Dermatan Sulfate/Chitosan Nanoparticles Loaded with an Anti-Inflammatory Peptide Increase the Response of Human Colorectal Cancer Cells to 5-Fluorouracil.

The gold standard drug for colorectal cancer (CRC) treatment, 5-Fluorouracil (5-FU), induces pharmacological tolerance in long-term management. The transcriptional factor nuclear factor kappa-light-chain-enhancer of activated B cells (NFκB) plays a key role in 5-FU resistance. The aim of this work is to study the capability of polyelectrolytes complex nanoparticles of dermatan sulfate (DS) and chitosan (CS), loaded with the anti-inflammatory tripeptide IRW, to sensitize colorectal cancer cells to 5-FU. Fluorescence and flow cytometry studies confirmed the recognition by the nanoformulation, of the cluster of differentiation 44 (CD44) receptor, involved in the initiation and progression of colorectal tumors. Dynamic light scattering (DLS) and flow cytometry reinforced the importance of DS and CD44 receptor in the interaction, as the addition of DS or anti-CD44 antibody blocked the binding. Moreover, the nanoformulation also interacts with 3D colon cancer cultures, namely colonospheres, enriched in cancer stem cells (CSC), subpopulation responsible for drug resistance and metastasis. To evaluate the consequences of this interaction, the subcellular distribution of the transcriptional factor NFκB, is determined by immunofluorescence analysis. Internalization and the intracellular release of IRW inhibited nuclear translocation of NFκB and increased cellular sensitivity to 5-FU. Altogether, the nanoformulation could provide a selective delivery platform for IRW distribution to colorectal tumors, being an innovative strategy toward overcoming 5-FU resistance in CRC therapy.

Glycosaminoglycan signatures in body fluids of mucopolysaccharidosis type II mouse model under long-term enzyme replacement therapy.

Mucopolysaccharidosis type II (MPS II) is a neurometabolic disorder, due to the deficit of the lysosomal hydrolase iduronate 2-sulfatase (IDS). This leads to a severe clinical condition caused by a multi-organ accumulation of the glycosaminoglycans (GAGs/GAG) heparan- and dermatan-sulfate, whose elevated levels can be detected in body fluids. Since 2006, enzyme replacement therapy (ERT) has been clinically applied, showing efficacy in some peripheral districts. In addition to clinical monitoring, GAG dosage has been commonly used to evaluate ERT efficacy. However, a strict long-term monitoring of GAG content and composition in body fluids has been rarely performed. Here, we report the characterization of plasma and urine GAGs in Ids knock-out (Ids-ko) compared to wild-type (WT) mice, and their changes along a 24-week follow-up, with and without ERT. The concentration of heparan-sulfate (HS), chondroitin-sulfate (CS), and dermatan-sulfate (DS), and of the non-sulfated hyaluronic acid (HA), together with their differentially sulfated species, was quantified by capillary electrophoresis with laser-induced fluorescence. In untreated Ids-ko mice, HS and CS + DS were noticeably increased at all time points, while during ERT follow-up, a substantial decrease was evidenced for HS and, to a minor extent, for CS + DS. Moreover, several structural parameters were altered in untreated ko mice and reduced after ERT, however without reaching physiological values. Among these, disaccharide B and HS 2s disaccharide showed to be the most interesting candidates as biomarkers for MPS II. GAG chemical signature here defined provides potential biomarkers useful for an early diagnosis of MPS II, a more accurate follow-up of ERT, and efficacy evaluations of newly proposed therapies. KEY MESSAGES : Plasmatic and urinary GAGs are useful markers for MPS II early diagnosis and prognosis. CE-LIF allows GAG structural analysis and the quantification of 17 different disaccharides. Most GAG species increase and many structural features are altered in MPS II mouse model. GAG alterations tend to restore to wild-type levels following ERT administration. CS+DS/HS ratio, % 2,4dis CS+DS, and % HS 2s are potential markers for MPS II pathology and ERT efficacy.

ROS-triggered nanoinducer based on dermatan sulfate enhances immunogenic cell death in melanoma.

Due to its complexity, diversity and heterogeneity, melanoma is a kind of malignant tumor. It has been proved that the enhancement of anti-tumor immune response such as immunogenic cell death (ICD) is an important therapeutic strategy. In previous studies, we confirmed that dermatan sulfate (DS) from skin tissue could specifically homing to melanoma B16F10 cells. In this study, we propose a nanoinducer (DOX/ADS NP) based on a functional DS for melanoma. This nanosystem is composed of DS as framework, aromatic thioketal derivative (ATK) as functional grafting unit and doxorubicin (DOX) designed as an ICD inducer. Through the intermolecular interaction between DOX and ATK, DOX/ADS NP with specific-homing, high-loading and ROS-triggering release was obtained via self-assemble. Compared with free DOX and non-functionalized nanomedicine, DOX/ADS NP could release DOX into B16F10 cells better, and strongly induce the translocation of calreticulin (CRT) to the cell membrane. CRT is a marker of ICD, also as a "eat me" signal to stimulate the maturation and antigen presentation of dendritic cells. Therefore, a series of subsequent immune responses were activated: maturation of dendritic cells, T cells proliferation, increased tumor-infiltrating CTLs and the ratio of CTLs to Tregs, and up-regulated cytotoxic cytokine expression. In conclusion, DOX/ADS NP promoted ICD-associated immune response through more specific targeting effect and sensitive responsive DOX release, achieving better inhibitory effect on melanoma than free DOX and other nanoformulation. This biomimetic ICD nanoinducer based on DS is expected to provide new strategies and references for the treatment of melanoma.

[Danaparoid Sodium Controlled Chronic Disseminated Intravascular Coagulation Associated with Chronic Aortic Dissection and Patent False Lumen for a Long Term:Report of a Case].

The management of chronic disseminated intravascular coagulation( DIC) caused by aortic dissection has not yet been established. We report the successful treatment of a case of aortic dissection with a patent false lumen using danaparoid sodium for acute exacerbation of chronic DIC. 2,000 U danaparoid sodium per day has been stabilizing the coagulative and fibrinolytic parameters and has been relieving bleeding tendencies with no side effects for a long term.

Sigmoid Colon Varices due to Massive Thrombosis of a Noncirrhotic Extrahepatic Portosystemic Shunt.

A 33-year-old man presented with hepatic encephalopathy and was diagnosed to have a noncirrhotic extrahepatic portosystemic shunt (NCPSS). He presented with abdominal pain 16 months after the NCPSS diagnosis. Computed tomography revealed thrombosis between the intrahepatic portal vein and the left internal iliac vein, including the NCPSS, and varices of the sigmoid colon. Thrombosis was treated with danaparoid sodium and antithrombin III followed by edoxaban. After treatment, the thrombosis disappeared from the intrahepatic portal vein, but it remained in the NCPSS. The sigmoid colon varices were followed up without any treatment. Follow-up is needed in NCPSS patients in order to make an early detection of complications.

Comparison of Danaparoid Sodium and Synthetic Protease Inhibitors for the Treatment of Disseminated Intravascular Coagulation Associated with Hematological Malignancies: A Retrospective Analysis.

BACKGROUND: Danaparoid sodium and synthetic protease inhibitors (SPIs) have been approved for the treatment of disseminated intravascular coagulation (DIC) in Japan. OBJECTIVES: To compare the clinical results of the treatment of DIC with danaparoid or SPIs. METHODS: We retrospectively examined 188 patients with hematological malignancy-related DIC. RESULTS: DIC resolution rate in the danaparoid group was higher than that in the SPIs group (61.5 vs. 42.6%; p = 0.031) on day 7. Multivariate analysis identified the response to chemotherapy as independent predictive factor for DIC resolution on day 7 (odds ratio, OR, 2.28; 95% confidence interval, CI, 1.21-4.31; p = 0.011). While there was no significant difference in the DIC resolution rate on day 14 (75.0 vs. 62.4%; p = 0.117), in a subgroup analysis of patients who did not show an improvement in the underlying disease, the danaparoid group showed a significantly better DIC resolution rate (OR 3.89; 95% CI 1.15-13.2; p = 0.030). There was no difference in the rate of cumulative mortality from bleeding within 28 days between the 2 groups (6.6 vs. 3.3%; p = 0.278). CONCLUSIONS: Danaparoid may be associated with more frequent resolution of DIC in patients with refractory underlying disease.

Danaparoid is effective and safe for patients with obstetric antiphospholipid syndrome.

Objectives: The objective is to evaluate whether danaparoid is effective in improving the live birth rate in patients with obstetric antiphospholipid syndrome (oAPS).Methods: This prospective study included 91 pregnancies of 60 patients with oAPS diagnosed according to criteria of the International Congress on APS. Live birth rates, adverse pregnancies and perinatal outcomes were compared among patients treated with danaparoid and low dose aspirin (danaparoid group, LDA), unfractionated heparin (UFH) and LDA (UFH group) and LDA and/or prednisolone (LDA group).Results: After excluding 11 miscarriages with abnormal embryonic chromosomes, one chemical pregnancy and one ectopic pregnancy, live birth rates were 87.5% (14/16) for the danaparoid group, 90.0% (36/40) for the UFH group and 63.6% (14/22) for the LDA group, respectively. The live birth rates of patients treated with danaparoid and UFH were similar and tended to be higher than that of patients treated with LDA, respectively (OR 4.0, 95% confidence interval 0.72-22.22 and 5.15, 1.33-20.00). No patient given danaparoid and one patient with UFH developed heparin-induced thrombocytopenia which resulted in a stillbirth. Another patient with UFH suffered a lumbar compression fracture.Conclusion: Danaparoid is effective for improving the live birth rate and is safe for patients with oAPS.

Danaparoid sodium-based anticoagulation therapy for portal vein thrombosis in cirrhosis patients.

BACKGROUND: Portal vein thrombosis (PVT) is a common complication of cirrhosis. However, in patients with PVT and cirrhosis, there is no clear evidence supporting effective treatment modalities. In this study, we examined the effectiveness and safety of anticoagulation therapy using danaparoid sodium for PVT in patients with cirrhosis. METHODS: This retrospective study assessed 52 cirrhotic patients with PVT treated with danaparoid sodium for 2 weeks between November 2008 and September 2018. The primary outcome measure was the post-treatment status of PVT assessed by reduction in thrombus volume and safety of the therapeutic intervention. PVT status was evaluated with contrast-enhanced computed tomography (CECT). All patients received 1250 units of danaparoid sodium twice daily by intravenous injection for 14 days. Patients on antithrombin III (AT-III) combination therapy were additionally administered 1500 units of AT-III on days 1-5 and days 8-12. Effectiveness was evaluated by CECT from between days 13 and 18. The secondary outcome measure was the prognosis of PVT. RESULTS: All patients showed reduction in PVT volume without complications. Return of plasma AT-III level to > 70% during the treatment period contributes to ≥75% reduction of PVT volume. The prognosis in PVT patients depends on hepatic reserve capacity. When limited to Child-Pugh B and C liver cirrhosis patients, a ≥ 75% reduction of PVT volume improved the prognosis. CONCLUSIONS: Danaparoid sodium-based anticoagulation therapy was effective and safe for PVT in patients with cirrhosis. Return of plasma AT-III level to the normal range during the treatment period contributes to reduction of PVT volume. A reduction of ≥75% in PVT volume may improve the prognosis of Child-Pugh B and C decompensated cirrhosis patients with PVT.

Danaparoid use for haemodialysis in a morbidly obese patient with heparin-induced thrombocytopenia - Need for a higher than recommended weight-based dosing.

WHAT IS KNOWN AND OBJECTIVE: Heparin is widely used to prevent clotting of the extracorporeal circuit during haemodialysis (HD). Heparin-induced thrombocytopenia (HIT) is a potentially devastating immune mediated adverse drug reaction caused by the emergence of antibodies that activate platelets in the presence of heparin, leading to a pro-thrombotic state. Danaparoid is an alternative anticoagulant used in patients on HD with HIT but its dosing recommendations in obese patients on HD are relatively scarce. CASE SUMMARY: We report a case of a 48-year-old morbidly obese patient who received weight-based dosing of danaparoid for HD with monitoring of anti-Xa activity. However, despite the patient's anti-Xa level being within the therapeutic range at various time points, the circuit lines kept clotting during HD. WHAT IS NEW AND CONCLUSION: The report provides evidence that the manufacturer's recommendations on dosing danaparoid based on body weight may lead to sub-optimal therapeutic benefit and highlight the need for higher than recommended weight-based dosing in obese individuals on dialysis.

Heparinoids Danaparoid and Sulodexide as clinically used drugs.

Heparin is the first glycosaminoglycan ever identified. All the heparin-like glycosaminoglycans that are also isolated from animal tissues or any polysaccharides that mimic the biological activities of heparin are called heparinoids. Heparin is the mostly sulfated glycosaminoglycan made by mast cells and an essential anticoagulant drug in modern medicine. Heparin inhibits both thrombin generation and thrombin activity, releases tissue factor pathway inhibitor, and possesses anti-inflammatory, anti-viral, anti-angiogenesis, anti-neoplastic, and anti-metastatic properties though high affinity interactions with a variety of proteins in the blood circulation. The multi-pharmacological effects of heparin are both sequence- and sulfation degree dependent. Less sulfated heparinoids have been indicated to have more physiological functions than heparin. Since the anticoagulant heparin is associated with severe side effects, such as bleeding and heparin-induced thrombocytopenia and thrombosis, it is expected that the less sulfated heparinoids might serve as alternative drugs for patients who cannot use heparin. The crude heparin isolated from animal tissues contains ~50% heparin and ~50% less sulfated heparinoids. Indeed, the less sulfated waste heparinoids 1 during heparin production is chemically degraded and developed into the clinical drug Danaparoid and the more sulfated waste heparinoids 2 during heparin production is chemically degraded and developed into the clinical drug Sulodexide. Moreover, clinical studies indicate that Danaparoid and Sulodexide have the expected pharmacological activities. We will provide an update on the chemical characteristics and clinical use of the heparinoids Danaparoid and Sulodexide. In addition, the potential clinical applications of Danaparoid and Sulodexide in other therapeutic area will also be discussed.

American Society of Hematology 2018 guidelines for management of venous thromboembolism: heparin-induced thrombocytopenia.

BACKGROUND: Heparin-induced thrombocytopenia (HIT) is an adverse drug reaction mediated by platelet-activating antibodies that target complexes of platelet factor 4 and heparin. Patients are at markedly increased risk of thromboembolism. OBJECTIVE: These evidence-based guidelines of the American Society of Hematology (ASH) are intended to support patients, clinicians, and other health care professionals in their decisions about diagnosis and management of HIT. METHODS: ASH formed a multidisciplinary guideline panel balanced to minimize potential bias from conflicts of interest. The McMaster University GRADE Centre supported the guideline development process, including updating or performing systematic evidence reviews. The panel prioritized clinical questions and outcomes according to their importance for clinicians and patients. The Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach was used to assess evidence and make recommendations, which were subject to public comment. RESULTS: The panel agreed on 33 recommendations. The recommendations address screening of asymptomatic patients for HIT, diagnosis and initial management of patients with suspected HIT, treatment of acute HIT, and special situations in patients with acute HIT or a history of HIT, including cardiovascular surgery, percutaneous cardiovascular intervention, renal replacement therapy, and venous thromboembolism prophylaxis. CONCLUSIONS: Strong recommendations include use of the 4Ts score rather than a gestalt approach for estimating the pretest probability of HIT and avoidance of HIT laboratory testing and empiric treatment of HIT in patients with a low-probability 4Ts score. Conditional recommendations include the choice among non-heparin anticoagulants (argatroban, bivalirudin, danaparoid, fondaparinux, direct oral anticoagulants) for treatment of acute HIT.

Heparin-induced thrombocytopaenia.

Heparin-induced thrombocytopaenia (HIT) is a severe and potentially life-threatening adverse drug reaction. Patients become extremely hypercoagulable, and this can lead to life-threatening and limb-threatening thrombosis with a mortality of 5%-10%. HIT is an antibody-mediated process in which platelet activation occurs. Diagnosis requires a high index of suspicion along with a scoring system and laboratory testing. Patients suspected of having HIT must not receive any further heparin or low-molecular weight heparin and must be started on an alternative anticoagulant such as argatroban or danaparoid. Fondaparinux may also be considered but is not licenced for this indication.

Radioprotective Effects of Dermatan Sulfate in a Preclinical Model of Oral Mucositis-Targeting Inflammation, Hypoxia and Junction Proteins without Stimulating Proliferation.

Oral mucositis is the most frequently occurring early side effect of head-and-neck cancer radiotherapy. Systemic dermatan sulfate (DS) treatment revealed a significant radioprotective potential in a preclinical model of oral mucositis. This study was initiated to elucidate the mechanistic effects of DS in the same model. Irradiation comprised daily fractionated irradiation (5 × 3 Gy/week) over two weeks, either alone (IR) or in combination with daily dermatan sulfate treatment of 4 mg/kg (IR + DS). Groups of mice (n = 5) were sacrificed every second day over the course of 14 days in both experimental arms, their tongues excised and evaluated. The response to irradiation with and without DS was analyzed on a morphological (cell numbers, epithelial thickness) as well as on a functional (proliferation and expression of inflammation, hypoxia and epithelial junction markers) level. The mucoprotective activity of DS can be attributed to a combination of various effects, comprising increased expression of epithelial junctions, reduced inflammation and reduced hypoxia. No DS-mediated effect on proliferation was observed. DS demonstrated a significant mucositis-ameliorating activity and could provide a promising strategy for mucositis treatment, based on targeting specific, radiation-induced, mucositis-associated signaling without stimulating proliferation.

Danaparoid reduces transplant-related mortality in stem cell transplantation for children.

In SCT, death from transplant-related complications is the major obstacle hindering improvement of transplant outcomes, and proper supportive care is essential to reduce TRM. The transplant outcomes of 210 pediatric patients with malignant and non-malignant disorders who consecutively underwent SCT in our institution from 2000 to 2013 were analyzed. The transplant years were divided into three periods: A (2000-2004), B (2005-2008), and C (2009-2013), and an improvement in 5-year OS and a decrease in 5-year TRM were observed over these time periods; that is, OS was 61.5%, 60.3%, and 79.5% (P = .062), and TRM was 19.9%, 7.9%, and 0.0% (P < .001) in periods A, B, and C, respectively. On multivariate analysis, the prognostic factor for TRM for all patients was administration of danaparoid (HR = 0.109, 95% CI = 0.033-0.363, P < .001), and for patients with hematological malignancies in allogeneic SCT, the prognostic factors were danaparoid (HR = 0.046, 95% CI = 0.006-0.326, P = .002) and advanced disease at SCT (HR = 4.802, 95% CI = 1.734-13.30, P = .003). A reduction in TRM after SCT was observed over the time periods, and supportive care with danaparoid was found to be significantly effective in reducing TRM in SCT for children.

Use of Fondaparinux Off-Label or Approved Anticoagulants for Management of Heparin-Induced Thrombocytopenia.

BACKGROUND: Life-threatening heparin-induced thrombocytopenia (HIT) is treated with the alternative nonheparin anticoagulants argatroban, lepirudin, or danaparoid. Frequently, the pentasaccharide fondaparinux is used off-label. OBJECTIVES: The authors sought to investigate the safety and efficacy of the different anticoagulants for treating HIT. METHODS: In a national, multicenter registry study, hospitalized patients who were diagnosed with HIT, an at least intermediate clinical HIT-risk (4Ts score ≥4 points), and received treatment with ≥1 dose of the aforementioned anticoagulants were included. Main outcome measures were the incidences of HIT-specific complications (thromboembolic venous/arterial events, amputations, recurrent/persistent thrombocytopenia, skin lesions) and bleedings. RESULTS: Of 195 patients, 46 (23.6%), 4 (2.1%), 61 (31.3%), and 84 (43.1%) had been treated first-line with argatroban, lepirudin, danaparoid, and fondaparinux, respectively. The composite endpoint of HIT-specific complications (thromboembolic events, amputation, skin necrosis) occurred in 11.7% of patients treated with approved alternative anticoagulation and in 0.0% of fondaparinux-treated patients. The all-cause in-hospital mortality rates were 14.4% during approved alternative anticoagulation and 0.0% during fondaparinux treatment. Bleeding complications occurred in alternatively anticoagulated patients and in fondaparinux-treated patients in 6.3% and 4.8%, respectively. Post hoc analysis of clinical and laboratory features confirmed "true" HIT in at least 74 of 195 (38.0%) patients; 35 of 74 (47.3%) were treated with fondaparinux. CONCLUSIONS: Fondaparinux is effective and safe in suspected acute HIT; no HIT-specific complications occurred in the fondaparinux-treated patients, even among those with a high clinical HIT probability. Further data from randomized controlled trials are urgently needed because lepirudin was recalled from the market; danaparoid access has been limited and is not approved in the United States; and argatroban is contraindicated in patients with impaired liver function, and activated partial thromboplastin time confounding may interfere with monitoring. (Retrospective Registry of Patients With Acute Heparin-induced Thrombocytopenia Type II; NCT01304238).

Portal vein thrombosis in liver cirrhosis: incidence, management, and outcome.

BACKGROUND: Portal vein thrombosis (PVT) is a serious complication in liver cirrhosis with portal hypertension. We examined the treatment, recurrence and prognosis of PVT in cirrhotic patients. METHODS: The study subjects were all 90 cirrhotic patients with PVT treated with danaparoid sodium (DS) at our department between July 2007 and September 2016. The mean age was 68 years and mean Child-Pugh score was 7. All patients received 2500 U/day of DS for 2 weeks, and repeated in those who developed PVT recurrence after the initial therapy. RESULTS: Complete response was noted in 49% (n = 44), partial response (shrinkage ≥70%) in 33% (n = 30), and no change (shrinkage <70%) in 18% (n = 16) of the patients after the initial course of treatment. DS treatment neither caused adverse events, particularly bleeding or thrombocytopenia, nor induced significant changes in serum albumin, total bilirubin, prothrombin time, and residual liver function. Re-treatment was required in 44 patients who showed PVT recurrence and 61% of these responded to the treatment. The cumulative recurrence rates at 1 and 2 posttreatment years were 26 and 30%, respectively. The recurrence rates were significantly lower in patients with acute type, compared to the chronic type (p = 0.0141). The cumulative survival rates at 1 and 3 years after treatment (including maintenance therapy with warfarin) were 83 and 60%, respectively, and were significantly higher in patients with acute type than chronic type (p = 0.0053). CONCLUSION: We can expect prognostic improvement of liver cirrhosis by warfarin following two-week DS therapy for the treatment of PVT in patients with liver cirrhosis safety and effectiveness. An early diagnosis of PVT along with the evaluation of the volume of PVT on CT and an early intervention would contribute to the higher efficacy of the treatment.

[Heparin-induced thrombocytopenia type II (HIT II) : A medical-economic view]. / Die heparininduzierte Thrombozytopenie (HIT II) : Eine medizinökonomische Betrachtung.

BACKGROUND: In the context of inpatient and increasingly ambulatory thrombosis prophylaxis, heparins have been recognised as standard therapy for decades. In addition to the therapeutic benefit, therapy with heparins also entails the risk of undesirable side effects, such as bleeding and thrombocytopenia. Heparin-induced thrombocytopenia (HIT II) is deemed a serious side effect. AIM: In the following work, HIT II is subjected to a medico-economic consideration (treatment, pharmaceuticals, subsequent costs due to possible complications) and, with regard to a possible HIT II prophylaxis, aspects of increasingly respected patient safety are also considered. METHODS: In the context of a literature search the active ingredients argatroban and danaparoid, which are approved for HIT II treatment, were evaluated. RESULTS: HIT II - especially in combination with thromboembolic complications - represents a medical-economic burden for the hospital. Although this is only an orientation guide, it shows that HIT II syndrome is not adequately cost-covered by the G­DRG system. An early thrombosis prophylaxis with argatroban/danaparoid for HIT II risk patients should therefore be taken into account for medical-related as well as patient safety-relevant aspects. According to experience, the pharmaceutical supply for these medically needed products (anticoagulants) should be ensured for reasons of patient safety. CONCLUSION: The risk of an immunological response to heparin therapy is known. Within the context of increased patient safety, thrombosis prophylaxis should be issued with a risk-adjusted prophylaxis.

Cross-Reactivity Between Heparin and Danaparoid Antibodies in Cardiac Surgery.

Management of heparin-induced thrombocytopenia (HIT) entails cessation of heparin and initiation of a nonheparin parenteral anticoagulant such as danaparoid. Danaparoid cross-reactivity with HIT antibodies is an uncommon complication of treatment of HIT. We report the case of confirmed HIT and in vivo cross-reactivity with danaparoid, complicating severe sepsis due to an infectious endocarditis treated by cardiac surgery.

Persistent heparin-induced thrombocytopenia: danaparoid cross-reactivity or delayed-onset heparin-induced thrombocytopenia? A case report.

Clinical suspicion of immune heparin-induced thrombocytopenia (HIT) requires cessation of heparin and initiation of an alternative anticoagulant. The platelet count will subsequently recover. This case report describes the clinical course of a patient after a cardiovascular surgery. HIT was clinically and biologically confirmed. Unexpectedly, the platelet count did not recover despite the arrest of heparin. Danaparoid was initiated, and thrombocytopenia persisted. Danaparoid cross-reactivity was suspected, and laboratory assay was performed. Results were misinterpreted because no comparative buffer control was performed to ensure that the platelet aggregation was caused by danaparoid. Moreover, plasma/serum must be diluted to demonstrate this effect. Danaparoid cross-reactivity was incorrectly concluded, and the patient was switched to bivalirudin. The severe thrombocytopenia persisted. Plasmapheresis was started, and platelet count finally increased. The clinical course suggested a delayed-onset HIT. This case report illustrates the need for appropriate testing to differentiate drug cross-reactivity from delayed-onset HIT.