B-cell-directed CAR-T cell therapy activates CD8+ cytotoxic CARneg bystander T-cells in non-human primates and patients

CAR-T cells hold promise as a therapy for B-cell-derived malignancies, yet despite their impressive initial response rates, a significant proportion of patients ultimately experience relapse. While recent studies have explored the mechanisms of in vivo CAR-T cell function, little is understood about the activation of surrounding CARneg bystander T-cells and their potential to enhance tumor responses. We performed single-cell RNA-Seq (scRNA-Seq) on non-human primate (NHP) and patient-derived T-cells to identify the phenotypic and transcriptomic hallmarks of bystander activation of CARneg T-cells following B-cell targeted CAR-T cell therapy. Utilizing a highly translatable CD20 CAR NHP model, we observed a distinct population of activated CD8+ CARneg T-cells emerging during CAR-T cell expansion. These bystander CD8+ CARneg T-cells exhibited a unique transcriptional signature with upregulation of NK-cell markers (KIR3DL2, CD160, KLRD1), chemokines and chemokine receptors (CCL5, XCL1, CCR9), and downregulation of naive T-cell-associated genes (SELL, CD28). A transcriptionally similar population was identified in patients following Tisagenlecleucel infusion. Mechanistic studies revealed that IL-2 and IL-15 exposure induced bystander-like CD8+ T-cells in a dose dependent manner. In vitro activated and patient-derived T-cells with the bystander phenotype efficiently killed leukemic cells through a TCR-independent mechanism. Collectively, this dataset provides the first comprehensive identification and profiling of CARneg bystander CD8+ T-cells following B-cell targeting CAR-T cell therapy and suggests a novel mechanism through which CAR-T cell infusion might trigger enhanced anti-leukemic responses.

Relevance of lymphocyte proliferation to PHA in severe combined immunodeficiency (SCID) and T cell lymphopenia

Severe combined immunodeficiency (SCID) is characterized by a severe deficiency in T cell numbers. We analyzed data collected (n = 307) for PHA-based T cell proliferation from the PIDTC SCID protocol 6901, using either a radioactive or flow cytometry method. In comparing the two groups, a smaller number of the patients tested by flow cytometry had <10% of the lower limit of normal proliferation as compared to the radioactive method (p = 0.02). Further, in patients with CD3+ T cell counts between 51 and 300 cells/μL, there was a higher proliferative response with the PHA flow assay compared to the 3H-T assay (p < 0.0001), suggesting that the method of analysis influences the resolution and interpretation of PHA results. Importantly, we observed many SCID patients with profound T cell lymphopenia having normal T cell proliferation when assessed by flow cytometry. We recommend this test be considered only as supportive in the diagnosis of typical SCID.

Allogeneic hematopoietic cell transplantation is effective for p47phox chronic granulomatous disease: A Primary Immune Deficiency Treatment Consortium study

BACKGROUND

P47phox (neutrophil cytosolic factor-1) deficiency is the most common cause of autosomal recessive chronic granulomatous disease (CGD) and is considered to be associated with a milder clinical phenotype. Allogeneic hematopoietic cell transplantation (HCT) for p47phox CGD is not well-described.

OBJECTIVES

We sought to study HCT for p47phox CGD in North America.

METHODS

Thirty patients with p47phox CGD who received allogeneic HCT at Primary Immune Deficiency Treatment Consortium centers since 1995 were included.

RESULTS

Residual oxidative activity was present in 66.7% of patients. In the year before HCT, there were 0.38 CGD-related infections per person-years. Inflammatory diseases, predominantly of the lungs and bowel, occurred in 36.7% of the patients. The median age at HCT was 9.1 years (range 1.5-23.6 years). Most HCTs (90%) were performed after using reduced intensity/toxicity conditioning. HCT sources were HLA-matched (40%) and -mismatched (10%) related donors or HLA-matched (36.7%) and -mismatched (13.3%) unrelated donors. CGD-related infections after HCT decreased significantly to 0.06 per person-years (P = .038). The frequency of inflammatory bowel disease and the use of steroids also decreased. The cumulative incidence of graft failure and second HCT was 17.9%. The 2-year overall and event-free survival were 92.3% and 82.1%, respectively, while at 5 years they were 85.7% and 77.0%, respectively. In the surviving patients evaluated, ≥95% donor myeloid chimerism at 1 and 2 years after HCT was 93.8% and 87.5%, respectively.

CONCLUSIONS

Patients with p47phox CGD suffer from a significant disease burden that can be effectively alleviated by HCT. Similar to other forms of CGD, HCT should be considered for patients with p47phox CGD.

Posttransplantation late complications increase over time for patients with SCID: A Primary Immune Deficiency Treatment Consortium (PIDTC) landmark study

BACKGROUND

The Primary Immune Deficiency Treatment Consortium (PIDTC) enrolled children in the United States and Canada onto a retrospective multicenter natural history study of hematopoietic cell transplantation (HCT).

OBJECTIVE

We investigated outcomes of HCT for severe combined immunodeficiency (SCID).

METHODS

We evaluated the chronic and late effects (CLE) after HCT for SCID in 399 patients transplanted from 1982 to 2012 at 32 PIDTC centers. Eligibility criteria included survival to at least 2 years after HCT without need for subsequent cellular therapy. CLE were defined as either conditions present at any time before 2 years from HCT that remained unresolved (chronic), or new conditions that developed beyond 2 years after HCT (late).

RESULTS

The cumulative incidence of CLE was 25% in those alive at 2 years, increasing to 41% at 15 years after HCT. CLE were most prevalent in the neurologic (9%), neurodevelopmental (8%), and dental (8%) categories. Chemotherapy-based conditioning was associated with decreased-height z score at 2 to 5 years after HCT (P < .001), and with endocrine (P < .001) and dental (P = .05) CLE. CD4 count of ≤500 cells/μL and/or continued need for immunoglobulin replacement therapy >2 years after transplantation were associated with lower-height z scores. Continued survival from 2 to 15 years after HCT was 90%. The presence of any CLE was associated with increased risk of late death (hazard ratio, 7.21; 95% confidence interval, 2.71-19.18; P < .001).

CONCLUSION

Late morbidity after HCT for SCID was substantial, with an adverse impact on overall survival. This study provides evidence for development of survivorship guidelines based on disease characteristics and treatment exposure for patients after HCT for SCID.

Genotype, oxidase status, and preceding infection or autoinflammation do not affect allogeneic HCT outcomes for CGD

Chronic granulomatous disease (CGD) is a primary immunodeficiency characterized by life-threatening infections and inflammatory conditions. Hematopoietic cell transplantation (HCT) is the definitive treatment for CGD, but questions remain regarding patient selection and impact of active disease on transplant outcomes. We performed a multi-institutional retrospective and prospective study of 391 patients with CGD treated either conventionally (non-HCT) enrolled from 2004 to 2018 or with HCT from 1996 to 2018. Median follow-up after HCT was 3.7 years with a 3-year overall survival of 82% and event-free survival of 69%. In a multivariate analysis, a Lansky/Karnofsky score <90 and use of HLA-mismatched donors negatively affected survival. Age, genotype, and oxidase status did not affect outcomes. Before HCT, patients had higher infection density, higher frequency of noninfectious lung and liver diseases, and more steroid use than conventionally treated patients; however, these issues did not adversely affect HCT survival. Presence of pre-HCT inflammatory conditions was associated with chronic graft-versus-host disease. Graft failure or receipt of a second HCT occurred in 17.6% of the patients and was associated with melphalan-based conditioning and/or early mixed chimerism. At 3 to 5 years after HCT, patients had improved growth and nutrition, resolved infections and inflammatory disease, and lower rates of antimicrobial prophylaxis or corticosteroid use compared with both their baseline and those of conventionally treated patients. HCT leads to durable resolution of CGD symptoms and lowers the burden of the disease. Patients with active infection or inflammation are candidates for transplants; HCT should be considered before the development of comorbidities that could affect performance status. This trial was registered at www.clinicaltrials.gov as #NCT02082353.

Intestinal microbiome and metabolome signatures in patients with chronic granulomatous disease

BACKGROUND

Chronic granulomatous disease (CGD) is caused by defects in any 1 of the 6 subunits forming the nicotinamide adenine dinucleotide phosphate oxidase complex 2 (NOX2), leading to severely reduced or absent phagocyte-derived reactive oxygen species production. Almost 50% of patients with CGD have inflammatory bowel disease (CGD-IBD). While conventional IBD therapies can treat CGD-IBD, their benefits must be weighed against the risk of infection. Understanding the impact of NOX2 defects on the intestinal microbiota may lead to the identification of novel CGD-IBD treatments.

OBJECTIVE

We sought to identify microbiome and metabolome signatures that can distinguish individuals with CGD and CGD-IBD.

METHODS

We conducted a cross-sectional observational study of 79 patients with CGD, 8 pathogenic variant carriers, and 19 healthy controls followed at the National Institutes of Health Clinical Center. We profiled the intestinal microbiome (amplicon sequencing) and stool metabolome, and validated our findings in a second cohort of 36 patients with CGD recruited through the Primary Immune Deficiency Treatment Consortium.

RESULTS

We identified distinct intestinal microbiome and metabolome profiles in patients with CGD compared to healthy individuals. We observed enrichment for Erysipelatoclostridium spp, Sellimonas spp, and Lachnoclostridium spp in CGD stool samples. Despite differences in bacterial alpha and beta diversity between the 2 cohorts, several taxa correlated significantly between both cohorts. We further demonstrated that patients with CGD-IBD have a distinct microbiome and metabolome profile compared to patients without CGD-IBD.

CONCLUSION

Intestinal microbiome and metabolome signatures distinguished patients with CGD and CGD-IBD, and identified potential biomarkers and therapeutic targets.

Treatment of recurrent pediatric myelodysplastic syndrome post hematopoietic stem cell transplantation

Treatment of recurrent myelodysplastic syndrome (MDS) after hematopoietic cell transplantation (HCT) remains challenging. We present a 4-year-old girl experiencing early MDS relapse post-HCT treated with a multimodal strategy encompassing a second HCT and innovative targeted therapies. We underscore the potential of a comprehensive treatment approach in managing recurrent pediatric MDS.

Real-world experience with low-dose IL-2 for children and young adults with refractory chronic graft-versus-host disease

The majority of patients with chronic graft-versus-host disease (cGVHD) are steroid refractory (SR), creating a need for safe and effective therapies. Subcutaneous low-dose interleukin-2 (LD IL-2), which preferentially expands CD4+ regulatory T cells (Tregs), has been evaluated in 5 clinical trials at our center with partial responses (PR) in ∼50% of adults and 82% of children by week 8. We now report additional real-world experience with LD IL-2 in 15 children and young adults. We conducted a retrospective chart review of patients with SR-cGVHD at our center who received LD IL-2 from August 2016 to July 2022 not on a research trial. The median age at start of LD IL-2 was 10.4 years (range, 1.2-23.2 years) at a median of 234 days from cGVHD diagnosis (range, 11-542 days). Patients had a median of 2.5 (range, 1-3) active organs at LD IL-2 start and received a median of 3 (range, 1-5) prior therapies. The median duration of LD IL-2 therapy was 462 days (range, 8-1489 days). Most patients received 1 × 106 IU/m2 per day. There were no serious adverse effects. The overall response rate in 13 patients who received >4 weeks of therapy was 85% (complete response, n = 5; PR, n = 6) with responses in diverse organs. Most patients significantly weaned corticosteroids. Tregs preferentially expanded with a median peak fold increase of 2.8 in the ratio of Tregs to CD4+ conventional T cells (range, 2.0-19.8) by 8 weeks on therapy. LD IL-2 is a well-tolerated, steroid-sparing agent with a high response rate in children and young adults with SR-cGVHD.

Measuring the effect of newborn screening on survival after haematopoietic cell transplantation for severe combined immunodeficiency: a 36-year longitudinal study from the Primary Immune Deficiency Treatment Consortium

BACKGROUND

Severe combined immunodeficiency (SCID) is fatal unless durable adaptive immunity is established, most commonly through allogeneic haematopoietic cell transplantation (HCT). The Primary Immune Deficiency Treatment Consortium (PIDTC) explored factors affecting the survival of individuals with SCID over almost four decades, focusing on the effects of population-based newborn screening for SCID that was initiated in 2008 and expanded during 2010-18.

METHODS

We analysed transplantation-related data from children with SCID treated at 34 PIDTC sites in the USA and Canada, using the calendar time intervals 1982-89, 1990-99, 2000-09, and 2010-18. Categorical variables were compared by χ2 test and continuous outcomes by the Kruskal-Wallis test. Overall survival was estimated by the Kaplan-Meier method. A multivariable analysis using Cox proportional hazards regression models examined risk factors for HCT outcomes, including the variables of time interval of HCT, infection status and age at HCT, trigger for diagnosis, SCID type and genotype, race and ethnicity of the patient, non-HLA-matched sibling donor type, graft type, GVHD prophylaxis, and conditioning intensity.

FINDINGS

For 902 children with confirmed SCID, 5-year overall survival remained unchanged at 72%-73% for 28 years until 2010-18, when it increased to 87% (95% CI 82·1-90·6; n=268; p=0·0005). For children identified as having SCID by newborn screening since 2010, 5-year overall survival was 92·5% (95% CI 85·8-96·1), better than that of children identified by clinical illness or family history in the same interval (79·9% [69·5-87·0] and 85·4% [71·8-92·8], respectively [p=0·043]). Multivariable analysis demonstrated that the factors of active infection (hazard ratio [HR] 2·41, 95% CI 1·56-3·72; p<0·0001), age 3·5 months or older at HCT (2·12, 1·38-3·24; p=0·001), Black or African-American race (2·33, 1·56-3·46; p<0·0001), and certain SCID genotypes to be associated with lower overall survival during all time intervals. Moreover, after adjusting for several factors in this multivariable analysis, HCT after 2010 no longer conveyed a survival advantage over earlier time intervals studied (HR 0·73, 95% CI 0·43-1·26; p=0·097). This indicated that younger age and freedom from infections at HCT, both directly driven by newborn screening, were the main drivers for recent improvement in overall survival.

INTERPRETATION

Population-based newborn screening has facilitated the identification of infants with SCID early in life, in turn leading to prompt HCT while avoiding infections. Public health programmes worldwide can benefit from this definitive demonstration of the value of newborn screening for SCID.

FUNDING

National Institute of Allergy and Infectious Diseases, Office of Rare Diseases Research, and National Center for Advancing Translational Sciences.

The diagnosis of severe combined immunodeficiency: Implementation of the PIDTC 2022 Definitions

BACKGROUND

Shearer et al in 2014 articulated well-defined criteria for the diagnosis and classification of severe combined immunodeficiency (SCID) as part of the Primary Immune Deficiency Treatment Consortium's (PIDTC's) prospective and retrospective studies of SCID.

OBJECTIVE

Because of the advent of newborn screening for SCID and expanded availability of genetic sequencing, revision of the PIDTC 2014 Criteria was needed.

METHODS

We developed and tested updated PIDTC 2022 SCID Definitions by analyzing 379 patients proposed for prospective enrollment into Protocol 6901, focusing on the ability to distinguish patients with various SCID subtypes.

RESULTS

According to PIDTC 2022 Definitions, 18 of 353 patients eligible per 2014 Criteria were considered not to have SCID, whereas 11 of 26 patients ineligible per 2014 Criteria were determined to have SCID. Of note, very low numbers of autologous T cells (<0.05 × 109/L) characterized typical SCID under the 2022 Definitions. Pathogenic variant(s) in SCID-associated genes was identified in 93% of patients, with 7 genes (IL2RG, RAG1, ADA, IL7R, DCLRE1C, JAK3, and RAG2) accounting for 89% of typical SCID. Three genotypes (RAG1, ADA, and RMRP) accounted for 57% of cases of leaky/atypical SCID; there were 13 other rare genotypes. Patients with leaky/atypical SCID were more likely to be diagnosed at more than age 1 year than those with typical SCID lacking maternal T cells: 20% versus 1% (P < .001). Although repeat testing proved important, an initial CD3 T-cell count of less than 0.05 × 109/L differentiated cases of typical SCID lacking maternal cells from leaky/atypical SCID: 97% versus 7% (P < .001).

CONCLUSIONS

The PIDTC 2022 Definitions describe SCID and its subtypes more precisely than before, facilitating analyses of SCID characteristics and outcomes.

Secondary Impact of the Coronavirus Disease 19 Pandemic on Patients and the Cellular Therapy Healthcare Ecosystem

The Coronavirus disease 2019 (COVID-19) pandemic, caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has significantly impacted global health and healthcare delivery systems. To characterize the secondary effects of the COVID-19 pandemic and mitigation strategies used in the delivery of hematopoietic stem cell transplantation (HSCT) care, we performed a comprehensive literature search encompassing changes in specific donor collection, processing practices, patient outcomes, and patient-related concerns specific to HSCT and HSCT-related healthcare delivery. In this review, we summarize the available literature on the secondary impacts the COVID-19 pandemic on the fields of HSCT and cellular therapy. The COVID-19 pandemic has had numerous secondary impacts on patients undergoing HSCT and the healthcare delivery systems involved in providing complex care to HSCT recipients. Institutions must identify these influences on outcomes and adjust accordingly to maintain and improve outcomes for the transplantation and cellular therapy community.

Outcomes following treatment for ADA-deficient severe combined immunodeficiency: a report from the PIDTC

Adenosine deaminase (ADA) deficiency causes ∼13% of cases of severe combined immune deficiency (SCID). Treatments include enzyme replacement therapy (ERT), hematopoietic cell transplant (HCT), and gene therapy (GT). We evaluated 131 patients with ADA-SCID diagnosed between 1982 and 2017 who were enrolled in the Primary Immune Deficiency Treatment Consortium SCID studies. Baseline clinical, immunologic, genetic characteristics, and treatment outcomes were analyzed. First definitive cellular therapy (FDCT) included 56 receiving HCT without preceding ERT (HCT); 31 HCT preceded by ERT (ERT-HCT); and 33 GT preceded by ERT (ERT-GT). Five-year event-free survival (EFS, alive, no need for further ERT or cellular therapy) was 49.5% (HCT), 73% (ERT-HCT), and 75.3% (ERT-GT; P < .01). Overall survival (OS) at 5 years after FDCT was 72.5% (HCT), 79.6% (ERT-HCT), and 100% (ERT-GT; P = .01). Five-year OS was superior for patients undergoing HCT at <3.5 months of age (91.6% vs 68% if ≥3.5 months, P = .02). Active infection at the time of HCT (regardless of ERT) decreased 5-year EFS (33.1% vs 68.2%, P < .01) and OS (64.7% vs 82.3%, P = .02). Five-year EFS (90.5%) and OS (100%) were best for matched sibling and matched family donors (MSD/MFD). For patients treated after the year 2000 and without active infection at the time of FDCT, no difference in 5-year EFS or OS was found between HCT using a variety of transplant approaches and ERT-GT. This suggests alternative donor HCT may be considered when MSD/MFD HCT and GT are not available, particularly when newborn screening identifies patients with ADA-SCID soon after birth and before the onset of infections. This trial was registered at www.clinicaltrials.gov as #NCT01186913 and #NCT01346150.

Quality Improvement in Hematopoietic Stem Cell Transplant and Cellular Therapy: Using the Model for Improvement to impact Outcomes

Quality improvement and quality assurance form a complementary and independent relationship. Quality assurance measures compliance against industry standards utilizing audits, whereas quality improvement is a continuous process focused on processes and systems that can improve care. The Model for Improvement is a robust quality improvement tool that transplant and cellular therapy teams can employ to redesign healthcare processes. The Model for Improvement utilizes several components addressed in sequence to organize and critically evaluate improvement activities. Unlike other health sciences clinical research, quality improvement projects, and research are based on dynamic hypotheses that develop into observable, serial tests of change with continuous collection and feedback of performance data to stakeholders.

Safety of Surgical Fertility Preservation Procedures in Children Prior to Hematopoietic Stem Cell Transplant

Long-term survival following hematopoietic stem cell transplant (HSCT) in childhood continues to improve, and patients are thus increasingly faced with the late effects of treatment. Infertility is very common for both males and females following HSCT and is one of the most distressing sequelae. Adoption and surrogate egg or sperm donation are possibilities for some patients, but post-HSCT reversal of gonadal failure is not possible. We have recently initiated an oncofertility program with a dedicated practitioner with specific expertise in this area. Our practice is for her to meet with all families and age-appropriate patients during the pre-HSCT evaluation period. This allows patients and families to be accurately informed about the expected treatment-related infertility risk and the available options for fertility preservation. Sperm banking and egg or embryo cryopreservation are established approaches but are not achievable for many children and adolescents. Recently, the harvesting and cryopreservation of ovarian and testicular tissue represents a novel surgical option that allows for the possibility of fertility preservation to be extended to children of all ages. The purpose of this investigation is to evaluate the safety of these procedures proximal to conditioning therapy and HSCT. This is a retrospective report on a consecutive cohort of all patients aged 0 to 25 years who, after discussion with our oncofertility specialist, chose to undergo surgical fertility preservation (laparoscopic unilateral oophorectomy or testicular biopsy) at our institution between March 2018 and April 2020. These procedures occurred under general anesthesia at the time of central line placement prior to the initiation of HSCT conditioning. We assess the safety of the procedures in terms of postoperative complications and impact on HSCT course. Twenty-two patients underwent fertility preservation surgical procedures. Thirteen patients (59%) were female, median age 13 years (1 to 22 years), and 9 (41%) were male, median age 8 years (5 to 12 years). Fourteen (63%) were prepubertal and 8 (36%) pubertal. HSCT indications were hematologic malignancies/solid tumor (40%) and nonmalignant diseases (60%). Most received an allogenic graft (68%) and 81% had myeloablative conditioning. All patients became neutropenic at a median of 10 days (0 to 51 days) from the surgical procedure; 1 was neutropenic at the time of testicular tissue cryopreservation (TTC). The mean duration for the procedures performed, including ovarian tissue cryopreservation (OTC) or TTC, was 98 minutes (49 to 260 minutes) and 97 minutes (56 to 178 minutes), respectively. Estimated blood loss was minimal and no postoperative site infections occurred. One postprocedure, blood culture-negative fever was reported without an identifiable source; the patient completed 48 hours of antibiotics with resolution of fever. Sixty-two percent of females and 56% of males started conditioning within 24 hours of OTC/TTC (15 hours to 113 days; median, 1 day). The median time to engraftment was 22 days (9 to 33 days) in females and 17 days (11 to 67 days) in males, consistent with our institutional benchmarks. One patient with aplastic anemia had primary graft failure, attributed to low cell dose. This patient engrafted after a second transplant from an alternative donor but ultimately died of multiorgan failure. He was neutropenic for over 60 days and never experienced surgical site infection. There were no procedure-related delays to start of conditioning or to discharge. Children of all ages can now be offered the possibility of fertility preservation following HSCT for benign and malignant conditions. Our review suggests that these procedure for both females and males can be performed close to the start of conditioning, which allows for coupling with central access placement. These procedures appear to be safe and do not add to transplant-related morbidity.

FRI0403 CLINICAL FEATURES OF PROSTHETIC JOINT INFECTIONS DIFFER IN PATIENTS WITH INFLAMMATORY ARTHRITIS AND OSTEOARTHRITIS

Background:

Inflammatory arthritis (IA) patients are at increased risk for prosthetic joint infections (PJI). However, because active IA patients without infections can have elevated inflammatory markers that mimic joint infection, PJI diagnosis is challenging in this population.

Objectives:

We used an institutional PJI registry to identify and compare the clinical, microbiologic, and histopathologic features of culture positive (CP) and culture negative (CN) total hip and knee PJI in IA and OA patients. We also evaluated the relationship between culture positivity, IA, and clinical outcomes.

Methods:

A retrospective cohort of THA/TKA PJIs, from 2009 to 2016, were identified by ICD codes, and confirmed by chart review. IA diagnosis was also confirmed by use of IA-specific medications. CN cases were defined as PJIs with no evidence of microbial growth in intraoperative cultures and CP PJI cases were defined by positive microbial growth in intraoperative cultures. Treatment failure was defined as subsequent surgical treatment for infection after the initial infection surgery. H&E slides of OA and IA PJI cases matched by age (+/-5) sex, and culture status were reviewed by a pathologist for evidence of the histopathologic features listed in Table 2. Fisher’s exact test, chi-square test, and Kaplan-Meier estimates were used.

TABLE 1.

Patient characteristics in IA and OA PJIs

IAOAN%/SDN%/SDp-valueTotal36771Age58.511.466.812<.001BMI30.26.7306.70.861Female2877.833243.1<.001CCI2.81.71.72.10.002Smoking411.18611.20.792Glucorticoids1027.8395.1<.001Culture Negative1027.810914.10.024Treatment Success at 2 years1952.8509660.146

IA- inflammatory arthritis; OA – osteoarthritis; PJI -prosthetic joint infection; CCI – Charlson Comorbidity Index

TABLE 2.

Histopathology and clinical presentation in IA and OA PJIs

OA (N=57)IA (N= 31)CP-IA (N=23)CN-IA (N=8)N (%)p-valueN (%)p-valuePathology Review>10 PMN per HPF42 (74)22 (71)0.80620 (87)2 (25)0.003Chronic Inflammation13 (23)23 (74)0.00118 (78)5 (63)0.393Necrosis17 (30)9 (29)18 (35)1 (13)0.38Clinical PresentationMSIS50 (88)26 (84)0.74722 (96)4 (50)0.009Sinus Tract7 (12)7 (23)0.2335 (22)2 (25)1Elevated ESR or CRP41 (72)24 (77)0.62217 (74)7 (88)1Elevated Synovial WBC33 (58)19 (61)0.82313 (57)6 (75)1Elevated Synovial %PMN31 (54)20 (65)0.37714 (61)6 (75)0.333

OA – osteoarthritis; IA – inflammatory arthritis; CP – culture positive; CN – culture negative; MSIS – meets Musculoskeletal Infection Society diagnostic criteria

Results:

807 PJI cases were identified including 36 IA (33 RA and 3 SLE) and 771 OA. A higher proportion of IA PJI were CN (N=10, 27%) vs. OA PJI (N=109, 14%, p=0.02). IA-PJI were younger, female, on glucocorticoids, and with more comorbidities. Type of surgical treatment did not differ significantly between IA and OA groups. Comparing CN-IA vs. CP-IA, no difference was observed in age, smoking, diabetes, surgical treatment, IA-specific meds or Charlson comorbidities. One-year survivorship of CN-IA and CN-OA were 66% and 87% (p>0.05). Across all CP cases, 57% were staphylococcal, with no differences between groups. Treatment failure was more frequent for CP-IA (42%) compared to CP-OA (30%), (p=0.2).

Histopathology of 88 PJIs (31 IA and 57 OA) was reviewed. The IA cohort presented with more chronic inflammation (p=0.001) than the OA cohort. Within the IA cohort, a higher proportion of CP-IA had >10PMN per HPF (p= 0.003) and met MSIS criteria (p=0.009). Comparing CP-OA and CN-OA, there were no significant differences in histopathology findings or number of patients meeting MSIS criteria.

Conclusion:

IA PJIs are more likely to be culture negative than OA PJIs. Although our analysis was limited by our cohort size, our findings including differences in histopathology, and better clinical outcomes suggest the presence of biologic differences between CN and CP PJI that require further study.

Disclosure of Interests:

Milan Kapadia: None declared, Tania Pannellini: None declared, Carine Moezinia: None declared, Andy Miller: None declared, Mark Figgie: None declared, Peter Sculco: None declared, Michael Cross: None declared, Michael Henry: None declared, Linda Russell: None declared, Laura Donlin Consultant of: Consultant – Genentech/Roche, Allina Nocon: None declared, Susan Goodman Shareholder of: Reginosine- Investment, Grant/research support from: Novartis, Horizon, Consultant of: Novartis, Celgene, UCB

RAG1 high expression associated with IKZF1 dysfunction in adult B-cell acute lymphoblastic leukemia

The recombination mediated by recombination activating gene (RAG) is not only the dominant mutational process but also the predominant driver of oncogenic genomic rearrangement in acute lymphoblastic leukemia (ALL). It is further responsible for leukemic clonal evolution. In this study, significant RAG1 increase is observed in the subsets of B-ALL patients, and high expression of RAG1 is observed to be correlated with high proliferation markers. IKZF1-encoded protein, IKAROS, directly binds to the RAG1 promoter and regulates RAG1 expression in leukemic cells. CK2 inhibitor by increasing IKAROS activity significantly suppresses RAG1 expression in ALL in an IKAROS-dependent manner. Patients with IKZF1 deletion have significantly higher expression of RAG1 compared to that without IKZF1 deletion. CK2 inhibitor treatment also results in an increase in IKZF1 binding to the RAG1 promoter and suppression of RAG1 expression in primary ALL cells. Taken together, these results demonstrate that RAG1 high expression is associated with high proliferation markers in B-ALL. Our data for the first time proved that RAG1 expression is directly suppressed by IKAROS. Our results also reveal drive oncogenesis of B-ALL is driven by high expression of RAG1 with IKAROS dysfunction together, which have significance in an integrated prognostic model for adult ALL.

Do Peri-Transplant Respiratory Viral Infections Increase Incidence of Idiopathic Pneumonia Syndrome or Bronchiolitis Obliterans in Pediatric Pateints?

Background

Upper respiratory viral infections are common in the pediatric population. Idiopathic pneumonia syndrome (IPS) and bronchiolitis obliterans (BO) are rare, but devastating and life-threatening complications post hematopoietic stem cell transplant (HSCT). It has been suggested in work by others that IPS and BO are consequences of early inflammation, and recent data support this hypothesis (Versluys et al, Translational and Clinical Immunology, 2018). Respiratory viral infections early in the peri-transplant period may result in inflammation leading to development of IPS and BO post HSCT.

Objectives

The primary objective of this study was to determine whether pre-transplant respiratory viral infection or colonization increase incidence of IPS and BO. We hypothesized that patients who acquire respiratory viral infections in the peri-transplant period have increased incidence of IPS and BO.

Methods

We abstracted and analyzed clinically collected data and compared the frequency of post-transplant respiratory viral complications with the presence of upper respiratory viral infections within 30 days prior to transplant. A Broncho alveolar lavage (BAL) or a nasal swab were used to identify upper respiratory viral infections. Epstein Barr virus (EBV), cytomegalovirus (CMV) and other upper respiratory viral infections were tested in 181 patients, transplanted between 2008 and 2018. Outcomes studied included IPS, BO, transplant associated thrombotic microangiopathy (TMA), graft versus host disease (GVHD), and overall survival (OS). Patients who did not have a BAL or a nasal swab within 30 days prior to transplant were excluded.

Results

Forty seven of 181 patients had a positive BAL or nasal swab prior to HSCT (group A). There were 53 documented respiratory viral infections in group A. Two tested positive for either coronavirus, herpes simplex virus (HSV) or para-influenza virus, 3 tested positive for adenovirus, human herpes 6, influenza, or respiratory syncytial virus (RSV), EBV and CMV were detected in 9 patients, 1 patient had human metapneumovirus and there were 16 rhino virus infections documented prior to HSCT. Some patients tested positive for more than 1 respiratory viral infection at the time of testing.

Results of our study are summarized below in Figure 1.

Conclusion

Contrary to our hypothesis, our data do not support an association between upper respiratory viral infections prior to transplant and post-transplant IPS or BO. Our data may differ from the findings of others due to a relatively small number of events in our population, or to differences in patient populations being studied, or to differences in transplant strategies.

Intracranial malignant peripheral nerve sheath tumor variant: an unusual neurovascular phenotype sarcoma case invading through the petrous bone

INTRODUCTION

Intracranial malignant peripheral nerve sheath tumor (MPNST) is exceedingly rare. Previously reported cases of intracranial MPNST have been associated with development within a prominent cranial nerve.

METHODS

This is the first report of an MPNST with both nerve sheath and vascular phenotype that follows the neurovascular bundle, without arising in a major cranial nerve or in the setting of neurofibromatosis type 1 (NF1).

RESULTS

The patient is a 14-year-old boy with a history of worsening headaches for the past several months, left-sided hearing loss, nausea, vomiting, and vertigo. MRI was performed that demonstrated a large extra-axial tumor compressing the left infratemporal posterior temporal region. The tumor was associated with significant destruction of the superior portion of the petrous bone and extension through the petrous into the upper posterior fossa, immediately below the tentorium. The patient underwent surgical debulking and adjuvant chemotherapy with doxorubicin and ifosfamide. Pathology demonstrated a variant malignant peripheral nerve sheath tumor with both nerve sheath and vascular phenotype by immunostains. The patient's symptoms improved following treatment.

CONCLUSION

We present the first reported case of an intracranial MPNST variant that developed along the neurovascular bundle as a sarcoma with both nerve sheath and vascular phenotype through the petrous bone and not associated with a major cranial nerve or with stigmata of neurofibromatosis type 1 (NF1). Although this is an extremely unusual presentation due to location and lack of prominent cranial nerves in that location, it is not unusual for benign nerve sheath tumors to follow the neurovascular bundle through foramen of cortical long bone or pelvis. This case suggests that physicians should incorporate intracranial MPNST variant into their differential diagnosis in the cranium, even when tumor is not located near a prominent cranial nerve. Surgical debulking and adjuvant chemotherapy with doxorubicin and ifosfamide has led to improvement in patient symptoms.

Abstract 5507: RAG1 high expression associated with IKZF1 dysfunction in adult B-cell acute lymphoblastic leukemia

The recombination activating gene (RAG)-mediated recombination is the dominant mutational process and the predominant driver of oncogenic genomic rearrangement in acute lymphoblastic leukemia (ALL). This then leads to further leukemic clonal evolution. IKZF1 encodes a kruppel-like zinc finger protein, IKAROS that is essential for normal hematopoiesis and acts as a tumor suppressor in ALL. The genetic defects of a single IKZF1 allele are linked to the development of human ALL, characterized by an increased risk of relapses and poorer prognosis. We observed that RAG1 is significantly increased in subsets of B-ALL patients. High RAG1 expression correlates with high proliferation markers. IKAROS directly binds to the RAG1 promoter in B-ALL cells by quantitative chromatin-immunoprecipitation assay. IKAROS suppresses RAG1 promoter activity by luciferase reporter assay. Lentiviral IKAROS expression significantly suppresses RAG1 expression, but IKAROS shRNA promotes RAG1 expression in B-ALL cells. CK2 inhibitor by restoring IKAROS activity, significantly suppresses RAG1 expression in an IKAROS-dependent manner in B-ALL cells. RAG1 expression is significantly higher in patients with IKZF1 deletion, as compared to patients without IKZF1 deletion. Treatment with CK2 inhibitor also results in an increase in IKZF1 binding to the RAG1 promoter and suppression of RAG1 expression in primary B-ALL cells. Taken together, our results demonstrate that high expression of RAG1 correlates with high proliferation markers in B-ALL, and are the first to demonstrate that IKAROS directly suppresses RAG1 expression. Our data suggest RAG1 high expression works together with IKAROS dysfunction to drive oncogenesis of B-ALL, which have significance in an integrated prognostic model for adult ALL.

Citation Format: zheng Ge, Qi Han, Jinlong Ma, Yan Gu, Huihui Song, Malika Kapadia, Sinisa Dovat, Chunhua Song. RAG1 high expression associated with IKZF1 dysfunction in adult B-cell acute lymphoblastic leukemia [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 5507.

Casein Kinase II (CK2) as a Therapeutic Target for Hematological Malignancies

BACKGROUND

Casein kinase II (CK2) is a pro-oncogenic protein, which is emerging as a promising therapeutic target in cancer. Recent studies have revealed an important role for CK2 in tumorigenesis. High levels of CK2 are noted in many malignancies including leukemia. Use of CK2 inhibitors in various malignancies including breast, prostate, and lung cancer are being tested. Although many CK2 inhibitors exist, only a few have emerged as selective inhibitors that are potent and effective. CX-4945 is a selective, orallybioavailable small molecule inhibitor, which has shown encouraging results in pre-clinical models of leukemia.

METHODS

In this review we will elaborate on the structure and physiological function of the CK2 protein as well as its role in cancer. We will review, in depth, the role of CK2 in leukemia and its mechanisms of tumorigenesis via phosphorylation of the tumor suppressor protein Ikaros. We will discuss both the importance of Ikaros in leukemia suppression and the restoration of Ikaros' tumor suppressor function after CK2 inhibition by CX-4945 (a CK2-specific inhibitor).

RESULTS

CK2 is an oncogene that is overexpressed in hematological malignancies. In high risk Pre-B ALL, CK2 phosphorylates Ikaros tumor suppressor and promotes leukemogenesis. Inhibition of CK2 using CX4945 restores Ikaros function and leads to anti leukemic effects in vitro and in pre-clinical leukemia models.

CONCLUSION

CK2 is an attractive target in treatment of various cancers. Currently only a few specific CK2 inhibitors are available. Preclinical studies using CK2 inhibitor, CX4945 in high risk pediatric leukemias have shown promising results and warrants further testing in other types of leukemia.

Abstract 5542: Regulation of cell cycle control in T-cell acute lymphoblastic leukemia by Ikaros and Casein Kinase II

T-cell acute lymphoblastic leukemia (T-ALL) is an aggressive hematological malignancy that represents a therapeutic challenge. Next-generation sequencing revealed that a subset of T-ALL harbors inactivating mutations or deletion of one allele of the IKZF1 tumor suppressor. These data suggest that IKZF1 acts as a tumor suppressor in T-ALL. The IKZF1 gene encodes the Ikaros protein that functions as a regulator of transcription and a tumor suppressor in B cell acute lymphoblastic leukemia. However, the molecular mechanism of Ikaros tumor suppressor function in T-ALL is unclear. Using quantitative chromatin immunoprecipitation (qChIP), we determined that Ikaros binds to the promoter regions of the CDC2 and CDC7 cell cycle genes in primary T-ALL cells in vivo. Gain-of function experiments showed that Ikaros overexpression in T-ALL results in reduced expression of CDC2 and CDC7, as evidenced by quantitative RT-PCR (qRT-PCR) and Western blot. The knock-down of Ikaros with shRNA in T-ALL cells resulted in increased transcription of CDC2 and CDC7 as indicated by qRT-PCR. These data suggest that Ikaros can regulate cell cycle progression in T-ALL by repressing transcription of the CDC2 and CDC7 genes. Next, we studied the mechanisms that regulate Ikaros’ ability to repress CDC2 and CDC7 in T-ALL. Ikaros function as a transcriptional repressor is regulated by Casein Kinase II (CK2). CK2 is overexpressed in hematopoietic malignancies and increased expression of CK2 results in T-ALL in murine models. We tested the effect of CK2 inhibition on Ikaros’ ability to regulate transcription of CDC2 and CDC7 in human T-ALL. Molecular inhibition of CK2 with shRNA against the CK2 catalytic subunit resulted in reduced transcription of CDC2 and CDC7, as evidenced by qRT-PCR. This was associated with increased DNA-binding of Ikaros to promoters of CDC2 and CDC7, as shown by qChIP. These data suggest that CK2 impairs Ikaros’ ability to transcriptionally repress CDC2 and CDC7 and to regulate cell cycle progression in T-ALL. Inhibition of CK2 enhances transcriptional repression of CDC2 and CDC7 by Ikaros, resulting in improved control of cell cycle progression in T-ALL. In conclusion, our results show that control of cell cycle progression in T-ALL occurs trough Ikaros-mediated transcriptional regulation of CDC2 and CDC7. Overexpession of CK2 impairs Ikaros ability to repress CDC2 and CDC7 expression, which contributes to deregulation of cell cycle control in T-ALL. Results suggest a potential mechanism of therapeutic action of CK2 inhibitors for the treatment of T-ALL.

Note: This abstract was not presented at the meeting.

Citation Format: Mario A. Soliman, Tommy Hu, Malika Kapadia, Elanora Dovat, Yali Ding, Chunhua Song, Jonathon L. Payne, Sinisa Dovat. Regulation of cell cycle control in T-cell acute lymphoblastic leukemia by Ikaros and Casein Kinase II [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 5542. doi:10.1158/1538-7445.AM2017-5542

Abstract 5533: Signaling pathways that regulate LMO2 oncogene expression in pediatric high risk T cell acute lymphoblastic leukemia

T-cell Acute Lymphoblastic Leukemia (T-ALL) accounts for about 15% of pediatric ALL and is characterized as a high-risk disease with frequent relapse, chemotherapy resistance, and a poorer prognosis. LIM domain only protein 2 (LMO2) is a regulator of hematopoiesis and an oncogene that is overexpressed in about 10% of T-ALL. The IKZF1 gene encodes a zinc finger protein called Ikaros which is a master regulator of lymphoid development and a tumor suppressor. In pediatric ALL, Ikaros alteration is considered independent prognostic marker for poor outcome. Pro oncogenic Casein Kinase II (CK2) is overexpressed in various malignancies including leukemia. CK2 directly phosphorylates Ikaros in vivo and inhibits its function as transcriptional regulator. Inhibition of CK2 restores Ikaros tumor suppressor function and results in anti-leukemic effect. Objective of this study is to understand the mechanisms of transcriptional regulation of LMO2 in T-cell ALL. Global chromatin immunoprecipitation (ChIP) coupled with the next-generation sequencing (ChIP-seq) studies in primary human ALL cells and in cell lines, demonstrated Ikaros occupancy of the promoter of LMO2 gene. We hypothesize that Ikaros negatively regulates expression of LMO2 at transcriptional level and CK2 impairs Ikaros mediated repression of LMO2 in T-cell ALL.

Results: qChIP in primary leukemia cells confirmed that Ikaros binds to the promoter region of LMO2. Using gain-of-function and loss-of-function experiments we dissected the role of Ikaros in regulation of LMO2 transcription in T-ALL. Ikaros silencing using shRNA transfection revealed increase in LMO2 expression as measured by qRT PCR. Conversely, overexpression of Ikaros was associated with strongly reduced transcription of LMO2. T-ALL cells that are derived from Ikaros-knockout mouse models express high level of LMO2. Retroviral transduction of these cells with Ikaros, resulted in significant reduction of LMO2 expression. Next we investigated how CK2 affects the regulatory functions of Ikaros towards LMO2. Molecular and pharmacological inhibition of CK2 resulted in reduced expression of LMO2 in primary human T-ALL. Ikaros binding at promoter of LMO2 was noted to be significantly increased following CK2 inhibition. This effect was not seen when cell were subjected to CK2 inhibition after Ikaros silencing. Further, we analyzed changes in the histone markers at the heterochromatin at the LMO2 promoter following Increased Ikaros binding such as reduced histone H3K9ac and H3K4me3 markers. This suggests that Ikaros regulates LMO2 transcription via chromatin remodeling.

Conclusion: This data reveals new regulatory mechanism for oncogene LMO2 in pediatric T-ALL. New evidence suggests that repression of LMO2 expression in T cell ALL via Ikaros can be potentiated using CK2 inhibitors. Findings provide the rationale for the use of CK2 inhibitors in T-ALL with LMO2 overexpression.

Citation Format: Chandrika S. Gowda, Yali Ding, Chunhua Song, Malika Kapadia, Kimberly J. Payne, Sinisa Dovat. Signaling pathways that regulate LMO2 oncogene expression in pediatric high risk T cell acute lymphoblastic leukemia [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 5533. doi:10.1158/1538-7445.AM2017-5533

Abstract 5540: Transcriptional control of signaling pathways in T-cell lymphoblastic leukemia by Ikaros tumor suppressor

Cellular proliferation in T-cell acute lymphoblastic leukemia is regulated by multiple signaling pathways. The Phosphoinositide 3-kinase (PI3K)/AKT pathway is frequently dysregulated in T-ALL. Targeting the PI3K pathway has shown promise as a novel therapeutic approach for T-ALL. However, regulation of the PI3K pathway is still not well understood. Here, we report that PI3K activity in T-ALL can be controlled by transcriptional regulation of key members of this pathway, PIK3CD and PIKFYVE. DNA binding analysis of primary T-ALL using qChIP revealed that the tumor suppressor protein, Ikaros, binds the promoter regions of PIK3CD and PIKFYVE. Since Ikaros acts as a regulator of transcription, we tested whether Ikaros binding to PIK3CD and PIKFYVE affects their expression. Overexpression of Ikaros results in reduced transcription of PIK3CD and PIKFYVE in T-ALL. Targeting Ikaros with a specific shRNA, resulted in increased transcription of PIK3CD and PIKFYVE in T-ALL. Together, these results demonstrate that Ikaros functions as a transcriptional repressor of both PIK3CD and PIKFYVE, and suggest that Ikaros can regulate the PI3K pathway in T-ALL. It has been previously shown that Ikaros function in B-cell acute lymphoblastic leukemia is regulated by oncogenic Casein Kinase II (CK2). We tested whether Ikaros ability to repress transcription of PIK3CD and PIKFYVE is regulated by CK2. Inhibition of CK2 by a specific pharmacological inhibitor, CX-4945, resulted in increased Ikaros binding to the promoters of PIK3CD and PIKFYVE, as well as in transcriptional repression of both of these genes. These results suggest that Ikaros function as a repressor of PIK3CD and PIKFYVE transcription is impaired by CK2 in T-ALL. CK2 inhibition restores Ikaros-mediated transcriptional repression of PIK3CD and PIKFYVE, which results in downregulation of the PI3K pathway. In conclusion, the presented data demonstrate that the PI3K signaling pathway is regulated by transcriptional repression of PIK3CD and PIKFYVE by Ikaros in T-ALL. Results reveal interplay between two signaling pathways in T-ALL, CK2 and PI3K, where CK2 positively regulates the PI3K pathway by inhibiting Ikaros function. These data reveal novel mechanisms that regulate cellular proliferation in T-ALL.

Citation Format: Tommy Hu, Mario Soliman, Malika Kapadia, Elanora Dovat, Jonathan Payne, Chunhua Song, Sinisa Dovat. Transcriptional control of signaling pathways in T-cell lymphoblastic leukemia by Ikaros tumor suppressor [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 5540. doi:10.1158/1538-7445.AM2017-5540

Casein Kinase II (CK2), Glycogen Synthase Kinase-3 (GSK-3) and Ikaros mediated regulation of leukemia

Signaling networks that regulate cellular proliferation often involve complex interactions between several signaling pathways. In this manuscript we review the crosstalk between the Casein Kinase II (CK2) and Glycogen Synthase Kinase-3 (GSK-3) pathways that plays a critical role in the regulation of cellular proliferation in leukemia. Both CK2 and GSK-3 are potential targets for anti-leukemia treatment. Previously published data suggest that CK2 and GSK-3 act synergistically to promote the phosphatidylinositol-3 kinase (PI3K) pathway via phosphorylation of PTEN. More recent data demonstrate another mechanism through which CK2 promotes the PI3K pathway - via transcriptional regulation of PI3K pathway genes by the newly-discovered CK2-Ikaros axis. Together, these data suggest that the CK2 and GSK-3 pathways regulate AKT/PI3K signaling in leukemia via two complementary mechanisms: a) direct phosphorylation of PTEN and b) transcriptional regulation of PI3K-promoting genes. Functional interactions between CK2, Ikaros and GSK3 define a novel signaling network that regulates proliferation of leukemia cells. This regulatory network involves both direct posttranslational modifications (by CK and GSK-3) and transcriptional regulation (via CK2-mediated phosphorylation of Ikaros). This information provides a basis for the development of targeted therapy for leukemia.

Regulation of cellular proliferation in acute lymphoblastic leukemia by Casein Kinase II (CK2) and Ikaros

The IKZF1 gene encodes the Ikaros protein, a zinc finger transcriptional factor that acts as a master regulator of hematopoiesis and a tumor suppressor in leukemia. Impaired activity of Ikaros is associated with the development of high-risk acute lymphoblastic leukemia (ALL) with a poor prognosis. The molecular mechanisms that regulate Ikaros' function as a tumor suppressor and regulator of cellular proliferation are not well understood. We demonstrated that Ikaros is a substrate for Casein Kinase II (CK2), an oncogenic kinase that is overexpressed in ALL. Phosphorylation of Ikaros by CK2 impairs Ikaros' DNA-binding ability, as well as Ikaros' ability to regulate gene expression and function as a tumor suppressor in leukemia. Targeting CK2 with specific inhibitors restores Ikaros' function as a transcriptional regulator and tumor suppressor resulting in a therapeutic, anti-leukemia effect in a preclinical model of ALL. Here, we review the genes and pathways that are regulated by Ikaros and the molecular mechanisms through which Ikaros and CK2 regulate cellular proliferation in leukemia.

Protein signaling and regulation of gene transcription in leukemia: role of the Casein Kinase II-Ikaros axis

Protein signaling and regulation of gene expression are the two major mechanisms that regulate cellular proliferation in leukemia. Discerning the function of these processes is essential for understanding the pathogenesis of leukemia and for developing the targeted therapies. Here, we provide an overview of one of the mechanisms that regulates gene transcription in leukemia. This mechanism involves the direct interaction between Casein Kinase II (CK2) and the Ikaros transcription factor. Ikaros (IKZF1) functions as a master regulator of hematopoiesis and a tumor suppressor in acute lymphoblastic leukemia (ALL). Impaired Ikaros function results in the development of high-risk leukemia. Ikaros binds to the upstream regulatory elements of its target genes and regulates their transcription via chromatin remodeling. In vivo, Ikaros is a target for CK2, a pro-oncogenic kinase. CK2 directly phosphorylates Ikaros at multiple amino acids. Functional experiments showed that CK2-mediated phosphorylation of Ikaros, regulates Ikaros’ DNA binding affinity, subcellular localization and protein stability. Recent studies revealed that phosphorylation of Ikaros by CK2 regulates Ikaros binding and repression of the terminal deoxytransferase (TdT) gene in normal thymocytes and in T-cell ALL. Available data suggest that the oncogenic activity of CK2 in leukemia involves functional inactivation of Ikaros and provide a rationale for CK2 inhibitors as a potential treatment for ALL.

Interactions between attention, context and learning in primary visual cortex

Attention in early visual processing engages the higher order, context dependent properties of neurons. Even at the earliest stages of visual cortical processing neurons play a role in intermediate level vision - contour integration and surface segmentation. The contextual influences mediating this process may be derived from long range connections within primary visual cortex (V1). These influences are subject to perceptual learning, and are strongly modulated by visuospatial attention, which is itself a learning dependent process. The attentional influences may involve interactions between feedback and horizontal connections in V1. V1 is therefore a dynamic and active processor, subject to top-down influences.

Bioremediation of crude oil contamination with Acinetobacter sp. A3

Acinetobacter sp. A3 is able to extensively degrade Bombay High Crude Oil (BHCO) and utilize it as the sole source of carbon. A total degradation of 70% BHCO was noted by the end of 120 h of growth of Acinetobacter sp. A3 under shake flask condition, 60% of which was due to biodegradation. In crude oil-contaminated soil (5%) amended with Acinetobacter sp. A3, there was both an increase in colony-forming units (CFU) and crude oil degradation. This is in contrast to a decrease in CFU of the indigenous microorganisms and lower degradation in unamended soil within the same 30-day period. Also, Acinetobacter sp. A3-treated soil permitted better germination of Mung beans (Phaseolus aureus) and growth as evidenced by better length and weight of the plants and chlorophyll content of its leaves, which was attributed to the reduction in phytotoxicity of the crude oil owing to its degradation. This crude oil degradative capability of Acinetobacter sp. A3 could be exploited for bioremediation purposes.

Spatial integration and cortical dynamics

Cells in adult primary visual cortex are capable of integrating information over much larger portions of the visual field than was originally thought. Moreover, their receptive field properties can be altered by the context within which local features are presented and by changes in visual experience. The substrate for both spatial integration and cortical plasticity is likely to be found in a plexus of long-range horizontal connections, formed by cortical pyramidal cells, which link cells within each cortical area over distances of 6-8 mm. The relationship between horizontal connections and cortical functional architecture suggests a role in visual segmentation and spatial integration. The distribution of lateral interactions within striate cortex was visualized with optical recording, and their functional consequences were explored by using comparable stimuli in human psychophysical experiments and in recordings from alert monkeys. They may represent the substrate for perceptual phenomena such as illusory contours, surface fill-in, and contour saliency. The dynamic nature of receptive field properties and cortical architecture has been seen over time scales ranging from seconds to months. One can induce a remapping of the topography of visual cortex by making focal binocular retinal lesions. Shorter-term plasticity of cortical receptive fields was observed following brief periods of visual stimulation. The mechanisms involved entailed, for the short-term changes, altering the effectiveness of existing cortical connections, and for the long-term changes, sprouting of axon collaterals and synaptogenesis. The mutability of cortical function implies a continual process of calibration and normalization of the perception of visual attributes that is dependent on sensory experience throughout adulthood and might further represent the mechanism of perceptual learning.

Purinergic receptors in ocular ciliary epithelial cells

Adenosine and ATP have been shown to activate separate cell surface purinergic receptors which have been designated P1 for adenosine and P2 for ATP. The pharmacological characterization of P1 and P2 purinergic receptor-mediated signal transduction has been performed in cultured cell lines of the ciliary epithelium. In ODM Clone-2, a cell line derived from human nonpigmented ciliary epithelium (NPE) and in a clone derived from bovine pigmented ciliary epithelium (PE), we observed that adenosine inhibits adenylate cyclase activity at high potency (nM) and stimulates adenylate cyclase activity at low potency (microM) suggesting the presence of P1 subtypes on these cell membranes. The selective agonist cyclopentyladenosine (CPA) was effective at inhibiting forskolin-stimulated adenylate cyclase in these cells. The IC50 for CPA in both NPE and PE was approximately 1 nM in the absence, and 11 nM in the presence of 3-isobutyl-1-methylxanthine (IBMX). In NPE, the selective agonist 2-[p-(2-carboxyethyl)phenethylamino]-5'-N-ethylcarboxamido adenosine (CGS 21680) stimulated adenylyl cyclase with an EC50 of 11 +/- 4 nM in the presence of 4-(3-butoxy-4-methyoxybenzyl)-2-imidazolidinone (RO-20-1724), a phosphodiesterase inhibitor devoid of adenosine receptor antagonism, and 61 +/- 8 microM in the presence of IBMX. In PE cells, EC50 value of RO-20-1724 was 19 +/- 5 nM (n = 3). The characterization of P2 receptors based upon the ability of ATP and its related analogues to stimulate inositol phosphate production reveal the presence of a putative P2u receptor in both cell types.

Abnormal processing of pro-IGF-II in patients with hepatoma and in some hepatitis B virus antibody-positive asymptomatic individuals

Hepatomas are a common malignancy in countries with a high prevalence of hepatitis B virus infections. These tumors may present with severe persistent hypoglycemia. We have studied the possible relationship of production of insulin-like growth factor II (IGF-II) by these tumors and the development of hypoglycemia. Mean IGF-II concentration was not significantly higher in 23 patients with hypoglycemia than in nine patients with euglycemia (542 +/- 61 [SE] micrograms/L vs 382 +/- 52 micrograms/L). Serum IGF-I was more suppressed in patients with hypoglycemia (16 +/- 3 micrograms/L) than in patients with euglycemia (57 +/- 18 micrograms/L). Because an increased percentage of IGF-II in serum of patients with hypoglycemia who have other tumors is present as partially processed pro-IGF-II ("big" IGF-II), we passed sera of patients with hypoglycemia and patients with euglycemia with hepatomas through acidic Bio-Gel P-60 columns. We found that 57% +/- 4.6% of the IGF-II in sera from patients with hypoglycemia was present as big IGF-II compared with 22% +/- 3% in patients with euglycemia with hepatomas (not significantly different from that in normal controls). Four of 11 apparently healthy control subjects who were hepatitis B virus positive also had increased percentages of big IGF-II, suggesting that abnormal processing of pro-IGF-II may result from subtle changes in liver function with this infection. It remains to be determined whether these subjects with increased big IGF-II are at increased risk for the development of hepatomas. In conclusion, we have confirmed marked suppression of IGF-I in the sera of patients with hepatoma and hypoglycemia.(ABSTRACT TRUNCATED AT 250 WORDS)

Significance of abnormal serum binding of insulin-like growth factor II in the development of hypoglycemia in patients with non-islet-cell tumors

We reported that serum and tumor from a hypoglycemic patient with a fibrosarcoma contained insulin-like growth factor II (IGF-II), mostly in a large molecular form designated "big IGF-II." We now describe two additional patients with non-islet-cell tumor with hypoglycemia (NICTH) whose sera contained big IGF-II. Removal of the tumor eliminated most of the big IGF-II from the sera of two patients. Because specific IGF-binding proteins modify the bioactivity of IGFs, the sizes of the endogenous IGF-binding protein complexes were determined after neutral gel filtration through Saphadex G-200. Normally about 75% of IGFs are carried as a ternary complex of 150 kDa consisting of IGF, a growth hormone (GH)-dependent IGF-binding protein, and an acid-labile complexing component. The three patients with NICTH completely lacked the 150-kDa complex. IGF-II was present as a 60-kDa complex with variable contributions of smaller complexes. In the immediate postoperative period, a 110-kDa complex appeared rather than the expected 150-kDa complex. Abnormal IGF-II binding may be important in NICTH because the 150-kDa complexes cross the capillary membrane poorly. The smaller complexes present in our patients' sera would be expected to enter interstitial fluid readily, and a 4- to 5-fold increase in the fraction of IGFs reaching the target cells would result.

Synthesis and secretion of insulin-like growth factor II by a leiomyosarcoma with associated hypoglycemia

We describe a case of recurrent hypoglycemia apparently caused by secretion of insulin-like growth factor II (IGF-II) by a leiomyosarcoma. A 67-year-old woman presented with recurrent severe hypoglycemia and a large mass in the thorax. During hypoglycemia, plasma cortisol was elevated, but insulin and growth hormone levels were low. After resection of a large leiomyosarcoma, the hypoglycemia resolved. After an eight-year remission, both the tumor and symptomatic hypoglycemia recurred. During a second operation a second large tumor was removed, with relief of the patient's hypoglycemia. The tumor contained high concentrations of IGF-II mRNA and 2100 ng of IGF-II immunoreactive peptide per gram. Filtration through a BioGel P-60 gel column established that 77 percent of the IGF-II was present as a larger molecule, demonstrating incomplete processing of the pro-IGF-II peptides. A similar fraction of high-molecular-weight IGF-II was present in the serum, indicating that the tumor was the chief source of IGF-II. The high-molecular-weight IGF-II found in both the tumor and serum was fully reactive with the IGF-II receptor. Radioimmunoassay showed that the concentrations of insulin-like growth factor I (IGF-I) in tumor and serum were low, suggesting feedback inhibition of growth hormone secretion by IGF-II. Eight months after reoperation, plasma concentrations of IGF-I and IGF-II were normal, and high-molecular-weight IGF-II was virtually undetectable. We conclude that the most likely cause of this patient's recurrent hypoglycemia was IGF-II produced by the leiomyosarcoma.

Reduced 125I-hGH binding by serum of dwarf pigs but not by serum of dwarfed poodles

1. Normal and growth-deficient poodle and swine strains were characterized for serum growth hormone-binding protein (GH-BP) content as well as other growth-related hormones, and the relationship between these factors and body size was examined. 2. GH-BPs were found in all strains of pigs and poodles. Concentrations of GH-BPs (as expressed by specific bindings) did not vary among the poodle breeds, but did correlate with body size in pigs. 3. Insulin-like growth factors (IGFs) I and II were decreased 71 and 44% respectively in miniature compared to standard size poodles. 4. Only the Yucatan micro pig strain had reduced serum IGF-I concentrations compared to normal controls. 5. Growth hormone concentrations however were normal to elevated in all micro and miniature pig strains. 6. Serum triiodothyronine concentrations were reduced in Yucatan mini and micro pigs in spite of normal circulating levels of thyroxine. 7. Body size reductions in the swine and dog strains are probably attributable to different primary defects of various growth related hormones or hormone receptors. 8. Each species breed therefore could serve as a model for a different human growth-deficient condition.

Serum somatomedin binding proteins: physiologic significance and interference in radioligand assay

Mammalian sera contain binding proteins that specifically complex with somatomedins (insulin-like growth factor I and II) so that there are no detectable free somatomedins. There is immunologic evidence of two distinct types of serum binding proteins. The major binding protein complex (150,000 Mr) is growth hormone dependent. Binding proteins protect somatomedins from proteolytic degradation, retard plasma clearance, and decrease the availability to tissue receptors. The presence of serum binding proteins interferes with radioimmunoassays and radioreceptor assays for somatomedins. Proposed strategies to neutralize the interference from binding proteins without their elimination do not achieve this goal. Extraction of somatomedins by acid ethanol, hydrophobic absorption on C18 silicates (SepPak), and acid gel filtration are effective with human serum, but only acid gel filtration is satisfactory with rat serum. Failure to eliminate binding proteins from assays can lead to serious artifacts in conditions where abnormalities of binding proteins exist.

Insulin-like growth factors I and II in maternal and fetal guinea pig serum

The role of insulin-like growth factors (IGFs) in fetal development has been the subject of much speculation. We undertook studies of maternal and fetal IGF I and II in the guinea pig because the long gestation period and greater size of the fetuses permitted blood sampling over a longer period of gestation and maturation than is possible in the rat. Acid gel filtrates of fetal and maternal serum were prepared, and the IGF I was measured by RIA; IGF II was measured by rat placental membrane radioreceptor assay. Fetal IGF I levels were lower than maternal levels from the 33rd day of estimated gestation to term. Fetal IGF II levels from the 33rd day to the 49th day of gestation were not significantly different from those of maternal serum [1597 +/- 377 (SE) ng/ml vs. 1295 +/- 224] ng/ml. Very high levels of IGF II, in excess of 5000 ng/ml, were observed in fetuses at 50, 55, and 60 days of gestation. Thereafter, fetal IGF II levels fell markedly before term. Fetal and maternal IGFs after 49, 50, 60, and 65 days of pregnancy were compared by isoelectric focusing. The guinea pig normally has two major basic peaks of IGF I, which were present both in maternal and fetal serum. Most maternal and fetal guinea pig sera contained only a single, slightly acidic peak of IGF II. No evidence of a unique fetal IGF was detected by our methods. The very high levels of IGF II reached in fetal guinea pig sera suggest that it may have a role in fetal development.