Normal B cells express ZAP70 in chronic lymphocytic leukemia: A link between autoimmunity and lymphoproliferation?

ZAP70 has a prognostic value in chronic lymphocytic leukemia (CLL), through altered B-cell receptor signaling, which is important in CLL pathogenesis. A good correlation between ZAP70 expression in CLL cells and the occurrence of autoimmune phenomena has been reported. Yet, the great majority of CLL-associated autoimmune cytopenia is due to polyclonal immunoglobulin (Ig) G synthesized by nonmalignant B cells, and this phenomenon is poorly understood. Here, we show, using flow cytometry, that a substantial percentage of CD5- nonmalignant B cells from CLL patients expresses ZAP70 compared with CD5- B cells from healthy subjects. This ZAP70 expression in normal B cells from CLL patients was also evidenced by the detection of ZAP70 mRNA at single-cell level with polyclonal Ig heavy- and light-chain gene transcripts. ZAP70+ normal B cells belong to various B-cell subsets and their presence in the naïve B-cell subset suggests that ZAP70 expression may occur during early B-cell development in CLL patients and potentially before malignant transformation. The presence of ZAP70+ normal B cells is associated with autoimmune cytopenia in CLL patients in our cohort of patients, and recombinant antibodies produced from these ZAP70+ nonmalignant B cells were frequently autoreactive including anti-platelet reactivity. These results provide a better understanding of the implication of ZAP70 in CLL leukemogenesis and the mechanisms of autoimmune complications of CLL.

One-step totally robotic Hartmann reversal and complex abdominal wall reconstruction with bilateral posterior component separation: a technical note.

AIM: This paper describes a robotic approach to combined gastrointestinal continuity restoration and complex abdominal wall reconstruction after Hartmann's procedure complicated by large midline and parastomal hernias. METHODS: A robotic Hartmann reversal is performed, followed by robotic retromuscular abdominal wall reconstruction of all ventral defects with bilateral posterior component separation using the double-docking approach. Surgical steps are thoroughly described, and the accompanying video highlights critical steps of the procedure, anatomical landmarks and technical details relevant to successful completion. RESULTS: Complete restoration of the anatomy was achieved with an operative time of 6.5 h. Mobilization occured on day 1, and bowels were opened on day 3. Surgical discharge was possible on day 5. No intra-operative surgical complication occurred and follow-up at 6 months showed no recurrence or mid-term complication. CONCLUSION: Combined minimally invasive reconstruction of the gastrointestinal tract and abdominal wall was feasible using a robotic system. In addition, potential advantages of postoperative rehabilitation and reduced surgical site complications are suggested. Prospective evaluation of the technique is ongoing.

Full-scale simulations to improve disaster preparedness in hospital pharmacies.

PURPOSE: Assess whether full-scale simulation exercises improved hospital pharmacies' disaster preparedness. METHODS: Swiss hospital pharmacies performed successive full-scale simulation exercises at least four months apart. An interprofessional team created two scenarios, each representing credible regional-scale disasters involving approximately fifty casualties (a major road accident and a terrorist attack). Four exercise assessors used appraisal forms to evaluate participants' actions and responses during the simulation (rating them using five-point Likert scales). RESULTS: Four hospital pharmacies performed two full-scale simulation exercises each. Differences between exercises one and two were observed. On average, the four hospitals accomplished 69% ± 6% of the actions expected of them during exercise one. The mean rate of expected actions accomplished increased to 84% ± 7% (p < 0.005) during exercise two. Moreover, the average quality of actions improved from 3.0/5 to 3.6/5 (p = 0.01), and the time required to gather a crisis management team drastically decreased between simulations (from 23 to 5 min). The main challenges were communication (reformulation) and crisis management. Simulation exercise number one resulted in three hospital pharmacies creating disaster action plans and the fourth improving its already existing plan. CONCLUSION: This study highlighted the value of carrying out full-scale disaster simulations for hospital pharmacies as they improved overall institutional preparedness and increased staff awareness. The number of expected actions accomplished increased significantly. In the future, large-scale studies and concept dissemination are warranted.

Sacro-coxxygial hygiene, a key factor in the outcome of pilonidal sinus surgical treatment?

BACKGROUND: Surgical wound infection contributes to prolonged recovery time after pilonidal sinus excision. As a standard procedure after surgery, we recommend our patients to perform water irrigations in the intergluteal cleft 4 to 6 times a day during the post-operative period. Our hypothesis is that this should reduce healing time and complication rates. The aim of this study was to measure the importance of sacro coccygeal hygiene in the management of pilonidal sinus disease. METHODS: We retrospectively collected data after surgical management of pilonidal sinus (sinusectomy procedures) in our division over a 10-year period. Patients were divided into three groups according to their local hygiene during postoperative follow-up and scored one (G1: good hygiene) to three (G3: poor hygiene). Primary outcome was complication rates. Secondary endpoints were, healing time, follow-up, time off work, and recurrence rate. RESULTS: In G1 (N = 112), complication rate was 3.6%. In G2 (N = 109), it was 5.5%, whereas in G3 (N = 71), it reached 7.03%. However, there were no statistically significant differences between hygiene groups regarding complication rates in both univariate and multivariable analysis. Regarding secondary outcomes, there were significant differences between hygiene groups concerning median follow-up (p = 0.0001) and median time off work (p = 0.0127). CONCLUSION: Good hygiene of wound is essential for optimal, rapid healing without complications. The importance of this report is to show that thanks to our hygiene follow-up strategy with frequent perineal irrigations and regular follow-up checks, patients with at a first glance "unclean local conditions", reached similar complications, median healing time and recurrences rates to patients with medium and good wound hygiene level.

Antithrombotic prophylaxis for surgery-associated venous thromboembolism risk in patients with inherited platelet disorders. The SPATA-DVT Study.

Major surgery is associated with an increased risk of venous thromboembolism (VTE), thus the application of mechanical or pharmacologic prophylaxis is recommended. The incidence of VTE in patients with inherited platelet disorders (IPD) undergoing surgical procedures is unknown and no information on the current use and safety of thromboprophylaxis, particularly of low-molecular-weight-heparin in these patients is available. Here we explored the approach to thromboprophylaxis and thrombotic outcomes in IPD patients undergoing surgery at VTE-risk participating in the multicenter SPATA study. We evaluated 210 surgical procedures carried out in 155 patients with well-defined forms of IPD (VTE-risk: 31% high, 28.6% intermediate, 25.2% low, 15.2% very low). The use of thromboprophylaxis was low (23.3% of procedures), with higher prevalence in orthopedic and gynecological surgeries, and was related to VTE-risk. The most frequently employed thromboprophylaxis was mechanical and appeared to be effective, as no patients developed thrombosis, including patients belonging to the highest VTE-risk classes. Low-molecular-weight-heparin use was low (10.5%) and it did not influence the incidence of post-surgical bleeding or of antihemorrhagic prohemostatic interventions use. Two thromboembolic events were registered, both occurring after high VTE-risk procedures in patients who did not receive thromboprophylaxis (4.7%). Our findings suggest that VTE incidence is low in patients with IPD undergoing surgery at VTE-risk and that it is predicted by the Caprini score. Mechanical thromboprophylaxis may be of benefit in patients with IPD undergoing invasive procedures at VTE-risk and low-molecular-weight-heparin should be considered for major surgery.

Pathogenic and likely pathogenic variants in at least five genes account for approximately 3% of mild isolated nonsyndromic thrombocytopenia.

BACKGROUND: Thrombocytopenia has a variety of different etiologies, both acquired and hereditary. Inherited thrombocytopenia may be associated with other symptoms (syndromic forms) or may be strictly isolated. To date, only about half of all the familial forms of thrombocytopenia have been accounted for in terms of well-defined genetic abnormalities. However, data are limited on the nature and frequency of the underlying causative genetic variants in individuals with mild isolated nonsyndromic thrombocytopenia. STUDY DESIGN AND METHODS: Thirteen known or candidate genes for isolated thrombocytopenia were included in a gene panel analysis in which targeted next-generation sequencing was performed on 448 French blood donors with mild isolated nonsyndromic thrombocytopenia. RESULTS: A total of 68 rare variants, including missense, splice site, frameshift, nonsense, and in-frame variants (all heterozygous) were identified in 11 of the 13 genes screened. Twenty-nine percent (N = 20) of the variants detected were absent from both the French Exome Project and gnomAD exome databases. Using stringent criteria and an unbiased approach, we classified seven predicted loss-of-function variants (three in ITGA2B and four in TUBB1) and four missense variants (one in GP1BA, two in ITGB3 and one in ACTN1) as being pathogenic or likely pathogenic. Altogether, they were found in 13 members (approx. 3%) of our studied cohort. CONCLUSION: We present the results of gene panel sequencing of known and candidate thrombocytopenia genes in mild isolated nonsyndromic thrombocytopenia. Pathogenic and likely pathogenic variants in five known thrombocytopenia genes were identified, accounting for approximately 3% of individuals with the condition.

[Ventral hernia surgery†: New minimally invasive approaches]. / Chirurgie des hernies ventrales†: nouvelles approches minimalement invasives.

Ventral hernia surgery has undergone major changes over the past decade with the emergence of new minimally invasive techniques. They merge fundamental concepts of parietal reconstruction of open surgery into a laparoscopic approach, aiming to reduce surgical site complications and to enhance recovery. The spread of robotic assistance systems in the field of abdominal wall surgery facilitates access to this type of procedures and allows their application in increasingly complex cases. Parietal relaxation techniques allow large hernial orifices to be closed without tension. They are now also performed with a minimally invasive approach and in a less aggressive manner. Even if the exact place of all these techniques still needs to be better defined depending on the different hernia types, these laparoscopic or robot-assisted approaches already tend to allow faster post-operative recovery.

Avec l'apparition de nouvelles techniques minimalement invasives, la chirurgie des hernies ventrales connaît depuis une dizaine d'années de profonds remaniements. Elles ont en commun d'intégrer les concepts fondamentaux de reconstruction pariétale de la chirurgie ouverte à une voie d'abord laparoscopique, dans le but de réduire les taux de complication du site opératoire et de permettre une réhabilitation accélérée. La diffusion des systèmes d'assistance robotique en chirurgie de la paroi facilite l'accès à ce type de procédure et permet d'envisager leur application dans des cas de plus en plus complexes. Les techniques de relaxation pariétale permettent la fermeture sans tension d'orifices herniaires larges. Elles sont maintenant aussi réalisées par voie minimalement invasive et de manière moins délabrante. Même si la place exacte de l'ensemble de ces techniques doit encore être mieux définie en fonction du type de hernie, ces prises en charge laparoscopiques ou robot-assistées semblent déjà permettre une récupération postopératoire plus rapide.

Gangrenous gas necrosis of the spleen: a case report.

BACKGROUND: Splenic abscess usually arises from hematogenous spread. Causative pathogens are various and anaerobic pathogens are rarely reported. CASE PRESENTATION: We report the case of a 50-year-old male patient who was admitted for sepsis due to gangrenous necrosis of the spleen associated with bacteremia. Causative pathogens were Clostridium perfringens and Streptococcus gallolyticus. The patient was successfully treated by splenectomy and targeted intravenous antibiotics. No underlying or predisposing disease was found. CONCLUSION: Gangrenous necrosis of the spleen is a rare entity that can be successfully treated by splenectomy and antibiotics.

Immobilized fibrinogen activates human platelets through glycoprotein VI.

Glycoprotein VI, a major platelet activation receptor for collagen and fibrin, is considered a particularly promising, safe antithrombotic target. In this study, we show that human glycoprotein VI signals upon platelet adhesion to fibrinogen. Full spreading of human platelets on fibrinogen was abolished in platelets from glycoprotein VI- deficient patients suggesting that fibrinogen activates platelets through glycoprotein VI. While mouse platelets failed to spread on fibrinogen, human-glycoprotein VI-transgenic mouse platelets showed full spreading and increased Ca2+ signaling through the tyrosine kinase Syk. Direct binding of fibrinogen to human glycoprotein VI was shown by surface plasmon resonance and by increased adhesion to fibrinogen of human glycoprotein VI-transfected RBL-2H3 cells relative to mock-transfected cells. Blockade of human glycoprotein VI with the Fab of the monoclonal antibody 9O12 impaired platelet aggregation on preformed platelet aggregates in flowing blood independent of collagen and fibrin exposure. These results demonstrate that human glycoprotein VI binds to immobilized fibrinogen and show that this contributes to platelet spreading and platelet aggregation under flow.

In vitro quality of amotosalen-UVA pathogen-inactivated mini-pool plasma prepared from whole blood stored overnight.

BACKGROUND AND OBJECTIVES: Small batch-pooled (mini-pool) whole blood (WB)-derived plasma could be an alternative cost-effective source of therapeutic plasma (TP), but carries an increased risk of transfusion-transmitted infection due to exposure of the recipient to several donors. This risk can be mitigated by inactivation of pathogens susceptible to the amotosalen-UVA (AUVA)-treatment. We evaluated the conservation of coagulation factors in AUVA-plasma prepared from WB stored overnight under routine operating conditions, to determine its therapeutic efficacy. Thrombin generation (TG) by the AUVA-plasma was used to provide an integrated measure of the hemostatic capacity. MATERIALS AND METHODS: WB-donations (~450 ml) stored overnight were processed to prepare five leucocyte-depleted plasma mini-pools (1300 ml), which were divided into two parts and treated with AUVA. Each mini-pool yielded six AUVA-plasma units (200 ml) which were frozen (-25°C) within 19 h of WB-collection. Their hemostatic quality was evaluated before and after treatment for up to 12 months of storage. RESULTS: Immediately after AUVA-treatment, the regulatory criteria for FVIII activity and fibrinogen content were met. As compared to untreated plasma there was a reduction in fibrinogen (14%), FV (9%), FVII (25%) and FVIII (32%). However, TG was similar in treated and untreated plasma at all-time-points. CONCLUSIONS: Frozen WB-derived AUVA-plasma prepared from mini-pools within 19 h of WB-collection met the quality standards required for TP and retained hemostatic capacity for up to 12 months. This product could provide a cost-effective convenient substitute for apheresis plasma.

Identification of a new dysfunctional platelet P2Y12 receptor variant associated with bleeding diathesis.

Defects of the platelet P2Y12 receptor (P2Y12R) for adenosine diphosphate (ADP) are associated with increased bleeding risk. The study of molecular abnormalities associated with inherited qualitative defects of the P2Y12R protein is useful to unravel structure-function relationships of the receptor. We describe the case of 2 brothers, sons of first cousins, with lifelong history of abnormal bleeding, associated with dysfunctional P2Y12R and a previously undescribed missense mutation in the encoding gene. ADP (4-20 µM)-induced aggregation of patients' platelets was markedly reduced and rapidly reversible. Other agonists induced borderline-normal aggregation. Inhibition of vasodilator-stimulated phosphoprotein phosphorylation and prostaglandin E1-induced increase in cyclic adenosine monophosphate (cAMP) by ADP was impaired, whereas inhibition of cAMP increase by epinephrine was normal. [(3)H]PSB-0413, a selective P2Y12R antagonist, bound to a normal number of binding sites; however, its affinity, and that of the agonists ADP and 2-methylthio-adenosine-5'-diphosphate, was reduced. Patients' DNA showed a homozygous c.847T>A substitution that changed the codon for His-187 to Gln (p.His187Gln). Crystallographic data and molecular modeling studies indicated that His187 in transmembrane 5 is important for agonist and nucleotide antagonist binding and located in a region undergoing conformational changes. These studies delineate a region of P2Y12R required for normal function after ADP binding.

The contribution of mouse models to the understanding of constitutional thrombocytopenia.

Constitutional thrombocytopenias result from platelet production abnormalities of hereditary origin. Long misdiagnosed and poorly studied, knowledge about these rare diseases has increased considerably over the last twenty years due to improved technology for the identification of mutations, as well as an improvement in obtaining megakaryocyte culture from patient hematopoietic stem cells. Simultaneously, the manipulation of mouse genes (transgenesis, total or conditional inactivation, introduction of point mutations, random chemical mutagenesis) have helped to generate disease models that have contributed greatly to deciphering patient clinical and laboratory features. Most of the thrombocytopenias for which the mutated genes have been identified now have a murine model counterpart. This review focuses on the contribution that these mouse models have brought to the understanding of hereditary thrombocytopenias with respect to what was known in humans. Animal models have either i) provided novel information on the molecular and cellular pathways that were missing from the patient studies; ii) improved our understanding of the mechanisms of thrombocytopoiesis; iii) been instrumental in structure-function studies of the mutated gene products; and iv) been an invaluable tool as preclinical models to test new drugs or develop gene therapies. At present, the genetic determinants of thrombocytopenia remain unknown in almost half of all cases. Currently available high-speed sequencing techniques will identify new candidate genes, which will in turn allow the generation of murine models to confirm and further study the abnormal phenotype. In a complementary manner, programs of random mutagenesis in mice should also identify new candidate genes involved in thrombocytopenia.

Total laparoscopic bypass is safe and effective for aortoiliac occlusive disease.

OBJECTIVE: We reviewed our experience of total laparoscopic aortic bypass surgery performed for aortoiliac occlusive disease (AIOD), focusing on early 30-day mortality and morbidity and short-term and midterm outcomes. METHODS: A monocentric retrospective study was conducted between October 2002 and October 2011; we performed 173 total laparoscopic aortic surgeries to treat AIOD. RESULTS: Patients included 135 men and 38 women. The mean age was 57.2 years (range, 34-77 years). The median operative time was 205 minutes (range, 120-420 minutes), the median aortic clamping time was 50 minutes (range, 20-120 minutes), and the mean blood loss was 263 mL (range, 0-3200 mL). Conversion to open surgery was necessary in 12.1% of patients. The 30-day postoperative mortality rate was 2.3% (four of 173 patients). Major morbidity occurred in 6.9% of patients. Wound complications occurred in 8%. Four patients had a groin infection (2.3%), treated by surgical trimming in three patients and replacement of the prosthesis by venous bypass in one patient. Early graft thrombosis (within 30 days) occurred in one patient (0.6%), requiring reintervention. With a mean follow-up of 42 months (standard deviation, 37 months), 96% of bypasses were patent. Patency rates at 3 and 5 years were 97% and 85% respectively. CONCLUSIONS: In selected patients, laparoscopic aortic bypass surgery for AIOD is a safe procedure with an acceptable morbidity rate, short intensive care unit and hospital stay, fast recovery, and early return to general diet. It is a good indication after failure of endovascular surgery.

Incidence and outcomes of emergency department patients requiring emergency general surgery: a 5-year retrospective cohort study.

AIMS: Patients undergoing emergency general surgery are at high risk of complications and death. Our objectives were to estimate the incidence of emergency general surgery in a Swiss University Hospital, to describe the characteristics and outcomes of patients undergoing such procedures, and to study the impact of age on clinical outcomes. METHODS: This was a retrospective cohort study of adult patients who visited the emergency department (ED) of Geneva University Hospitals between January 2015 and December 2019. Routinely collected data were extracted from electronic medical records. The primary outcome was the incidence of emergency general surgery among patients visiting the emergency department, defined as general surgery within three days of emergency department admission. We also assessed demographic characteristics, mortality, intensive care unit admission and patient disposition. Multivariable log-binomial regression was used to study the associations of age with intensive care unit (ICU) admission, one-year mortality and dependence at discharge. Age was modelled as a continuous variable using restricted cubic splines and we compared older patients (75th percentile) with younger patients (25th percentile). RESULTS: Between January 2015 and December 2019, a total of 310,914 emergency department visits met our inclusion criteria. Among them, 3592 patients underwent emergency general surgery within 3 days of emergency department admission, yielding an annual incidence of 116 events per 10,000 emergency department visits (95% CI: 112-119), with a higher incidence in females and young patients. Overall, 5.3% of patients were admitted to ICU, 7.8% were dependent on rehabilitation or assisted living at discharge and 4.8% were dead after one year. Older patients had a higher risk of ICU admission (adjusted risk ratio (aRR) 2.9 [1.5-5.4]), dependence at discharge (aRR 15.3 [5.5-42.4]) and one-year mortality (aRR 5.4 [2.2-13.4]). CONCLUSION: Emergency department visits resulting in emergency general surgery are frequent, but their incidence decreases with patient age. Mortality, ICU admission and dependence at discharge following emergency general surgery are more frequent in older patients. Taking into account the increased risk for older patients, a shared process is appropriate for making more informed decisions about their options for care.

Anti-HLA Class I alloantibodies in platelet transfusion refractoriness: From mechanisms and determinants to therapeutic prospects.

Patients with hematological disorders and severe thrombocytopenia require extensive and iterative platelet transfusion support. In these patients, platelet transfusion refractoriness represents a serious adverse transfusion event with major outcomes for patient care. Recipient alloantibodies against the donor HLA Class I antigens expressed at the cell surface of platelets result in a rapid removal of transfused platelets from the circulation and thus, therapeutic and prophylactic transfusion failure leading to a major bleeding risk. In this case, the only way to support the patient relies on the selection of HLA Class I compatible platelets, an approach restricted by the limited number of HLA-typed donors available and the difficulty of meeting the demand in an emergency. However, not all patients with anti-HLA Class I antibodies develop refractoriness to platelet transfusions, raising the question of the intrinsic characteristics of the antibodies and the immune-mediated mechanisms of platelet clearance associated with a refractory state. In this review, we examine the current challenges in platelet transfusion refractoriness and detail the key features of the antibodies involved that should be considered. Finally, we also provide an overview of future therapeutic strategies.

A Unique Case of Perforated Appendicitis in a Giant Incarcerated Right-Sided Inguinal Hernia: Challenges and Surgical Management.

BACKGROUND Amyand hernia is a rare condition described as the presence of the appendix within an inguinal hernia. The clinical presentation of can be atypical, depending on the length of the defect's history and the size of the hernia. As inguinal hernia repair is considered a routine surgical procedure, giant hernias are mostly encountered in countries with limited medical care or with patient rejection of surgical management. CASE REPORT We report a case of a 56-year-old patient with a history of a chronic giant inguinal-scrotal hernia for more than 10 years who presented himself to the Emergency Department with acute pain in the scrotum and fever. Computed tomography revealed a perforated appendicitis located in the inferior part of the scrotum. The patient underwent a surgical procedure with an inguinal and middle laparotomy approach, revealing a full incarceration of the right and traverse colon, terminal ileal loop, and omentum, along with evidence of a perforated appendicitis. Standard appendectomy and direct hernia repair were successfully performed. CONCLUSIONS To the best of our knowledge, this is the first case of a perforated appendicitis within a right giant inguinal hernia described in the modern English-language literature. Rare in our daily practice, giant hernias are a real challenge regarding their surgical management during and after surgery, making this case with a perforated appendicitis even more arduous.

Reverse Abdominoplasty in a Patient Presenting with Subcostal Nephrectomy Scar and Transverse Muscle Incisional Hernia.

Abdominoplasty and its different approaches have been widely described to improve abdominal wall contour. However, the role of reverse abdominoplasty, a less commonly performed technique, and its indications are not fully understood. Recent advances in the understanding of the vascular supply to the anterior abdominal wall have made this technique more popular, but there is still limited information available in the literature. In this report, we present the case of a 52-year-old woman who underwent a reverse abdominoplasty using an existing subcostal scar from a previous nephrectomy. No surgical complications were observed, and the patient achieved both aesthetic and functional improvement after 6 months of follow-up. Reverse abdominoplasty can be a reliable option for maintaining adequate blood supply and achieving a satisfactory cosmetic result in cases where there is a pre-existing subcostal scar.

Discriminating young platelets on human leukocyte antigen-I expression highlights their extremely high reactivity potential.

Background: The platelet population is heterogeneous, with different subsets that differ on the basis of their function and reactivity. An intrinsic factor participating in this difference of reactivity could be the platelet age. The lack of relevant tools allowing a formal identification of young platelets prevents so far to draw solid conclusions regarding platelet reactivity. We recently reported that human leukocyte antigen-I (HLA-I) molecules are more expressed on human young platelets. Objectives: The aim of this study was to assess platelet reactivity according to their age based on HLA-I expression level. Methods: Platelet activation was assessed by flow cytometry (FC) for different platelet subsets based on their HLA-I expression. These populations were further cell sorted and their intrinsic properties were determined by FC and electron microscopy (EM). Statistical analyses were performed with GraphPad Prism 5.02 software using two-way ANOVA followed by a Tukey post hoc test. Results: HLA-I expression level allowed the identification of 3 platelet subpopulations regarding to their age (HLA low, dim, and high). HLA-I was reliable to guide platelet cell sorting and highlighted the features of young platelets in the HLA-Ihigh population. In response to different soluble agonists, HLA-Ihigh platelets were the most reactive subset as shown by the level of P-selectin secretion and fibrinogen binding assessed by flow cytometry. Moreover, the highest capacity of HLA-Ihigh platelets to simultaneously express annexin-V and von Willebrand factor or activated αIIbß3 after coactivation with TRAP and CRP indicated that the procoagulant feature of platelets was age-related. Conclusion: The young HLA-Ihigh population is the most reactive and prone to become procoagulant. These results open up new perspectives to investigate deeply the role of young and old platelets.

High-throughput microfluidic blood testing to phenotype genetically linked platelet disorders: an aid to diagnosis.

Linking the genetic background of patients with bleeding diathesis and altered platelet function remains challenging. We aimed to assess how a multiparameter microspot-based measurement of thrombus formation under flow can help identify patients with a platelet bleeding disorder. For this purpose, we studied 16 patients presenting with bleeding and/or albinism and suspected platelet dysfunction and 15 relatives. Genotyping of patients revealed a novel biallelic pathogenic variant in RASGRP2 (splice site c.240-1G>A), abrogating CalDAG-GEFI expression, compound heterozygosity (c.537del, c.571A>T) in P2RY12, affecting P2Y12 signaling, and heterozygous variants of unknown significance in the P2RY12 and HPS3 genes. Other patients were confirmed to have Hermansky-Pudlak syndrome type 1 or 3. In 5 patients, no genetic variant was found. Platelet functions were assessed via routine laboratory measurements. Blood samples from all subjects and day controls were screened for blood cell counts and microfluidic outcomes on 6 surfaces (48 parameters) in comparison with those of a reference cohort of healthy subjects. Differential analysis of the microfluidic data showed that the key parameters of thrombus formation were compromised in the 16 index patients. Principal component analysis revealed separate clusters of patients vs heterozygous family members and control subjects. Clusters were further segregated based on inclusion of hematologic values and laboratory measurements. Subject ranking indicated an overall impairment in thrombus formation in patients carrying a (likely) pathogenic variant of the genes but not in asymptomatic relatives. Taken together, our results indicate the advantages of testing for multiparametric thrombus formation in this patient population.