Revision and Update of the Consensus Definitions of Invasive Fungal Disease From the European Organization for Research and Treatment of Cancer and the Mycoses Study Group Education and Research Consortium.

BACKGROUND: Invasive fungal diseases (IFDs) remain important causes of morbidity and mortality. The consensus definitions of the Infectious Diseases Group of the European Organization for Research and Treatment of Cancer and the Mycoses Study Group have been of immense value to researchers who conduct clinical trials of antifungals, assess diagnostic tests, and undertake epidemiologic studies. However, their utility has not extended beyond patients with cancer or recipients of stem cell or solid organ transplants. With newer diagnostic techniques available, it was clear that an update of these definitions was essential. METHODS: To achieve this, 10 working groups looked closely at imaging, laboratory diagnosis, and special populations at risk of IFD. A final version of the manuscript was agreed upon after the groups' findings were presented at a scientific symposium and after a 3-month period for public comment. There were several rounds of discussion before a final version of the manuscript was approved. RESULTS: There is no change in the classifications of "proven," "probable," and "possible" IFD, although the definition of "probable" has been expanded and the scope of the category "possible" has been diminished. The category of proven IFD can apply to any patient, regardless of whether the patient is immunocompromised. The probable and possible categories are proposed for immunocompromised patients only, except for endemic mycoses. CONCLUSIONS: These updated definitions of IFDs should prove applicable in clinical, diagnostic, and epidemiologic research of a broader range of patients at high-risk.

Thyroid dysfunctions in adult patients after allogeneic hematopoietic stem cell transplantation.

INTRODUCTION: Thyroid dysfunction (TD) is one of the major endocrinopathies shown after allogeneic hematopoietic stem cell transplantation over the long term. The incidence and the risk factors for TD have varied widely. PATIENTS AND METHODS: Two hundred and fifty-nine patients with pre-transplant normal thyroid function tests who survived at least 1 year after allo-HSCT between 2006-2016 were included in the study. RESULTS: Sixty-four patients (25%) developed TD at median of 34 months (range, 1-112 months). Hypothyroidism was detected in 32 patients (12%): 5 patients had primary hypothyroidism, and subclinical hypothyroidism occurred in 27 patients. 18 patients (7%) were diagnosed with hyperthyroidism: 2 patients (0.07%) were treated for primary hyperthyroidism, and 16 patients (6%) were followed for subclinical hyperthyroidism. Euthyroid sick syndrome occurred in 14 cases. None of the patients with thyroid dysfunction developed secondary thyroid malignancy. Receiving high-dose TBI (P = .001) was found to be significant risk for hypothyroidism; older age than median (P = .01) and pre-transplant active disease (P < .0001) were related to hyperthyroidism. CONCLUSIONS: Thyroid dysfunction, mostly hypothyroidism, is a long-term complication after allo-HSCT in 25% of patients. Older age, pre-transplant active disease, and receiving TBI are among the risk factors. Sustained long-term monitoring of thyroid function test should be considered post allo-HSCT.

Toxoplasmosis in Transplant Recipients, Europe, 2010-2014.

Transplantation activity is increasing, leading to a growing number of patients at risk for toxoplasmosis. We reviewed toxoplasmosis prevention practices, prevalence, and outcomes for hematopoietic stem cell transplant (HSCT) and solid organ transplant (SOT; heart, kidney, or liver) patients in Europe. We collected electronic data on the transplant population and prevention guidelines/regulations and clinical data on toxoplasmosis cases diagnosed during 2010-2014. Serologic pretransplant screening of allo-hematopoietic stem cell donors was performed in 80% of countries, screening of organ donors in 100%. SOT recipients were systematically screened in 6 countries. Targeted anti-Toxoplasma chemoprophylaxis was heterogeneous. A total of 87 toxoplasmosis cases were recorded (58 allo-HSCTs, 29 SOTs). The 6-month survival rate was lower among Toxoplasma-seropositive recipients and among allo-hematopoietic stem cell and liver recipients. Chemoprophylaxis improved outcomes for SOT recipients. Toxoplasmosis remains associated with high mortality rates among transplant recipients. Guidelines are urgently needed to standardize prophylactic regimens and optimize patient management.

Antimicrobial Resistance in Gram-Negative Rods Causing Bacteremia in Hematopoietic Stem Cell Transplant Recipients: Intercontinental Prospective Study of the Infectious Diseases Working Party of the European Bone Marrow Transplantation Group.

BACKGROUND: This intercontinental study aimed to study gram-negative rod (GNR) resistance in hematopoietic stem cell transplantation (HSCT). METHODS: GNR bacteremias occurring during 6 months post-HSCT (February 2014-May 2015) were prospectively collected, and analyzed for rates and risk factors for resistance to fluoroquinolones, noncarbapenem anti-Pseudomonas ß-lactams (noncarbapenems), carbapenems, and multidrug resistance. RESULTS: Sixty-five HSCT centers from 25 countries in Europe, Australia, and Asia reported data on 655 GNR episodes and 704 pathogens in 591 patients (Enterobacteriaceae, 73%; nonfermentative rods, 24%; and 3% others). Half of GNRs were fluoroquinolone and noncarbapenem resistant; 18.5% carbapenem resistant; 35.2% multidrug resistant. The total resistance rates were higher in allogeneic HSCT (allo-HSCT) vs autologous HSCT (auto-HSCT) patients (P < .001) but similar in community-acquired infections. Noncarbapenem resistance and multidrug resistance were higher in auto-HSCT patients in centers providing vs not providing fluoroquinolone prophylaxis (P < .01). Resistance rates were higher in southeast vs northwest Europe and similar in children and adults, excluding higher fluoroquinolone- and ß-lactam/ß-lactamase inhibitor resistance rates in allo-HSCT adults. Non-Klebsiella Enterobacteriaceae were rarely carbapenem resistant. Multivariable analysis revealed resistance risk factors in allo-HSCT patients: fluoroquinolone resistance: adult, prolonged neutropenia, breakthrough on fluoroquinolones; noncarbapenem resistance: hospital-acquired infection, breakthrough on noncarbapenems or other antibiotics (excluding fluoroquinolones, noncarbapenems, carbapenems), donor type; carbapenem resistance: breakthrough on carbapenem, longer hospitalization, intensive care unit, previous other antibiotic therapy; multidrug resistance: longer hospitalization, breakthrough on ß-lactam/ß-lactamase inhibitors, and carbapenems. Inappropriate empiric therapy and mortality were significantly more common in infections caused by resistant bacteria. CONCLUSIONS: Our data question the recommendation for fluoroquinolone prophylaxis and call for reassessment of local empiric antibiotic protocols. Knowledge of pathogen-specific resistance enables early appropriate empiric therapy. Monitoring of resistance is crucial. CLINICAL TRIALS REGISTRATION: NCT02257931.

Epidemiology and outcome of fungemia in a cancer Cohort of the Infectious Diseases Group (IDG) of the European Organization for Research and Treatment of Cancer (EORTC 65031).

BACKGROUND: Anti-cancer treatment and the cancer population have evolved since the last European Organisation for Research and Treatment of Cancer (EORTC) fungemia survey, and there are few recent large epidemiological studies. METHODS: This was a prospective cohort study including 145 030 admissions of patients with cancer from 13 EORTC centers. Incidence, clinical characteristics, and outcome of fungemia were analyzed. RESULTS: Fungemia occurred in 333 (0.23%; 95% confidence interval [CI], .21-.26) patients, ranging from 0.15% in patients with solid tumors to 1.55% in hematopoietic stem cell transplantation recipients. In 297 evaluable patients age ranged from 17 to 88 years (median 56 years), 144 (48%) patients were female, 165 (56%) had solid tumors, and 140 (47%) had hematological malignancies. Fungemia including polymicrobial infection was due to: Candida spp. in 267 (90%), C. albicans in 128 (48%), and other Candida spp. in 145 (54%) patients. Favorable overall response was achieved in 113 (46.5%) patients by week 2. After 4 weeks, the survival rate was 64% (95% CI, 59%-70%) and was not significantly different between Candida spp. Multivariable logistic regression identified baseline septic shock (odds ratio [OR] 3.04, 95% CI, 1.22-7.58) and tachypnoea as poor prognostic factors (OR 2.95, 95% CI, 1.66-5.24), while antifungal prophylaxis prior to fungemia (OR 0.20, 95% CI, .06-.62) and remission of underlying cancer (OR, 0.18; 95% CI, .06-.50) were protective. CONCLUSIONS: Fungemia, mostly due to Candida spp., was rare in cancer patients from EORTC centers but was associated with substantial mortality. Antifungal prophylaxis and remission of cancer predicted better survival.

Recommendations for the Treatment of Invasive Fungal Infections in Hematological Malignancies: A Critical Review of Evidence and Turkish Expert Opinion (TEO-1).

The introduction of novel antifungal agents for the treatment of invasive fungal disease in hematological malignancies and also changing treatment strategies have had a great impact in managing affected patients. The medical literature includes some important clinical studies that are being used as evidence for guidelines. The problem with these studies and the guidelines is that they are not very easy to interpret, they include controversial issues, and they are not easy to apply to every patient or country. This paper was designed to critically show the main problems associated with these approaches and provide important information that will help Turkish doctors to adopt them in daily clinical practice.

Diagnosis of Invasive Fungal Diseases in Hematological Malignancies: A Critical Review of Evidence and Turkish Expert Opinion (TEO-2).

One of the most problematic issues in hematological malignancies is the diagnosis of invasive fungal diseases. Especially, the difficulty of mycological diagnosis and the necessity of immediate intervention in molds have led to the adoption of "surrogate markers" that do not verify but rather strongly suggest fungal infection. The markers commonly used are galactomannan (GM), beta-glucan, and imaging methods. Although there are numerous studies on these diagnostic approaches, none of these markers serve as a support for the clinician, as is the case in human immunodeficiency virus (HIV) or cytomegalovirus (CMV) infections. This paper has been prepared to explain the diagnostic tests. As molecular tests have not been standardized and are not used routinely in the clinics, they will not be mentioned here.

Preventing invasive fungal disease in patients with haematological malignancies and the recipients of haematopoietic stem cell transplantation: practical aspects.

Invasive fungal disease (IFD), predominantly aspergillosis, is associated with significant morbidity and mortality in immunocompromised patients, especially those with haematological malignancies and recipients of allogeneic haematopoietic stem cell transplantation. There has been a great deal of scientific debate as to the effectiveness of antifungal prophylaxis in preventing infection in different patient groups and in which patients it is an appropriate management option. Deciding on an appropriate prophylaxis regimen for IFD is challenging as the incidence varies among different patient groups, due to the varied nature of their underlying haematological disease, and in different regions and centres. Attempts have been made to define risk factors and include them in treatment protocols. Impaired immune status of the patient, especially neutropenia, is a key risk factor for IFD and can sometimes be related to specific polymorphisms of genes controlling innate immunity. Risk factors also vary according to the type of fungal pathogen. Consequently, prophylaxis needs to be tailored to individual patient groups. Furthermore, the choice of antifungal agent for prophylaxis depends on the potential for drug-drug interactions with the patients' concomitant medications. Additional challenges are optimal timing of antifungal prophylaxis, when to change from prophylaxis to antifungal treatment and how to prevent recurrence of IFD. This article considers the use of antifungal prophylaxis for patients at risk of IFD in daily clinical practice, with clinical profiles that may be distinct from those covered by guidelines, and aims to provide practical advice for treatment of these patient groups.

Secondary infections in cancer patients with febrile neutropenia.

OBJECTIVE: Patients with neutropenia due to cancer chemotherapy are prone to severe infections. Cancer patients canexperience >1 infectious episode during the same period of neutropenia. This study aimed to determine the etiologicaland clinical characteristics of secondary infectious episodes in cancer patients with febrile neutropenia and to identifythe factors associated with the risk of secondary infectious episodes. MATERIAL AND METHODS: All cancer patients that received antineoplastic chemotherapy at Ankara University, School ofMedicine, Department of Hematology between May 2004 and May 2005 and developed neutropenia were included in thestudy. Data were collected using survey forms that were completed during routine infectious diseases consultation visits.Categorical data were analyzed using the chi-square test, whereas Student's t-test was used for continuous variables.Multivariate logistic regression analysis was performed to identify independent predictors of secondary infections (SIs). RESULTS: SIs were observed during 138 (53%) of 259 febrile neutropenic episodes. Of the 138 episodes, 89 (64.5%)occurred in male patients with a mean age of 40.9 years (range: 17-76 years). In total, 80% of the SIs were clinically ormicrobiologically documented. Factors on d 4 of the initial febrile episode were analyzed via a logistic regression model. The presence of a central intravenous catheter (OR: 3.01; P<0.001), acute myeloid leukemia (AML) as the underlyingdisease (OR: 2.12; P=0.008), diarrhea (OR: 4.59; P=0.005), and invasive aspergillosis (IA) during the initial febrileepisode (OR: 3.96; P=0.009) were statistically significant risk factors for SIs. CONCLUSION: Among the cancer patients with neutropenia in the present study, AML as the underlying disease, thepresence of a central venous catheter, diarrhea, and IA during the initial febrile episode were risk factors for thedevelopment of SIs.

Antifungal prophylaxis in stem cell transplantation centers in Turkey.

OBJECTIVE: This study aimed to determine the current state of antifungal prophylaxis in Turkish stem cell transplantation (SCT) centers. METHODS: he were 38 active stem cell transplantation centers in Turkey, 28 of which were registered with the European Group for Blood and Marrow Transplantation (EBMT). Survey questionnaires were sent to the 28 EBMT centers in an effort to collect data on antifungal prophylaxis in different settings. In all, 24 of the centers completed the survey; 1 of the 24 centers was excluded from the study, as it was under construction at the time and was not performing transplantation. RESULTS: In all, 15 (65%) of the 23 centers were adult SCT centers, 7 (31%) were pediatric SCT centers, and 1 center treated both adult and pediatric patients. All centers (23/23) performed both allogeneic and autologous transplants, 20 centers performed non-myeloablative transplants, 8 performed cord blood transplants, and 7 performed unrelated transplants. Primary antifungal prophylaxis was used at all 23 centers during allogeneic transplants, whereas 18 of the 23 centers used it during every autologous transplant and 2 of the 23 centers used it during autologous transplants on a per case basis. The most common drug used for prophylaxis was fluconazole (F) (21/23), followed by itraconazole (I) (3/23), amphotericin-B (2/23), and posaconazole (1/23). Among the 23 centers, 3 reported that for allogenic transplants they changed the antifungal prophylactic in cases of graft versus host disease (GVHD), and 12 of the 23 centers reported that they changed the antifungal prophylactic in case of nearby construction. All 23 centers performed secondary prophylaxis. CONCLUSION: Antifungal prophylaxis for hematopoetic SCT patients was the standard protocol in the 23 centers included in the study, usually with such azoles as F. The introduction of posaconazole in Turkey and the potential approval of voriconazole for antifungal prophylaxis will eventually alter prophylaxis practice in Turkey, which we plan to assess in the future.

Intercontinental study on pre-engraftment and post-engraftment Gram-negative rods bacteremia in hematopoietic stem cell transplantation patients: Risk factors and association with mortality.

OBJECTIVES: We present here data on Gram-negative rods bacteremia (GNRB) rates, risk factors and associated mortality. METHODS: Data on GNRB episodes were prospectively collected in 65 allo-/67 auto-HSCT centers in 24 countries (Europe, Asia, Australia). In patients with and without GNRB, we compared: demography, underlying disease, HSCT-related data, center` fluoroquinolone prophylaxis (FQP) policy and accreditation status, and involvement of infection control team (ICT). RESULTS: The GNRB cumulative incidence among 2818 allo-HSCT was: pre-engraftment (pre-eng-allo-HSCT), 8.4 (95% CI 7-9%), post-engraftment (post-eng-allo-HSCT), 5.8% (95%CI: 5-7%); among 3152 auto-HSCT, pre-eng-auto-HSCT, 6.6% (95%CI: 6-7%), post-eng-auto-HSCT, 0.7% (95%CI: 0.4-1.1%). GNRB, especially MDR, was associated with increased mortality. Multivariate analysis revealed the following GNRB risk factors: (a) pre-eng-allo-HSCT: south-eastern Europe center location, underlying diseases not at complete remission, and cord blood source; (b) post-eng-allo-HSCT: center location not in northwestern Europe; underlying non-malignant disease, not providing FQP and never accredited. (c) pre-eng-auto-HSCT: older age, autoimmune and malignant (vs. plasma cell) disease, and ICT absence. CONCLUSIONS: Benefit of FQP should be explored in prospective studies. Increased GNRB risk in auto-HSCT patients transplanted for autoimmune diseases is worrying. Infection control and being accredited are possibly protective against bacteremia. GNRB are associated with increased mortality.

Baseline Chest Computed Tomography as Standard of Care in High-Risk Hematology Patients.

Baseline chest computed tomography (BCT) in high-risk hematology patients allows for the early diagnosis of invasive pulmonary aspergillosis (IPA). The distribution of BCT implementation in hematology departments and impact on outcome is unknown. A web-based questionnaire was designed. International scientific bodies were invited. The estimated numbers of annually treated hematology patients, chest imaging timepoints and techniques, IPA rates, and follow-up imaging were assessed. In total, 142 physicians from 43 countries participated. The specialties included infectious diseases (n = 69; 49%), hematology (n = 68; 48%), and others (n = 41; 29%). BCT was performed in 57% (n = 54) of 92 hospitals. Upon the diagnosis of malignancy or admission, 48% and 24% performed BCT, respectively, and X-ray was performed in 48% and 69%, respectively. BCT was more often used in hematopoietic cell transplantation and in relapsed acute leukemia. European centers performed BCT in 59% and non-European centers in 53%. Median estimated IPA rate was 8% and did not differ between BCT (9%; IQR 5-15%) and non-BCT centers (7%; IQR 5-10%) (p = 0.69). Follow-up computed tomography (CT) for IPA was performed in 98% (n = 90) of centers. In high-risk hematology patients, baseline CT is becoming a standard-of-care. Chest X-ray, while inferior, is still widely used. Randomized, controlled trials are needed to investigate the impact of BCT on patient outcome.

Vitiligo after hematopoietic cell transplantation: six cases and review of the literature.

AIM: To investigate the prevalence and clinical characteristics of vitiligo after allogeneic hematopoietic cell transplantation (AHCT). METHODS: The development of vitiligo was analyzed among 421 patients who underwent AHCT in Ibni Sina Hospital (University of Ankara) between 1988 and 2004. RESULTS: Among 421 patients, we describe 6 with generalized vitiligo occurring after AHCT for chronic myelogenous leukemia. Five of them had severe chronic graft-versus-host disease (GVHD). Vitiligo was accompanied by alopecia areata and acquired ichthyosis in 2 patients with GVHD. CONCLUSION: Melanocyte destruction caused by the autoimmune reactions triggered by chronic GVHD as well as a genetic predisposition might have played a role in the development of vitiligo in our patients. These data support the hypothesis that vitiligo is an autoimmune entity.

Allogeneic hematopoietic stem cell transplantation (allo-HSCT) in acute myeloblastic leukemia (AML): A single center experience.

OBJECTIVE: We retrospectively analyzed the impact of pre- and post-transplant variables on the outcome of transplanta¬tion in 145 consecutive patients with acute myeloblastic leukemia (AML) allografted from their HLA-identical siblings in our single center cohort. RESULTS: The stem cell source used was bone marrow (BM) (36.6%) or peripheral blood (PB) (63.4%). Both neutrophil and platelet engraftments were observed on the median 14th day. Engraftment was faster in the PB group than in the BM group (p<0.0001). Severe acute graft versus host disease (aGvHD) was observed in 27.9% of the patients while chronic (c)GvHD developed in 61.2%. The use of PB was associated with more severe aGvHD. Estimated leukemia-free survival (LFS) and overall survival (OS) at 10 years were 43.4%±5.2% and 52.7%±4.6%, respectively. CONCLUSION: Both in univariate and multivariate analyses for LFS and OS, remission status at transplant and the presence of aGvHD were independent risk factors.

Is cytomegalovirus a risk factor for haemorrhagic cystitis in allogeneic haematopoietic stem cell transplantation recipients?

BACKGROUND: Haemorrhagic cystitis (HC) is usually a serious complication in allogeneic haematopoietic stem cell transplantation (allo-HSCT) recipients. In this study, our aim was to define risk factors and outcomes for patients with HC in an allo-HSCT setting. METHODS: We retrospectively evaluated 249 allo-HSCTs performed between 2011 and 2016 in our centre. RESULTS: HC was diagnosed in 98 patients (39%) at a median of 119 days (range 5-580) and 91 (93%) of the patients had late onset disease. In univariate analysis, HC was related to cytomegalovirus (CMV) reactivation (P<0.001) and BK viraemia (P<0.001); in multivariate analysis, the presence of CMV reactivation was determined to be an independent risk factor (odds ratio: 22.1; 95% CI 1.73, 282.44; P=0.017). There was no association detected between acute graft versus host disease and patients diagnosed with HC within 100 days of transplant. HC was significantly increased by the presence of myelo-ablative conditioning (odds ratio: 31.28; 95% CI 3.98, 246.87; P=0.001) and BK viraemia (odds ratio: 3.93; 95% Cl 1.10, 14.05; P=0.035) in patients with HC grade II and beyond. Forced hydration was recommended in all patients with grade I HC. Patients with HC and clots were treated with continuous bladder irrigation, and 14 of 44 patients with BK viraemia received cidofovir ± ribavirin. Eight of these patients (57%) responded to treatment. Refractory HC was detected in 17 patients (17%) and resolved by a variety of procedures. CONCLUSIONS: This study suggests that CMV reactivation is associated with increased risk of HC in multivariate analysis, however, this result is not confirmed in patients with HC grade II and beyond.

Clinical research in Turkey.

The History of Clinical Drug Trials in Turkey The history of clinical trials in Turkey dates back to the beginning of the 20th century, but many years had passed with studies done with no compliance to the Good Clinical Practice (GCP) guidelines. This was not due to the lack of legal documents. On the contrary, the first mention of clinical trials in a legal document occurred in 1926; "The Code of Pharmaceutical Products and Preparations No. 1262" law carried the statement: "Experimental drugs can be used in a patient only by his/her permission."

Allogeneic Transplantation in Chronic Myeloid Leukemia and the Effect of Tyrosine Kinase Inhibitors on Survival: A Quasi-Experimental Study.

OBJECTIVE: Tyrosine kinase inhibitors (TKIs) have changed the indications for allogeneic hematopoietic stem cell transplantation (allo-HSCT) in chronic myeloid leukemia (CML). Therefore, we aimed to evaluate the effect of TKIs on allo-HSCT in CML. MATERIALS AND METHODS: In this quasi-experimental study, we compared patient, disease, and transplantation characteristics as well as allo-HSCT outcomes between the pre-TKI era (before 2002) and the post-TKI era (2002 and later) in patients with CML. A total of 193 allo-HSCTs were performed between 1989 and 2012. RESULTS: Patients in the post-TKI era had more advanced disease (>chronic phase 1) at the time of transplant and more frequently received reduced-intensity conditioning compared to patients in the pre-TKI era. Relapse/progression occurred more frequently in the year ≥2002 group than in the year <2002 group (48% vs. 32% at 5 years, p=0.01); however, overall survival (OS) was similar in these two groups (5-year survival was 50.8% vs. 59.5%, respectively; p=0.3). TKIs (with donor lymphocyte infusions or alone) for treatment of relapse after allo-HSCT were available in the post-TKI era and were associated with improved OS. While the rates of hematologic remission at 3 months after allo-HSCT were similar between TKI eras, patients having remission had better disease-free survival (DFS) [relative risk (RR): 0.15, confidence interval (CI) 95%: 0.09-0.24, p<0.001] and OS (RR: 0.14, CI 95%: 0.09-0.23, p<0.001). Male allo-HSCT recipients had worse DFS (RR: 1.7, CI 95%: 1.2-2.5, p=0.007) and OS (RR: 1.7, CI 95%: 1.1-2.6, p=0.02) than females. CONCLUSION: TKIs are an effective option for the treatment of relapse after allo-HSCT in CML. Hematologic remission after allo-HSCT is also an important factor for survival in CML patients.

Cystatin C can be affected by nonrenal factors: a preliminary study on leukemia.

OBJECTIVE: The aim of this study was to evaluate the influence of malignancy and the impact of nephrotoxic drugs used in bone marrow transplantation (BMT) on the circulating levels of cystatin C in leukemia. METHODS: We studied nineteen patients (eleven men and eight women; mean age 30.1 +/- 11.2, 27.9 +/- 7.1 years) with acute lymphoblastic leukemia, acute myeloid leukemia and chronic myeloid leukemia. Cystatin C, urea, creatinine and creatinine clearance (CrCl) were measured 24 h before BMT, 1 week after BMT, 2 weeks after BMT and 3 weeks after BMT. The control group consisted of twenty healthy adults, and the mean age was 29.1 +/- 8.9. RESULTS: At the pretransplantation period, values of cystatin C were significantly higher than in the control group (P < 0.05). Urea, creatinine and CrCl values were not statistically different from the controls. One week after BMT, the level of cystatin C was significantly low as compared to the levels measured 24 h before BMT, but was still significantly higher than the controls (P < 0.05), whereas the levels of urea, creatinine and CrCl were in accordance with the levels of the controls. Two and three weeks after BMT, cystatin C values maintained the significant increase (P < 0.05), whereas the values of urea, creatinine and CrCl still corresponded with those of the controls in both group. CONCLUSIONS: Our preliminary data expose that cystatin C is not a reliable GFR marker in patients during leukemia or for monitoring nephrotoxic drugs used in BMT, but we can not reach definitive conclusion due to no gold standard for comparing the diagnostic accuracy of cystatin C. Further study is needed to elucidate the precise mechanism underlying this observation.