Sequential inverse dysregulation of the RNA helicases DDX3X and DDX3Y facilitates MYC-driven lymphomagenesis.

DDX3X is a ubiquitously expressed RNA helicase involved in multiple stages of RNA biogenesis. DDX3X is frequently mutated in Burkitt lymphoma, but the functional basis for this is unknown. Here, we show that loss-of-function DDX3X mutations are also enriched in MYC-translocated diffuse large B cell lymphoma and reveal functional cooperation between mutant DDX3X and MYC. DDX3X promotes the translation of mRNA encoding components of the core translational machinery, thereby driving global protein synthesis. Loss-of-function DDX3X mutations moderate MYC-driven global protein synthesis, thereby buffering MYC-induced proteotoxic stress during early lymphomagenesis. Established lymphoma cells restore full protein synthetic capacity by aberrant expression of DDX3Y, a Y chromosome homolog, the expression of which is normally restricted to the testis. These findings show that DDX3X loss of function can buffer MYC-driven proteotoxic stress and highlight the capacity of male B cell lymphomas to then compensate for this loss by ectopic DDX3Y expression.

Host range of a parasitoid wasp is linked to host susceptibility to its mutualistic viral symbiont.

Parasitoid wasps are one of the most species-rich groups of animals on Earth, due to their ability to successfully develop as parasites of nearly all types of insects. Unlike most known parasitoid wasps that specialize towards one or a few host species, Diachasmimorpha longicaudata is a generalist that can survive within multiple genera of tephritid fruit fly hosts, including many globally important pest species. Diachasmimorpha longicaudata has therefore been widely released to suppress pest populations as part of biological control efforts in tropical and subtropical agricultural ecosystems. In this study, we investigated the role of a mutualistic poxvirus in shaping the host range of D. longicaudata across three genera of agricultural pest species: two of which are permissive hosts for D. longicaudata parasitism and one that is a nonpermissive host. We found that permissive hosts Ceratitis capitata and Bactrocera dorsalis were highly susceptible to manual virus injection, displaying rapid virus replication and abundant fly mortality. However, the nonpermissive host Zeugodacus cucurbitae largely overcame virus infection, exhibiting substantially lower mortality and no virus replication. Investigation of transcriptional dynamics during virus infection demonstrated hindered viral gene expression and limited changes in fly gene expression within the nonpermissive host compared with the permissive species, indicating that the host range of the viral symbiont may influence the host range of D. longicaudata wasps. These findings also reveal that viral symbiont activity may be a major contributor to the success of D. longicaudata as a generalist parasitoid species and a globally successful biological control agent.

Challenging our understanding of B-cell lymphomagenesis and risk: Paediatric high-grade B-cell lymphoma, not otherwise specified with a DDX3X::MLLT10 fusion and an IGH deletion.

We report a unique case of high-grade B-cell lymphoma, not otherwise specified in a 5-year-old child. Whole-genome sequencing revealed a DDX3X::MLLT10 fusion, usually seen in T-cell acute lymphoblastic leukaemia (ALL). This suggests the novel idea that MLLT10 fusions are capable of driving B-cell malignancies. An IGH deletion usually only seen in adults was also found. These unique genetic findings provide novel insights into B-cell lymphomagenesis. The child remains in remission 7 year post chemotherapy, which demonstrates that novel complex molecular findings do not always denote high-risk disease.

Patient-derived xenograft models of ALK+ ALCL reveal preclinical promise for therapy with brigatinib.

Anaplastic large-cell lymphoma (ALCL) is a T-cell malignancy predominantly driven by the oncogenic anaplastic lymphoma kinase (ALK), accounting for approximately 15% of all paediatric non-Hodgkin lymphoma. Patients with central nervous system (CNS) relapse are particularly difficult to treat with a 3-year overall survival of 49% and a median survival of 23.5 months. The second-generation ALK inhibitor brigatinib shows superior penetration of the blood-brain barrier unlike the first-generation drug crizotinib and has shown promising results in ALK+ non-small-cell lung cancer. However, the benefits of brigatinib in treating aggressive paediatric ALK+ ALCL are largely unknown. We established a patient-derived xenograft (PDX) resource from ALK+ ALCL patients at or before CNS relapse serving as models to facilitate the development of future therapies. We show in vivo that brigatinib is effective in inducing the remission of PDX models of crizotinib-resistant (ALK C1156Y, TP53 loss) ALCL and furthermore that it is superior to crizotinib as a second-line approach to the treatment of a standard chemotherapy relapsed/refractory ALCL PDX pointing to brigatinib as a future therapeutic option.

Rituximab for High-Risk, Mature B-Cell Non-Hodgkin's Lymphoma in Children.

BACKGROUND: Rituximab added to chemotherapy prolongs survival among adults with B-cell cancer. Data on its efficacy and safety in children with high-grade, mature B-cell non-Hodgkin's lymphoma are limited. METHODS: We conducted an open-label, international, randomized, phase 3 trial involving patients younger than 18 years of age with high-risk, mature B-cell non-Hodgkin's lymphoma (stage III with an elevated lactate dehydrogenase level or stage IV) or acute leukemia to compare the addition of six doses of rituximab to standard lymphomes malins B (LMB) chemotherapy with standard LMB chemotherapy alone. The primary end point was event-free survival. Overall survival and toxic effects were also assessed. RESULTS: Analyses were based on 328 patients who underwent randomization (164 patients per group); 85.7% of the patients had Burkitt's lymphoma. The median follow-up was 39.9 months. Events were observed in 10 patients in the rituximab-chemotherapy group and in 28 in the chemotherapy group. Event-free survival at 3 years was 93.9% (95% confidence interval [CI], 89.1 to 96.7) in the rituximab-chemotherapy group and 82.3% (95% CI, 75.7 to 87.5) in the chemotherapy group (hazard ratio for primary refractory disease or first occurrence of progression, relapse after response, death from any cause, or second cancer, 0.32; 95% CI, 0.15 to 0.66; one-sided P = 0.00096, which reached the significance level required for this analysis). Eight patients in the rituximab-chemotherapy group died (4 deaths were disease-related, 3 were treatment-related, and 1 was from a second cancer), as did 20 in the chemotherapy group (17 deaths were disease-related, and 3 were treatment-related) (hazard ratio, 0.36; 95% CI, 0.16 to 0.82). The incidence of acute adverse events of grade 4 or higher after prephase treatment was 33.3% in the rituximab-chemotherapy group and 24.2% in the chemotherapy group (P = 0.07); events were related mainly to febrile neutropenia and infection. Approximately twice as many patients in the rituximab-chemotherapy group as in the chemotherapy group had a low IgG level 1 year after trial inclusion. CONCLUSIONS: Rituximab added to standard LMB chemotherapy markedly prolonged event-free survival and overall survival among children and adolescents with high-grade, high-risk, mature B-cell non-Hodgkin's lymphoma and was associated with a higher incidence of hypogammaglobulinemia and, potentially, more episodes of infection. (Funded by the Clinical Research Hospital Program of the French Ministry of Health and others; ClinicalTrials.gov number, NCT01516580.).

Molecular characterization and clinical outcome of B-cell precursor acute lymphoblastic leukemia with IG-MYC rearrangement.

Rarely, immunophenotypically immature B-cell precursor acute lymphoblastic leukemia (BCP-ALL) carries an immunoglobulin- MYC rearrangement (IG-MYC-r). This can result in diagnostic confusion with Burkitt lymphoma/leukemia and use of individualized treatment schedules of unproven efficacy. Here we compare the molecular characteristics of these conditions and investigate historic clinical outcome data. We identified 90 cases registered in a national BCP-ALL clinical trial/registry. When present, diagnostic material underwent cytogenetic, exome, methylome and transcriptome analyses. The outcomes analyzed were 3-year event-free survival and overall survival. IG-MYC-r was identified in diverse cytogenetic backgrounds, co-existing with either established BCP-ALL-specific abnormalities (high hyperdiploidy, n=3; KMT2A-rearrangement, n=6; iAMP21, n=1; BCR-ABL1, n=1); BCL2/BCL6-rearrangements (n=15); or, most commonly, as the only defining feature (n=64). Within this final group, precursor-like V(D)J breakpoints predominated (8/9) and KRAS mutations were common (5/11). DNA methylation identified a cluster of V(D)J-rearranged cases, clearly distinct from Burkitt leukemia/lymphoma. Children with IG-MYC-r within that subgroup had a 3-year event-free survival of 47% and overall survival of 60%, representing a high-risk BCP-ALL. To develop effective management strategies this group of patients must be allowed access to contemporary, minimal residual disease-adapted, prospective clinical trial protocols.

The NHS England 100,000 Genomes Project: feasibility and utility of centralised genome sequencing for children with cancer.

BACKGROUND: Whole-genome sequencing (WGS) of cancers is becoming an accepted component of oncological care, and NHS England is currently rolling out WGS for all children with cancer. This approach was piloted during the 100,000 genomes (100 K) project. Here we share the experience of the East of England Genomic Medicine Centre (East-GMC), reporting the feasibility and clinical utility of centralised WGS for individual children locally. METHODS: Non-consecutive children with solid tumours were recruited into the pilot 100 K project at our Genomic Medicine Centre. Variant catalogues were returned for local scrutiny and appraisal at dedicated genomic tumour advisory boards with an emphasis on a detailed exploration of potential clinical value. RESULTS: Thirty-six children, representing one-sixth of the national 100 K cohort, were recruited through our Genomic Medicine Centre. The diagnoses encompassed 23 different solid tumour types and WGS provided clinical utility, beyond standard-of-care assays, by refining (2/36) or changing (4/36) diagnoses, providing prognostic information (8/36), defining pathogenic germline mutations (1/36) or revealing novel therapeutic opportunities (8/36). CONCLUSION: Our findings demonstrate the feasibility and clinical value of centralised WGS for children with cancer. WGS offered additional clinical value, especially in diagnostic terms. However, our experience highlights the need for local expertise in scrutinising and clinically interpreting centrally derived variant calls for individual children.

IL10RA modulates crizotinib sensitivity in NPM1-ALK+ anaplastic large cell lymphoma.

Anaplastic large cell lymphoma (ALCL) is a T-cell malignancy predominantly driven by a hyperactive anaplastic lymphoma kinase (ALK) fusion protein. ALK inhibitors, such as crizotinib, provide alternatives to standard chemotherapy with reduced toxicity and side effects. Children with lymphomas driven by nucleophosmin 1 (NPM1)-ALK fusion proteins achieved an objective response rate to ALK inhibition therapy of 54% to 90% in clinical trials; however, a subset of patients progressed within the first 3 months of treatment. The mechanism for the development of ALK inhibitor resistance is unknown. Through genome-wide clustered regularly interspaced short palindromic repeats (CRISPR) activation and knockout screens in ALCL cell lines, combined with RNA sequencing data derived from ALK inhibitor-relapsed patient tumors, we show that resistance to ALK inhibition by crizotinib in ALCL can be driven by aberrant upregulation of interleukin 10 receptor subunit alpha (IL10RA). Elevated IL10RA expression rewires the STAT3 signaling pathway, bypassing otherwise critical phosphorylation by NPM1-ALK. IL-10RA expression does not correlate with response to standard chemotherapy in pediatric patients, suggesting that a combination of crizotinib and chemotherapy could prevent ALK inhibitor resistance-specific relapse.

Vinblastine monotherapy induction prior to radiotherapy for patients with intracranial germinoma during the COVID-19 pandemic.

BACKGROUND: Patients with localized intracranial germinoma have excellent survival. Reducing treatment burden and long-term sequelae is a priority. Intensive inpatient chemotherapy (e.g., carboPEI = carboplatin/etoposide/ifosfamide) has been effectively employed to reduce radiotherapy treatment volume/dose. Outpatient-based carboplatin monotherapy is associated with excellent outcomes in metastatic testicular seminoma (an identical pathology), and successful vinblastine monotherapy induction (with 77% tumor volume reduction after just two weekly vinblastine doses) has recently been reported in an intracranial germinoma patient. METHODS: Adapted UK guidelines for germ cell tumor management were distributed during the COVID-19 pandemic, including nonstandard treatment options to reduce hospital visits and/or admissions. This included vinblastine monotherapy for intracranial germinoma (6 mg/m2 intravenously, or 4 mg/m2 for moderate count suppression, delivered weekly). We describe two such patients treated using this approach. RESULTS: A 30-year-old male with a localized pineal tumor received 12-week vinblastine induction, with >60% volume reduction, prior to definitive radiotherapy. A 12-year-old female with a metastatic suprasellar tumor and progression at all sites of disease whilst awaiting proton radiotherapy received two vinblastine doses with good early response, including 36% primary tumor volume reduction. The patients tolerated vinblastine well. CONCLUSION: Patients with intracranial germinoma have excellent outcomes, and reduction of late effects remains a priority. The description of vinblastine monotherapy in these intracranial germinoma patients warrants further exploration.

Clinical utility of vinblastine therapeutic drug monitoring for the treatment of infantile myofibroma patients: A case series.

Infantile myofibroma is a rare, benign tumour of infancy typically managed surgically. In a minority of cases, more aggressive disease is seen and chemotherapy with vinblastine and methotrexate may be used, although evidence for this is limited. Chemotherapy dosing in infants is challenging, and vinblastine disposition in infants is unknown. We describe the use of vinblastine therapeutic drug monitoring in four cases of infantile myofibroma. Marked inter- and intrapatient variability was observed, highlighting the poorly understood pharmacokinetics of vinblastine in children, the challenges inherent in treating neonates, and the role of adaptive dosing in optimising drug exposure in challenging situations.

Rare non-Hodgkin lymphoma of childhood and adolescence: A consensus diagnostic and therapeutic approach to pediatric-type follicular lymphoma, marginal zone lymphoma, and nonanaplastic peripheral T-cell lymphoma.

Pediatric-type follicular (PTFL), marginal zone (MZL), and peripheral T-cell lymphoma (PTCL) account each for <2% of childhood non-Hodgkin lymphoma. We present clinical and histopathological features of PTFL, MZL, and few subtypes of PTCL and provide treatment recommendations. For localized PTFL and MZL, watchful waiting after complete resection is the therapy of choice. For PTCL, therapy is subtype-dependent and ranges from a block-like anaplastic large cell lymphoma (ALCL)-derived and, alternatively, leukemia-derived therapy in PTCL not otherwise specified and subcutaneous panniculitis-like T-cell lymphoma to a block-like mature B-NHL-derived or, preferentially, ALCL-derived treatment followed by hematopoietic stem cell transplantation in first remission in hepatosplenic and angioimmunoblastic T-cell lymphoma.

Mechanisms of cell death induced by arginase and asparaginase in precursor B-cell lymphoblasts.

Arginase has therapeutic potential as a cytotoxic agent in some cancers, but this is unclear for precursor B acute lymphoblastic leukaemia (pre-B ALL), the commonest form of childhood leukaemia. We compared arginase cytotoxicity with asparaginase, currently used in pre-B ALL treatment, and characterised the forms of cell death induced in a pre-B ALL cell line 697. Arginase and asparaginase both efficiently killed 697 cells and mature B lymphoma cell line Ramos, but neither enzyme killed normal lymphocytes. Arginase depleted cellular arginine, and arginase-treated media induced cell death, blocked by addition of arginine or arginine-precursor citrulline. Asparaginase depleted both asparagine and glutamine, and asparaginase-treated media induced cell death, blocked by asparagine, but not glutamine. Both enzymes induced caspase cleavage and activation, chromatin condensation and phosphatidylserine exposure, indicating apoptosis. Both arginase- and asparaginase-induced death were blocked by caspase inhibitors, but with different sensitivities. BCL-2 overexpression inhibited arginase- and asparaginase-induced cell death, but did not prevent arginase-induced cytostasis, indicating a different mechanism of growth arrest. An autophagy inhibitor, chloroquine, had no effect on the cell death induced by arginase, but doubled the cell death induced by asparaginase. In conclusion, arginase causes death of lymphoblasts by arginine-depletion induced apoptosis, via mechanism distinct from asparaginase. Therapeutic implications for childhood ALL include: arginase might be used as treatment (but antagonised by dietary arginine and citrulline), chloroquine may enhance efficacy of asparaginase treatment, and partial resistance to arginase and asparaginase may develop by BCL-2 expression. Arginase or asparaginase might potentially be used to treat Burkitt lymphoma.

From bench to bedside: the past, present and future of therapy for systemic paediatric ALCL, ALK.

Anaplastic large cell lymphoma (ALCL) is a T cell Non-Hodgkin Lymphoma that mainly presents in paediatric and young adult patients. The majority of cases express a chimeric fusion protein resulting in hyperactivation of anaplastic lymphoma kinase (ALK) as the consequence of a chromosomal translocation. Rarer cases lack expression of ALK fusion proteins and are categorised as ALCL, ALK-. An adapted regimen of an historic chemotherapy backbone is still used to this day, yielding overall survival (OS) of over 90% but with event-free survival (EFS) at an unacceptable 70%, improving little over the past 30 years. It is clear that continued adaption of current therapies will probably not improve these statistics and, for progress to be made, integration of biology with the design and implementation of future clinical trials is required. Indeed, advances in our understanding of the biology of ALCL are outstripping our ability to clinically translate them; laboratory-based research has highlighted a plethora of potential therapeutic targets but, with high survival rates combined with a scarcity of funding and patients to implement paediatric trials of novel agents, progress is slow. However, advances must be made to reduce the side-effects of intensive chemotherapy regimens whilst maintaining, if not improving, OS and EFS.

Sonographic markers of fetal adiposity and risk of Cesarean delivery.

OBJECTIVE: Increased fetal size is associated with shoulder dystocia during labor and subsequent need for assisted delivery. We sought to investigate if increased fetal adiposity diagnosed sonographically in late pregnancy is associated with increased risk of operative delivery. METHODS: This secondary analysis of the Genesis Study recruited 2392 nulliparous women with singleton pregnancy in cephalic presentation, in a prospective, multicenter study, to examine prenatal and intrapartum predictors of Cesarean delivery. Participants underwent ultrasound and clinical evaluation between 39 + 0 and 40 + 6 weeks' gestation. Data on fetal biometry were not revealed to patients or to their managing clinicians. A fetal adiposity composite of fetal thigh adiposity and fetal abdominal wall thickness was compiled for each infant in order to determine whether fetal adiposity > 90th centile was associated with an increased risk of Cesarean or operative vaginal delivery. RESULTS: After exclusions, data were available for 2330 patients. Patients with a fetal adiposity composite > 90th centile had a higher maternal body mass index (BMI) (25 ± 5 kg/m2 vs 24 ± 4 kg/m2 ; P = 0.005), birth weight (3872 ± 417 g vs 3585 ± 401 g; P < 0.0001) and rate of induction of labor (47% (108/232) vs 40% (834/2098); P = 0.048) than did those with an adiposity composite ≤ 90th centile. Fetuses with adiposity composite > 90th centile were more likely to require Cesarean delivery than were those with adiposity composite ≤ 90th centile (P < 0.0001). After adjusting for birth weight, maternal BMI and need for induction of labor, fetal adiposity > 90th centile remained a risk factor for Cesarean delivery (P < 0.0001). A fetal adiposity composite > 90th centile was more predictive of the need for unplanned Cesarean delivery than was an estimated fetal weight > 90th centile (odds ratio, 2.20 (95% CI, 1.65-2.94; P < 0.001) vs 1.74 (95% CI, 1.29-2.35; P < 0.001). Having an adiposity composite > 90th centile was not associated with an increased likelihood of operative vaginal delivery when compared with having an adiposity composite ≤ 90th centile (P = 0.37). CONCLUSIONS: Fetuses with increased adipose deposition are more likely to require Cesarean delivery than are those without increased adiposity. Consideration should, therefore, be given to adding fetal thigh adiposity and abdominal wall thickness to fetal sonographic assessment in late pregnancy. Copyright © 2019 ISUOG. Published by John Wiley & Sons Ltd.

Development and validation of Spasticity Index-Amyotrophic Lateral Sclerosis.

OBJECTIVES: Spasticity is a common and disabling feature of amyotrophic lateral sclerosis (ALS). There are currently no validated ALS-specific measures of spasticity. The aim of this study was to develop and use a self-report outcome measure for spasticity in ALS. METHODS: Following semi-structured interviews with 11 ALS patients, a draft scale was administered across ALS clinics in the UK. Internal validity of the scale was examined using the Rasch model. The numerical rating scale (NRS) for spasticity and Leeds Spasticity scale (LSS) were co-administered. The final scale was used in a path model of spasticity and quality of life. RESULTS: A total of 465 patients (mean age 64.7 years (SD 10), 59% male) with ALS participated. Spasticity was reported by 80% of subjects. A pool of 71 items representing main themes of physical symptoms, negative impact and modifying factors was subject to an iterative process of item reduction by Rasch analysis resulting in a 20-item scale-the Spasticity Index for ALS (SI-ALS)-which was unidimensional and free from differential item functioning. Moderate correlations were found with LSS and NRS-spasticity. Incorporating the latent estimate of spasticity into a path model, greater spasticity reduced quality of life and motor function; higher motor function was associated with better quality of life. CONCLUSIONS: The SI-ALS is a disease-specific self-report scale, which provides a robust interval-level measure of spasticity in ALS. Spasticity has a substantial impact on quality of life in ALS.

The significance of breastfeeding on sleep patterns during the first 48 hours postpartum for first time mothers.

Postpartum women sleep less during the early days following delivery. Long-term sleep disturbance and fatigue can have significant implications for physical and mental health, relationships, employment and parental competence. Most studies focus on the quality and quantity of maternal sleep between weeks one and six postpartum. We explored sleep patterns and reasons for wakefulness of first-time mothers immediately following delivery. Thirty first-time mothers completed a postnatal sleep questionnaire, detailing their total sleep time (TST), the reasons for being awake and their level of fatigue. The logs were completed in real time during the first 48 h postpartum, while they were still in a hospital environment. The data collected from the mothers in the study indicated that the mean TST in the first 48 h was 9.7 h. Of the factors explored only breastfeeding influenced the TST. Breastfeeding women slept on average 2.6 h longer than women who bottle-fed (p = .042). Impact statement What is already known on this subject: Childbearing affects women's sleep in many ways. Hormonal changes during pregnancy and postpartum as well as physiological and anatomical alterations, and the process of adaptation to the new parent's responsibilities contribute to changes in sleep architecture. Since first study of sleep and pregnancy published in 1968 there have been very few publications addressing maternal sleep postpartum. Most studies which have focussed on quality of maternal sleep in the first 6-months postpartum period describe the relationships between poor maternal sleep and postpartum depression and other mental health outcomes. What the results of this study add: We explored sleep patterns and reasons for wakefulness of first-time mothers immediately following delivery while they remained in the hospital environment. We found that environmental factors such as background noise, shared rooms, type of delivery, feeding and worrying about the neonate did not influence the total sleep time, however, the main outcome of our study is that breastfeeding promotes maternal sleep. What the implications are of these findings for clinical practice and/or further research: We believe that this study would be of interest to many obstetricians, general practitioners, nurses and midwives as well as to the general public. Appropriate counselling of patients early in postnatal period can improve their sleep patterns and reduce the risk of depression and other abnormal physical, psychological and social outcomes.

Risk Factors for Type 1 Diabetes Recurrence in Immunosuppressed Recipients of Simultaneous Pancreas-Kidney Transplants.

Patients with type 1 diabetes (T1D) who are recipients of pancreas transplants are believed to rarely develop T1D recurrence in the allograft if effectively immunosuppressed. We evaluated a cohort of 223 recipients of simultaneous pancreas-kidney allografts for T1D recurrence and its risk factors. With long-term follow-up, recurrence was observed in approximately 7% of patients. Comparing the therapeutic regimens employed in this cohort over time, lack of induction therapy was associated with recurrence, but this occurs even with the current regimen, which includes induction; there was no influence of maintenance regimens. Longitudinal testing for T1D-associated autoantibodies identified autoantibody positivity, number of autoantibodies, and autoantibody conversion after transplantation as critical risk factors. Autoantibodies to the zinc transporter 8 had the strongest and closest temporal association with recurrence, which was not explained by genetically encoded amino acid sequence donor-recipient mismatches for this autoantigen. Genetic risk factors included the presence of the T1D-predisposing HLA-DR3/DR4 genotype in the recipient and donor-recipient sharing of HLA-DR alleles, especially HLA-DR3. Thus, T1D recurrence is not uncommon and is developing in patients treated with current immunosuppression. The risk factors identified in this study can be assessed in the transplant clinic to identify recurrent T1D and may lead to therapeutic advances.

Pretransplant CD4 Count Influences Immune Reconstitution and Risk of Infectious Complications in Human Immunodeficiency Virus-Infected Kidney Allograft Recipients.

In current practice, human immunodeficiency virus-infected (HIV(+) ) candidates with CD4 >200 cells/mm(3) are eligible for kidney transplantation; however, the optimal pretransplant CD4 count above this threshold remains to be defined. We evaluated clinical outcomes in patients with baseline CD4 >350 and <350 cells/mm(3) among 38 anti-thymocyte globulin (ATG)-treated HIV-negative to HIV(+) kidney transplants performed at our center between 2006 and 2013. Median follow-up was 2.6 years. Rates of acute rejection and patient and graft survival were not different between groups. Occurrence of severe CD4 lymphopenia (<200 cells/mm(3) ), however, was more common among patients with a baseline CD4 count 200-349 cells/mm(3) compared with those transplanted at higher counts (75% vs. 30% at 4 weeks [p = 0.04] and 71% vs. 5% at 52 weeks [p = 0.001], respectively, after transplant). After adjusting for age, baseline CD4 count of 200-349 cells/mm(3) was an independent predictor of severe CD4 lymphopenia at 4 weeks (relative risk [RR] 2.6; 95% confidence interval [CI] 1.3-5.1) and 52 weeks (RR 14.3; 95% CI 2-100.4) after transplant. Patients with CD4 <200 cells/mm(3) at 4 weeks had higher probability of serious infections during first 6 months after transplant (19% vs. 50%; log-rank p = 0.05). These findings suggest that ATG must be used with caution in HIV(+) kidney allograft recipients with a pretransplant CD4 count <350 cells/mm(3) .