The clinical significance of circulating B cells secreting anti-glycoprotein IIb/IIIa antibody and platelet glycoprotein IIb/IIIa in patients with primary immune thrombocytopenia

High dimensional proteomic mapping of bone marrow immune characteristics in immune thrombocytopenia

To investigate the role of co-stimulatory and co-inhibitory molecules on immune tolerance in immune thrombocytopenia (ITP), this study mapped the immune cell heterogeneity in the bone marrow of ITP at the single-cell level using Cytometry by Time of Flight (CyTOF). Thirty-six patients with ITP and nine healthy volunteers were enrolled in the study. As soluble immunomodulatory molecules, more sCD25 and sGalectin-9 were detected in ITP patients. On the cell surface, co-stimulatory molecules like ICOS and HVEM were observed to be upregulated in mainly central memory and effector T cells. In contrast, co-inhibitory molecules such as CTLA-4 were significantly reduced in Th1 and Th17 cell subsets. Taking a platelet count of 30×109 L-1 as the cutoff value, ITP patients with high and low platelet counts showed different T cell immune profiles. Antigen-presenting cells such as monocytes and B cells may regulate the activation of T cells through CTLA-4/CD86 and HVEM/BTLA interactions, respectively, and participate in the pathogenesis of ITP. In conclusion, the proteomic and soluble molecular profiles brought insight into the interaction and modulation of immune cells in the bone marrow of ITP. They may offer novel targets to develop personalized immunotherapies.

Relationships of platelet glycoprotein specific antibody with therapeutic efficacy of short-term high-dose dexamethasone and bleeding score in the newly diagnosed adult patients with primary immune thrombocytopenia

Objectives: We aimed to investigate relationships of platelet glycoprotein (GP) specific antibody with therapeutic efficacy of high-dose dexamethasone (HD-DXM) and bleeding score in primary immune thrombocytopenia (ITP) adults. Methods: A retrospective study was carried out to analyze relationships of polymorphism of GP specific antibody with initial therapeutic efficacy of HD-DXM and bleeding score of newly diagnosed ITP adults between 1 June, 2016 and 31 January, 2020. Results: 59 patients were involved in the study, with 33 cases of responders and 26 cases of non-responders between June 2016 and January 2020. At admission, there were 31 (52.5%) GP antibody-positive patients. Initial therapy of HD-DXM was effective for 78.6% GP antibody-negative patients and 35.5% GP antibody-positive patients, with a better therapeutic efficacy in patients with anti-GP Ib/IX antibody or anti-GP IIb/IIIa antibody but not in those with anti-GP Ib/IX antibody plus anti-GP IIb/IIIa antibody. Notably, therapeutic efficacy is much worse for minority (Uyghur) patients compared with corresponding Han patients. Similarly, it was much lower in GP antibody-positive patients compared with corresponding negative ones at low and medium bleeding score, with no response in GP antibody-positive patients at high bleeding score. Furthermore, there was a moderate negative correlation between therapeutic efficacy and GP-specific antibody (p < 0.05), but no obvious linear relationship between clinical bleeding degree and GP-specific antibody (p > 0.05). Conclusion: Collectively, the newly diagnosed ITP adults with GP-specific antibody have a poor response to short-term HD-DXM, especially in minority (Uyghur) patients with GP-specific antibody in China.

Rituximab resistance in ITP and beyond

The pathophysiology of immune thrombocytopenia (ITP) is complex and encompasses innate and adaptive immune responses, as well as megakaryocyte dysfunction. Rituximab is administered in relapsed cases and has the added benefit of inducing treatment-free remission in over 50% of patients. Nevertheless, the responses to this therapy are not long-lasting, and resistance development is frequent. B cells, T cells, and plasma cells play a role in developing resistance. To overcome this resistance, targeting these pathways through splenectomy and novel therapies that target FcγR pathway, FcRn, complement, B cells, plasma cells, and T cells can be useful. This review will summarize the pathogenetic mechanisms implicated in rituximab resistance and examine the potential therapeutic interventions to overcome it. This review will explore the efficacy of established therapies, as well as novel therapeutic approaches and agents currently in development.

Diffuse large B‑cell lymphoma and monoclonal gammopathy secondary to immune thrombocytopenic purpura: A case report

The present study reports the case of a patient with diffuse large B-cell lymphoma (DLBCL) and monoclonal gammopathy (MG) secondary to immune thrombocytopenia purpura (ITP). The clinical diagnoses and investigations of this case are reported. To the best of our knowledge, this is the first study to report DLBCL and MG secondary to ITP. The patient presented with a rare constellation of diseases, which made the diagnosis and treatment difficult for the physicians. The patient was followed up for 10 years using the morphological examination of bone marrow cells after chemotherapy, and currently continues with follow-up examinations. Treatments and prognoses for ITP, DLBCL and MG are common. However, treatments and prognoses are unclear for patients with all three conditions. The different clinical manifestations and disease processes of DLBCL and MG secondary to ITP cause difficulties for physicians in terms of treatment and prognosis. The present case report describes the comprehensive evaluation, diagnosis and treatment of a patient with DLBCL and MG secondary to, and concurrent with, ITP.

The association between platelet glycoprotein-specific antibodies and response to short-term high-dose dexamethasone with prednisone maintenance treatment in adult patients with primary immune thrombocytopenia

OBJECTIVE

The aim of the present study was to detect the association between platelet glycoprotein-specific autoantibodies and the patient response to short-term high-dose dexamethasone (HD-DXM) + prednisone maintenance treatment.

METHODS

The data from 112 adult patients newly diagnosed with ITP who were administered first-line HD-DXM + prednisone maintenance therapy between January 2016 and January 2021 were retrospectively analyzed.

RESULTS

A total of 72 patients positive for platelet glycoprotein-specific antibodies were enrolled in the antibody-positive group, and 40 patients not positive for platelet glycoprotein-specific antibodies were enrolled in the antibody-negative group. In the antibody-positive group, six platelet glycoprotein-specific antibody types were found: 41.67% of the patients were anti-GP IIb/IIIa-positive only, 5.56% were anti-GP Ib/IX-positive only, 5.56% were anti-P-selectin-positive only, 19.44% were anti-GP IIb/IIIa- and anti-GP Ib/IX-positive, 16.67% were anti-GP Ib/IX- and P-selectin-positive and 11.11% were positive for all three antibodies. There was no significant difference in the overall response rate between the antibody-positive group and the antibody-negative group (94.44 versus 80.00%, p = .221). However, the CR rate was significantly higher in the antibody-positive group than in the antibody-negative group (69.44% versus 40.00%, p = .032). The logistic regression analysis revealed that platelet glycoprotein-specific antibody positivity and age were two factors that could affect patient response.

CONCLUSIONS

The present study discovered that adult patients newly diagnosed with ITP who had positive platelet glycoprotein-specific antibody test results were likely to achieve a better response after treatment with HD-DXM + prednisone maintenance.

Association between P-Selectin Autoantibody Positive and Response to Steroid Treatment in Newly Diagnosed Immune Thrombocytopenia Patients

OBJECTIVE

This study aimed to detect the association between P-selectin autoantibody positive and response to steroid treatment in newly diagnosed immune thrombocytopenia (ITP) patients.

METHODS

The data from 105 newly diagnosed adult ITP patients administered with first-line of steroid treatment from October 2016 to May 2021 were retrospectively analyzed. Treatment responses were evaluated within 3 months after the onset of treatment.

RESULTS

Among the 105 patients, 80.00% (84/105) of patients presented with platelet glycoprotein-specific antibody positive; 44.76% (47/105) patients were anti-P-selectin positive, while 35.24% (37/105) were anti-P-selectin negative. No significant difference in overall response was observed between patients who were anti-P-selectin positive and those who were anti-P-selectin negative (74.47% vs. 89.19, χ2 = 2.910, p = 0.088). But patients who were anti-P-selectin negative had significantly higher complete response rate, compared to those who were anti-P-selectin positive (72.97% vs. 48.94%, χ2 = 4,965, p = 0.026). Logistic regression analysis revealed that anti-GP IIb/IIIa positive (OR = 3.114, p = 0.010, 95% CI: 1.313-7.388) and anti-P-selectin positive (OR = 0.309, p = 0.036, 95% CI: 0.127-0.753) were two factors that could affect patients' response.

CONCLUSIONS

Our study found that ITP patients with anti-GP IIb/IIIa may have a higher response to steroid treatment, but anti-P-selectin-mediated-ITP might be less responsive to steroid treatment. In adults with ITP, the presence of anti-P-selectin autoantibodies is a predictive factor for poor response to steroid treatment.

Predictive Value of B reg and Serum IL-10 Concentration Levels for Acute ITP Progression to Chronic Phase

INTRODUCTION

Pediatric immune thrombocytopenia (ITP) is a potentially life threating autoimmune disorder with different responses to therapy and different bleeding phenotypes in critical organs. The molecular basis for the variable response has not yet been fully elucidated. This study was designed to address the predictive value of regulatory B-cell (B reg ) count and interleukin-10 (IL-10) serum levels for acute ITP patients who progress to chronic phase. The present study included 80 children with acute ITP )38 males and 42 females (with median age of 8 years and 40 matched healthy controls. Assessment of B reg (CD19 + CD24 hi CD38 hi ) was carried out by a multicolor flowcytometry, however, IL-10 serum levels were evaluated by enzyme-linked immunosorbent assay. A significant reduction of B reg percentage and a significant increase in serum IL-10 levels were identified in children with acute ITP as compared with controls ( P <0.001 for both). Fourteen ITP patients passed to chronic phase, while 66 patients achieved remission within 6 months. The absolute B reg was significantly lower, while IL-10 was significantly higher in patients with acute ITP who progressed to chronic phase in comparison with acute ITP patients who achieved complete remission. Cox proportional hazards for ITP chronicity revealed that IL-10 OR was 2.46 (confidence interval: 1.42-4.27; P =0.001) and absolute B reg OR was 0.147 (confidence interval: 0.128-0.624; P =0.005) in the peripheral blood. Therefore, they could predict chronicity in ITP cases.

CONCLUSION

Reduced B reg count and elevated IL-10 levels in patients with acute ITP at diagnosis can predict chronicity.

A modern reassessment of glycoprotein-specific direct platelet autoantibody testing in immune thrombocytopenia

Platelet autoantibody (PA) testing has previously shown poor sensitivity for immune thrombocytopenia (ITP) diagnosis, but no previous study used both 2011 American Society of Hematology (ASH) guidelines for ITP diagnosis and 2012 International Society on Thrombosis and Haemostasis (ISTH) PA testing recommendations. We therefore performed a comprehensive retrospective study of PA testing in adult patients with ITP strictly applying these criteria. Of 986 PA assays performed, 485 assays in 368 patients met criteria and were included. Sensitivity and specificity of a positive test result for diagnosis of active ITP (n = 228 patients) were 90% and 78%, respectively. Sensitivity and specificity of a negative test result for clinical remission (n = 61 assays) were 87% and 91%. Antibodies against both glycoprotein IIb (GPIIb)/IIIa and GPIb/IX were required for the presence of antibodies against GPIa/IIa in patients with ITP. Logistic regression analysis revealed that more positive autoantibodies predicted more severe disease (relative to nonsevere ITP, relative risk ratio for severe ITP and refractory ITP was 2.27 [P < .001] and 3.09 [P < .001], respectively, per additional autoantibody); however, serologic testing did not meaningfully predict treatment response to glucocorticoids, intravenous immunoglobulin, or thrombopoietin receptor agonists. Sixty-four patients with ITP had multiple PA assays performed longitudinally: all 10 patients achieving remission converted from positive to negative serologic results, and evidence for epitope spreading was observed in 35% of patients with ongoing active disease. In conclusion, glycoprotein-specific direct PA testing performed using ISTH recommendations in patients meeting ASH diagnostic criteria is sensitive and specific for ITP diagnosis and reliably confirms clinical remission. More glycoproteins targeted by autoantibodies predicts for more severe disease.

Aberrant Expression of a Proliferation-Inducing Ligand Underlies Autoimmune Mechanisms in Immune Thrombocytopenia

Purpose

To study the relationship between surface membrane-bound APRIL and ITP.

Methods

The peripheral blood of all subjects, 50 patients diagnosed with ITP and 25 healthy controls, was collected. Flow cytometry was used to detect the expression of membrane-bound APRIL on immune cells and platelets. ELISA was used to detect the content of soluble APRIL in plasma.

Results

Membrane-bound APRIL was only expressed on the surface of platelets in both ITP patients and controls. APRIL expression on the platelet surface was significantly lower in newly diagnosed (P < 0.001) and chronic (P < 0.001) ITP patients than in controls. Platelet surface APRIL level was significantly enhanced in patients with complete remission after treatment (P = 0.02) but not in those with no response after treatment. Platelet surface APRIL level in ITP patients was negatively correlated with serum APRIL level (r = −0.09765, P = 0.0424).

Conclusions

Platelet surface APRIL may play a key immunoregulative role. Platelet surface APRIL is likely to be one source of the excessive serum APRIL in ITP patients. The effectiveness of treatment may be measured by determining the platelet surface APRIL levels in ITP patients.

Increased let-7b-5p is associated with enhanced BAFF-R expression and B cell survival in immune thrombocytopenia

BACKGROUND

B cells play a key role in the pathogenesis of immune thrombocytopenia (ITP) by producing platelet autoantibodies. Accumulating evidence suggest that microRNA (miRNA) is a critical regulator in B cells. The contribution of miRNA to B cell dysfunction in ITP has not been described. The aim of this study was to examine the expression of miRNA let-7b-5p in B cells of ITP patients and investigate its possible association with B cell function in ITP.

METHODS

The CD19⁺ cells were isolated from peripheral mononuclear cells of ITP patients and healthy controls using immunomagnetic microbeads. B cell survival in vitro was evaluated by cell counting. The level of let-7b-5p was quantified by quantitative PCR. The surface expression of B cell activating factor receptor (BAFF-R) was detected by flow cytometry. The role of let-7b-5p was examined in isolated B cells by transfecting miRNA mimics or inhibitors.

RESULTS

The results showed that let-7b-5p in B cells was elevated, and B cell survival was enhanced in ITP patients compared with healthy controls. BAFF and B cell receptor stimulation can induce the expression of let-7b-5p in vitro. Overexpression of let-7b-5p in B cells enhanced the expression of surface BAFF-R and promoted B cell survival. Moreover, let-7b-5p enhanced the phosphorylation of NF-κB2 p100 and upregulated the expression of survival factor Bcl-xL after BAFF induction.

CONCLUSION

Let-7b-5p is a pro-survival miRNA in B cells and increased let-7b-5p is associated with enhanced surface BAFF-R in ITP.

Immunomodulatory cytokine interleukin-35 and immune thrombocytopaenia

Considerable attention has been paid to interleukin (IL)-35 because of its immunosuppressive effects in a variety of autoimmune diseases. IL-35, a recently identified cytokine of the IL-12 family, is a negative regulatory factor secreted by IL-35-inducible regulatory T cells (iTr35 cells) and the recently reported regulatory B cells (Breg cells). Four biological effects of IL-35 have been discovered in vitro and in vivo: (i) suppression of T cell proliferation; (ii) conversion of naive T cells into iTr35 cells; (iii) downregulation of type 17 helper T (Th17) cells; and (iv) conversion of Breg cells into a Breg subset that produces IL-35 and IL-10. IL-35 plays an important role in a variety of autoimmune diseases, such as rheumatoid arthritis, allergic asthma and systemic lupus erythematosus. Primary immune thrombocytopaenia (ITP), which is characterized by isolated thrombocytopaenia and mild mucocutaneous to life-threatening bleeding, is an autoimmune disease with complex dysregulation of the immune system. Both antibody-mediated and/or T cell-mediated platelet destruction are key processes. In addition, impairment of T cells and cytokine imbalances have now been recognized to be important. This review summarizes the immunomodulatory effects of IL-35 and its role in the pathogenesis of ITP as mediated by T and B cells.

The sensitivity and specificity of platelet autoantibody testing in immune thrombocytopenia: a systematic review and meta-analysis of a diagnostic test

Essentials The diagnosis of ITP is based on a platelet count < 100 × 109  L-1 and exclusion of other causes. There are no standard tests or biomarkers to diagnose ITP. The sensitivity of platelet autoantibody testing is low (53%). The specificity is high (> 90%). A positive autoantibody test can be useful to rule in ITP but a negative does not rule out ITP. SUMMARY: Background Immune thrombocytopenia (ITP) is an autoimmune disorder characterized by a low platelet count and an increased risk of bleeding. The sensitivity and specificity of platelet autoantibody tests is variable and their utility is uncertain. Objective The purpose of this study was to perform a systematic review and meta-analysis of platelet autoantibody tests in the diagnosis of ITP. Methods Ovid Medline, PubMed, and Web of Science were searched from inception until 31 May 2018. Two reviewers independently assessed studies for eligibility and extracted data. Studies that reported testing results for antiplatelet autoantibodies on platelets (direct tests) or in plasma/serum (indirect tests) for 20 or more ITP patients were included. Results Pooled estimates for sensitivity and specificity were calculated using a random effects model. Pooled estimates for the sensitivity and specificity of direct anti-platelet autoantibody testing for either anti-glycoprotein IIbIIIa or anti-glycoprotein IbIX were 53% (95% confidence interval [CI], 44-61%) and 93% (95% CI, 81-99%), respectively. For indirect testing, the pooled estimates for the sensitivity and specificity were 18% (95% CI, 12-24%) and 96% (95% CI, 87-100%), respectively. Conclusions Autoantibody testing in ITP patients has a high specificity but low sensitivity. A positive autoantibody test can be useful for ruling in ITP, but a negative test does not rule out ITP.

[The value of platelet count in predicting the efficacy of rituximab treatment in adult patients with chronic primary immune thrombocytopenia]

目的

探讨血小板计数水平在成人慢性原发免疫性血小板减少症（ITP）患者利妥昔单抗疗效预测中的价值。

方法

回顾性分析2011年1月1日至2014年12月31日期间接受利妥昔单抗治疗（100 mg每周1次，连用4次）慢性ITP患者的临床资料，计算利妥昔单抗治疗后不同随访时间截点血小板计数预测疗效的敏感性、特异性和阳性预测值、阴性预测值，并通过ROC曲线下面积得出最佳截断点。

结果

103例患者纳入研究，男46例，女57例，中位年龄30（18~67）岁。首剂利妥昔单抗后第1、5、7天，成功组（治疗后PLT≥50×10⁹/L且未接受其他药物治疗）与无效组（治疗后PLT<50×10⁹/L）中位血小板计数差异均无统计学意义（P>0.05）；利妥昔单抗治疗后第14天，成功组中位血小板计数高于无效组[41（8~384）×10⁹/L对23（0~106）×10⁹/L，P=0.003]；在随后的各随访截点，成功组中位血小板计数进一步回升并维持于正常水平，无效组中位血小板计数均低于正常水平。以ROC曲线获得的预测治疗反应的优化界限值血小板计数50×10⁹/L为基础，首剂妥昔单抗治疗后第14、30、60天血小板计数能够组成一个预后评估体系。

结论

利妥昔单抗治疗后第14、30、60天血小板计数能够组成一个疗效预测评估体系，有助于随访和制定治疗计划。

Cellular expression of CD markers in immune thrombocytopenic purpura: implications for prognosis

Immune thrombocytopenic purpura (ITP) is an autoimmune bleeding disorder associated with platelet destruction. Abnormalities in frequency and function of different immune cells can play a crucial role in this disease. The aim of this study was to evaluate the prognostic value of CD markers' expressions by immune cells in ITP. Peripheral blood samples were collected from 25 ITP patients before and after treatment. The expression of CD markers was evaluated by flow cytometry technique. The expression of CD38 and CD56 was significantly lower before treatment than after it (p = 0.025 and p = 0.036, respectively). Furthermore, a positive correlation was found between CD38 expression with platelet count before (r = 0.496, p = 0.012) and after treatment (r = 0.404, p = 0.045). No significant relationship was found between this marker and platelet count while CD4 expression was higher before treatment than after it (p = 0.002). In conclusion, CD38 may have independent prognostic value in ITP and we suggest that it can be a prognostic marker for this disease.

Pathogenesis and Therapeutic Mechanisms in Immune Thrombocytopenia (ITP)

Immune thrombocytopenia (ITP) is a complex autoimmune disease characterized by low platelet counts. The pathogenesis of ITP remains unclear although both antibody-mediated and/or T cell-mediated platelet destruction are key processes. In addition, impairment of T cells, cytokine imbalances, and the contribution of the bone marrow niche have now been recognized to be important. Treatment strategies are aimed at the restoration of platelet counts compatible with adequate hemostasis rather than achieving physiological platelet counts. The first line treatments focus on the inhibition of autoantibody production and platelet degradation, whereas second-line treatments include immunosuppressive drugs, such as Rituximab, and splenectomy. Finally, third-line treatments aim to stimulate platelet production by megakaryocytes. This review discusses the pathophysiology of ITP and how the different treatment modalities affect the pathogenic mechanisms.

Advances in Diagnosis and Treatments for Immune Thrombocytopenia

Immune thrombocytopenia (ITP) is an acquired hemorrhagic condition characterized by the accelerated clearance of platelets caused by antiplatelet autoantibodies. A platelet count in peripheral blood <100 × 10⁹/L is the most important criterion for the diagnosis of ITP. However, the platelet count is not the sole diagnostic criterion, and the diagnosis of ITP is dependent on additional findings. ITP can be classified into three types, namely, acute, subchronic, and persistent, based on disease duration. Conventional therapy includes corticosteroids, intravenous immunoglobulin, splenectomy, and watch-and-wait. Second-line treatments for ITP include immunosuppressive therapy [eg, anti-CD20 (rituximab)], with international guidelines, including rituximab as a second-line option. The most recently licensed drugs for ITP are the thrombopoietin receptor agonists (TRAs), such as romiplostim and eltrombopag. TRAs are associated with increased platelet counts and reductions in the number of bleeding events. TRAs are usually considered safe, effective treatments for patients with chronic ITP at risk of bleeding after failure of first-line therapies. Due to the high costs of TRAs, however, it is unclear if patients prefer these agents. In addition, some new agents are under development now. This manuscript summarizes the pathophysiology, diagnosis, and treatment of ITP. The goal of all treatment strategies for ITP is to achieve a platelet count that is associated with adequate hemostasis, rather than a normal platelet count. The decision to treat should be based on the bleeding severity, bleeding risk, activity level, likely side effects of treatment, and patient preferences.

Role of platelet function and platelet membrane glycoproteins in children with primary immune thrombocytopenia

The aim of the present study was to examine and understand changes in platelet functions prior to and after the treatment of primary immune thrombocytopenia (ITP) in children. An automatic hematology analyzer and whole blood flow cytometry were used to detect immature platelet fraction (IPF), IPC and membrane glycoproteins (CD62p, PAC-1 and CD42b) in ITP children (ITP group), children with complete response after ITP treatment (ITP-CR group) and children with elective surgery (normal control group). The results showed that, levels of platelet count (PLT) and plateletcrit in the ITP group were lower alhtough the levels of mean platelet volume, platelet distribution width and platelet-large cell ratio (P-LCR) were higher than those in the normal control and ITP-CR groups. PLT in the ITP-CR group was lower than that in the normal controls. Additionally, IPF% was higher in the normal control and ITP-CR groups, IPC was lower in the ITP group compared to the normal control and ITP-CR groups. Furthermore, prior to ADP activation, the expression levels of CD62p, PAC-1 and CD42b in the ITP group were lower in ITP group than those in the normal control and ITP-CR groups. The expression level of PAC-1 was lower in the ITP-CR and normal control groups. No differences were identified in CD62p and CD42b expression levels. Following ATP activation, CD62p, PAC-1 and CD42b expression in the ITP group was lower than that in the normal control and ITP-CR groups. PAC-1 expression was lower while CD62p expression was higher in the ITP-CR group compared to the normal control group. In conclusion, the activation of platelets in ITP children was low. Decreased platelet function, platelet parameters and platelet glycoproteins may be used as markers for monitoring the treatment efficacy in ITP children.

Modeling HIV-1 Induced Neuroinflammation in Mice: Role of Platelets in Mediating Blood-Brain Barrier Dysfunction

The number of HIV-1 positive individuals developing some form of HIV-associated neurocognitive disorder (HAND) is increasing. In these individuals, the integrity of the blood-brain barrier (BBB) is compromised due to an increase in exposure to pro-inflammatory mediators, viral proteins, and virus released from infected cells. It has been shown that soluble CD40L (sCD40L) is released upon platelet activation and is an important mediator of the pathogenesis of HAND but the underlying mechanisms are unclear, emphasizing the need of an effective animal model. Here, we have utilized a novel animal model in which wild-type (WT) mice were infected with EcoHIV; a derivative of HIV-1 that contains a substitution of envelope protein gp120 with that of gp80 derived from murine leukemia virus-1 (MuLV-1). As early as two-weeks post-infection, EcoHIV led to increased permeability of the BBB associated with decreased expression of tight junction protein claudin-5, in CD40L and platelet activation-dependent manner. Treatment with an antiplatelet drug, eptifibatide, in EcoHIV-infected mice normalized BBB function, sCD40L release and platelet activity, thus implicating platelet activation and platelet-derived CD40L in virally induced BBB dysfunction. Our results also validate and underscore the importance of EcoHIV infection mouse model as a tool to explore therapeutic targets for HAND.