Analysis of regulatory T-cell changes in patients with idiopathic thrombocytopenic purpura receiving B cell-depleting therapy with rituximab

The effects of B-cell depletion with rituximab on regulatory T cells (Tregs) have not been determined. We investigated Tregs in patients receiving rituximab for chronic idiopathic thrombocytopenic purpura (ITP). The peripheral blood Tregs, identified as CD4+FOXP3+ T cells, were measured by flow cytometry prior to and after the immunotherapy. In addition, Tregs were analyzed for their usage of the T-cell receptor (TCR) beta-variable (VB) region gene as well as their regulatory function as assessed by cell proliferation assays. Pretreatment data revealed a reduced number and a defective suppressive capacity of Tregs in ITP patients compared with control individuals. In addition, Tregs showed a polyclonal spectratype. Patients, particularly responders, showed restored numbers of Tregs as well as a restored regulatory function upon treatment with rituximab. These results indicate that patients with active ITP have a defective T regulatory cell compartment that can be modulated by a B cell-targeted therapy.     

New immunomodulators in the treatment of Graves' ophthalmopathy

Steroids have been used in the therapy of the moderate to severe forms of Graves' ophthalmopathy (GO) and other autoimmune diseases as they act only as general immunosuppressants. Previous work has shown that blocking the CD-20 receptor on B lymphocytes has significantly affected the clinical course of GO, by rapidly reducing inflammation and the degree of proptosis. We have studied nine patients with Graves' disease, of whom seven had active GO and two, with newly diagnosed hyperthyroidism, only mild lid signs. We also studied a group of 20 consecutive patients, treated with intravenous glucocorticoids (IVGC) according to a standard protocol. Patients treated with RTX (1000mg i.v. twice at two-week interval) and those treated with IVGC (500mg i.v. for 16 weeks) were studied monthly up to 12 months after the first drug infusion. By ophthalmological examination, GO was assessed by the clinical activity score (CAS) and by the NOSPECS score. Thyroid function and lymphocyte count were measured by standardized methods. RTX was well-tolerated and only minor side-effects were reported in 30% of patients during the first infusion. All patients attained peripheral B-cell depletion with the first RTX infusion. All but one patients showed both CD20+ cells and CD19+ cells depletion, while one had persistent 3-5% CD19+ cells in the periphery, mostly CD19+5+. Thyroid function was not affected by RTX therapy. Titers of antithyroglobulin (TgAb), antithyroperoxidase and anti-TSH receptor antibodies (TRAb) did not change significantly (P=NS) and did not correlate to CD20+ depletion (P=NS). CAS values decreased significantly (P<0.0001). Proptosis decreased significantly after RTX in both patients with active GO (ANOVA; P<0.0001) and in those with Graves' hyperthyroidism and lid signs (ANOVA; P<0.003). The degree of inflammation (NOSPECS class 2) decreased significantly in response to RTX (ANOVA; P<0.001). In patients treated with IVGC, mean CAS value decreased significantly less than in those treated with RTX (P<0.05). Adverse effects were more frequent after IVGC (45% of patients). Seventy-five percent of patients responded to IVGC and 10% showed relapse of active GO six to eight weeks after withdrawal. The results of this study on RTX in GO suggest that the drug is effective in modifying the disease course and that the improvement of the clinical activity of GO after RTX was more significant than after IVGC. We did not observe relapse of active GO, even after B-cell return in peripheral blood. This might be related to the persistence of a significant degree of B-cell depletion after RTX observed in the peripheral blood as late as two years of follow-up. RTX therapy was also effective in improving proptosis and soft tissue inflammation. The mechanism by which RTX affects GO is unknown. It may act as a true immunosuppressor by switching off reactions inducing the active phase of TAO, perhaps by influencing the cytokine production in the orbit or by inducing depletion of antigen presenting B-cells.     

Thymic retention of CD4+CD25+FoxP3+ T regulatory cells is associated with their peripheral deficiency and thrombocytopenia in a murine model of immune thrombocytopenia

Immune thrombocytopenia (ITP) is a bleeding disorder in which antibodies and/or T cells lead to enhanced peripheral platelet destruction and reduced bone marrow platelet production. Several reports have observed that ITP is associated with a peripheral deficiency of tolerance-inducing CD4(+)CD25(+)FoxP3(+) T regulatory cells (Tregs). Using a murine model of ITP, we analyzed Tregs in the spleen and thymus. CD61 knockout mice were immunized against wild-type (CD61(+)) platelets, and their splenocytes were transferred into severe combined immunodeficient (SCID) mice. Compared with SCID mice receiving naive splenocytes, within 2 weeks after transfer, the ITP SCID mice became thrombocytopenic (< 200 × 10(9) platelets/L) and had increased serum anti-CD61 antibodies. The quantity of thymic Tregs by 2 weeks after transfer was significantly elevated, whereas Tregs in the spleens were significantly reduced. Treatment of the ITP mice with 2 g/kg intravenous immunoglobulin raised the platelet counts, reduced antibody production, and normalized the thymic and splenic Treg populations. Compared with thymocytes from ITP mice treated with intravenous immunoglobulin, thymocytes from untreated ITP mice delayed the onset of ITP when administered before engraftment with immune splenocytes. These results suggest that ITP in mice is associated with a peripheral Treg deficiency because of thymic retention and therapy normalizes the Tregs.     

Functional role of CD4+CD25+ regulatory T cells and transforming growth factor-beta1 in childhood immune thrombocytopenic purpura

CD4+CD25+ regulatory T cells (Tregs) are critical in maintaining self tolerance and preventing organ specific autoimmune diseases. Their role in childhood immune thrombocytopenic purpura (ITP), an immune disorder in which the production of platelet autoantibodies might be caused by cytokine network dysregulation, has not been clearly defined. Transforming Growth Factor-beta1 (TGF-beta1) has been suggested to mediate Tregs suppressive function. The aim of this study was to assess cell populations of CD4+CD25+ T regulatory cells as well as mRNA expression of TGF-beta1 level in peripheral blood of children with ITP and evaluate their possible role in prediction of disease severity and response to therapy. Thirty-three children with ITP (13 acute and 20 chronic cases) and 10 healthy controls were studied. CD4+CD25+ regulatory T cells were assessed in peripheral blood by flowcytometry. Expression of TGF-beta1 mRNA was examined by real-time quantitative polymerase chain reaction assay. The frequency of CD4+CD25+ Tregs was significantly decreased in acute and chronic ITP patients as compared to controls. Acute ITP patients had significantly lower percentage of Tregs compared with chronic ITP patients. Higher frequency of CD4+CD25+ Tregs was detected in chronic ITP patients with platelet count >100 x 10(9)/L compared with patients with platelet count <100 x 10(9)/L and in steroid responsive patients compared with steroid resistant patients. The expression of mRNA TGF-beta1 level was significantly lower in acute and chronic ITP patients compared with controls and in chronic ITP patients with pltc <100 x 10(9)/L in comparison with patients with pltc > 100 x l0(9)/L. A significant positive correlation was found between percentage of CD4+CD25+ Tregs and mRNA expression of TGF-beta1 in chronic ITP patients. In conclusion, immune regulation of TGF-beta1 by Tregs may play a fundamental role in the pathogenesis of childhood immune thrombocytopenic purpura. This might form a base for future specific immunomodulatory therapies for ITP.     

B cells expressing CD5 antigen are markedly increased in peripheral blood and spleen lymphocytes from patients with immune thrombocytopenic purpura

By two-colour flow cytometric analysis, we examined the proportion of B lymphocytes bearing CD5 cell surface antigen (CD 5+ B cells), which are capable of producing autoantibodies, both in peripheral blood and spleen from patients with chronic immune thrombocytopenic purpura (ITP). The percentage of CD5+ B cells in peripheral blood lymphocytes (PBLs) was significantly increased (P less than 0.005) in patients with ITP (3.7 +/- 2.2%, n = 30) as compared with normal controls (1.7 +/- 0.7%, n = 28). However, there was no correlation between the percentages of circulating CD5+ B cells and platelet counts. The percentage of splenic CD5+ B cells in ITP patients was much more increased (9.0 +/- 4.5%, n = 9), P less than 0.005) compared with that of other disorders (3.2 +/- 0.5%, n = 5). Furthermore, isolated splenic CD5+ B cells from two out of five ITP patients produced high levels of IgM-type, platelet-bindable antibodies (PBIgM) after stimulation with Staphylococcus aureus Cowan I (SAC), while CD5- B cells isolated from the same spleen or splenic CD5+ B cells from other non-autoimmune disorders failed to produce significant amount of PBIgM. In three ITP patients, no increase in PBIgM was detected despite SAC stimulation. The increased proportion of CD5+ B cells in peripheral blood and spleen, and their ability to produce anti-platelet antibodies indicate that they are directly involved in the autoimmune pathogenesis in ITP.     

In vitro TNF blockade enhances ex vivo expansion of regulatory T cells in patients with immune thrombocytopenia

Tumour necrosis factor‐α (TNF) is an inflammatory cytokine that is elevated in a number of autoimmune diseases including immune thrombocytopenia (ITP), a bleeding disorder characterized by low platelet counts. In vitro TNF blockade increases expansion of the regulatory T cell (Treg) IKZF2 (also termed Helios) subset in T cell‐monocyte cocultures from healthy donors, but its role on proliferative responses of Tregs in ITP patients, who have altered immunoregulatory compartment, remains unclear. TNF in CD4+ T cells from patients with chronic ITP were elevated and negatively correlated with peripheral Treg frequencies, suggesting a possible inhibitory effect of TNF on ITP Tregs. In vitro antibody neutralization with anti‐TNF in T cell‐monocyte cocultures resulted in a robust expansion of pre‐existing ITP Tregs, higher than in healthy controls. Similar to the effects of anti‐TNF antibodies, TNF blockade with antibodies against TNFRSF1B (anti‐TNFRSF1B, previously termed anti‐TNFRII) almost doubled ITP Treg expansion whereas neutralization with anti‐TNFRSF1A (anti‐TNFRI) antibodies had no effect on proliferative responses of Tregs. In addition, TNFRSF1B levels on ITP Tregs were significantly elevated, which may explain the increased susceptibility of patient Tregs to the actions of TNF blockade. Altogether, these data raise the possibility that TNF blockers, through their ability to increase Treg proliferation, may be efficacious in ITP patients.     

Immune dysregulation in primary immune thrombocytopenia patients

Objectives: To explore the immunological abnormalities in patients with primary immune thrombocytopenia (ITP), and analyze its relationship with treatment.

Methods: Proportion of different immune cell subsets were detected in the peripheral blood of 124 ITP patients at different time points and 45 normal controls by flow cytometry. The treatments included glucocorticoids, intravenous IgG as first-line treatment and second-line drugs.

Results: Elevated CD4/CD8 ratio and decreased the proportion of NK and CD4?+?CD25?+?CD127low regulatory T cells (Tregs) were found in pre-treated ITP patients than healthy controls. The newly diagnosed group had a significantly higher CD4/CD8 ratio than the relapsed group, but no differences in the proportion of B cells, NK cells and Tregs. No relationships were found between the curative effect and the pre-treated cell subsets within both the effective and ineffective groups. Furthermore, compared with the ineffective group, the effective group had higher Tregs and lower CD4/CD8 ratio post-treatment, but no significant differences in NK and B cells.

Conclusion: ITP patients presented with a high CD4/CD8 ratio and low levels of Tregs and NK cells, suggesting that immune deregulation was involved in the pathogenesis of ITP. The pre-treated immune status of ITP patients may not be related to the curative effect. Tregs significantly increased in the effective group post-treatment, highlighting that the mechanism of restoring Tregs may be involved in the treatment of ITP. However, whether or not the targeted regulation of Tregs is an effective treatment for ITP still requires further studies.     

B cells and antibodies in refractory immune thrombocytopenia

Immune thrombocytopenia (ITP) is an acquired bleeding disorder mediated by pathogenic autoantibodies secreted by plasma cells (PCs) in many patients. In refractory ITP patients, the persistence of splenic and bone marrow autoreactive long-lived PCs (LLPCs) may explain primary failure of rituximab and splenectomy respectively. The reactivation of autoreactive memory B cells generating new autoreactive PCs contributes to relapses after initial response to rituximab. Emerging strategies targeting B cells and PCs aim to prevent the settlement of splenic LLPCs with the combination of anti-BAFF and rituximab, to deplete autoreactive PCs with anti-CD38 antibodies, and to induce deeper B-cell depletion in tissues with novel anti-CD20 monoclonal antibodies and anti-CD19 therapies. Alternative strategies, focused on controlling autoantibody mediated effects, have also been developed, including SYK and BTK inhibitors, complement inhibitors, FcRn blockers and inhibitors of platelet desialylation.     

Pathophysiology and management of chronic immune thrombocytopenia: focusing on what matters

Immune thrombocytopenia (ITP) is a common autoimmune disease characterized by low platelet counts and an increased risk of bleeding. Antibody-mediated platelet destruction has been the prevailing hypothesis to explain ITP pathogenesis, supported by the efficacy of B-cell depletion therapy; however, the recent success of thrombopoietin receptor agonists lends support to the notion that platelet production is also insufficient. Best practice for the management of chronic ITP has not yet been established because data from comparative trials are lacking. Despite renewed interest in novel drugs capable of increasing platelet counts, ultimate treatment goals for ITP patients must be kept in mind: to improve patients' health and well-being. In this article, the pathophysiology of ITP is reviewed and key remaining questions about mechanism are explored. A rational approach to the management of ITP in adults is outlined, acknowledging evidence and evidence gaps, and highlighting the need for clinically important endpoints in future clinical trials.     

Response to B-cell depleting therapy with rituximab reverts the abnormalities of T-cell subsets in patients with idiopathic thrombocytopenic purpura

Rituximab, an anti-CD20 monoclonal antibody, has been used to treat autoimmune disorders such as idiopathic thrombocytopenic purpura (ITP). However, its mechanisms of action as well as the effects on cellular immunity remain poorly defined. We investigated the changes of different peripheral blood T-cell subsets, the apoptosis profile, as well as the changes of T-cell receptor (TCR) beta-variable (VB) region gene usage of CD4+ and CD8+ T-cell subpopulations following rituximab therapy. The study involved 30 patients with chronic ITP who received rituximab, of whom 14 achieved a durable (> 6 months) response. Compared with the control group, pretreatment abnormalities of T cells in ITP patients included an increase of the Th1/Th2 ratio and of the Tc1/Tc2 ratios (P < .001), increased expression of Fas ligand on Th1 and Th2 cells (P < .001), increased expression of Bcl-2 mRNA (P = .003) and decreased expression of bax mRNA (P = .025) in Th cells, and expansion of oligoclonal T cells with no preferential use of any TCR VB subfamily. These abnormalities were reverted in responders at 3 and 6 months after treatment, whereas they remained unchanged in nonresponders. Our findings indicate that in patients with ITP, response to B-cell depletion induced by rituximab is associated with significant changes of the T-cell compartment.     

Rituximab in the treatment of autoimmune haematological disorders

Current treatment regimens for haematological autoimmune diseases are relatively non-selective and are often associated with considerable toxicity. Recently, it has become clear that B cells play a key role in both the development and perpetuation of autoimmunity, suggesting that B-cell depletion could be a valuable treatment approach for patients with autoimmune diseases. This article reviews data supporting the use of rituximab – an anti-CD20 monoclonal antibody that specifically depletes B cells – in four key autoimmune haematological disorders: idiopathic thrombocytopenic purpura (ITP); autoimmune haemolytic anaemia (AIHA); acquired haemophilia; and thrombotic thrombocytopenic purpura (TTP). Although treatment of ITP, AIHA, acquired haemophilia and TTP with rituximab is still relatively uncommon, results from case series and small phase II trials indicate that patients of all ages can respond to rituximab, irrespective of the number or type of prior treatments that they have received. Moreover, patients with these diseases receiving rituximab experienced predominantly mild adverse events, with only a few serious adverse events reported. These data suggest that rituximab provides an effective and well-tolerated alternative treatment option for patients with ITP, AIHA, acquired haemophilia and TTP, many of whom have limited treatment choices.     

B cell depletion for autoimmune diseases in paediatric patients

Data on B cell depletion therapy in severe autoimmune diseases in paediatric patients are very limited. We conducted a retrospective cohort study and recruited patients who were treated with rituximab (RTX) and followed up for at least 6?months through the German societies of paediatric rheumatology and nephrology. The aim was to describe the spectrum of autoimmune disorders for which RTX was used and to describe the applied therapeutic regimens, the observed efficacy, as well as potential immunological side effects. The need to develop standard treatment guidelines for future trials should be discussed. Sixty-five patients were included. Nineteen patients suffered from systemic lupus erythematosus, 13 from vasculitic disorders, 12 from hematological autoimmune diseases, 5 from mixed connective tissue disorders, 4 from juvenile idiopathic arthritis, and 9 had other autoimmune diseases. Adverse, infusion-related events were reported in 12/65 (18%) patients. Considering laboratory and clinical parameters, 13 patients (22%) were in complete remission, 31 (52%) were in partial remission, 6 (10%) were unchanged and 10 (17%) had progressed after 6?months. In 46% of the patients, the steroid dose could be more than halved. IgG, IgM and IgA decreased from normal levels prior to RTX therapy to below normal levels at 6?months in 2/22 (9%), 10/21 (48%), and 4/22 (18%) patients, respectively. Immunoglobulin deficiency or prolonged CD20 depletion was reported in eight patients after an observation period longer than 12?months. RTX therapy led to a perceivable reduction in disease activity. However, long-term immunological alterations may occur in more than 10% of the patients. Guidelines and protocols for off-label therapy are desirable to document reasonable follow-up data. Controlled prospective studies for RTX therapies in children with standardised therapeutic and diagnostic protocols are urgently needed.     

B-cell depletion with rituximab as treatment for immune hemolytic anemia and chronic thrombocytopenia

BACKGROUND AND OBJECTIVES: Rituximab reacts specifically with the CD20 antigen and induces B-cell depletion. This could interfere with the production of autoantibodies in some immune diseases. The objective of this study was to assess the effects of rituximab in autoimmune hemolytic anemia and thrombocytopenia. DESIGN AND METHODS: Seven patients (one with cold agglutinin disease, two with warm antibody autoimmune hemolytic anemia, four with chronic idiopathic thrombocytopenic purpura) previously refractory to conventional treatments were treated with weekly infusions of rituximab, 375 mg/m2, for 4 weeks. Only treatment with steroids, if strictly necessary, was allowed during the period of rituximab administration, but only patients who reached steroid suspension were considered responders. The pharmacokinetics of rituximab were quantified during therapy and the follow-up period. RESULTS: All patients had marked, even if temporary, B-cell depletion. Three patients, 1 with cold agglutinin disease (CAD) and 2 with chronic idiopathic thrombocytopenic purpura (ITP), had a complete hematologic response. In the patient with cold agglutinin disease a decrease in the agglutinin titer was observed. The hematologic improvement was prompt, appearing by the second or third infusion of rituximab. The response duration was CAD 96+, ITP 17+ and 13+ weeks in these 3 patients. Treatment tolerance was satisfactory and no infections or other late events were registered. Serum rituximab concentrations appeared to be similar to those calculated in a historical control group of patients with follicular non-Hodgkin's lymphoma who received rituximab as consolidation of response after first-line CHOP chemotherapy. INTERPRETATION AND CONCLUSIONS: Rituximab appeared to be active and safe in some patients with refractory autoimmune hemolytic anemia and thrombocytopenia. These results, along with data from literature, suggest that this agent may have a therapeutic role in autoimmune diseases.     

Clonal B-cell populations in patients with idiopathic thrombocytopenic purpura.

Idiopathic thrombocytopenic purpura (ITP) may be associated with other autoimmune diseases and the development of lymphoproliferative malignancies. In Sj?gren's disease, Graves' disease, and essential mixed cryoglobulinemia, which are also associated with the development of B-cell neoplasia, clonal B-cell expansions have been detected. Eleven patients with ITP were investigated for the presence of a clonal excess (CE) using kappa-lambda flow cytometry and DNA analysis for rearrangement of immunoglobulin heavy and light chain genes in blood and/or spleen lymphocytes. In 10 of 11 patients, clonal B-cell populations were found by one or both tests. In three of these patients, oligoclonal B-cell populations were suggested by the combined findings. In all four patients with a small paraproteinemia, the isotype was confirmed by either flow cytometry or DNA rearrangement analysis. Our data suggest that the oligoclonal expansions are not restricted to CD5+ B cells, as in the majority of patients this subset was below the detection level of flow cytometry or DNA rearrangement analysis. None of the patients developed clinical manifestations of malignant lymphoma during a follow-up period of 10 to 44 months after sampling. We conclude that clonal excess populations of B cells are not a unique feature of malignant lymphoma, but may occur in autoimmune diseases, suggesting a benign (oligo)clonal B-cell proliferation.     

Treatment of Graves' disease and associated ophthalmopathy with the anti-CD20 monoclonal antibody rituximab: an open study

INTRODUCTION: Hyperthyroid Graves' disease (GD) is a B-cell-mediated condition caused by TSH receptor antibodies (TRAb), which decline when GD remits. Anti-CD20 monoclonal antibody rituximab (RTX) induces transient B-cell depletion that may potentially modify the active inflammatory phase of thyroid-associated ophthalmopathy (TAO). METHODS: Nine patients with GD, (seven with active TAO, two with mild lid signs) were studied. The trial was only approved as an open pilot study; thus we compared the effect of RTX therapy to that of i.v. glucocorticoids (IVGC) in 20 consecutive patients. Patients were treated with RTX (1000 mg i.v. twice at 2-week interval) or with IVGC (500 mg i.v. for 16 weeks). TAO was assessed by the clinical activity score (CAS) and severity was classified using NOSPECS (No signs or symptoms; Only signs (lid); Soft tissue involvement; Proptosis, Extraocular muscle involvement; Corneal involvement; Sight loss). Thyroid function and lymphocyte count were measured by standardized methods. RESULTS: All patients attained peripheral B-cell depletion with the first RTX infusion. Minor side effects were reported in three patients. Thyroid function was not affected by RTX therapy and hyperthyroid patients required therapy with methimazole. After RTX, the changes in the levels of thyroglobulin antibodies, thyroperoxidase antibodies and TRAb were neither significant nor correlated with CD20+ depletion (P = NS). CAS values before RTX were 4.7 +/- 0.5 and decreased to 1.8 +/- 0.8 at the end of follow-up (P < 0.0001) and more significantly compared with IVGC (P < 0.05). Proptosis decreased significantly after RTX both in patients with active TAO (ANOVA; P < 0.0001) and those with lid signs (ANOVA; P < 0.003). The degree of inflammation (class 2) decreased significantly in response to RTX (ANOVA; P < 0.001). Relapse of active TAO was not observed in patients treated with RTX, but occurred in 10% of those treated with IVGC, who also experienced adverse effects more frequently (45 vs 33% of patients). CONCLUSIONS: RTX positively affects the clinical course of TAO, independently of either thyroid function or circulating antithyroid antibodies, including TRAb. If our findings are confirmed in large controlled studies, RTX may represent a useful therapeutic tool in patients with active TAO.     

Low percentages of regulatory T cells in common variable immunodeficiency (CVID) patients with autoimmune diseases and its association with increased numbers of CD4+CD45RO+ T and CD21low B cells

BackgroundCommon variable immunodeficiency (CVID) is a heterogeneous group of primary antibody deficiencies defined by marked reductions in serum IgG, IgA and/or IgM levels and recurrent bacterial infections. Some patients are associated with defects in T cells and regulatory T cells (Tregs), resulting in recurrent viral infections and early-onset autoimmune disease.MethodsWe analyzed whether there is an association between Tregs cells (CD4+CD25+CD127^low and CD4+CD25+FoxP3+); memory T cells (CD4+CD45RO+); memory B cells (CD19+CD27-IgD-); and CD21^low B cells (CD19+CD38^lowCD21^low); as well as autoimmune manifestations in 36 patients with CVID (25 women and 11 men, mean age 24 years), all by flow cytometry.ResultsFourteen patients presented with autoimmune diseases (AI) (39%), including 11 with autoimmune thrombocytopenia (ITP) (31%); two with vitiligo (6%); one with systemic lupus erythematosus (LES) (3%); and one with multiple sclerosis (MS) (3%). CVID patients with AI had a reduced proportion of Tregs (both CD4+CD25+CD127^low and FoxP3+ cells) compared with healthy controls. CVID patients with AI had expanded CD21^low B cell populations compared with patients who did not have AI. A correlation between increased CD4+CD45RO T cell populations and reduced Tregs was also observed.ConclusionsOur results showed that 39% of patients with CVID had AI and reduced Tregs populations. Research in this area might provide noteworthy data to better understand immune dysfunction and dysregulation related to CVID.     

Thrombopénie immunologique : de la physiopathologie aux traitements

Immune thrombocytopenia (ITP) is a rare autoimmune disease due to an immune peripheral destruction of platelets and an inappropriate platelet production. The pathogenesis of ITP is now better understood: it involves a humoral immune response which dependents on the stimulation of B cells by specific T cells called T follicular helper cells, leading to their differentiation into plasma cells that produce antiplatelet antibodies thus promoting the phagocytosis of platelets mainly by splenic macrophages. The deciphering of ITP pathogenesis has led to a better understanding of the inefficiency of treatments such as rituximab, although it has not provided yet the determination of biological predictive factor of response to treatments. Moreover, new therapeutic perspectives have been opened in the last few years with the development of molecules targeting Fcγ receptor signalling such as Syk inhibitor, or molecules increasing the clearance of pathogenic autoantibodies such as inhibitors of the neonatal Fc receptor (FcRn).     

Splenectomy in immune thrombocytopenic purpura: recent controversies and long-term outcomes

Immune thrombocytopenic purpura (ITP) is an uncommon disorder but a relatively frequent cause of isolated thrombocytopenia. The pathogenesis of ITP involves enhanced platelet clearance, primarily in the spleen, caused by antiplatelet glycoprotein antibodies. Most patients with ITP respond transiently to an initial course of corticosteroids, although only 20% of adult patients achieve a durable remission after such therapy. Classically, patients who fail corticosteroid therapy undergo splenectomy, with approximately two thirds of these individuals maintaining partial remissions 5 years later. However, due to evidence suggesting a continuous relapse rate in splenectomized patients with ITP, in addition to the emergence of newer agents associated with durable remissions in ITP patients with intact spleens, the therapeutic approach to ITP is evolving. This article reviews the role of splenectomy in patients with ITP and reviews new approaches to management of ITP in patients who fail an initial trial of corticosteroids.     

Splenic irradiation for chronic autoimmune thrombocytopenic purpura in patients with contra-indications to splenectomy

Summary We treated by splenic irradiation eight patients with chronic idiopathic thrombocytopenic purpura (ITP, seven cases) or secondary autoimmune thrombocytopenic purpura (one case) who had contra-indications to splenectomy. A total dose of 15 Gy was delivered to the spleen, with left kidney protection. One patient had a good durable response (>1 year); two patients had a good transient response (of 3 months duration) but they responded again to a second course of irradiation; two patients had only partial response, but have required no other treatments for 2 years; the three remaining patients had no response. Side-effects were minor. Therefore splenic irradiation appears to be a therapeutic option in patients with chronic ITP who have contra-indications to splenectomy.     

Efficacy of rituximab treatment for thyroid-associated ophthalmopathy as a result of intraorbital B-cell depletion in one patient unresponsive to steroid immunosuppression

One patient with Graves' hyperthyroidism and ophthalmopathy in its active phase and unresponsive to steroid, was treated with the anti-CD20 monoclonal antibody, rituximab (RTX), as part of an open study. The effect of RTX in the thyroid and the orbital tissues was studied. The ophthalmopathy responded to RTX therapy by ameliorating the eye signs with a decrease in the clinical activity score from 5 to 2 in 3 months, while the patient had peripheral B-cell depletion. Hyperthyroidism did not improve during the 6 months of B-cell depletion and serum TSH-receptor antibodies (TRAb) levels did not significantly change after RTX therapy. Therefore, the patient underwent total thyroidectomy and few B-cells were found in the thyroid tissue specimens. While the patient eye disease remained stable (clinical activity score = 2), we performed corrective orbital decompression and we found absence of lymphocytes in the orbital tissue specimens. We believe that RTX treatment in Graves' disease may cause amelioration of ophthalmopathy by depleting total lymphocytes population in the orbit. The persistence of Graves' hyperthyroidism suggests that a single cycle of RTX does not result in complete lymphocyte depletion in thyroid tissue and thus no decline in serum TRAb was observed.