A Bayesian quantile joint modeling of multivariate longitudinal and time-to-event data.

Linear mixed models are traditionally used for jointly modeling (multivariate) longitudinal outcomes and event-time(s). However, when the outcomes are non-Gaussian a quantile regression model is more appropriate. In addition, in the presence of some time-varying covariates, it might be of interest to see how the effects of different covariates vary from one quantile level (of outcomes) to the other, and consequently how the event-time changes across different quantiles. For such analyses linear quantile mixed models can be used, and an efficient computational algorithm can be developed. We analyze a dataset from the Acute Lymphocytic Leukemia (ALL) maintenance study conducted by Tata Medical Center, Kolkata. In this study, the patients suffering from ALL were treated with two standard drugs (6MP and MTx) for the first two years, and three biomarkers (e.g. lymphocyte count, neutrophil count and platelet count) were longitudinally measured. After treatment the patients were followed nearly for the next three years, and the relapse-time (if any) for each patient was recorded. For this dataset we develop a Bayesian quantile joint model for the three longitudinal biomarkers and time-to-relapse. We consider an Asymmetric Laplace Distribution (ALD) for each outcome, and exploit the mixture representation of the ALD for developing a Gibbs sampler algorithm to estimate the regression coefficients. Our proposed model allows different quantile levels for different biomarkers, but still simultaneously estimates the regression coefficients corresponding to a particular quantile combination. We infer that a higher lymphocyte count accelerates the chance of a relapse while a higher neutrophil count and a higher platelet count (jointly) reduce it. Also, we infer that across (almost) all quantiles 6MP reduces the lymphocyte count, while MTx increases the neutrophil count. Simulation studies are performed to assess the effectiveness of the proposed approach.

Current treatment strategies targeting histone deacetylase inhibitors in acute lymphocytic leukemia: a systematic review.

Acute lymphocytic leukemia is a hematological malignancy that primarily affects children. Long-term chemotherapy is effective, but always causes different toxic side effects. With the application of a chemotherapy-free treatment strategy, we intend to demonstrate the most recent results of using one type of epigenetic drug, histone deacetylase inhibitors, in ALL and to provide preclinical evidence for further clinical trials. In this review, we found that panobinostat (LBH589) showed positive outcomes as a monotherapy, whereas vorinostat (SAHA) was a better choice for combinatorial use. Preclinical research has identified chidamide as a potential agent for investigation in more clinical trials in the future. In conclusion, histone deacetylase inhibitors play a significant role in the chemotherapy-free landscape in cancer treatment, particularly in acute lymphocytic leukemia.

A Bayesian joint model for multivariate longitudinal and time-to-event data with application to ALL maintenance studies.

The most common type of cancer diagnosed among children is the Acute Lymphocytic Leukemia (ALL). A study was conducted by Tata Translational Cancer Research Center (TTCRC) Kolkata, in which 236 children (diagnosed as ALL patients) were treated for the first two years (approximately) with two standard drugs (6MP and MTx) and were then followed nearly for the next 3 years. The goal is to identify the longitudinal biomarkers that are associated with time-to-relapse, and also to assess the effectiveness of the drugs. We develop a Bayesian joint model in which a linear mixed model is used to jointly model three biomarkers (i.e. white blood cell count, neutrophil count, and platelet count) and a semi-parametric proportional hazards model is used to model the time-to-relapse. Our proposed joint model can assess the effects of different covariates on the progression of the biomarkers, and the effects of the biomarkers (and the covariates) on time-to-relapse. In addition, the proposed joint model can impute the missing longitudinal biomarkers efficiently. Our analysis shows that the white blood cell (WBC) count is not associated with time-to-relapse, but the neutrophil count and the platelet count are significantly associated with it. We also infer that a lower dose of 6MP and a higher dose of MTx jointly result in a lower relapse probability in the follow-up period. Interestingly, we find that relapse probability is the lowest for the patients classified into the "high-risk" group at presentation. The effectiveness of the proposed joint model is assessed through the extensive simulation studies.

A Bayesian joint model for multivariate longitudinal and time-to-event data with application to ALL maintenance studies.

The most common type of cancer diagnosed among children is the acute lymphocytic leukemia (ALL). A study was conducted by Tata Translational Cancer Research Center (TTCRC) Kolkata, in which 236 children (diagnosed as ALL patients) were treated for the first two years (approximately) with two standard drugs (6MP and MTx) and were then followed nearly for the next three years. The goal is to identify the longitudinal biomarkers that are associated with time-to-relapse, and also to assess the effectiveness of the drugs. We develop a Bayesian joint model in which a linear mixed model is used to jointly model three biomarkers (i.e. white blood cell count, neutrophil count, and platelet count) and a semi-parametric proportional hazards model is used to model the time-to-relapse. Our proposed joint model can assess the effects of different covariates on the progression of the biomarkers, and the effects of the biomarkers (and the covariates) on time-to-relapse. In addition, the proposed joint model can impute the missing longitudinal biomarkers efficiently. Our analysis shows that the white blood cell (WBC) count is not associated with time-to-relapse, but the neutrophil count and the platelet count are significantly associated with it. We also infer that a lower dose of 6MP and a higher dose of MTx jointly result in a lower relapse probability in the follow-up period. Interestingly, we find that relapse probability is the lowest for the patients classified into the "high-risk" group at presentation. The effectiveness of the proposed joint model is assessed through the extensive simulation studies.

Clinical outcomes and early immune reconstitution in patients with acute lymphoblastic leukemia underwent allogeneic hematopoietic stem cell transplantation / 中国输血杂志

【Objective】 To investigate the correlation between early immune reconstitution and clinical outcomes in patients with acute lymphoblastic leukemia (ALL) underwent allogeneic hematopoietic stem cell transplantation (allo-HSCT). 【Methods】 The basic information and treatment data of 99 patients with ALL undering allo-HSCT from December 2018 to February 2022 were collected. The proportions of CD3+ T, CD3+CD4+ T, CD3+CD8+ T and CD3-CD16+CD56+ NK cells were detected before and 30, 60 and 90 days after transplantation using flow cytometry. The correlation between early cellular immune reconstitution and neutrophil engraftment, platelet engraftment, infection, and acute and chronic graft-versus-host disease (GVHD) was analyzed. 【Results】 Among 99 ALL patients, the median time of neutrophil engraftment was day +11 (range, 8-28), and the median time of platelet engraftment was day +14 (range, 10-120). The cumulative incidence of blood stream infection (BSI) was 11.10% and the cumulative incidence of CMV within 100 days of transplantation was 40.40%. The cumulative incidence of EBV within 100 days was 7.10%. The cumulative incidence of acute graft-versus-host disease (aGVHD) was 22.30%. The cumulative incidence of chronic graft-versus-host disease (cGVHD) within 1 year of transplantation was 16.20%. 1 -year cumulative relapse rate was 13.84%. The 1 -year cumulative disease-free survival (DFS) for all patients was 80.60% and the 1-year overall survival (OS) was 90.30%. The CD4+/CD8+ ratio was positively associated with the development of aGVHD at 30 days post-transplant (OR 1.21, 95CI 1.01-1.45, P<0.05). The proportion of CD16+ CD56+ NK cell were higher in the group without BSI than that in the BSI group before and 30 days after transplantation (P < 0.05). The proportion of CD4+ T-cell were lower in the CMV infection group than that in the group without CMV infection at 60 and 90 days post-transplant(P<0.05). The higher level of CD4+ T-cells at 60 days post-transplant was a protective factor for CMV infection within 100 days (HR 0.91, 95CI 0.84-0.99, P<0.05). 【Conclusion】 Early immune reconstitution after allo-HSCT in patients with ALL is associated with aGVHD, CMV and BSI.

Distinct power of bone marrow microRNA signatures and tumor suppressor genes for early detection of acute leukemia

BackgroundAcute leukemia involving lymphocytic and myeloid cells is cancer with a high mortality rate. Swift and timely diagnosis might be a potential approach to improving patient prognosis and survival. The microRNA (miRNA) signatures are emerging nowadays for their promising diagnostic potential. MiRNA levels from bone marrow can be used as prognostic biomarkers.MethodsThe current study was designed to evaluate if the microRNAs and tumor suppressor genes (TSGs) profiling of hematopoietic bone marrow could help in acute leukemia early detection. Also, we assessed the DNA methyltransferase 3A (DNMT3A) expression and its possible epigenetic effects on miRNAs plus TSGs expression levels. The expression levels of ten miRNAs and four TSGs involved in acute lymphocytic leukemia (ALL) as well as acute myeloid leukemia (AML) were quantified in 43 and 40 bone marrow samples of ALL and AML patients in comparison with cancer-free subjects via real-time quantitative PCR (RT-qPCR). The receiver-operating-characteristic (ROC) analysis of miRNAs was performed in the study groups. Further, the correlation between the DNMT3A and TSGs was calculated.ResultsSignificant differences were detected in the bone marrow expression of miRNAs and TSGs (P < 0.05) between acute leukemia patients and healthy group. ROC analysis confirmed the ability of miR-30a, miR-101, miR-132, miR-129, miR-124, and miR-143 to discriminate both ALL and AML patients with an area under the ROC curve of ≥ 0.80 (P < 0.001) and high accuracy. The correlation between DNMT3A and P15/P16 TSGs revealed that DNMT3A plays a vital role in epigenetic control of TSGs expression. Our findings indicated that the downregulation of bone marrow miRNAs and TSGs was accompanied by acute leukemia development.ConclusionsThe authors conclude that this study could contribute to introducing useful biomarkers for acute leukemia diagnosis.

The role of miRNAs as a big master regulator of signaling pathways involved in lymphoblastic leukemia.

MicroRNAs (miRNAs) belong to small noncoding RNAs, which have long attracted researchers' attention because of their potency in acting either as oncogenes or tumor-suppressors in cancers. acute lymphocytic leukemia (ALL) and chronic lymphocytic leukemia (CLL) are two known types of leukemia with high mortality rates in adults and children. On a molecular basis, various signaling pathways are active in both types, making researchers consider the potential role of miRNAs in activating or suppressing these pathways to further hinder cancer development. In this review, we summarized the potential miRNAs, especially circulating ones, involved in essential signaling pathways in the ALL and CLL patients which serve as biomarkers and valuable targets in the treatment fields.

Distinct power of bone marrow microRNA signatures and tumor suppressor genes for early detection of acute leukemia.

BACKGROUND: Acute leukemia involving lymphocytic and myeloid cells is cancer with a high mortality rate. Swift and timely diagnosis might be a potential approach to improving patient prognosis and survival. The microRNA (miRNA) signatures are emerging nowadays for their promising diagnostic potential. MiRNA levels from bone marrow can be used as prognostic biomarkers. METHODS: The current study was designed to evaluate if the microRNAs and tumor suppressor genes (TSGs) profiling of hematopoietic bone marrow could help in acute leukemia early detection. Also, we assessed the DNA methyltransferase 3A (DNMT3A) expression and its possible epigenetic effects on miRNAs plus TSGs expression levels. The expression levels of ten miRNAs and four TSGs involved in acute lymphocytic leukemia (ALL) as well as acute myeloid leukemia (AML) were quantified in 43 and 40 bone marrow samples of ALL and AML patients in comparison with cancer-free subjects via real-time quantitative PCR (RT-qPCR). The receiver-operating-characteristic (ROC) analysis of miRNAs was performed in the study groups. Further, the correlation between the DNMT3A and TSGs was calculated. RESULTS: Significant differences were detected in the bone marrow expression of miRNAs and TSGs (P < 0.05) between acute leukemia patients and healthy group. ROC analysis confirmed the ability of miR-30a, miR-101, miR-132, miR-129, miR-124, and miR-143 to discriminate both ALL and AML patients with an area under the ROC curve of ≥ 0.80 (P < 0.001) and high accuracy. The correlation between DNMT3A and P15/P16 TSGs revealed that DNMT3A plays a vital role in epigenetic control of TSGs expression. Our findings indicated that the downregulation of bone marrow miRNAs and TSGs was accompanied by acute leukemia development. CONCLUSIONS: The authors conclude that this study could contribute to introducing useful biomarkers for acute leukemia diagnosis.

A bis-pyridinium fullerene derivative induces apoptosis through the generation of ROS in BCR-ABL-positive leukemia cells.

A fusion protein, Breakpoint cluster region-Abelson (BCR-ABL) is responsible for the development of chronic myeloid leukemia (CML) and acute lymphocytic leukemia (ALL). Inhibitors against BCR-ABL are effective for the treatment of leukemia; however, a gatekeeper mutation (T315I) in BCR-ABL results in resistance to these inhibitors, which markedly impedes their efficacy. We herein demonstrated that a bis-pyridinium fullerene derivative (BPF) significantly induced apoptosis in human CML-derived K562 cells and ALL-derived SUP-B15 cells via the generation of reactive oxygen species (ROS). BPF reduced the expression of Bcr-Abl mRNA by inhibiting expression of c-Myc through ROS production. BPF also accelerated protein degradation of BCR-ABL through ROS production. Furthermore, BPF down-regulated the expression of not only BCR-ABL but also T315I-mutated BCR-ABL in ROS-dependent manner. As a result, BPF effectively induced apoptosis in transformed Ba/F3 cells expressing both BCR-ABL and T315I-mutated BCR-ABL. Collectively, these results indicate the potential of BPF as an effective leukemia drug that overcomes resistance to BCR-ABL inhibitors.

Donor cell leukemia/myelodysplastic syndrome after allogeneic stem cell transplantation: a rare phenomenon with more challenges for hematologists.

Donor cell leukemia (DCL) or Donor cell myelodysplastic syndrome (DC-MDS) is a rare type of leukemia or MDS and originates from the donor cells. It has very low frequency, but it seems to be steadily increasing as the physiopathology and mechanisms remain largely unknown. Here we report one case of acute lymphocytic leukemia (ALL) and one case of MDS of donor origin after allogeneic hematopoietic stem cell transplantation (HSCT). We also collated and reviewed literatures regarding DCL, and discuss the morbidity of DCL, the methods used to confirm donor origin and the etiology and pathogenesis of DCL. A new proposed theory will help us to better understand the mechanism for the oncogenesis of DCL.

CAR T in adult ALL: When and for whom?

Chimeric antigen receptor T cell therapy targeting CD19 (CART19) has shown remarkable results in patients with relapsed/refractory (r/r) B cell acute lymphoblastic leukemia (ALL). In patients 25 years of age or younger CART19 therapy is an accepted standard of care, while the treatment of older adults is less straight forward and possible only in the context of a clinical trial. Treatment of older patients with CAR T cells requires careful consideration of overall treatment goals, suitability of a consolidative hematopoietic stem cell transplant (HSCT), alternative treatment options, patient risk profile, and anticipated responses and toxicities of the specific CAR T cell products available. Here we use patient guided examples to inform approaches to care.

The expression and clinical significance of murine double minute 2, lysosome-associated membrane protein 1, and P-glycoprotein in pediatric acute lymphoblastic leukemia.

BACKGROUND: To analyze the expression and clinical significance of murine double minute 2 (MDM2), lysosome-associated membrane protein (LAMP1) and P-glycoprotein (P-gp) in children with acute lymphoblastic leukemia (ALL). METHODS: Thirty-three children with ALL who were admitted to our hospital between January 2017 and January 2018 were enrolled as the ALL group. The expression of MDM2, LAMP1 and P-gp was compared between the two groups, as well as between ALL patients with different clinical characteristics. Logistic regression was used to analyze the risk factors that affect the prognosis and survival of ALL patients. Kaplan-Meier survival curves were used to analyze the correlations of MDM2, LAMP1 and P-gp on the prognosis and survival of ALL patients. RESULTS: The expression levels of MDM2, LAMP1 and P-gp in the ALL group were higher than those in the control group (P<0.05). The average survival time of the group with low expression of MDM2 was (34.92±0.56) months, the average survival time of the group with high expression of MDM2 was (31.32±0.42) months, and the difference was statistically significant (P<0.05). The average survival time of the group with low expression of LAMP1 was (36.71±0.55) months, the average survival time of the group with high expression of LAMP1 was (29.87±0.40) months, the difference was statistically significant (P<0.05). The average survival time of the group with low expression of P-gp was (36.29±0.41) months, the average survival time of the group with high expression of P-gp was (26.46±0.37) months, and the difference was statistically significant (P<0.05). CONCLUSIONS: Abnormal expression levels of MDM2, LAMP1 and P-gp protein are related to the occurrence and development of ALL, and are closely related to patient prognosis and survival. Therefore, MDM2, LAMP1and P-gp can serve as molecular markers for predicting the prognosis of children with ALL.

Mechanisms underlying CD19-positive ALL relapse after anti-CD19 CAR T cell therapy and associated strategies.

Chimeric antigen receptor (CAR) T cell therapy, especially anti-CD19 CAR T cell therapy, has shown remarkable anticancer activity in patients with relapsed/refractory acute lymphoblastic leukemia, demonstrating an inspiring complete remission rate. However, with extension of the follow-up period, the limitations of this therapy have gradually emerged. Patients are at a high risk of early relapse after achieving complete remission. Although there are many studies with a primary focus on the mechanisms underlying CD19- relapse related to immune escape, early CD19+ relapse owing to poor in vivo persistence and impaired efficacy accounts for a larger proportion of the high relapse rate. However, the mechanisms underlying CD19+ relapse are still poorly understood. Herein, we discuss factors that could become obstacles to improved persistence and efficacy of CAR T cells during production, preinfusion processing, and in vivo interactions in detail. Furthermore, we propose potential strategies to overcome these barriers to achieve a reduced CD19+ relapse rate and produce prolonged survival in patients after CAR T cell therapy.

Pak1 gene functioned differentially in different BCR-ABL subtypes in leukemiagenesis and treatment response through STAT5 pathway.

The BCR-ABL fusion gene (BCR-ABL) has different subtypes such as p210 and p190 with p190 appear to lead to a worse prognosis. To explore the mechanism of difference in pathogenesis and prognosis in different BCR-ABL subtype-related leukemia, expression profile microarray analysis was conducted between p190 and p210 patients and verified by RT-PCR. The p21-activated kinase (PAK1) gene was chosen and regulation of the PAK1-STAT5 biological axis and its influence on proliferation and apoptosis in leukemia cells were also analyzed. The results showed that PAK1 might be an important molecular mechanism of the pathogenic difference between different BCR-ABL subtypes. In P210 (+) chronic myelogenous leukemia (CML), down-regulated PAK1 gene expressions may lead to the suppression of cell proliferation and promotion of apoptosis through phosphorylation of STAT5, with a reverse effect in P190 (+) acute lymphoblastic leukemia(ALL), especially acute B lymphoblastic leukemia (B-ALL). Additionally, in P210 (+) CML, down-regulated PAK1 expression may enhance the effect of TKI, whereas the reverse is true in P190 (+) B-ALL, demonstrating that PAK1 might also be an important therapeutic target between different BCR-ABL subtypes.

A novel generation 1928zT2 CAR T cells induce remission in extramedullary relapse of acute lymphoblastic leukemia.

BACKGROUND: Anti-CD19 chimeric antigen receptor (CAR) T cells have shown promise in the treatment of B cell acute lymphocytic leukemia (B-ALL). However, its efficacy in B-ALL patients with extramedullary involvement is limited due to poor responses and neurotoxicity. Here, we utilized a third generation of CAR T cell vector, which contains the Toll/interleukin-1 receptor (ITR) domain of Toll-like receptor 2 (TLR2), to generate 1928zT2 T cells targeting CD19, and evaluated the efficacy of 1928zT2 T cells in relapse or refractory B-ALL patients with extramedullary involvement. METHODS: 1928zT2 T cells were generated by 19-28z-TLR2 lentiviral vector transfection into primary human T lymphocytes. The anti-leukemia effect of 1928zT2 T cells were determined by killing assays and in xenografts. Three patients diagnosed as relapse or refractory ALL with extramedullary involvement were infused with 1928zT2 T cells, and the clinical responses were evaluated by BM smear, B-ultrasonography, PET/CT, histology, flow cytometry, qPCR, ELISA, and luminex assay. RESULTS: 1928zT2 T cells exhibited enhanced effector function against CD19+ leukemic cells in vitro and in a xenograft model of human extramedullary leukemia. Notably, the 1928zT2 T cells eradicated extramedullary leukemia and induced complete remission in the three relapse and refractory ALL patients without serious adverse effects. 1928zT2 T cells expanded robustly in the circulation of these three patients and were detected in the cerebrospinal fluid of patient 3. These three patients experienced cytokine release syndrome (CRS) with grade 2 or 3, which remitted spontaneously or after tocilizumab treatment. None of the three patients suffered neurotoxicity or needed further intensive care. CONCLUSIONS: Our results demonstrate that 1928zT2 T cells with TLR2 incorporation augment anti-leukemic effects, particularly for eradicating extramedullary leukemia cells, and suggest that the infusion of 1928zT2 T cells is an encouraging treatment for relapsed/refractory ALL patients with extramedullary involvement. TRIAL REGISTRATION: ClinicalTrials.gov identifier NCT02822326 . Date of registration: July 4, 2016.

Analysis of malnutrition status in pediatric acute lymphoblastic leukemia patients dur-ing the induced remission stage / 中国肿瘤临床

Objective: To investigate the nutritional status of children acute lymphoblastic leukemia (ALL) during induced remission stage. The effects of the disease itself, treatment, and complications of malnutrition were all analyzed. Methods: From the medical re-cords of children with ALL in the pediatric hematological department of the Affiliated Hospital of Guizhou Medical University, we col-lected basic information of the children; monitored the height and weight of the children on the first, 15th, and 33rd days of induced remission treatment; and calculated their body mass index (BMI), as well as results of laboratory tests such as serum albumin and se-rum prealbumin. SPSS 23.0 software was used for data analysis. Results: In 40 children with ALL, there were 16 cases of malnutrition on the first day of induced remission treatment accounting for 40%, 14 cases on both the 15th day and the 33rd day of treatment ac-counting for 35%. Among children with malnutrition, 4 cases of moderate to severe malnutrition occurred on the first day of treat-ment accounting for 25.0%, 9 cases on the 15th day accounting for 64.3%, and 12 cases on the 33rd day accounting for 85.7%. Com-pared with day 1 and day 33, the difference was statistically significant (P<0.017). In the induced remission period, the BMI on the first day was (15.98±2.17) kg/m2; on the 15th day, it was (15.65±2.20) kg/m2; and on the 33rd day, it was (15.66±1.92) kg/m2. The differ-ence between the three was not statistically significant (P=0.730). In the single-factor analysis of factors related to the nutritional sta-tus of children, infection, digestive system involvement, and serum albumin levels were related to the occurrence of malnutrition, and we performed multifactor analysis of these three factors. The difference between the level of infection and serum albumin and the oc-currence of malnutrition was statistically significant (P<0.05). Conclusions: During the induced remission, the malnutrition degree of some children with ALL was aggravated. Infection was a high-risk factor for malnutrition in children with ALL. The decrease in serum al-bumin level may indicate the occurrence of malnutrition. Dynamic monitoring of nutritional status in children with ALL is necessary.

Cellular Immunotherapy in B-Cell Malignancy.

In recent years, cellular immunotherapy in B-cell malignancies has been driven by adoptive transfer of genetically engineered T cells expressing chimeric antigen receptors (CARs). CARs consist of a single chain variable fragment (scFv) of a monoclonal antibody, a spacer domain, a transmembrane domain, an intracellular signaling domain, and additional costimulatory domains. The bulk of clinical data available is on CD19-targeting CAR T cells for the treatment of B-cell acute lymphocytic leukemia (B-ALL), chronic lymphocytic leukemia, and B-cell non-Hodgkin lymphoma. Results so far have been promising with impressive rates and depth of remission especially among B-ALL patients. However, CAR T-cell therapy is a complex multi-step process, and clinical trials so far differ profoundly in CAR construct used, gene transfer method, composition of the cellular product, lymphodepletion, and CAR T-cell dose used. Randomized trials will be needed to conclusively evaluate the implications of these differences. The treatment concept is associated with significant neurotoxicity and potentially lethal cytokine release syndrome, both of which require specific management. Improvements in CAR design may help to overcome toxicity, the effects of an immunosuppressive microenvironment, and tumor escape by development of antigen-negative clones. This review will explain the mechanism of action, summarize the clinical experience with this treatment modality so far, and explore future developments in the field.

Campylobacter jejuni Bacteremia in a Patient With Acute Lymphocytic Leukemia.

INTRODUCTION: Campylobacter jejuni is a slender, motile, non-spore-forming, helical-shaped, gram-negative bacterium. It is one of the most common causes of human gastroenteritis in the world. The aim of this study was to present a patient with acute lymphocytic leukemia (ALL), who was infected with Campylobacter jejuni. CASE PRESENTATION: We describe the medical records of a pediatric ALL patient with bacteremia caused by C. jejuni, who was diagnosed at Amir hospital, Shiraz, Iran. This 14-year-old male visited the emergency department of Amir hospital with night sweats, severe polar high-grade fever, reduced appetite, and nausea in August 2013. Given the suspected presence of an anaerobic or microaerophilic microorganism, aerobic and anaerobic blood cultures were performed using an automated blood cultivator, the BACTEC 9240 system. In order to characterize the isolate, diagnostic biochemical tests were used. Antibiotic susceptibility testing was done with the disk diffusion method. The primary culture was found to be positive for Campylobacter, and the subculture of the solid plate yielded a confluent growth of colonies typical for Campylobacter, which was identified as C. jejuni by morphological and biochemical tests. The isolate was resistant to ciprofloxacin, cefotaxime, cephalexin, piperacillin/tazobactam, nalidixic acid, aztreonam, cefuroxime, cefixime, ceftazidime, and tobramycin. CONCLUSIONS: C. jejuni should be considered in the differential diagnosis as a potential cause of bacteremia in immunosuppressed patients. In cases where the BACTEC result is positive in aerobic conditions but the organism cannot be isolated, an anaerobic culture medium is suggested, especially in immunocompromised patients.