Utilization and outcome disparities in allogeneic hematopoietic stem cell transplant in the United States.

Allogeneic hematopoietic stem cell transplant (allo-HSCT) is increasingly being used in the United States (US) and across the world as a curative therapeutic option for patients with certain high-risk hematologic malignancies and non-malignant diseases. However, racial and ethnic disparities in utilization of the procedure and in outcome following transplant remain major problems. Racial and ethnic minority patients are consistently under-represented in the proportion of patients who undergo allo-HSCT in the US. The transplant outcomes in these patients are also inferior. The interrelated driving forces responsible for the differences in the utilization and transplant outcome of the medical intervention are socioeconomic status, complexity of the procedure, geographical barriers, and the results of differences in the genetics and comorbidities across different races. Bridging the disparity gaps is important not only to provide equity and inclusion in the utilization of this potentially life-saving procedure but also in ensuring that minority groups are well represented for research studies about allo-HSCT. This is required to determine interventions that may be more efficacious in particular racial and ethnic groups. Various strategies at the Federal, State, and Program levels have been designed to bridge the disparity gaps with varying successes. In this review paper, we will examine the disparities and discuss the strategies currently available to address the utilization and outcome gaps between patients of different races in the US.

Effects of GBT1118, a voxelotor analog, on intestinal pathophysiology in sickle cell disease.

Voxelotor is an allosteric haemoglobin (Hb) modulator that binds covalently and reversibly to Hb alpha chain to facilitate improved Hb-O2 affinity and arterial oxygen. It, therefore, reduces the susceptibility of erythrocytes carrying Haemoglobin S to sickle. In this study, we have used GBT1118, an analog of voxelotor, to treat male Townes sickle cell disease (SCD) mice to investigate whether the Hb modulator could attenuate the intestinal pathophysiologic changes associated with SCD. Compared with mice fed with control chow, GBT1118-treated mice showed improvement in the intestinal pathophysiology. These mice exhibited improved small intestinal barrier functions, reduced intestinal microbial density, reduced enterocyte injury, lower serum lipopolysaccharides and smaller spleens. These improvements were observed after only 3 weeks of GBT1118 treatment. Benefits were also observed after experimentally-induced vaso-occlusive crisis (VOC). Recovery from the VOC-induced changes was faster in mice that were treated with GBT1118. The improved small intestinal barrier function was associated with higher expression of genes encoding enterocyte E-cadherin, JAM-A, ZO-1, MUC-2 and occludin while the lower intestinal microbial density associated with higher expression of genes encoding the antimicrobial peptides defensin-α 1 and defensin-α 4. Our findings provide the evidence to support the beneficial effects of GBT1118 in SCD-related intestinal pathophysiology.

Intestinal barrier functions in hematologic and oncologic diseases.

The intestinal barrier is a complex structure that not only regulates the influx of luminal contents into the systemic circulation but is also involved in immune, microbial, and metabolic homeostasis. Evidence implicating disruption in intestinal barrier functions in the development of many systemic diseases, ranging from non-alcoholic steatohepatitis to autism, or systemic complications of intestinal disorders has increased rapidly in recent years, raising the possibility of the intestinal barrier as a potential target for therapeutic intervention to alter the course and mitigate the complications associated with these diseases. In addition to the disease process being associated with a breach in the intestinal barrier functions, patients with hematologic and oncologic diseases are particularly at high risks for the development of increased intestinal permeability, due to the frequent use of broad-spectrum antibiotics and chemoradiation. They also face a distinct challenge of being intermittently severely neutropenic due to treatment of the underlying conditions. In this review, we will discuss how hematologic and oncologic diseases are associated with disruption in the intestinal barrier and highlight the complications associated with an increase in the intestinal permeability. We will explore methods to modulate the complication. To provide a background for our discussion, we will first examine the structure and appraise the methods of evaluation of the intestinal barrier.

Intestinal pathophysiological abnormalities in steady state and after vaso-occlusive crisis in murine sickle cell disease.

We showed in the present study that, not unlike in adult patients with sickle cell disease (SCD), Townes mice exhibit increases in serum intestinal fatty acid binding proteins and lipopolysaccharides (LPS), together with a breach in the intestinal barrier. These abnormalities increased rapidly after the induction of vaso-occlusive crisis (VOC). We also confirmed higher intestinal microbial density in SCD. These findings support the concept that SCD and/or its complications, and not hospitalisation or medications, are responsible for the intestinal pathophysiological changes. The present results provide the basis for use of Townes mice to further elucidate the mechanistic relationship between intestinal pathophysiology and VOC.

L-glutamine for sickle cell disease: more than reducing redox.

Oxidative stress is a major contributor to the pathophysiology of sickle cell disease (SCD) including hemolysis and vaso-occlusive crisis (VOC). L-glutamine is a conditionally essential amino acid with important roles, including the synthesis of antioxidants, such as reduced glutathione and the cofactors NAD(H) and NADP(H), as well as nitric oxide. Given the increased levels of oxidative stress and lower (NADH):(NAD + + NADH) ratio in sickle erythrocytes that adversely affects the blood rheology compared to normal red blood cells, L-glutamine was investigated for its therapeutic potential to reduce VOC. While L-glutamine was approved by the United States (US) Food and Drug Administration to treat SCD, its impact on the redox environment in sickle erythrocytes is not fully understood. The mechanism through which L-glutamine reduces VOC in SCD is also not clear. In this paper, we will summarize the results of the Phase 3 study that led to the approval of L-glutamine for treating SCD and discuss its assumed mechanisms of action. We will examine the role of L-glutamine in health and propose how the extra-erythrocytic functions of L-glutamine might contribute to its beneficial effects in SCD. Further research into the role of L-glutamine on extra-erythrocyte functions might help the development of an improved formulation with more efficacy.

Genes modulating intestinal permeability and microbial community are dysregulated in sickle cell disease.

Based on previous studies showing abnormalities in the intestinal pathophysiology characterized by disruption in the gut barrier functions, and alteration in the intestinal microbial load and composition, we set out in the study to examine the expression of genes that might be involved in mediating these changes in Townes sickle cell disease (SCD) mice at 6 months old compared to non-SCD control mice. Using qPCR on total RNA isolated from the intestine, we found downregulation of the TJ genes JAM-A, Occludin, and ZO-1 in both the small intestine and colon. E-Cadherin and MUC2 were also downregulated. In contrast, gene encoding claudin-2 that mediates increase permeability to water and ions was upregulated in the small intestine. Claudin-2 upregulation is usually also associated with ongoing inflammation. Intestinal epithelium also includes Paneth cells that produce antimicrobial peptides (AMPs) that regulate intestinal microbial community. We also found that the expression of the genes encoding the AMPs defensin-α4 was reduced in the small intestine and colon and defensin-α1 in the colon in the SCD mice. Our findings are novel and provide direction for further studies into the characteristics and mechanisms of the intestinal pathophysiologic changes observed in SCD.

Vaso-occlusive crisis in sickle cell disease: a vicious cycle of secondary events.

Painful vaso-occlusive crisis (VOC) remains the most common reason for presenting to the Emergency Department and hospitalization in patients with sickle cell disease (SCD). Although two new agents have been approved by the Food and Drug Administration for treating SCD, they both target to reduce the frequency of VOC. Results from studies investigating various approaches to treat and shorten VOC have so far been generally disappointing. In this paper, we will summarize the complex pathophysiology and downstream events of VOC and discuss the likely reasons for the disappointing results using monotherapy. We will put forward the rationale for exploring some of the currently available agents to either protect erythrocytes un-involved in the hemoglobin polymerization process from sickling induced by the secondary events, or a multipronged combination approach that targets the complex downstream pathways of VOC.

Obesity and diabetes mellitus in patients with sickle cell disease.

Obesity and diabetes mellitus are prevalent among the African-American/Black population. They result in multiple chronic conditions that impact the quality and lifespan of the patients. Their occurrence in patients with sickle cell disease (SCD) will increase the risks for multimorbidity in these patients. We have carried out a chart survey of a cohort of 449 patients with SCD to determine the prevalence rates of obesity and diabetes mellitus in these patients. SCD patients were less likely to develop obesity and diabetes mellitus, compared to their peers of the same race/ethnicity. The lower prevalence rates were observed in those over the age of 6 years, irrespective of the gender of the patients. Their life-time probabilities for obesity and diabetes mellitus were also low. Within this group of SCD patients, obesity was associated with significantly higher prevalence of diabetes mellitus. The underlying reasons for our observed results of low prevalence rate of obesity in SCD remain speculative but may be related to reduced calorie intake, increased calorie use due to hypermetabolism, reduced intestinal absorption, or intestinal dysbiosis.

Intestinal pathophysiological and microbial changes in sickle cell disease: Potential targets for therapeutic intervention.

There is a large therapeutic gap in the treatment of sickle cell disease (SCD). Recent studies demonstrated the presence of pathophysiological and microbial changes in the intestine of patients with SCD. The intestinal microbes have also been found to regulate neutrophil ageing and possible basal activation of circulating neutrophils. Both aged and activated neutrophils are pivotal for the pathogenesis of vaso-occlusive crisis in SCD. In this paper, we will provide an overview of the intestinal pathophysiological and microbial changes in SCD. Based on these changes, we will propose therapeutic approaches that could be investigated for treating SCD.

Intestinal injury and gut permeability in sickle cell disease.

BACKGROUND: Due to recurrent hypoxia-reperfusion injury induced by vaso-occlusive crises (VOC), patients with sickle cell disease (SCD) may have intestinal injury and increased permeability. These may explain the qualitative and quantitative neutrophil abnormalities observed in these patients. METHODS: Serum intestinal fatty-acid binding protein (iFABP), lipopolysaccharides (LPS), and CD62L were measured by ELISA. Multicolor flow cytometry was used to measure circulating aged neutrophils. RESULTS: Compared to controls, SCD individuals had higher iFABP (median: 1.38 ng/ml vs 0.81 ng/ml; p = 0.04) and LPS (median: 2.15 µg/ml vs 0.69 µg/ml; p = 0.03), indicating intestinal injury and increased intestinal bacterial translocation into the systemic circulation. They also had higher soluble CD62L (median: 1.38 µg/ml vs 1.11 µg/ml; p = 0.04). Among SCD individuals, soluble CD62L correlated positively with circulating aged neutrophils (R = 0.7, p = 0.03) and LPS (R = 0.66, p = 0.027). Surprisingly, serum iFABP in SCD correlated negatively with both LPS (R = - 0.7, p = 0.02) and soluble CD62L (R = - 0.56, p = 0.08). CONCLUSIONS: Since LPS translocation across the intestinal barrier may be due to increases in the intestinal bacterial density, gut permeability, or both, the negative correlations between iFABP and LPS, and CD62L raise the possibility that any damage-associated molecular patterns induced by intestinal injury may modulate the degree of bacterial translocation. Our results provide the first evidence of the presence of intestinal injury and increased gut permeability in SCD.

Peripheral monocytes and neutrophils predict response to immune checkpoint inhibitors in patients with metastatic non-small cell lung cancer.

We carried out a retrospective cohort study on patients with metastatic non-small cell lung cancer (mNSCLC) to identify the peripheral blood count parameters associated with response to immune checkpoint inhibitors (ICIs). There were 17 males and 15 females. Their median age was 64.5 years (range 20-84). History of smoking was present in 25/32 (78%) patients. Twelve patients received pembrolizumab, 19 patients nivolumab, and one patient nivolumab followed by pembrolizumab. Responses were observed in 19/32 (59%) patients, all partial responses. There was no difference in the distribution of sex, age, and smoking status between responders and non-responders. The median time to response (TTR) was 12 weeks (range 6-24) and the median duration of response (DoR) was 24 weeks (range 7-112). Higher pre-therapy absolute monocyte counts (AMCs) correlated to shorter TTR (p = 0.03), but not to response rate or DoR. Within the group of responders, those with AMCs > 700/mm3 had a significantly shorter median TTR than those with AMCs ≤ 700/mm3 (8 weeks vs 12 weeks; p = 0.048). Although baseline absolute neutrophil counts (ANCs) did not have any prognostic value, ANCs after first dose predicted response to ICI (p = 0.02). Patients with ANCs ≤ 4200/mm3 after first dose were more likely to respond than those with ANCs > 4200/mm3 (OR = 6.8; 95% CI 1.1-41.8; p = 0.05). Analysis of AMC and ANC before and during therapy may, therefore, provide an easy method to identify those mNSCLC patients most likely to benefit from ICI therapy.

Invasive non-typhoidal Salmonella in sickle cell disease in Africa: is increased gut permeability the missing link?

Non-typhoidal Salmonella usually induces self-limiting gastroenteritis. However, in many parts of Africa, especially in individuals who are malnourished, infected with malaria, or have sickle cell disease, the organism causes serious and potentially fatal systemic infections. Since the portal of entry of non-typhoidal Salmonella into the systemic circulation is by way of the intestine, we argue that an increased gut permeability plays a vital role in the initiation of invasive non-typhoidal Salmonella in these patients. Here, we will appraise the evidence supporting a breach in the intestinal barrier and propose the mechanisms for the increased risks for invasive non-typhoidal Salmonella infections in these individuals.

Sleep-disordered breathing in patients with sickle cell disease.

Sickle cell disease is one of the most common hereditary hemoglobinopathies worldwide, and its vaso-occlusive and hemolytic crises cause considerable patient morbidity. A growing body of evidence has shown that sleep-disordered breathing, and in particular, obstructive sleep apnea, occurs at high frequency in the sickle cell population, and that there is significant overlap in the underlying pathophysiology of these two conditions. Through a variety of mechanisms including nocturnal hypoxemia and increased oxidative stress, production of pro-inflammatory cytokines, and endothelial dysfunction, sickle cell anemia and sleep-disordered breathing potentiate each other's clinical effects and end-organ complications. Here, we will review the shared pathophysiologic mechanisms of these conditions and discuss their clinical sequelae. We will also examine the results of studies that have been carried out with clinical intervention of nocturnal hypoxemia in patients with sickle cell disease in the attempts to overcome the complications of the disease. Finally, we will propose the areas of investigation that merit further investigations in future in patients with sickle cell disease and sleep-disordered breathing.

Changes in intestinal microbiota and their effects on allogeneic stem cell transplantation.

The human intestinal microbiota is essential for microbial homeostasis, regulation of metabolism, and intestinal immune tolerance. Rapidly evolving understanding of the importance of the microbiota implicates changes in the composition and function of intestinal microbial communities in an assortment of systemic conditions. Complications following allogeneic stem cell transplant now join the ever-expanding list of pathologic states regulated by intestinal microbiota. Dysbiosis, or disruption of the normal ecology of this microbiome, has been directly implicated in the pathogenesis of entities such as Clostridium difficile infections, graft-versus-host disease (GVHD), and most recently disease relapse, all of which are major causes of morbidity and mortality in patients undergoing allogeneic stem cell transplant. In this review, we elucidate the key origins of microbiotic alterations and discuss how dysbiosis influences complications following allogeneic stem cell transplant. Our emerging understanding of the importance of a balanced and diverse intestinal microbiota is prompting investigation into the appropriate treatment of dysbiosis, reliable and early detection of such, and ultimately its prevention in patients to improve the outcome following allogeneic hematopoietic stem cell transplant.

Successful use of rituximab in glomerular basement membrane nephritis associated with HIV interstitial nephritis secondary to Castleman disease
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We report a case of glomerular basement membrane crescentic glomerulonephritis and multicentric Castleman disease-associated interstitial nephritis in a patient with human immunodeficiency virus (HIV) infection. The patient received corticosteroids, cyclophosphamide, and plasmapheresis, and within 3 weeks, there was worsening thrombocytopenia, anemia, and renal function requiring initiation of hemodialysis. He then received 8 weekly doses of rituximab, and there was steady improvement in renal function, such that he stopped dialysis within 6 weeks and has remained in disease remission at 1-year follow-up. This is the first case report of acute kidney injury caused by both antiglomerular basement membrane disease and multicentric Castleman disease, with a favorable response to rituximab.
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The multi-faceted potential of CD38 antibody targeting in multiple myeloma.

CD38, an adenine dinucleotide phosphate (ADP) ribose cyclase and a cyclic ADP ribose hydrolase, is widely expressed on the surface of multiple myeloma (MM) cells. It is known to play a pivotal role in the downstream pathways that mediate MM cell growth, signal transduction, and adhesion. The clinical use of CD38 monoclonal antibodies (MoAbs), such as daratumumab, either as monotherapy or in combination with other anti-MM agents, has produced impressive results in patients who have failed standard MM therapy. CD38 MoAbs exhibit several cytotoxic mechanisms on MM cells. In addition to the classical effector mechanisms associated with antibody therapy, CD38 MoAbs induce MM apoptosis and clonal T-cell expansion. Here, we summarize the results of some pivotal clinical studies using a human CD38 MoAb, daratumumab, in patients with MM, discuss the anti-MM effector mechanisms induced by CD38 MoAbs, and review the potential tumor antigens that may be suitable targets for immunotherapy of MM. Finally, we present a paradigm of immunotherapy for MM patients using CD38 MoAbs followed by GM-CSF and an immune checkpoint inhibitor in patients who have undergone high dose chemotherapy and autologous stem cell transplant. CD38 MoAbs have emerged as a novel and ultimately very promising immunotherapeutic agent for MM because of its ability to induce MM cytotoxicity through both arms of the adaptive immune responses.

Molecular targeting in acute myeloid leukemia.

Acute myeloid leukemia (AML) is a heterogenous disease associated with distinct genetic and molecular abnormalities. Somatic mutations result in dysregulation of intracellular signaling pathways, epigenetics, and apoptosis of the leukemia cells. Understanding the basis for the dysregulated processes provides the platform for the design of novel targeted therapy for AML patients. The effort to devise new targeted therapy has been helped by recent advances in methods for high-throughput genomic screening and the availability of computer-assisted techniques for the design of novel agents that are predicted to specifically inhibit the mutant molecules involved in these intracellular events. In this review, we will provide the scientific basis for targeting the dysregulated molecular mechanisms and discuss the agents currently being investigated, alone or in combination with chemotherapy, for treating patients with AML. Successes in molecular targeting will ultimately change the treatment paradigm for the disease.

Phase 1 clinical trial of adoptive immunotherapy using "off-the-shelf" activated natural killer cells in patients with refractory and relapsed acute myeloid leukemia.

BACKGROUND AIMS: Activated NK cells (aNK) generated by expansion of a human interleukin-2-dependent NK cell line (NK-92) were shown to mediate strong anti-leukemia activity. This phase 1 study evaluated feasibility, safety, and activity of aNK cells adoptively transferred to patients with refractory/relapsed acute myeloid leukemia (AML). In addition, effects of these aNK cells on the patient's immune system were evaluated. METHODS: Two cell-dose levels (1 × 109 cells/m2 and 3 × 109 cells/m2) were used. One treatment course consisted of two infusions of the same cell dose, each cell infusion delivered 24 h apart. The aNK cells were administered in the outpatient setting. RESULTS: Seven patients with refractory/relapsed AML were treated with a total of 20 aNK cell infusions. None of the 7 patients experienced dose-limiting toxicities during the aNK cell administration or during 21 days of the post-infusion observation period. No grade 3-4 toxicities (probable or definite) related to aNK cell infusions occurred. Activity was transient in 3 of 7 patients. No significant changes in the patient's lymphocyte counts, subsets frequency, phenotype or activity were observed post-infusion. Cell dose-dependent effects in the plasma levels of several cytokines were observed. DISCUSSION: The trial demonstrated the safety and feasibility of adoptive cell therapy with "off-the-shelf" aNK cells in patients with refractory/relapsed AML. These data provide the foundation for future combination immunotherapy trials and for the optimization of aNK cell based therapies in patients with AML.

Day 14 bone marrow examination in the management of acute myeloid leukemia.

The National Comprehensive Cancer Network (NCCN) recommends that a repeat bone marrow evaluation is carried out seven to ten days following completion of induction therapy so that if a patient's day 14 bone marrow shows residual blast cell counts of >10%, the patient would proceed early to a second cycle of induction therapy. Although blast cell counts of <5% on day 14 bone marrow is sensitive in predicting remission on day 28, various studies have found that day 14 bone marrow is highly nonspecific because a large proportion of patients with blast cell counts of >5% on day 14 bone marrow would still attain a complete remission of the disease without any further chemotherapy. Clinical decision based on day 14 bone marrow will result in some of these patients being given a second induction therapy unnecessarily. A second cycle of chemotherapy is associated with not only higher risk for treatment-related mortality but also increased use of hospital resources such as increased intravenous antimicrobials use, longer hospital stay, and higher demand for blood products. In this article, we examined the utility, discussed the shortfalls, and re-appraised the values of day 14 bone marrow in the management of patients with AML. On the basis of our review, we suggest that the practice of day 14 bone marrow examination should be re-evaluated and should probably only be carried out in the setting of clinical trials with clear questions to address its role in predicting outcome of the therapeutic intervention.