Bone Marrow Transplantation (2019) 54:1022–1028 https://doi.org/10.1038/s41409-018-0374-3 ARTICLE Clinical and morphological practices in the diagnosis of transplant- associated microangiopathy: a study on behalf of Transplant Complications Working Party of the EBMT 1 2 3 4 5 Ivan S. Moiseev ● Tatyana Tsvetkova ● Mahmoud Aljurf ● Randa M Alnounou ● Janet Bogardt ● 6 7 7 8 9 Yves Chalandon ● Mikhail Yu. Drokov ● Valentina Dvirnyk ● Maura Faraci ● Lone Smidstrup Friis ● 10 11 12 13 14 Fabio Giglio ● Hildegard T. Greinix ● Brian Thomas Kornblit ● Christiane Koelper ● Christian Koenecke ● 15 16 17 18 19 Krzysztof Lewandowski ● Dietger Niederwieser ● Jakob R. Passweg ● Christophe Peczynski ● Olaf Penack ● 20 21 22 23 24 Zinaida Peric ● Agnieszka Piekarska ● Paola Erminia Ronchi ● Alicia Rovo ● Piotr Rzepecki ● 8 25 26 13 27 Francesca Scuderi ● Daniel Sigrist ● Sanna M. Siitonen ● Friedrich Stoelzel ● Kazimierz Sulek ● 28 29 30 31 32 Dimitrios A. Tsakiris ● Urszula Wilkowojska ● Rafael F Duarte ● Tapani Ruutu ● Grzegorz W Basak Received: 29 August 2018 / Revised: 25 September 2018 / Accepted: 2 October 2018 / Published online: 25 October 2018 © Springer Nature Limited 2018 Abstract 1234567890();,: 1234567890();,: Transplant-associated thrombotic microangiopathy (TA-TMA) is a life-threatening complication of allogeneic hematopoietic stem cell transplantation (HSCT). This study evaluated clinical and morphological practices of TA-TMA diagnosis in EBMT centers. Two questionnaires, one for transplant physician and one for morphologist, and also a set of electronic blood slides from 10 patients with TA-TMA and 10 control patients with various erythrocyte abnormalities, were implemented for evaluation. Seventeen EBMT centers participated in the study. Regarding criteria used for TA-TMA diagnosis, centers reported as follows: 41% of centers used the International Working Group (IWG) criteria, 41% used “overall TA-TMA” criteria and 18% used physician’s decision. The threshold of schistocytes to establish TA-TMA diagnosis in the participating centers was significantly associated with morphological results of test cases evaluations (p = 0.002). The mean number of schistocytes reported from blood slide analyses were 4.3 ± 4.5% for TA-TMA cases (range 0–19.6%, coefficient of variation (CV) 0.7) and 1.3 ± 1.6% for control cases (range 0–8.3%, CV 0.8). Half of the centers reported schistocyte levels below 4% for 7/10 TA-TMA cases. The intracenter variability was low, indicating differences in the institutional practices of morphological evaluation. In conclusion, the survey identified the need for the standardization of TA-TMA morphological diagnosis. Introduction other organ involvement, hypertension and complement activation in the subset of patients [1, 2]. This complication, Transplant-associated thrombotic microangiopathy (TA- despite broadened understanding of its pathogenesis [3] and TMA) is a complication of hematopoietic stem cell trans- the significant improvement in the supportive care, may be plantation (HSCT) characterized by microangiopathic associated with a high mortality exceeding 50% [4, 5]. hemolytic anemia, renal and neurologic dysfunction, or Unfortunately, even recent patient cohorts with this com- plication have relatively poor outcome [6]. A number of novel therapies are currently investigated for the treatment of this syndrome, including complement inhibitors and These authors contributed equally: Tapani Ruutu, Grzegorz W. Basak coagulation modulators [7–9]. Thus, timely and accurate Electronic supplementary material The online version of this article diagnosis of TA-TMA is of vital importance. (https://doi.org/10.1038/s41409-018-0374-3) contains supplementary Due to significant variability of clinical and laboratory material, which is available to authorized users. presentation and overlap with the symptoms of other HSCT * Ivan S. Moiseev complications, the diagnosis of TA-TMA is difficult. Before [email protected] the introduction of consensus statement criteria by Blood Extended author information available on the last page of the article. and Marrow Transplant Clinical Trials Network (BMT Clinical and morphological practices in the diagnosis of transplant-associated microangiopathy: a study. 1023 CTN) [10] and International Working Group/European the differential diagnosis of different entities. A set of digita- Leukemia Net (IWG/ELN) [11], the reported incidence of lized blood slides of 20 patients including 20 (40-fold mag- TA-TMA varied significantly from 6 to 31% [12–15]. nification) pictures per case was provided for evaluation. The However, the variability in the reported incidence has not blood slide set comprised 10 cases with TA-TMA and 10 been reduced after the publication of criteria and still controls. TA-TMA cases were diagnosed based on Interna- reaches 5 to 29% [16–18]. Also, another definition of tional Working Group/European Leukemia Net (IWG/ELN) “overall TA-TMA” was formulated by Cho et al. [19]andis criteria between 2008 and 2013 at Pavlov First Saint Peters- used in several centers. The variability of the reported burg State Medical University or Helsinki University Hospital. incidences might be due to the different criteria used, risk The 10 control blood slides were from patients with other factors like the intensity of the conditioning or graft-versus- HSCT complications (acute GVHD, hemorrhagic cystitis, host disease (GVHD) prophylaxis with a combination of veno-occlusive disease), autoimmune hemolytic anemia calcineurin and mammalian target of rapamycinm inhibitors (AIHA), untreated myelofibrosis, myelodysplastic syndrome [20] and, on the other hand, it might be related to variability and B12 deficiency anemia (Supplement 1, Table 1S). All in the practices of diagnosis. digital images study materials are available in Supplement 2. The most subjective laboratory measure in the TA- The cases were placed in a random order and blinded to the TMA criteria is the morphological evaluation of frag- investigators. The number of schistocytes and comments for mented erythrocytes. Although currently existing recom- each case were requested. The number of erythrocytes in each mendations by the International Council for picture was pre-calculated and placed in excel file with auto- Standardization in Haematology (ICSH) provide adequate matic calculation of percentage after filling in the number of guidance for the morphological diagnosis in other throm- schistocytes observed in each digital image. For each case, 2– botic microangiopathies [21], it does not contain recom- 5digitalimagesaccordingtothedensityofthebloodslides mendations for microangiopathies occurring after HSCT. were mandatory for evaluation and included a total of 1000 Aspects like significant poikilocytosis, dysplasia or dys- erythrocytes, and the rest 15–18 were optional. The study erythropoiesis due to underlying hematologic disorder, materials were circulated in 17 EBMT transplantation centers, autoimmune or alloimmune hemolysis are not covered in including 3 in Switzerland, 3 in Germany, 3 in Poland, 2 in these recommendations. There is a lack of agreement Italy,2inRussia,1inHelsinki,1inDenmark,1inAustria regarding the value of the number or percentage of and 1 in Saudi Arabia. 6/17 centers were JACIE (Joint schistocytes in the diagnosis of TA-TMA. According to Accreditation Committee of the ISCT and the EBMT)- the Zini et al. [22], TA-TMA should be suspected when accredited. the level of fragmented erythrocytes is above 1%; how- ever, Lesesve et al. [23] reported that the mean number of Statistical analysis schistocytes after allogeneic HSCT without TA-TMA is already about 0.8%, and is slightly higher after myeloa- Descriptive statistics were to evaluate the questionnaire blative conditioning. Thus, the margin between TA-TMA answers and the number of schistocytes from evaluations and non-TA-TMA patients is very narrow, and might be of the blood slides. The mixed model was used to assess additionally blurred by the other complications of HSCT. the association between the answers in the questionnaires The present multicenter study was conducted within the and the number of schistocytes reported. Mixed model European Society for Blood and Marrow Transplantation explained percentage of schistocytes by considering (EBMT) to evaluate the practices of TA-TMA diagnosis. question as a fixedeffect,adjustedbyanotherfixed effect, Type (TA-TMA vs Control), and by adding a random effect for Question by Center. The intra-class Methods coefficient for the schistocyte within the center was 0.29 (0.16–0.54). The level of significancewassetat0.05for This multicenter study was conducted between 2015 and all tests. 2017. The centers that agreed to participate in the study received two questionnaires: one for transplant physician and one for morphologist. The questionnaire for transplant physi- Results cian included 8 questions seeking for the parameters and guidelines used to diagnose TA-TMA in the center, and three Clinical and morphological practices in the diagnosis bibliography references were provided at the end of the of TA-TMA questionnaire summarizing the current consensus on TA- TMA. The morphologists’ questionnaire included 16 ques- The transplantation physicians in 94% of the centers used tions assessing morphology concepts and its application for diagnostic criteria for the diagnosis of TA-TMA, while in 1024 I. S. Moiseev et al. 6% this complication was diagnosed based on physician decision. In 41% of centers IWG criteria are used to establish the diagnosis