Melissa R. George

Hemophagocytic lymphohistiocytosis: review of etiologies and management

Hemophagocytic lymphohistiocytosis (HLH) covers a wide array of related life-threatening conditions featuring ineffective immunity characterized by an uncontrolled hyperinflammatory response. HLH is often triggered by infection. Familial forms result from genetic defects in natural killer cells and cytotoxic T-cells, typically affecting perforin and intracellular vesicles. HLH is likely under-recognized, which contributes to its high morbidity and mortality. Early recognition is crucial for any reasonable attempt at curative therapy to be made. Current treatment regimens include immunosuppression, immune modulation, chemotherapy, and biological response modification, followed by hematopoietic stem-cell transplant (bone marrow transplant). A number of recent studies have contributed to the understanding of HLH pathophysiology, leading to alternate treatment options; however, much work remains to raise awareness and improve the high morbidity and mortality of these complex conditions.

T-Cell Immunoglobulin and ITIM Domain (TIGIT) Associates with CD8+ T-Cell Exhaustion and Poor Clinical Outcome in AML Patients

Purpose: T-cell immunoglobulin and immunoreceptor tyrosine–based inhibitory motif (ITIM) domain (TIGIT) is a recently identified T-cell coinhibitory receptor. In this study, we aimed to determine the clinical impact of TIGIT in patients with acute myelogenous leukemia (AML) and dissect the role of TIGIT in the pathogenesis of leukemia progression. Experimental Design: TIGIT expression on T cells from peripheral blood collected from patients with AML was examined by flow cytometry. The correlation of TIGIT expression to clinical outcomes, including rate of complete remission and relapse post-allogeneic stem cell transplantation (alloSCT) in AML patients, was analyzed. Phenotypic and functional study (cytokine release, proliferation, killing, and apoptosis) of TIGIT-expressing T cells were performed. Using siRNA to silence TIGIT, we further elucidated the regulatory role of TIGIT in the T-cell immune response by dissecting the effect of TIGIT knockdown on cytokine release and apoptosis of T cells from AML patients. Results: TIGIT expression on CD8+ T cells is elevated in AML patients and high-TIGIT correlates with primary refractory disease and leukemia relapse post-alloSCT. TIGIT+ CD8+ T cells display phenotypic features of exhaustion and exhibit functional impairment manifested by low production of cytokines and high susceptibility to apoptosis. Importantly, their functional defects are reversed by TIGIT knockdown. Conclusions: TIGIT contributes to functional T-cell impairment and associates with poor clinical outcome in AML. Our study suggests that blockade of TIGIT to restore T-cell function and antitumor immunity may represent a novel effective leukemia therapeutic. Clin Cancer Res; 22(12); 3057–66. ©2016 AACR.

International normalized ratio versus plasma levels of coagulation factors in patients on vitamin K antagonist therapy.

CONTEXT The key question when managing patients on warfarin therapy who present with life-threatening bleeding is how to use the international normalized ratio (INR) to best direct corrective therapy. The corollary question for the clinical laboratory is at what level will the INR reflect a critical value that requires notifying the clinician. OBJECTIVE To determine the levels of vitamin K-dependent factors over a range of INR values. DESIGN Evaluation of the vitamin K-dependent coagulation factor levels on plasma remnants from patients in whom a prothrombin time and INR was ordered to monitor warfarin therapy. There were a total of 83 specimens evaluated with an INR range from 1.0 to 8.26. RESULTS The mean activity levels of all 4 factors remained near or above 50% when the INR was less than 1.5. The average factor X level was 23% when the INR range was 1.6 to 2.5, but levels of factors II, VII, and IX did not drop below the hemostatic range until the INR was greater than 2.5. At an INR of 3.6 or more, the activity levels of all 4 factors were less than 30% in more than 90% of the specimens. CONCLUSION Levels of factors II, VII, IX, and X declined with increasing INR but not at the same rate and not to the same level at a given INR. However, most of the values were below the hemostatic value once the INR was 3.6 or more, the level that was also considered critical for physician notification.

Description of a Formal Clinical Pathology On-Call Simulation Workshop in Preparing Pathology Residents to Address Common After-Hours Phone Calls

OBJECTIVES Residents take clinical pathology call beginning in the second year of residency. However, this additional responsibility often causes anxiety in residents who may have had only limited contact with laboratory sections they will be covering on call. We set out to improve the practical knowledge and comfort of the residents before taking clinical pathology call. METHODS A scenario-based simulation-style workshop was developed to acquaint residents with the common issues that arise, and guide them through acquiring the necessary data and developing an action plan. A nine-question survey was given before and after the workshop to determine if the workshop improved their comfort level with taking call. RESULTS Of the nine questions, the six questions dealing with clinical pathology laboratory section-specific knowledge showed that residents were less anxious and more confident about taking call after the workshop. CONCLUSIONS A scenario-based workshop is an effective way to acquaint residents with the basics of taking call, and teaches practical approaches to common clinical pathology issues.

Evaluation of different testing methods for identification of RhIG in red blood cell antibody detection

RhIG has had great success in protecting fetuses from potential harm; however, little work has been done to demonstrate how long RhIG reactivity is detected in the mother after administration when using common red blood cell antibody detection methods.

Platelet refractoriness in acquired hemophagocytic syndrome.

BACKGROUND: Acquired hemophagocytic syndrome (AHPS) is a severe inflammatory disorder often caused by Epstein‐Barr virus (EBV). Proliferation of activated macrophages produces uncontrolled cytokine production. Thrombocytopenia is common in AHPS, previously attributed to inadequate or ineffective marrow platelet (PLT) production. PLT transfusion response is not well reported. Two patients with fatal AHPS developed unexplained PLT transfusion refractoriness before definitive diagnosis.

Optimizing donor scheduling before recruitment: An effective approach to increasing apheresis platelet collections

Background/Aims Typical approach for increasing apheresis platelet collections is to recruit new donors. Here, we investigated the effectiveness of an alternative strategy: optimizing donor scheduling, prior to recruitment, at a hospital-based blood donor center. Methods Analysis of collections, during the 89 consecutive months since opening of donor center, was performed. Linear regression and segmented time-series analyses were performed to calculate growth rates of collections and to test for statistical differences, respectively. Results Pre-intervention donor scheduling capacity was 39/month. In the absence of active donor recruitment, during the first 29 months, the number of collections rose gradually to 24/month (growth-rate of 0.70/month). However, between month-30 and -55, collections exhibited a plateau at 25.6 ± 3.0 (growth-rate of -0.09/month) (p<0.0001). This plateau-phase coincided with donor schedule approaching saturation (65.6 ± 7.6% schedule booked). Scheduling capacity was increased by following two interventions: adding an apheresis instrument (month-56) and adding two more collection days/week (month-72). Consequently, the scheduling capacity increased to 130/month. Post-interventions, apheresis platelet collections between month-56 and -81 exhibited a spontaneous renewed growth at a rate of 0.62/month (p<0.0001), in absence of active donor recruitment. Active donor recruitment in month-82 and -86, when the donor schedule had been optimized to accommodate further growth, resulted in a dramatic but transient surge in collections. Conclusion Apheresis platelet collections plateau at nearly 2/3rd of the scheduling capacity. Optimizing the scheduling capacity prior to active donor recruitment is an effective strategy to increase platelet collections at a hospital-based donor center.

Development of Professionalism in Graduate Medical Education: A Case-Based Educational Approach From the College of American Pathologists’ Graduate Medical Education Committee

Professionalism and physician well-being are important topics in academic medicine. Lapses in professional judgment may lead to disciplinary action and put patient’s health at risk. Within medical education, students and trainees are exposed to professionalism in the institution’s formal curriculum and hidden curriculum. Development of professionalism starts early in medical school. Trainees entering graduate medical education already have developed professional behavior. As a learned behavior, development of professional behavior is modifiable. In addition to role modeling by faculty, other modalities are needed. Use of case vignettes based on real-life issues encountered in trainee and faculty behavior can serve as a basis for continued development of professionalism in trainees. Based on the experience of program directors and pathology educators, case vignettes were developed in the domains of service, research, and education and subdivided into the areas of duty, integrity, and respect. General and specific questions pertaining to each case were generated to reinforce model behavior and overcome professionalism issues encountered in the hidden curriculum. To address physician burnout, cases were generated to provide trainees with the skills to deal with burnout and promote well-being.

Advanced platelet parameters: underutilized tools in the diagnosis and management of thrombopoietic states?: EDITORIAL

I n this issue of TRANSFUSION, Stefaniuk and colleagues present a case report entitled “Dynamic changes in absolute immature platelet count suggest the presence of a co-existing immune process in the setting of thrombotic thrombocytopenic purpura.” Despite many advances in the understanding of thrombotic thrombocytopenia purpura (TTP), the diagnosis has been largely based on clinical parameters of microangiopathic hemolytic anemia (MAHA) in the setting of thrombocytopenia. While low levels of ADAMTS13 activity and presence of an ADAMTS13 inhibitor are useful and often diagnostic, treatment cannot wait for the return of these results, nor are repeat measurements generally available in real-time to better guide the course of therapy. This problem often leads to overdiagnosis of TTP and empirical initiation of therapeutic plasma exchange (TPE). Therapeutic response in the management of TTP has ultimately been based on an increase in platelet count, most specifically, a sustained normalization of platelet count over 150 x 10/L for at least 2 days. As any provider who treats TTP knows, these criteria for treatment response can be unreliable as rising platelet counts may be deceptive and patients can sometimes show a decline after an initially promising response. It would be useful for providers to have more clinically accessible and timely parameters on which to base diagnosis and assess response to TPE. A growing body of literature is demonstrating the clinical utility of advanced platelet parameters from automated hematology analyzers to discern among thrombocytopenic conditions, increasing diagnostic accuracy and optimizing therapy. Stefaniuk’s article focuses on the absolute immature platelet count (A-IPC); a novel parameter that is calculated as the product of the total platelet count and immature platelet fraction (IPF) measured on a Sysmex XN series automated hematology analyzer. On this instrument, the IPF is determined by simultaneous measurements of forward scatter and side-fluorescence signal intensity of oxazine dye-labeled platelets utilizing semiconductor laser flow cytometry. The oxazine dye binds to RNA and mitochondrial DNA (mtDNA) in platelets and immature platelets are defined by the combination of high forward scatter and high fluorescence signal intensity measurements. Accordingly, IPF corresponds to the fraction of total platelets in circulating blood that represent large platelets with high RNA and mtDNA content that have also been referred to as “reticulated platelets” emphasizing the similarity between percent reticulocytes and IPF as measures of immature RBC and platelets, respectively, that have just emerged from the bone marrow. As with immune-mediated RBC destruction where there is anemia with a compensatory increase in reticulocyte production, immune-mediated thrombocytopenias are associated with high IPF values. A-IPC in many ways represents the equivalent of the absolute reticulocyte count as a measure of compensatory platelet production in the setting of increased peripheral platelet destruction. However, whereas the presence of antibodies to RBC surface membrane antigens can distinguish between immunemediated and other causes of increased peripheral RBC destruction, there is no reliable equivalent to the Coomb’s test to make this distinction for platelets. Thus, the A-IPC is elevated in conditions of both immune-mediated platelet destruction and abnormal platelet activation in TTP 4,5 and it is very challenging to distinguish between these different causes of increased platelet destruction based on measurements of A-IPC alone. Laying the groundwork for this issue’s article, Hong and colleagues demonstrated a positively skewed bell curve in A-IPC production in idiopathic TTP patients, showing a negative feedback loop correlating with response to TPE. In Hong’s study, at the onset of idiopathic TTP, patients had reduced platelet count, increased %-IPF, and significantly reduced A-IPC, as opposed to healthy controls and non-TTP MAHA patients. A cut-off value of A-IPC less than 5 x 10/L had a sensitivity of 84.6% and specificity of 80%, and PPV of 91.7% for detection of TTP. These results may be useful in distinguishing between MAHA types, especially in the setting of moderate rather than severe ADAMTS13 deficiency. These parameters are particularly beneficial in that they are cost-effective, readily and quickly available, as opposed to ADAMTS13 testing. In the present case report, the authors follow the complicated case of a 17-year-old female with presumed idiopathic TTP with strong supporting evidence including ADAMTS13 activity less than 5% and a high ADAMTS13 inhibitor titer of 8. The authors appropriately initiated treatment with corticosteroids and TPE and followed the patient’s A-IPC daily while on treatment. They noted that an A-IPC ratio (A-IPC on treatment/A-IPC before treatment) greater than 3 was achieved while doi:10.1111/trf.14044