Hemolysis dictates monocyte differentiation via two distinct pathways in sickle cell disease vaso-occlusion

Sickle cell disease (SCD) is a hereditary hemoglobinopathy characterized by painful vaso-occlusive crises (VOC) and chronic hemolysis. The mononuclear phagocyte system is pivotal to SCD pathophysiology, but the mechanisms governing monocyte/macrophage differentiation remain unknown. This study examined the influence of hemolysis on circulating monocyte trajectories in SCD. We discovered that hemolysis stimulated CSF-1 production, partly by endothelial cells via Nrf2, promoting classical monocyte (CMo) differentiation into blood patrolling monocytes (PMo) in SCD mice. However, hemolysis also upregulated CCL-2 through IFN-I, inducing CMo transmigration and differentiation into tissue monocyte-derived macrophages. Blocking CMo transmigration by anti-P selectin antibody in SCD mice increased circulating PMo, corroborating that CMo-to-tissue macrophage differentiation occurs at the expense of CMo-to-blood PMo differentiation. We observed a positive correlation between plasma CSF-1/CCL-2 ratios and blood PMo levels in patients with SCD, underscoring the clinical significance of these two opposing factors in monocyte differentiation. Combined treatment with CSF-1 and anti-P selectin antibody more effectively increased PMo numbers and reduced stasis compared with single-agent therapies in SCD mice. Altogether, these data indicate that monocyte fates are regulated by the balance between two heme pathways, Nrf2/CSF-1 and IFN-I/CCL-2, and suggest that the CSF-1/CCL-2 ratio may present a diagnostic and therapeutic target in SCD.

Angiotensin II Type 1 Receptor Antibody-Mediated Kidney Rejection Unresponsive to Treatment

Allograft rejection is a significant cause of renal transplant failure which needs prompt diagnosis and treatment for graft salvage. Angiotensin II type 1 receptor antibody-mediated rejection (AT1R-AMR) is increasingly being identified as the etiology of antibody-mediated rejection in kidney transplant recipients with allograft rejection but without detectable human leukocyte antigen (HLA) antibodies. While some reports have suggested that AT1R-AMR may be refractory to standard therapy, others have reported improvement or stabilization of graft function. We present two patients in which anti-rejection therapy including therapeutic plasma exchange was unable to salvage the allograft.

How do we operate a large monthly red blood cell exchange program

BACKGROUND

Red blood cell (RBC) exchange for sickle cell disease presents unique difficulties due to RBC phenotyping, complex antibody work-ups, large number of RBC units required, and vascular access considerations, any of which can delay the procedure. Multidisciplinary coordination and systemic processes ensure that monthly appointments remain on schedule.

STUDY DESIGN AND METHODS

A high-volume chronic RBC exchange program is described, highlighting the importance of multidisciplinary coordination and process improvement strategies involving initial referral, vascular access, order sets, and allocation of antigen-negative or phenotypically matched RBCs.

RESULTS

Approximately 50 outpatient RBC exchanges are performed each month with an 82% kept-appointment rate. Specific factors for program success include open communication across services and improvements to referrals and standardized order sets.

CONCLUSION

A combination of multidisciplinary coordination and process improvement can ensure the success of a high volume RBC exchange program. Frequent communication of upcoming appointments between the referring hematologists, the hemapheresis clinic, transfusion service, and interventional radiology is critical. Advance notice to the immunohematology reference lab of upcoming appointments is needed to allow enough time for allocating antigen-negative RBCs. Order sets can be leveraged to standardize and streamline RBC exchanges. Lastly, numerous mechanisms help patients compensate for the cognitive sequelae of stroke.

A Comparison of Four Leukapheresis Methods to Harvest an Optimal Dose of CD34+ Cells: A Single Center Experience

BACKGROUND

Chemokine receptor CXCR4 antagonist plerixafor (Px) as well as high volume (HV) leukapheresis have been shown to reduce hematopoietic stem progenitor cell (HSPC) mobilization failure rates. However, no direct comparisons of such methods currently exists.

METHODS AND MATERIALS

We compared the HSPC collection yield based on basal peripheral blood CD34+ cell numbers in patients diagnosed with multiple myeloma or non-Hodgkin's lymphoma undergoing autologous stem cell transplantation in a retrospective chart review. The leukapheresis methods used included HV vs. regular volume (RV) with or without Px. There were 116 patients in the study group while the historical control group had 34 patients.

RESULTS AND CONCLUSIONS

Control group underwent RV leukapheresis without Px. Addition of Px or HV in the study group failed to display significant improvement in CD34+ cell collection yield; however, when basal CD34+ cell numbers were taken into account, both Px+RV and HV without Px increased CD34+ cell collection yield. The collection failure rates of HV without Px group were comparable to Px+RV when the basal CD34+ cell numbers were over 20/μL. Of interest, multivariate linear regression analysis did not detect any significant difference between HV vs Px+RV or other leukapheresis methods in CD34 yields or collection failure rates from a single collection after controlling for other factors (sex, age or underlying disease). In multivariate analysis, pre apheresis CD34+ cell number was significantly and positively associated with the CD34+ cell yields from a single apheresis. In our studies, the majority of patients can be rescued without Px by HV alone as a potential cost saving approach. In summary, trend in our studies reflects that both Px and HV are capable of reducing the mobilization failure rates except the poorest mobilizers which will need to be validated in larger studies. This article is protected by copyright. All rights reserved.

Association between convalescent plasma treatment and mortality in COVID-19: a collaborative systematic review and meta-analysis of randomized clinical trials

BACKGROUND

Convalescent plasma has been widely used to treat COVID-19 and is under investigation in numerous randomized clinical trials, but results are publicly available only for a small number of trials. The objective of this study was to assess the benefits of convalescent plasma treatment compared to placebo or no treatment and all-cause mortality in patients with COVID-19, using data from all available randomized clinical trials, including unpublished and ongoing trials (Open Science Framework, https://doi.org/10.17605/OSF.IO/GEHFX ).

METHODS

In this collaborative systematic review and meta-analysis, clinical trial registries (ClinicalTrials.gov, WHO International Clinical Trials Registry Platform), the Cochrane COVID-19 register, the LOVE database, and PubMed were searched until April 8, 2021. Investigators of trials registered by March 1, 2021, without published results were contacted via email. Eligible were ongoing, discontinued and completed randomized clinical trials that compared convalescent plasma with placebo or no treatment in COVID-19 patients, regardless of setting or treatment schedule. Aggregated mortality data were extracted from publications or provided by investigators of unpublished trials and combined using the Hartung-Knapp-Sidik-Jonkman random effects model. We investigated the contribution of unpublished trials to the overall evidence.

RESULTS

A total of 16,477 patients were included in 33 trials (20 unpublished with 3190 patients, 13 published with 13,287 patients). 32 trials enrolled only hospitalized patients (including 3 with only intensive care unit patients). Risk of bias was low for 29/33 trials. Of 8495 patients who received convalescent plasma, 1997 died (23%), and of 7982 control patients, 1952 died (24%). The combined risk ratio for all-cause mortality was 0.97 (95% confidence interval: 0.92; 1.02) with between-study heterogeneity not beyond chance (I2 = 0%). The RECOVERY trial had 69.8% and the unpublished evidence 25.3% of the weight in the meta-analysis.

CONCLUSIONS

Convalescent plasma treatment of patients with COVID-19 did not reduce all-cause mortality. These results provide strong evidence that convalescent plasma treatment for patients with COVID-19 should not be used outside of randomized trials. Evidence synthesis from collaborations among trial investigators can inform both evidence generation and evidence application in patient care.

Hyperhemolysis Syndrome Following Pre-Operative Red Blood Cell Exchange

Introduction/Objective

Pre-operative red blood cell exchange (RBCX) for patients with Sickle Cell Disease (SCD) is a category III indication. In our institution, RBCX is routinely performed pre-operatively when general anesthesia is necessary with the goal of HbS%<30 and reduction in adverse events related to general anesthesia. In the context of elective surgery, the risks and benefits of both the operation and any pre-operative transfusion must be discussed with the patient. Herein, we present an extreme case of Hyperhemolysis Syndrome resulting from a pre-operative RBCX.

Methods/Case Report

A 23-year-old transgender female with SCD (Hb S Lepore) treated with Hydroxyurea presented for elective breast augmentation for gender-affirmation. Her pre-operative plan included a RBCX. Her pre-exchange hemoglobin (Hb) and hematocrit (Hct) were 10.3 g/dL and 29.3%, respectively. Hb electrophoresis revealed HbS 52%, HbF 41.4%, HbA2 7.4%, and HbA was not detected. Type and Screen (T&S) demonstrated O + blood group, with a negative antibody screen, and with no known historical alloantibodies.

RBCX was performed using the Spectra Optia (TerumoBCT, Lakewood, CO, USA) with exchange volume of 1.9 L of group O+ RBCs, phenotypically matched for C, E, and K, an end Hct of 30% and an FCR of 30%. Her post-exchange Hb and Hct were 10.2g/dL and 29.5%, respectively. Hemoglobin fractionation revealed HbS 12% and HbA 73%.

She underwent surgery without intraoperative complications. Two weeks post RBCX, her Hb had decreased to 5.3 g/dl, and her LDH and Total Bilirubin had increased to 253 ul and 1.8 mg/dl, respectively. A repeat T&S drawn 8 days after RBCX revealed a positive antibody screen and direct antiglobulin test (DAT). Three new alloantibodies were identified: anti-Fya (present in plasma and eluate); anti-Jkb (present in plasma); anti-S (eluate). She was treated with IVIG, 0.4 g/Kg/day for 5 consecutive days and 2 doses of subcutaneous darbepoetin 100 mcg and subsequently discharged with close outpatient follow up. Her Hb returned to baseline at 11 g/dL, 48 days post RBCX.

Results (if a Case Study enter NA)

N/A

Conclusion

Pre-operative RBCX decreases morbidity in sickle cell patients undergoing general anesthesia. In the setting of elective surgery, patients must be counseled on the benefits and risks of surgery as well as the requisite RBCX. In our case, the patient developed multiple alloantibodies, with lifelong implications should she ever need future blood transfusions.

Race/ethnicity and underlying disease influences hematopoietic stem/progenitor cell mobilization response: A single center experience

BACKGROUND

Whether race/ethnicity plays a role in hematopoietic stem/progenitor cells (HSPC) mobilization in autologous donors has not been studied. We hypothesize that donor characteristic including race/ethnicity, age, sex, body mass index, and diagnostic groups influences HSPC mobilization. Diagnostic groups include healthy allogeneic donors, autologous multiple myeloma (MM) and non-MM donors.

STUDY DESIGN AND METHODS

Here, we conducted a single-center retrospective study in 64 autologous patients and 48 allogeneic donors. Autologous donors were patients diagnosed with MM or non-MM. All donors were grouped as African American (AA), White (W), or "Other"(O).

RESULTS

Multivariate analysis demonstrated diagnostic group differences for CD34+ cell yields between race/ethnicity. Specifically, non-MM patients had the lowest CD34+ cell yields in AA and O, but not in W. For pre-apheresis peripheral blood (PB) CD34+ cell numbers, race/ethnicity had a significant effect both in bivariate and multivariate analyses. Non-MM patients had the lowest, and AA patients had the highest PB CD34+ cells. The results support the view that past therapies used in MM are likely more conducive of recovery of HSPC.

CONCLUSIONS

Our study shows that race/ethnicity and diagnostic group differences influenced CD34+ cell mobilization response across donor types. Interestingly, autologous MM donors with the aid of plerixafor displayed comparable CD34 yields to allogeneic donors. Even though both MM and non-MM donors received plerixafor, non-MM donors had significantly lower CD34 yields among AA and O donors but not in W donors. Larger studies would be required to validate the role of diagnostic groups and race/ethnicity interactions.

Removal of Anti-Thymocyte Globulin by Plasma Exchange in ABO-Incompatible and Positive Crossmatch Kidney Transplant Recipients

BACKGROUND

Recipients of ABO-incompatible (ABOI) and positive crossmatch (PXM) kidney transplants are at high risk for antibody-mediated acute rejection. Despite aggressive immunosuppression in high-risk patients, the incidence of acute rejection remains considerably higher than in other groups. No published studies have examined plasma concentrations of anti-thymocyte globulin (ATG) in patients undergoing plasma exchange. The objectives of this study were to compare plasma ATG concentrations before and after plasma exchange in ABOI and PXM kidney transplant patients to determine the amount removed.

MATERIALS AND METHODS

This prospective pharmacokinetic evaluation enrolled 10 patients undergoing ABOI or PXM kidney transplant at an academic medical center. Blood and waste plasma samples from 5 patients were assayed for total and active ATG concentrations. Patient records were monitored for renal function and rejection rates in the first 6 months post-transplant.

RESULTS

Total ATG concentrations decreased a mean of 59.78 ± 13.91% after each plasma exchange session, and active ATG levels decreased a mean of 56.8 ± 17.08%. Mean daily concentrations reflect a lack of expected ATG accumulation. Only 1 of 4 patients had detectable ATG concentrations after 30 days. After 6 months, the incidence of acute rejection in this sample was 44% and graft survival was 89%.

CONCLUSIONS

This is the first study to show that plasma exchange removes a substantial amount of ATG in high-risk kidney transplant patients. Based on these results, we believe these high-risk patients have been traditionally underdosed.

Red blood cell exchange to avoid intubating a COVID-19 positive patient with sickle cell disease?

As the COVID‐19 pandemic continues to claim lives across the globe, insufficient data exists regarding the optimal treatment. It is well known that patients 55 years of age or older and patients with certain chronic diseases are at higher risk of severe illness, including acute respiratory distress syndrome and death. A potentially fatal pulmonary complication of sickle cell disease, acute chest syndrome, can be precipitated by acute infections, including respiratory viruses. We report the case of a patient with sickle cell disease (HbSC) who developed COVID‐19 pneumonia and acute chest syndrome who was treated with emergent red blood cell exchange in order to avoid endotracheal intubation.

Haploidentical Peripheral Blood Stem Cell Transplantation Demonstrates Stable Engraftment in Adults with Sickle Cell Disease

We report on the screening and development of haploidentical hematopoietic stem cell transplantation (HSCT) for adult patients with clinically aggressive sickle cell disease (SCD) at our institution. Of 50 adult SCD patients referred for HSCT between January 2014 and March 2017, 20% were denied by insurance. Of 41 patients initially screened, 10% lacked an available haploidentical donor, 29% had elevated donor-specific antibodies (DSAs), and 34% declined to proceed to HSCT. All 10 patients who were transplanted received peripheral blood stem cells. The initial 2 were conditioned with alemtuzumab/total body irradiation (TBI) 3 Gy followed by post-transplant cyclophosphamide and failed to engraft. The next 8 patients received the regimen developed at Johns Hopkins University with TBI 3 Gy. Granulocyte colony-stimulating factor was administered from day +12 in those with HbS < 30%. All 8 patients engrafted with a median time to neutrophil >.5 × 109/L of 22 days (range, 18 to 23). One patient subsequently lost the graft, and 7 (87.5%) maintained >95% donor cell chimerism at 1-year post-HSCT. Two patients developed acute graft-versus-host disease (GVHD) of at least grade II. One had chronic GVHD and died >1 year after HSCT of unknown causes. With a median follow-up of 16 months (range, 11 to 29), 7 patients (87.5%) are alive. Our findings suggest that limited insurance coverage, high rate of DSAs, and patient declining HSCT may limit the availability of haploidentical HSCT in adult SCD patients. The modified Hopkins regimen used here demonstrates high engraftment and low morbidity rates and should be tested in larger, multicenter, prospective clinical trials.

Nonmyeloablative Stem Cell Transplantation with Alemtuzumab/Low-Dose Irradiation to Cure and Improve the Quality of Life of Adults with Sickle Cell Disease

Allogeneic hematopoietic stem cell transplantation (HSCT) is rarely performed in adult patients with sickle cell disease (SCD). We utilized the chemotherapy-free, alemtuzumab/total body irradiation 300 cGy regimen with sirolimus as post-transplantation immunosuppression in 13 high-risk SCD adult patients between November 2011 and June 2014. Patients received matched related donor (MRD) granulocyte colony-stimulating factor-mobilized peripheral blood stem cells, including 2 cases that were ABO incompatible. Quality-of-life (QoL) measurements were performed at different time points after HSCT. All 13 patients initially engrafted. A stable mixed donor/recipient chimerism was maintained in 12 patients (92%), whereas 1 patient not compliant with sirolimus experienced secondary graft failure. With a median follow-up of 22 months (range, 12 to 44 months) there was no mortality, no acute or chronic graft-versus-host disease (GVHD), and no grades 3 or 4 extramedullary toxicities. At 1 year after transplantation, patients with stable donor chimerism have normalized hemoglobin concentrations and improved cardiopulmonary and QoL parameters including bodily pain, general health, and vitality. In 4 patients, sirolimus was stopped without rejection or SCD-related complications. These results underscore the successful use of a chemotherapy-free regimen in MRD HSCT for high-risk adult SCD patients and demonstrates a high cure rate, absence of GVHD or mortality, and improvement in QoL including the applicability of this regimen in ABO mismatched cases (NCT number 01499888).

Absence of hemolytic disease of fetus and newborn despite maternal high-titer IgG anti-Ku

Anti-Ku seen in K(o) (Kell-null) individuals has previously been shown to cause severe hemolytic transfusion reactions. Maternal anti-Ku can cause none or moderate to severe hemolytic disease of the fetus and newborn (HDFN). In two of four previously described HDFN cases, intrauterine transfusions were required because of severe anemia. We report a case in which maternal anti-Ku did not cause HDFN. Standard serologic methods were used for RBC antibody screening and identification, adsorption and elution of RBC antibodies, and antigen typing. A gravida 3, para 3 (G3P3) woman was first evaluated in 2006 and was found to have an IgG RBC antibody that reacted against all panel RBCs in the anti-human globulin phase. A panel of RBCs treated with DTT did not react with the antibody. The antibody failed to react with one example of K(o) RBCs. The patient’s RBCs typed negative for the following Kell blood group antigens: KEL1, KEL2, KEL3, KEL4, KEL6, KEL7, KEL11, KEL13, and KEL18. These results established the presence of anti-Ku in maternal serum. The newborn was group A, D+ and required phototherapy for hyperbilirubinemia, but did not require transfusion. The woman was seen again in January 2010 during the third trimester (G4P3). At this time, anti-Ku titer was 256. She delivered a healthy group O, D+ baby boy at 37 weeks' gestation. Cord RBCs were 4+ for IgG by DAT. An eluate reacted with all RBCs tested, but did not react when tested against a panel of DTT-treated RBCs. K(o) phenotype is rare to begin with, and the maternal anti-Ku formation may require more than one pregnancy. Therefore, cases that can be evaluated for anti-Ku–related HDFN are rare. Our case contributes to serologic and clinical aspects of such rare cases.

Antibody, complement and accommodation in ABO-incompatible transplants

Many facets of accommodation have been explored since this process was first observed in ABO-incompatible renal allografts over 17 years ago. Intriguing new pieces of the puzzle have emerged to be fitted into the picture in several places. For example, vascular endothelial cells can be stimulated to secrete substantial amounts of blood group A and B antigens linked to von Willebrand factor; the antibody response to A and B antigens stimulated by ABO-incompatible renal allografts can show epitope spreading; complement can inhibit inflammation through actions of some complement split products, particularly iC3b and C3a; endothelial cells can upregulate various cytoprotective mechanisms; and clinically, new protocols for achieving accommodation have been implemented with improved results.

The contribution of sociodemographic, medical, and attitudinal factors to blood donation among the general public

BACKGROUND

Few studies have simultaneously assessed the relative importance of sociodemographic, medical, and attitudinal factors in explaining which individuals are more likely to donate blood.

STUDY DESIGN AND METHODS

A cross-sectional telephone survey of households in Maryland was conducted to identify the relation of sociodemographic, medical, and attitudinal factors to blood donation history among the general public. Random digit dialing was used to identify households; individuals aged 18 to 75 years were randomly selected within households. In multivariate analyses, the independent relationship of these factors with prior history of blood donation was assessed, and the amount of variation in prior history of blood donation among the study population that could be explained by these factors was determined.

RESULTS

Of 385 participants (84% of randomized homes), 228 (59%) had donated blood at least once in the past. After adjusting for potential confounders, women, black participants, and those agreeing with the statement "I am afraid of hospitals" had 60 to 80 percent lower odds of prior donation when compared with men, white participants, and those who did not agree with the statement (OR [95% CI]: 0.2 [0.1-0.4], 0.4 [0.2-0.8], and 0.3 [0.2-0.6], respectively). The effect of fear of hospitals was consistent across sex and race. Trust, fear, and suspicion of hospitals were among factors contributing most to variation in prior donation history.

CONCLUSION

Female sex, black race, and fear of hospitals are three major factors negatively associated with prior history of blood donation. Fear of hospitals affects blood donation patterns across race and sex groups. Future study is needed to determine whether recruitment of blood donors may be more efficient if focused toward women, minorities, and donors' fears of healthcare facilities or hospitals.