient-to-control ratio, correlated significantly with both activity and severity indices (r=0.71, p=0.034 and r=0.67, p=0.044, respectively). ELISA-measured production of TGF-beta and IL-10 by CD4(+) cells was similar in patients and controls. CONCLUSIONS Increased numbers of Treg cells are present in patients with SSc, correlating with activity and severity of the disease. This expansion of Treg cells was not accompanied, however, by heightened TGF-beta or IL-10 production. Further studies to elaborate the causes and functional significance of Treg cell expansion in SSc are needed.

Cyclosporine-A in severe chronic urticaria: the option for long-term therapy

To cite this article: Kessel A, Toubi E. Cyclosporine‐A in severe chronic urticaria: the option for long‐term therapy. Allergy 2010; 65: 1478–1482.

Changes in macrophage function after rituximab treatment in patients with rheumatoid arthritis

Objective: To assess changes in macrophage phenotype and function after rituximab-induced B cell depletion in patients with rheumatoid arthritis (RA). Methods: 10 patients with RA were treated with rituximab, achieving significant B cell depletion 4 months later. Clinical improvement, rheumatoid factor (RF), anti-cyclic citrullinated peptide (anti-CCP) antibodies, mRNA of B cell activating factor (BAFF), interleukin (IL) 10 and CD86 in human monocyte-derived macrophages (HMDMs) and tumour necrosis factor α (TNFα) secretion from cultured HMDMs were assessed at baseline and after the depletion. Results: A clinical response of American College of Rheumatology (ACR) 50% improvement was noted in six patients, and another two patients responded with moderate improvement, equivalent to ACR 20–50% improvements. RF and anti-CCP antibodies were positive at baseline in seven of ten patients. RF disappeared or declined in six patients 4 months after treatment, correlating with clinical improvement. By contrast, anti-CCP remained unchanged in six patients. After rituximab treatment, and in association with clinical improvement, BAFF, IL10 and CD86 mRNA expression in HMDM were significantly upregulated compared with values at baseline. A significant decrease in TNFα in the supernatant of cultured HMDM was also noted. Conclusions: In addition to B cell depletion and attenuation in some of the specific autoantibodies, clinical improvement in rituximab-treated patients with RA occurred in association with changes in macrophage function.

Age-related autoimmunity

Older persons have higher autoimmunity but a lower prevalence of autoimmune diseases. A possible explanation for this is the expansion of many protective regulatory mechanisms highly characteristic in the elderly. Of note is the higher production of peripheral T-regulatory cells.The frequent development of autoimmunity in the elderly was suggested to take place in part due to the selection of T cells with increased affinity to self-antigens or to latent viruses. These cells were shown to have a greater ability to be pro-inflammatory, thereby amplifying autoimmunity. During aging, thymic T-regulatory cell output decreases in association with the loss of thymic capacity to generate new T cells. However, to balance the above mentioned autoimmunity and prevent the development of autoimmune diseases, there is an age-related increase in peripheral CD4+ CD25highFoxP3+ T-regulatory cells. It remains unclear whether this is an age-related immune dysfunction or a defense response. Whatever the reason, the expansion of T-regulatory cells requires payment in terms of an increased incidence of cancer and higher susceptibility to infections.

Peripheral B-cell CD5 expansion and CD81 overexpression and their association with disease severity and autoimmune markers in chronic hepatitis C virus infection

Hepatitis C virus (HCV) infection is associated with immune‐mediated abnormalities and B‐cell lymphoproliferation evolving to an overt lymphoma. Recently, CD81 was identified as an HCV receptor on B‐lymphocytes, providing a mechanism by which B cells are infected and activated by the virus. In addition, expansion of CD5+ B lymphocytes was described to be associated with various non‐HCV related autoimmune disorders. Therefore, we studied the possible role of peripheral B cells CD81 and CD5 over‐expression in the development of HCV‐related autoimmunity and their association with disease severity in chronic HCV infection. Peripheral B cells CD5 expression and mean fluorescence intensity (MFI) of CD81 were determined in 30 HCV‐infected patients, 30 healthy controls and 15 patients with hepatitis B virus infection using fluorescence‐activated cell scan (FACS). We have also investigated the association between peripheral CD5 and CD81 B‐cell over‐expression and markers of autoimmunity and disease severity in patients chronically infected by HCV. CD5+ B‐cells were increased in chronic HCV infection (23·2 ± 7·2%) compared with those of healthy controls (15 ± 5·5%) (P < 0·0001) and chronic HBV infection (19 ± 3·7%) (P = 0·08). CD81 MFI was significantly higher in HCV‐infected compared to HBV‐infected patients and healthy controls. Both increased CD81 MFI and CD5+ B‐cell expansion were associated with the production of rheumatoid factor and mixed cryoglobulins and positively correlated with HCV viral load and histological activity index. The overexpression of CD81 and the expansion of CD5+ peripheral B‐cells in HCV‐infected patients may possibly play a role in the development of HCV‐associated autoimmunity and lymphoproliferation.