Thrombosis in Myeloproliferative Neoplasms: A Single Center Experience of Using Whole Blood Platelet Aggregation Studies for Risk Assessment and Thromboprophylaxis.

CONCLUSION: Routine use of WBPA studies enables safe and effective risk-adapted thromboprophylaxis in MPN patients, irrespective of the underlying driver mutation and their risk predicted by the IPSET- thrombosis criteria.

Comparison of proteolytic, cytotoxic and anticoagulant properties of chromatographically fractionated bromelain to un-fractionated bromelain.

Bromelain consisting of a number of proteolytic enzymes possess anticancer and thrombotic properties. Hence, four chromatically separated fractions were examined for their proteolytic, anticancer and antithrombotic activity. Bromelain fractions were separated using ion-exchange column chromatography. Proteolytic properties were assessed using standard azocasein assay. Anticancer properties were first assessed using four different cell lines PANC-1, HEP 2B, HEP 3G and OVCAR-3 on cells grown in 96 well plates. Subsequently, fraction 2 and fraction 3 combined with gemcitabine were tested in ASPC-1 cells. Then cytotoxicity of fraction 3 was compared to bromelain in combination with doxorubicin and N-acetylcysteine on HEP G2 and HEP 3B cells. Finally, the anticoagulation effect of fraction 3 or bromelain combined with N-acetylcysteine was evaluated using human blood. Fraction 3 showed the highest proteolytic activity (5% greater than standard bromelain) whilst others were less active. Cytotoxicity as assessed by IC50 indicated fraction 3 to be the most potent whilst the others did not follow their proteolytic potency order. OVCAR-3 was the most sensitive amongst the cell lines. Fraction 3 showed higher potency in combination with gemcitabine in ASPC-1 cells compared to fraction 2. Similarly, fraction 3 in combination with doxorubicin showed higher toxicity when compared to bromelain. Fraction 3 or bromelain only showed thrombolytic activity in combination with N-acetylcysteine. Fraction 3 may be developed for clinical use since it showed better cytotoxicity compared to bromelain.

A multicentre assessment of contemporary laboratory assays for heparin induced thrombocytopenia.

Heparin induced thrombocytopenia (HIT) is a rare but potentially fatal complication of heparin therapy. In some patients, HIT causes platelet activation and thrombosis (sometimes abbreviated HITT), which leads to adverse clinical sequalae ('pathological HIT'). The likelihood of HIT is initially assessed clinically, typically using a scoring system, of which the 4T score is that most utilised. Subsequent laboratory testing to confirm or exclude HIT facilitates exclusion or diagnosis and management. The current investigation comprises a multicentre (n=9) assessment of contemporary laboratory testing for HIT, as performed over the past 1-3 years in each site and comprising testing of over 1200 samples. The primary laboratory test used by study participants (n=8) comprised a chemiluminescence procedure (HIT-IgG(PF4-H)) performed on an AcuStar instrument. Additional immunological testing performed by study sites included lateral flow (STiC, Stago), enzyme linked immunosorbent assay (ELISA), Asserachrom (HPIA IgG), PaGIA (BioRad), plus functional assays, primarily serotonin release assay (SRA) or platelet aggregation methods. The chemiluminescence procedure yielded a highly sensitive screening method for identifying functional HIT, given high area under the curve (AUC, generally ≥0.9) in a receiver operator characteristic (ROC) analysis against SRA as gold standard. ELISA testing resulted in lower ROC AUC scores (<0.8) and higher levels of false positives. Although there is clear association with the likelihood of HIT, the 4T score had less utility than literature suggests, and was comparable to a previous study reported by some of the authors.

HIT or miss? A comprehensive contemporary investigation of laboratory tests for heparin induced thrombocytopenia.

Heparin induced thrombocytopenia (HIT) is a rare but potentially fatal complication of heparin therapy, which in a proportion of patients causes platelet activation and thrombosis. Initial clinical assessment of the likelihood of HIT is facilitated by laboratory testing to confirm or exclude HIT. This prospective investigation was performed over an 18-month period, and has involved testing of over 300 test samples from over 100 consecutive patients. Clinical assessment by 4T score was supplemented by laboratory tests that comprised both immunological [lateral flow ('STiC'), chemiluminescence (AcuStar; HIT-IgG(PF4-H)), ELISA (Asserachrom HPIA IgG)] and functional assays [SRA, platelet aggregation using whole blood ('Multiplate') and platelet rich plasma ('LTA')]. We observed both false positive and false negative test findings with most assays. Overall, the whole blood aggregation method provided a reasonable alternative to SRA for identifying functional HIT. STiC, AcuStar and ELISA procedures were fairly comparable in terms of screening for HIT, although STiC and AcuStar both yielded false negatives, albeit also resulting in fewer false positives than ELISA. The 4T score had less utility in our patient cohort than we were expecting, although there was an association with the likelihood of HIT. Nevertheless, we accept that our observations are based on limited test numbers. In conclusion, no single approach (clinical or laboratory) was associated with optimal sensitivity or specificity of HIT exclusion or identification, and thus, a combination of clinical evaluation and laboratory testing will best ensure the accuracy of diagnosis.