Influence of donor characteristics on the milk donation volume and microbiological quality of donated human milk in first 3 years of work of the Croatian human milk bank-retrospective observational study

OBJECTIVES

Donated human milk is the best possible alternative when mother's own milk is not available. The aim of this study is to investigate whether there are differences in the milk donation volumes and microbiological quality of donated milk depending on human milk donors (HMDs) characteristics.

METHODS

We analyzed data on the HMDs who donated milk in the first three years of work of human milk bank (HMB) - November 2019 to January 2023. The data on the volume of donated milk in L and suitable microbiological quality assessed by the number and isolated species of bacteria were collected from questionnaires filled out by HMDs and documentation administered by HMB employees and are presented using descriptive and comparative statistics.

RESULTS

Two hundred HMDs were included in this study. The majority of them are between 26 and 35 years of age, reside in capital city or the surrounding county, have given birth to a full-term child vaginally, and express surplus milk through a breast pump. Donor mothers of preterm born infants (14.5 %) donated greater quantities, there is statistically significant difference in the median of volume of milk donated (9.6 vs. 6.4, p=0.026). Milk expressed manually shows better results in microbiological quality (median percentage 100 vs. 82 vs. 100, p=0.040), while by comparing other characteristics of the donors, no difference was found between the groups.

CONCLUSIONS

It is important to be aware of the characteristics of previous HMDs in order to direct the HMB future promotional and educational activities.

Vascular access for autologous peripheral blood stem cells collection by large volume leukapheresis: Single center experience

INTRODUCTION

Peripheral blood stem cell (PBSC) harvesting requires reliable and safe vascular access. In our institution, a change of practice was implemented and the central venous catheter (CVC) placement for all autologous PBSC collections was abandoned in favor of a careful evaluation of peripheral venous access (PVA) for each individual patient. The aim of this prospective study was to evaluate the rate of patients with adequate peripheral veins for autologous PBSC collection and compare patient characteristics, collection efficacy, and complication rate between patients with PVA and CVC.

METHOD

Peripheral veins were assessed by the apheresis nurse team in all patients referred between January 2020 and July 2021 to autologous PBSC collection. Only in case of difficult venous access, CVC was inserted. Large volume leukapheresis (LVL) procedures, which processed ≥3 total blood volumes, were performed.

RESULTS

In 65 (57%) patients PVA was used, while 49 (43%) patients required placement of short-term CVC. Peripheral venous access was successfully used significantly more often in males (69.8%) (P = 0.010), and patients with multiple myeloma (71.0%) than in patients with non-Hodgkin's lymphoma (35.9%) and Hodgkin's lymphoma patients (33.3%) (P < 0.001). There was a significant difference in the type of prior administered chemotherapy; in the patients who received cytostatics free chemotherapy, PVA was used more often (75.0%) (P = 0.007). In terms of the efficacy and safety of LVLs, there were no differences between procedures performed using PVA and CVCs.

CONCLUSION

Peripheral venous access is feasible for autologous PBSC collection in more than a half of patients, in particular in those with multiple myeloma. Changes in the treatment of multiple myeloma, using new proteasome inhibitors-based and immunomodulatory agents that do not adversely affect peripheral veins, have enabled the use of PVA even at the high blood flow rates required by LVL. Peripheral venous access is not associated with safety issues or with a lesser collection efficiency, and it is cost-effective as well. Each patient referred to autologous PBSC collection needs to be evaluated individually by the experienced apheresis team for the most appropriate venous access.

The impact of cryoprotectant exposure time on post-thaw viability of autologous and allogeneic hematopoietic stem cells and leukocyte subpopulations

Although the use of cryoprotectant dimethyl sulfoxide (DMSO) is the gold standard in cryopreservation of hematopoietic stem cells, it is well known that it has a negative effect on cell viability. The aim of this prospective study was to examine how the length of post-thaw exposure to DMSO affects the cell viability and stability of peripheral blood stem cell (PBSC) samples. Additionally, the effects of donor type and pre-cryopreservation storage time on post-thaw viability during the stability study were evaluated. In 30 autologous and 30 allogeneic PBSC samples viable CD34+, CD14+, CD19+, CD16+/56+, and CD3+ cells were determined immediately after thawing, and one-and three-hours post-thaw. Analysis of the absolute count of viable cells in thawed samples showed a significant difference between all measurement points for CD34+ (p < 0.001), CD14+ (p < 0.001), and CD19+ cells (p < 0.001). No significant differences were observed for post-thaw stability of allogeneic samples analysed between products stored before cryopreservation ≥ 24 hours (N = 20), and those stored < 24 hours (N = 10), except for viable CD3+/CD4+ cells after three hours post-thaw (p = 0.028). In conclusion, DMSO had different effects on leukocyte subpopulations in cryopre-served PBSC samples. The type of donors and the length of storage before cryopreservation did not affect the post-thaw stability of cryopreserved PBSC samples.

Variable recovery of cryopreserved hematopoietic stem cells and leukocyte subpopulations in leukapheresis products

INTRODUCTION

Due to the expansion of cell therapy using not only haematopoietic stem cells (HSC) but also other leukocyte subpopulations, the loss of these cells in cryopreserved apheresis products needs to be evaluated. Various factors that could negatively affect post-thaw recovery, such as leukapheresis product characteristics, storage time and cryopreservation protocols have been identified.

METHODS

The post-thaw recovery of HSCs, lymphocytes, NK cells and monocytes, as well as the factors that could adversely affect it were analysed in autologous and allogeneic leukapheresis products.

RESULTS

The lowest post-thaw recovery was observed in autologous and allogeneic CD34+ cells, with the median of 73.7% and 68.1%, respectively. In leukocyte subpopulation, the lowest post-thaw recovery was observed for CD14+ cells, both autologous and allogeneic. The highest post-thaw recovery was observed for CD3+/CD8+ cells in autologous, and for CD19+ cells in allogeneic samples. The statistically significant difference was observed between autologous and allogeneic PBSC products for CD3+ cell recovery (P = 0.031) and CD3+/CD8+ cell recovery (P = 0.009). The evaluation of factors that could adversely affect the post-thaw recovery in autologous samples showed weak negative correlations between platelet concentration and CD3+ recovery, as well as between storage time and CD3+CD8+ recovery. In allogeneic samples, a strong negative correlation was observed only between the percentage of granulocytes and CD3+, CD3+/CD8+ and CD3+/CD4+ cell recoveries.

CONCLUSION

Since various post-thaw recoveries of leukocyte subpopulations were observed, the cell therapy manufacturing centers should evaluate how their cryopreservation method and other factors affect the recovery of cell population of interest in their settings.

P31-A150 SARS-CoV-2 real time polymerase chain reaction testing of corneas from post-mortem SARS-CoV-2 positive donors

PURPOSE

Possible transmission of SARS-CoV-2 from donors to recipients via cornea grafts is still a concern of the transplantation community. Current recommendations are to avoid corneal transplants from donors with ongoing SARS-CoV-2 infection or those recently exposed to it. During pandemic period in Croatia 21/1113; (1,9%) corneas were procured from donors positive for SARS-CoV-2 by postmortem nasopharyngeal swab tests. That tissue was discarded. Due to the lack of knowledge about the infectivity of such corneas, we started prospective study of SARS-CoV-2 presence in cornea tissue. Here we show our first results.

METHODS

In the study period we had four corneas procured from two post-mortem SARS-CoV-2 positive donors. For the presence of SARS-CoV-2, analysis is performed on donor serum, hypothermic storage medium and cornea tissue lysate. Corneas were stored in hypothermic condition for 8 to 10 days, after which tissue was macerated and washed with PBS. The intracellular content was released by incubation with lysis buffer, followed by centrifugation. Next, tissue lysate, serum and hypothermic storage medium were in parallel subjected to fully automated nucleic acid isolation and RNA expression was analyzed by qRT-PCR. During isolation, RNasaP was used as internal control for successful nucleic acids isolation.

RESULTS

No SARS-CoV-2 RNA was detected in the donors serum, storage medium and cornea tissue from donors who were SARS-CoV-2-positive upon tissue procurement. In nasopharyngeal swabs of post mortem positive donors cycle threshold values of viral copies were high (CT>34), indicating that there was small number of viral particles in infected donors that could have impact on negative results in tested tissue.

CONCLUSION

Our data suggested that corneas may not be SARS-CoV-2 permissive if the donor was postmortem positive. Further research is required to gain more coherent insight into SARS-CoV-2 transmission via corneal transplantation.

The appropriateness of platelet transfusions in hematological patients and the potential for improvement

BACKGROUND

Hematology patients are intensive platelet users. In clinical practice, a substantial proportion of platelet (PLT) transfusions are routinely administered outside the guidelines despite compelling evidence for recommendations. Those unnecessary PLT transfusions are an unjustified extra burden on a scarce healthcare resource and may also be detrimental to the patients. This study aims to evaluate indications and assess the appropriateness of PLT transfusion, as well as to identify common discrepancies and propose modalities for better compliance with guidelines.

MATERIAL AND METHODS

The audit of all PLT orders for adult hematological inpatients was conducted over 2 months. The assessment was performed using guidelines for PLT transfusion. Patient demographic, clinical, and transfusion data were collected from hospital electronic medical records.

RESULTS

Based on 286 PLT orders, 344 PCs were transfused to 67 patients: 235 (82.2%) prophylactical due to low PLT count, 34 (11.9%) preprocedural and 17 (5.9%) therapeutic. Overall, 105 (36.77%) PLT transfusions were inappropriate: 78 (33.2%) of all prophylactic PLT transfusions due to low PLT count, 17 (50%) off all preprocedural and 10 (58.8%) of all therapeutical transfusion. The major reason for PLT transfusion inappropriateness was transfusion above the recommended threshold. Double units of PCs were transfused in 36.7% of all PLT transfusions and 32.4% of them were considered inappropriate.

CONCLUSION

Our audit of PLT transfusion practice found a large proportion of inappropriate PLT transfusions. Based on the most common deviations from the guidelines a variety of targeted measures for improvement are proposed.

Propensity-score matched comparison between minimally invasive and conventional aortic valve replacement

AIM

To evaluate the impact of minimally invasive aortic valve replacement (mini-AVR) on clinical outcomes in comparison with the gold standard.

METHODS

We retrospectively reviewed the records of all patients who underwent isolated AVR at the University Hospital Center Zagreb from 2010 to 2020. Patients undergoing mini-AVR were compared with patients undergoing conventional AVR (fs-AVR). The primary outcome measure was blood product consumption. Propensity score matching was used to create a balanced covariate distribution across treatment groups. Additionally, we compared the contemporary outcomes with a historical control.

RESULTS

The final sample consisted of 1088 patients. In the unmatched cohorts, mini-AVR patients were younger (65±12 vs 68±10 years, P<0.001) and had lower risk profiles (EuroSCORE2 2.8±2.0 vs 3.5±3.1, P=0.003). After matching, mini-AVR patients required less blood transfusion than fs-AVR patients (270 [0-790] vs 510 [0-970] mL, P=0.029). The incidences of stroke, dialysis, new AV block, and mortality were comparable. Cross-clamp times were longer in the mini-AVR group (71 [60-87] vs 66 [53-83] minutes, P=0.013). Outcomes were improved in the contemporary mini-AVR era compared with our early mini-AVR experience across multiple metrics. Blood product consumption was reduced in the latter tercile of experience (0 [0-520] vs 500 [0-1018] mL, P<0.001), and the operation was performed more expeditiously (cross-clamp times: 63 [54,80] vs 74 [62,88] minutes, P<0.001) in comparison with earlier periods.

CONCLUSIONS

We showed that mini-AVR was associated with less blood product requirement than conventional surgery. Our data supports wider adoption of minimally invasive techniques in dedicated centers of excellence.

Platelet transfusion practice and related transfusion reactions in a large teaching hospital

BACKGROUND

Platelet transfusion practice varies widely since many aspects of platelet concentrate (PC) use have not been definitively determined. The objectives of this retrospective study were to present platelet transfusion practice and evaluate PC and patient characteristics, as well as their association with transfusion reaction (TR) rate.

MATERIAL AND METHODS

Platelet transfusions over a 5-year period were analysed regarding PC characteristics (the ABO and RhD compatibility, product type, and storage duration), patient characteristics (most responsible diagnosis, age, and gender), and TR type.

RESULTS

A total of 46,351 PCs were transfused: 76.4% whole blood-derived (WBD) and 23.6% single donor apheresis (SDA). Three thousand seven hundred seventy-six patients received platelet transfusions: 24.7% paediatric and 75.3% adult patients, 79.6% outpatients and 20.4% inpatients. As much as 63.1% of all transfused PCs were fresh (stored for≤3 days), 98.0% ABO-identical, and 87.3% of all PCs given to RhD- patients were RhD-. PCs were mainly transfused to haemato-oncology (76.8%) and cardiovascular surgery patients (6.5%). Overall, 84 (0.18%) TRs were reported, with allergic TRs (ATRs) being the most common. Although PC ABO compatibility and storage duration, as well as patient age and gender, showed differences in TR rate, only the use of PCs in platelet additive solution (PAS) showed a statistically significant reduction of TRs (P<0.001).

CONCLUSION

Transfusion practice at the University Hospital Centre Zagreb resulted in almost all patients receiving ABO and RhD identical PCs, and most of them were fresh PCs. The most important factor affecting the incidence of TRs was platelet storage solution. The use of PAS effectively reduced the rate of TRs, particularly allergic TRs.

Utilisation patterns of group O red blood cell transfusion by ABO and D non-identical recipients in large academic hospital

OBJECTIVES

Several studies have raised concerns that transfusion of O red blood cells (RBCs) to ABO and D non-identical recipients can intensify group O inventory shortages. The aim of this study was to retrospectively analyse particular clinical indications and polices responsible for O RBCs use by ABO and D non-identical recipients, as well as to assess the impact of this practice on the overall utilisation of O RBCs.

MATERIAL AND METHODS

Data of all transfused RBCs from 2014 to 2018 were extracted from the comprehensive database of transfusion service. Extracted variables included date of transfusion, ABO and D group of the transfused RBCs and recipients, recipient's demographic, and specific characteristics regarding transfusion requirements.

RESULTS

Over a 5-year period, 124,220 RBCs were transfused: 38,962 (31.4%) group O D+ and 9109 (7.3%) group O D-. ABO and D non-identical recipient received 4842 (10.1%) of all administered O RBCs: 2880 (7.4%) of all transfused O D+ and 1962 (21.5%) of all transfused O D- RBCs. The common indications for this practice were: ABO and D mismatched hematopoietic stem cell transplantation (HSCT) (52.5%), infants under the age of 4 months (18.6%), shortage of ABO identical RBCs (9.0%), phenotype-matched RBCs (8,1%), and urgent transfusion (7.2%).

CONCLUSIONS

A significant proportion of O RBCs was transfused to ABO and D non-identical recipients, mainly due to transfusion of ABO and D mismatched HSCT recipients. However, the proportion of all transfused RBCs O D+ and especially O D- remained relatively low.

Evaluation of the BD Stem Cell Enumeration Kit on the BD FACSCanto II flow cytometer using bd facscanto clinical and bd facsdiva software

INTRODUCTION

CD34+ hematopoietic stem cell (HSC) enumeration by cell flow cytometry is routinely used in clinical laboratories for monitoring of HSC mobilization into peripheral blood and assessment of the quality of HSC products. The modified ISHAGE protocol is the most often used procedure for determination of CD34+ cells using flow cytometry. The aim of this study was to evaluate BD Enumeration stem cell kit on flow cytometer BD facscanto II, using facscanto clinical and facsdiva softwares.

METHODS

Validation study included determination of within-run and between-run precision, trueness (bias), comparison of the test results analyzed on facscanto clinical and facsdiva softwares, assessment of linearity, specimen stability, and carryover.

RESULTS

For between-run precision, coefficients of variation (CVs) were all <10%, except for low control level on facsdiva software. CVs for within-run precision were <10%, except for high absolute count of CD34+ cells on facsdiva software. Comparison of data showed no statistically significant differences between facscanto clinical and facsdiva software (Spearman's rank correlation coefficients were .993 for % of CD34+ cells and 0.983 for absolute count of CD34+ cells). In linearity study, bias for all dilutions was < 20%, and carryover assessment cannot be considered significant on both softwares. There was a statistically significant difference (P = .044) in absolute count of CD34+ cells after 24 hours of storage, when using facscanto clinical software.

CONCLUSION

BD Stem Cell Enumeration Kit can be used in routine laboratory work on BD FACSCanto II instrument, whereas facscanto clinical and facsdiva software were used for acquisition and data analysis.

K antigens on neonatal red blood cells blocked by anti-K with titer of 32

The blocking of red blood cell (RBC) antigens occurs when potent maternal antibodies bind to antigens on fetal or neonatal RBCs, causing them to be negative when typed with human IgM antisera. This phenomenon is rare; when it does occur, the antibody is usually of a high titer. This reported finding is typically due to anti-D, with rare reports describing false-negative K phenotyping due to blocking by maternal anti-K. We report a case of a potent anti-K with a titer of 32 that blocked K antigens on neonatal RBCs, causing them to phenotype as K-. The neonate also had clinically significant anemia (i.e., hemolytic disease of the newborn) due to the anti-K.

LEUKOCYTAPHERESIS IN THE MANAGEMENT OF SEVERE STEROID-DEPENDENT ULCERATIVE COLITIS

Ulcerative colitis (UC) is a multifactorial disease of unknown precise etiology and immunopathogenesis. Peripheral blood granulocytes and monocytes/macrophages are the major sources of cytokines, which regulate inflammation. Leukocytapheresis (LCAP) is a method where blood is processed by apheresis system that removes lymphocytes and plasma before being returned to the body. We report the first case in Croatia where we used LCAP in the treatment of a patient with severe steroid-dependent UC. After 12 LCAP procedures, good clinical response was obtained and there were no significant adverse side effects noticed. The patient remained in clinical remission over two years in which he underwent regular follow ups at outpatient clinic. Over a 10-year follow-up period after LCAP, the patient had only occasional clinical symptoms of disease activity. The clinical course was complicated with the development of metastatic colorectal carcinoma, which points to the importance of regular disease monitoring rather than the increased risk of malignant disease after LCAP. Patients with UC are a demanding group of patients that warrant the search for novel treatment strategies other than conventional pharmacological therapies. Although LCAP is still not a common treatment modality in our daily practice, data from recent studies suggest it to be an effective and safe procedure in the management of active UC patients.