Role of Regulatory Cells in Immune Tolerance Induction in Hemophilia A

The main complication of hemophilia A treatment is the development of neutralizing antibodies (inhibitors) against factor VIII (FVIII). Immune tolerance induction (ITI) is the prescribed treatment for inhibitor eradication, although its working mechanism remains unresolved. To clarify this mechanism, we compared blood samples of hemophilia A patients with and without inhibitors for presence of immunoregulatory cells and markers, including regulatory B-cells (Bregs), regulatory T-cells (Tregs), myeloid-derived suppressor cells (MDSCs), and expression of regulatory markers on T-cells (programmed cell death protein 1 [PD1], inducable T-cell costimulator, cytotoxic T-lymphocyte-associated protein 4 [CTLA4]), by use of flow cytometry. By cross-sectional analysis inhibitor patients (N = 20) were compared with inhibitor-negative (N = 28) and ex-inhibitor (N = 17) patients. In another longitudinal study, changes in immunoregulatory parameters were evaluated during ITI (N = 12) and compared with inhibitor-negative hemophilia A patients (N = 36). The frequency of Bregs, but not of Tregs nor MDSCs, was significantly reduced in inhibitor patients (3.2%) compared with inhibitor-negative (5.9%) and ex-inhibitor patients (8.9%; P < 0.01). CTLA4 expression on T-cells was also reduced (mean fluorescence intensity 133 in inhibitor versus 537 in inhibitor-negative patients; P < 0.01). Fittingly, in patients followed during ITI, inhibitor eradication associated with increased Bregs, increased Tregs, and increased expression of CTLA4 and PD1 on CD4+ T-cells. In conclusion, inhibitor patients express significantly lower frequency of Bregs and Tregs marker expression, which are restored by successful ITI. Our findings suggest that an existing anti-FVIII immune response is associated with deficits in peripheral tolerance mechanisms and that Bregs and changes in immunoregulatory properties of CD4+ T-cells likely contribute to ITI in hemophilia A patients with inhibitors

No immunological changes after factor VIII product switch: An in depth analysis in haemophilia A patients

BACKGROUND: A challenging complication in the treatment of haemophilia A is the formation of neutralizing anti-FVIII antibodies (inhibitors). There is ongoing debate on the effect of FVIII product and inhibitor risk, rendering patients and physicians reluctant to switch FVIII-products. AIM: This study aimed to evaluate changes in the immune profile of haemophilia A patients after switching FVIII products and their possible relation to inhibitor development. Secondary, FVIII efficacy after switching were assessed. METHODS: Patients, who switched FVIII-products between 2017-2019, were included in this single centre cohort study. Prospective comparison of immunoregulatory cells and markers by flow-cytometry before and after the switch was performed in a subgroup. For the total cohort clinical data regarding inhibitor development and FVIII efficacy 1 year before and after switching were retrospectively collected. RESULTS: One-hundred patients (including 39 with prospective immunological assessment) were analyzed, of which 31% switched from plasma-derived (pdFVIII) to recombinant standard half-life FVIII (SHL-rFVIII), 47% between different SHL-rFVIII, and 22% from pdFVIII/SHL-rFVIII to rFVIII-Fc. No remarkable changes in immunoregulatory cell functions were observed after switching, regardless the type of switch. None of the patients developed an inhibitor. FVIII efficacy, that is, FVIII usage, half-life and annual bleeding rate (ABR), was similar before and after switch for the SHL products, whereas rFVIII-Fc associated with a longer half-life (13.1 vs. 15.0 h) and lower ABR (3.0 vs. 1.0). CONCLUSIONS: Switching to a different FVIII product was not associated with inhibitor development, nor with differences in the immune profile. Switching to rFVIII-Fc lead to lower ABR

Coordinating physiotherapy care for persons with haemophilia

Introduction: Physiotherapy is highly recommended for persons with haemophilia (PWH), to regain functioning after bleeding and to maintain functioning when dealing with haemophilic arthropathy. However, many PWH live too far from their Haemophilia Comprehensive Care Centre (HCCC) to receive regular treatment at their HCCC. Physiotherapists in primary care may have limited experience with a rare disease like haemophilia. Aim: To explore experiences of stakeholders with primary care physiotherapy for PWH and develop recommendations to optimize physiotherapy care coordination. Methods: A RAND approach was used, consisting of a Delphi procedure with e-mailed questionnaires and a consensus meeting. Included stakeholders were PWH, physiotherapists from HCCC's and primary care physiotherapists. HCCC physiotherapists approached patients from their centre and primary care physiotherapists from their network to fill in the questionnaires. Purposive sampling was used to select participants from the survey sample for the consensus meeting. Results: Ninety-six primary care physiotherapists, 54 PWH and eight HCCC physiotherapists completed the questionnaire. Subsequently, four PWH, three primary care physiotherapists and four HCCC physiotherapists participated in the consensus meeting. The questionnaires yielded 33 recommendations, merged into a final list of 20 recommendations based on the consensus meeting. The final rank-order consists of 13 recommendations prioritized by at least one stakeholder. Conclusion: Commitment to a formal network is considered not feasible for a rare disease like haemophilia. Development of a practice guideline, easy-accessible information and contact details, two-way and open communication between HCCC and primary care and criteria to refer back to the HCCC are recommended

Functional decline in persons with haemophilia and factors associated with deterioration

INTRODUCTION: The World Haemophilia Federation advises regular musculoskeletal assessment covering all International Classification of Functioning and Health (ICF) domains, including limitations in activities and participation in persons with haemophilia (PWH). This enables clinicians to detect changes early and enable adjustments in personalized healthcare when needed. However, data on the course of physical functioning and occurrence of decline is lacking. The aim of this study is to describe changes in perceived limitations in activities of PWH and to identify factors associated with a change. METHODS: Data were collected from medical health records of regular check-up visits of adults with moderate and severe haemophilia in two time periods. Perceived limitations in activities was measured with the Haemophilia Activities List (HAL). Association between variables (e.g., age, body mass index, bleeding rate and synovitis) and change in perceived limitations was assessed using a generalized linear model. RESULTS: A total of 104 PWH were included. At T0, the median HAL sum score was 79.5 (IQR 62.1-93.6) and at T1 the median HAL sum score was 74.2 (IQR 57.5-88.3). A functional decline was found in 35.6% of PWH, 55.8% remained stable and 8.7% improved. Among other variables, a BMI > 30 kg/m 2 appeared to be an important factor that negatively influenced the change in perceived functioning in adult PWH. With the included factors we could only explain a small part of this decline (R 2 adj : .12). CONCLUSION: The majority of PWH remained stable in their perceived functional ability over mid-long term (median 3.5 years). However, about a third showed a clinical relevant decline in their functional ability