Identification of the novel HLA-B*53:69 allele by sequencing-based typing

The HLA-B*53:69 allele differs from HLA-B*53:01:01:01 by two nucleotide changes in exon 3.

HLA-based banking of induced pluripotent stem cells in Saudi Arabia

BACKGROUND

Human iPSCs' derivation and use in clinical studies are transforming medicine. Yet, there is a high cost and long waiting time associated with autologous iPS-based cellular therapy, and the genetic engineering of hypo-immunogenic iPS cell lines is hampered with numerous hurdles. Therefore, it is increasingly interesting to create cell stocks based on HLA haplotype distribution in a given population. This study aimed to assess the potential of HLA-based iPS banking for the Saudi population.

METHODS

In this study, we interrogated the HLA database of the Saudi Stem Cell Donor Registry (SSCDR), containing high-resolution HLA genotype data from 64,315 registered Saudi donors at the time of analysis. This database was considered to be a representative sample of the Saudi population. The most frequent HLA haplotypes in the Saudi population were determined, and an in-house developed iterative algorithm was used to identify their HLA matching percentages in the SSCDR database and cumulative coverage. Subsequently, to develop a clinically relevant protocol for iPSCs generation, and to illustrate the applicability of the concept of HLA-based banking for cell therapy purposes, the first HLA-based iPS cell line in Saudi Arabia was generated. Clinically relevant methods were employed to generate the two iPS clones from a homozygous donor for the most prevalent HLA haplotype in the Saudi population. The generated lines were then assessed for pluripotency markers, and their ability to differentiate into all three germ layers, beating cardiomyocytes, and neural progenitors was examined. Additionally, the genetic stability of the HLA-iPS cell lines was verified by comparing the mutational burden in the clones and the original blood sample, using whole-genome sequencing. The standards set by the American College of Medical Genetics and Genomics (ACMG) were used to determine the clinical significance of identified variants.

RESULTS

The analysis revealed that the establishment of only 13 iPSC lines would match 30% of the Saudi population, 39 lines would attain 50% coverage, and 596 lines would be necessary for over 90% coverage. The proof-of-concept HLA-iPSCs, which cover 6.1% of the Saudi population, successfully demonstrated pluripotency and the ability to differentiate into various cell types including beating cardiomyocytes and neuronal progenitors. The comprehensive genetic analysis corroborated that all identified variants in the derived iPSCs were inherently present in the original donor sample and were classified as benign according to the standards set by the ACMG.

CONCLUSIONS

Our study sets a road map for introducing iPS-based cell therapy in the Kingdom of Saudi Arabia. It underscores the pragmatic approach of HLA-based iPSC banking which circumvents the limitations of autologous iPS-based cellular therapies. The successful generation and validation of iPSC lines based on the most prevalent HLA haplotype in the Saudi population signify a promising step toward broadening the accessibility and applicability of stem cell therapies and regenerative medicine in Saudi Arabia.

Perceptions and Attitudes Regarding Hematopoietic Stem Cell Donation Among Blood Donors in Riyadh, Saudi Arabia

Introduction In recent years, there has been a growing trend toward using stem cell transplantation for therapeutic purposes, making a positive impact in the medical field. Access to a compatible and willing donor is essential for those therapeutic purposes, yet the current number of registered donors remains inadequate. The present study aimed to investigate the attitude and perception of stem cell donation among blood donors in Saudi Arabia while also exploring their knowledge of hematopoietic stem cells, willingness towards donation, and fear of complications after stem cell donation. Methods A cross-sectional study was implemented to investigate the perception and attitude toward stem cell donation among blood donors in Riyadh, Saudi Arabia, through a validated self-administered questionnaire. The questionnaire comprised 35 questions divided into five sections, namely, demographics, knowledge, attitude, willingness, and fear of stem cell donation. Results The survey was distributed to 400 subjects. Out of the 400 respondents, 98.8% (n=395) were male, and 90.8% (n=363) were Saudi nationals. The majority had a high school level of education (n=259, 64.75%). Only 10.8% (n=43) of the participants were knowledgeable about stem cells. Knowledge of stem cells was highest among females aged 40-49 years, participants knowledgeable of platelet donation, and participants who donated blood more than 10 times (p-value <0.05). Participants with a bachelor's or master's degree had significantly more fear of stem cell donation complications, with a p-value of 0.003. The attitude toward stem cell donation was highly positive. Most participants strongly agreed to donate stem cells to a family member or anyone in need, 94.5% (n=378) and 62% (n=248), respectively. Conclusion Knowledge about stem cell donation among blood donors was scarce, while their willingness to donate after conversing was high. We highly recommend the initiation and establishment of educational programs to increase the knowledge of the public and, specifically, blood donors.

The effect of caffeine intake and passive smoking on umbilical cord blood unit's quality parameters

Today cord blood (CB) is a valuable source of hematopoietic stem cells to treat many hematological disorders. One of the limitations of CB utilization is the reduced number of nucleated cells including stem cells. Therefore, CB banks around the world have developed strategies in an attempt to improve donor selection and the quality of the CB inventory. This study aimed to determine the impact of passive smoking and caffeine consumption on CB quality. CBs were obtained from mothers who gave birth at King Abdulaziz Medical City. All mothers gave their informed consent. Personal interviews about the mother's demographics, smoking status and exposure, and caffeine consumption executed, followed by a chart review to analyze maternal and neonatal factors. Laboratory testing was performed on all collected CB units. Using descriptive statistics, maternal and newborn factors were analyzed. T-test or Mann-Whitney U Test, as appropriate, for continuous variables analysis to study the effect of second hand smoking and coffee consumption for the primary outcome. Our study demonstrated a reduction in CB MNC, including lymphocytes, in caffeine consumers among pregnant donors, as well as a reduction in cell potency activities, including total CFU and BFU-E. The effect of passive cigarette smoking on the same cohort was insignificant. Outcome of this study will help in optimizing the quality and quantity of stem cell harvesting from CB to get the maximum benefit and such knowledge will raise the awareness among pregnant women.

Association of KIR gene polymorphisms with COVID-19 disease

Background

Methods

Results

Conclusions

Real-World Issues and Potential Solutions in Hematopoietic Cell Transplantation during the COVID-19 Pandemic: Perspectives from the Worldwide Network for Blood and Marrow Transplantation and Center for International Blood and Marrow Transplant Research Health Services and International Studies Committee

The current COVID-19 pandemic, caused by SARS-CoV-2, has impacted many facets of hematopoietic cell transplantation (HCT) in both developed and developing countries. Realizing the challenges as a result of this pandemic affecting the daily practice of the HCT centers and the recognition of the variability in practice worldwide, the Worldwide Network for Blood and Marrow Transplantation (WBMT) and the Center for International Blood and Marrow Transplant Research's (CIBMTR) Health Services and International Studies Committee have jointly produced an expert opinion statement as a general guide to deal with certain aspects of HCT, including diagnostics for SARS-CoV-2 in HCT recipient, pre- and post-HCT management, donor issues, medical tourism, and facilities management. During these crucial times, which may last for months or years, the HCT community must reorganize to proceed with transplantation activity in those patients who urgently require it, albeit with extreme caution. This shared knowledge may be of value to the HCT community in the absence of high-quality evidence-based medicine. © 2020 American Society for Transplantation and Cellular Therapy. Published by Elsevier Inc.

HLA-A, -B, -C, -DRB1, -DQB1, and -DPB1 Allele and Haplotype Frequencies of 28,927 Saudi Stem Cell Donors Typed by Next-Generation Sequencing

Human leukocyte antigen (HLA) allele and haplotype frequency distribution varies widely between different ethnicities and geographical areas. Matching for HLA alleles is essential for successful related and unrelated stem cell transplantation. Among the Saudi population, data on HLA alleles and haplotypes are limited. A cross-sectional study was performed on 28,927 bone marrow donors. The most frequent HLA alleles were HLA-A*02:01:01G (20.2%), A*24:02:01G (7.5%); B*51:01:01G (19.0%), B*50:01:01G (12.3%); C*06:02:01G (16.7%), C*07:02:01G (12.2%); DRB1*07:01:01 (15.7%), DRB1*03:01:01G (13.3%); DQB1*02:01:01G (29.9%), DQB1*03:02:01G (13.2%); and DPB1*04:01:01G (35.2%), DPB1*02:01:02G (21.8%). The most frequent HLA-A~C~B~DRB1~DQB1 haplotypes were A*02:01:01G~C*06:02:01G~B*50:01:01G~DRB1*07:01:01G~DQB1*02:01:01G (1.9%) and A*02:05:01G~C*06:02:01G~B*50:01:01G~DRB1*07:01:01G~DQB1*02:01:01G (1.6%). The most frequent HLA-A~C~B~DRB1~DQB1~DPB1 haplotypes were A*02:01:01G~C*15:02:01G~B*51:01:01G~DRB1*04:02~DQB1*03:02:01G~DPB1*04:01:0G (1%) and A*02:01:01G~C*07:02:01G~B*07:02:01G~DRB1*15:01:01G~DQB1*06:02:01G~ DPB1*04:01:01G (0.9%). Based on these haplotype frequencies, we provide forecasts for the fraction of patients with full matching and single mismatched donors for 3 to 6 loci depending on the registry size. With one million donors, about 50% of the patients would find an 8/8 match and 90% a 7/8 match. These data are essential for registry planning, finding unrelated stem cell donors, population genetic studies, and HLA disease associations.

Screening for pre-leukemia TEL-AML1 chromosomal translocation in banked cord blood units: cord blood bank perspective

Acute lymphocytic leukemia is the most common leukemia in children. Many studies suggest the existence of two subsequent hits in order for the disease to occur. TEL-AML1 (ETV6-RUNX1) is considered an initial genetic hit that occurs prenatally and generates a pre-leukemia clone. In cord blood (CB) stem cell transplantation, donor cell leukemia (DCL) is one of the complications associated with the presence of the pre-leukemic clone. The aim of this study was to identify the prevalence of ETV6-RUNX1 translocation in CB units and the feasibility in implementing such a screening test, to ensure the safety of the CB units. A total of 424 CB samples were tested from the CB units banked at KAIMRC-CBB. RNA was extracted and cDNA synthesis was performed on 1 ug input RNA using Reverse Transcriptase RT-PCR methodology. Chromosomal translocation ETV6-RUNX1 was tested using real time quantitative PCR methodology. Our study showed undetectable levels of ETV6-RUNX1 in all tested CB samples. The samples were analyzed for the chromosomal translocation ETV6-RUNX1 under controlled conditions, using control and fusion genes with known concentrations. The result of this study does not rule out the importance of this screening test in predicting and/or preventing DCL. Moreover, the outcome strengthens the adopted system in our CBB for mother medical history screening prior to donation. We propose adding this test during the verification testing stage, prior to the release of CB units selected for transplantation rather than at the banking stage.

Common, intermediate and well-documented HLA alleles in world populations: CIWD version 3.0.0

A catalog of common, intermediate and well-documented (CIWD) HLA-A, -B, -C, -DRB1, -DRB3, -DRB4, -DRB5, -DQB1 and -DPB1 alleles has been compiled from over 8 million individuals using data from 20 unrelated hematopoietic stem cell volunteer donor registries. Individuals are divided into seven geographic/ancestral/ethnic groups and data are summarized for each group and for the total population. P (two-field) and G group assignments are divided into one of four frequency categories: common (≥1 in 10 000), intermediate (≥1 in 100 000), well-documented (≥5 occurrences) or not-CIWD. Overall 26% of alleles in IPD-IMGT/HLA version 3.31.0 at P group resolution fall into the three CIWD categories. The two-field catalog includes 18% (n = 545) common, 17% (n = 513) intermediate, and 65% (n = 1997) well-documented alleles. Full-field allele frequency data are provided but are limited in value by the variations in resolution used by the registries. A recommended CIWD list is based on the most frequent category in the total or any of the seven geographic/ancestral/ethnic groups. Data are also provided so users can compile a catalog specific to the population groups that they serve. Comparisons are made to three previous CWD reports representing more limited population groups. This catalog, CIWD version 3.0.0, is a step closer to the collection of global HLA frequencies and to a clearer view of HLA diversity in the human population as a whole.

Novel HLA-C*06:284 allele, identified by next-generation sequencing in a Saudi individual

HLA-C*06:284 differs from HLA-C*06:02:01:02 by two single nucleotide substitutions in codon 24 (Ser > Thr).

Novel HLA-DPB1*10:01:05 allele, identified by next-generation sequencing in a Saudi individual

HLA-DPB1*10:01:05 differs from HLA-DPB1*10:01:01:01 by a single synonymous nucleotide substitution in exon 2, 38 G>A.

Novel HLA-B*50:66 allele, identified by next-generation sequencing in a Saudi individual

HLA-B*50:66 differs from HLA-B*50:01:01:01 by a single nucleotide substitution (C>A) in codon 153.

Novel HLA-DPB1*14:01:11 allele, identified by next-generation sequencing in a Saudi individual

HLA-DPB1*14:01:11 differs from HLA-DPB1*14:01:01:01 by a single synonymous nucleotide substitution in codon 52.

The novel HLA-A*68:227 allele, identified by Next-Generation Sequencing in a Saudi individual

HLA-A*68:227 differs from HLA-A*68:84 by two single nucleotide substitutions in codon 10 and 90.

The novel HLA-DRB1*13:290 allele, identified by next-generation sequencing in a Saudi individual

HLA-DRB1*13:290 differs from HLA-DRB1*13:02:01:01 by a single nucleotide substitution in codon 86 (Gly > Ala).

The novel HLA-B*07:387 allele, identified by next-generation sequencing in a Saudi individual

HLA-B*07:387 differs from HLA-B*07:05:01:01 by a single nucleotide substitution in codon 91 (Glycine to Tryptophan).

The novel HLA-DRB3*03:39 allele, identified by next-generation sequencing in a Saudi individual

HLA-DRB3*03:39 differs from HLA-DRB3*03:01:01 by a single nucleotide substitution in codon 22 (Glutamic acid to Lysine).

HLA-A, B, C, DRB1 and DQB1 allele and haplotype frequencies in volunteer bone marrow donors from Eastern Region of Saudi Arabia

We analyzed HLA allele and haplotype frequencies from donors from the Eastern region of Saudi Arabia. A cross-sectional study was performed on 2405 bone marrow donors from the Eastern region. HLA typing was carried out by sequencing. The most common HLA allele groups were HLA-A*02:01:01G (11.08%), A*01:01:01G (10.40%), HLA-B*52:01:01G (8.79%), B*18:01:01G (8.07%), HLA-C*04:01:01G (17.88%), C*12:03:01G (10.23%), HLA-DRB1*10:01 (14.89%), DRB1*03:01:01G (14.10%), HLA-DQB1*02:01:01G (24.53%) and DQB1*05:01:01G (20.17%). The most frequent HLA-A^~ C^~ B^~ DRB1^~ DQB1 haplotypes were HLA-A*01:03^~ C*15:05:01G^~ B*73:01^~ DRB1*10:01:01^~ DQB1*05:01:01G (3.11%) and HLA-A*01:01:01G^~ C*12:02:01G^~ B*52:01:01G^~ DRB1*15:02:01^~ DQB1*06:01:01G (2.25%). When comparing the allele and haplotype frequencies of the Eastern regions' population to those from the Central region we found significant differences in several allele frequencies including A*01:01:01G (P ≤ 0.0001), B*52:01:01G (P ≤ 0.0001), B*18:01:01G (P = 0.0001), C*12:03:01G (P < 0.0001), DRB1*10:01:01 (P < 0.0001) and DQB1*05:01:01G (P < 0.0001). Our data confirms genetic heterogeneity among the Saudi population.

Decidua Basalis Mesenchymal Stem Cells Favor Inflammatory M1 Macrophage Differentiation In Vitro

Placental mesenchymal stem cells from maternal decidua basalis tissue (DBMSCs) are promising cells for tissue repair because of their multilineage differentiation and ability to protect endothelial cells from injury. Here, we examined DBMSC interaction with macrophages and whether this interaction could modulate the characteristics and functions of these macrophages. We induced monocytes to differentiate into M1-like macrophages in the presence of DBMSCs. DBMSC effects on differentiation were evaluated using microscopy, flow cytometry, and ELISA. DBMSC effects on M1-like macrophage induction of T cell function were also examined. The culture of DBMSCs with monocytes did not inhibit monocyte differentiation into M1-like inflammatory macrophages. This was confirmed by the morphological appearance of M1-like macrophages, increased expression of inflammatory molecules, and reduced expression of anti-inflammatory molecules. In addition, DBMSCs did not interfere with M1-like macrophage phagocytic activity; rather, they induced stimulatory effects of M1-like macrophages on CD4⁺ T cell proliferation and subsequent secretion of inflammatory molecules by T cells. We showed that DBMSCs enhanced the differentiation of M1-like inflammatory macrophages, which function as antitumor cells. Therefore, our findings suggest that DBMSCs are inflammatory cells that could be useful in cancer treatment via the enhancement of M1- like macrophages.

Preconditioning human natural killer cells with chorionic villous mesenchymal stem cells stimulates their expression of inflammatory and anti-tumor molecules

Background

Mesenchymal stem cells derived from the chorionic villi of human placentae (pMSCs) produce a unique array of mediators that regulate the essential cellular functions of their target cells. These properties make pMSCs attractive candidates for cell-based therapy. Here, we examined the effects of culturing human natural killer (NK) cells with pMSCs on NK cell functions.

Methods

pMSCs were cultured with IL-2-activated and non-activated NK cells. NK cell proliferation and cytolytic activities were monitored. NK cell expression of receptors mediating their cytolytic activity against pMSCs, and the mechanisms underlying this effect on pMSCs, were also investigated.

Results

Our findings show that IL-2-activated NK cells, but not freshly isolated NK cells, efficiently lyse pMSCs and that this response might involve the activating NK cell receptor CD69. Interestingly, although pMSCs expressed HLA class I molecules, they were nevertheless lysed by NK cells, suggesting that HLA class I antigens do not play a significant role in protecting pMSCs from NK cell cytolytic activity. Co-culturing NK cells with pMSCs also inhibited NK cell expression of receptors, including CD69, NKpG2D, CD94, and NKp30, although these co-cultured NK cells were not inhibited in lysing cancer cells in vitro. Importantly, co-cultured NK cells significantly increased their production of molecules with anti-tumor effects.

Conclusions

These findings suggest that pMSCs might have potential applications in cancer therapy.

Permissive underfeeding, cytokine profiles and outcomes in critically ill patients

Background

During critical illness in humans, the effects of caloric restriction on the inflammatory response are not well understood. The aim of this study is to examine the associations of caloric restriction, inflammatory response profiles and outcomes in critically ill patients.

Methods

This is a sub-study of the PermiT trial (Permissive Underfeeding or Standard Enteral Feeding in Critically Ill Adults Trial- ISRCTN68144998). Serum samples were collected on study days 1, 3, 5, 7 and 14 and analyzed for a panel of 29 cytokines. We used principal component analysis to convert possibly correlated variables (cytokine levels) into a limited number of linearly uncorrelated variables (principal components). We constructed repeated measures mixed linear models to assess whether permissive underfeeding compared to standard feeding was associated with difference cytokine levels over time.

Results

A total of 72 critically ill patients were enrolled in this study (permissive underfeeding n = 36 and standard feeding n = 36). Principal component analysis identified 6 components that were responsible for 78% of the total variance. When adjusted to principal components, permissive underfeeding was not associated with 90-day mortality (adjusted odds ratio 1.75, 95% confidence interval 0.44, 6.95, p = 0.43) or with incident renal replacement therapy. The cytokines did not differ with time between permissive underfeeding and standard feeding groups.

Conclusions

The association of permissive underfeeding compared to standard feeding with mortality was not influenced by the inflammatory profile. Permissive underfeeding compared to standard feeding was not associated with differences in the serum levels of cytokines in critically ill patients.

Oxidative stress, caloric intake and outcomes of critically ill patients

BACKGROUND

The aim of this study was to investigate the patterns of oxidative stress in critically ill patients and the association with caloric intake and outcomes.

METHODS

In this pre-planned sub-study of the PermiT (Permissive Underfeeding versus Target Enteral Feeding in Adult Critically Ill Patients Trial- ISRCTN68144998), we included patients expected to stay in the ICU for ≥14 days. Serum samples were collected on days 1, 3, 5, 7 and 14 of enrollment. We measured total anti-oxidant capacity (TAC), protein carbonyl concentration (a measure of protein oxidation) and 8-hydroxy-7,8-dihydro-2'-deoxyguanosine (8-OHdG) (a measure of DNA oxidation). We used principal component analysis (PCA) and hierarchical cluster analysis (HCA) to group patients according to oxidative stress.

RESULTS

Principal component analysis identified 2 components that were responsible for 79% of the total variance, and cluster analysis grouped patients in three statistically distinct clusters. Majority of patients 78.6% (44/55) were included in cluster 1 with lowest TAC, protein carbonyl and 8-OHdG levels and cluster 2 which accounted for 16.1% (9/55) of patients had the highest levels of TAC and intermediate levels of protein carbonyl levels. Cluster 3 patients 5.4% (3/56) had the highest protein carbonyl levels. Incident renal replacement therapy was highest in cluster 2 (4/8, 50.0%), compared to cluster 1 (4/42, 9.5%) and cluster 3 (1/3, 33.3%, p 0.01). When adjusted to oxidative stress cluster membership, permissive underfeeding was not associated with 90-day mortality (adjusted odds ratio, aOR 1.37, 95% CI 0.36, 5.25, p 0.64) but was associated significantly with lower incident renal replacement therapy (aOR 0.02, 95% CI < 0.001, 0.57, p 0.02).

CONCLUSIONS

There are different distinct patterns of oxidative stress in critically ill patients. Incident renal replacement therapy was different among the three clusters. Our data suggest a protective effect of permissive underfeeding on incident renal replacement therapy that may differ by clusters of oxidative stress.

The prevalence of CCR5-Δ32 mutation in a cohort of Saudi stem cell donors

CCR5 is a chemokine receptor that was found to be used by HIV as a co-receptor for entering target cells. A 32 bp deletion was described in certain people that rendered CCR5 non-functional. The mutant allele CCR5-Δ32 has been shown to prevent HIV infection. In addition, stem cell transplantation with the CCR5-Δ32 homozygous genotype can lead to clearance of HIV infection. In this study, our aim was to investigate the frequency of CCR5-Δ32 mutation in a cohort of stem cell donors from cord blood bank and stem cell donor registry. A total of 3025 samples were collected from healthy stem cell donors (2625) and from cord blood units (400). DNA was extracted and the CCR5 gene was amplified by polymerase chain reaction (PCR) in a light cycler system using SYBR Green dye. The mutated gene was further confirmed by direct gene sequencing. We found 38 heterozygous for CCR5-Δ32 and one homozygous CCR5 mutation (Δ32/Δ32) out of the 3025 tested individuals. We conclude that the protective CCR5-Δ32 allele appears to be rarely present in Saudi Arabia.

Umbilical Cord Blood Natural Killer Cells, Their Characteristics, and Potential Clinical Applications

Natural killer (NK) cells are lymphocytes of the innate immune system able to kill different targets such as cancer cells and virally infected cells without prior activation making then attractive candidates for cancer immunotherapy. Umbilical cord blood (UCB) has become a source of hematopoietic stem cells for transplantation but as we gain a better understanding of the characteristics of each immune cell that UCB contains, we will also be able to develop new cell therapies for cancer. In this review, we present what is currently known of the phenotype and functions of UCB NK cells and how these cells could be used in the future for cancer immunotherapy.

Organ trade using social networks

Organ transplantation is recognized worldwide as an effective treatment for organ failure. However, due to the increase in the number of patients requiring a transplant, a shortage of suitable organs for transplantation has become a global problem. Human organ trade is an illegal practice of buying or selling organs and is universally sentenced. The aim of this study was to search social network for organ trade and offerings in Saudi Arabia. The study was conducted from June 22, 2015 to February 19, 2016. The search was conducted on Twitter, Google answers, and Facebook using the following terms: kidney for sale, kidneys for sale, liver for sale, kidney wanted, liver wanted, kidney donor, and liver donor. We found a total of 557 adverts on organ trade, 165 (30%) from donors or sellers, and 392 (70%) from recipients or buyers. On Twitter, we found 472 (85%) adverts, on Google answers 61 (11%), and on Facebook 24 (4%). Organ trade is a global problem, and yet it is increasingly seen in many countries. Although the Saudi Center for Organ Transplantation by-laws specifically prohibits and monitors any form of commercial transplantation, it is still essential to enforce guidelines for medical professionals to detect and prevent such criminal acts.

Factor predicting total nucleated cell counts in cord blood units

BACKGROUND

Cord blood (CB) stem cells have been used worldwide in transplant medicine to treat various diseases. The efficacy of stem cells in umbilical CB (UCB) can be predicted by the number of total nucleated cells (TNCs). To optimize the clinical use of stem cells in our population, this study addresses several variables affecting the TNC count.

STUDY DESIGN AND METHODS

This observational, cross-sectional study was conducted in a single center from 2012 to 2014. In total, 957 CB units (CBUs) were collected from consented mothers. Data analyses of clinically accepted CBUs were correlated with maternal and infant factors.

RESULTS

Based on the TNC accepted level of banking, 188 CBUs (19.64%) were rejected. Of the 16 maternal and infant variables evaluated, three factors demonstrated a statistically significant predictive value for the accepted TNC level. CB volume was the best predictive factor (p ≤ 0.0001), followed by newborn birth weight (p = 0.025), and the method of delivery (p = 0.002).

CONCLUSIONS

Several maternal, neonatal, and obstetric factors appear to play a major role in predicting an accepted TNC count, which can be used to improve criteria for the donation of stem cells in CBUs.

Human Chorionic Villous Mesenchymal Stem Cells Modify the Functions of Human Dendritic Cells, and Induce an Anti-Inflammatory Phenotype in CD1+ Dendritic Cells

BACKGROUND

Mesenchymal stem cells derived from the chorionic villi of human term placenta (pMSCs) have drawn considerable interest because of their multipotent differentiation potential and their immunomodulatory capacity. These properties are the foundation for their clinical application in the fields of stem cell transplantation and regenerative medicine. Previously, we showed that pMSCs induce an anti-inflammatory phenotype in human macrophages. In this study, we determined whether pMSCs modify the differentiation and maturation of human monocytes into dendritic cells (DCs). The consequences on dendritic function and on T cell proliferation were also investigated.

METHODS

Interleukin-4 (IL-4) and granulocyte-macrophage colony stimulating factor (GM-CSF) were used to stimulate the differentiation of monocytes into immature dendritic cells (iDCs), which were subsequently co-cultured with pMSCs. Lipopolysaccharide (LPS) was used to induce maturation of iDCs into mature dendritic cells (mDCs). Flow cytometry and enzyme-linked immunosorbent assays (ELISA) were used to quantify the effect pMSC co-culturing on DC differentiation using CD1a, a distinctive marker of DCs, as well as other molecules important in the immune functions of DCs. The phagocytic activity of iDCs co-cultured with pMSCs, and the effects of iDCs and mDC stimulation on T cell proliferation, were also investigated.

RESULTS

Monocyte differentiation into iDCs was inhibited when co-cultured with pMSCs and maturation of iDCs by LPS treatment was also prevented in the presence of pMSCs as demonstrated by reduced expression of CD1a and CD83, respectively. The inhibitory effect of pMSCs on iDC differentiation was dose dependent. In addition, pMSC co-culture with iDCs and mDCs resulted in both phenotypic and functional changes as shown by reduced expression of costimulatory molecules (CD40, CD80, CD83 and CD86) and reduced capacity to stimulate CD4(+) T cell proliferation. In addition, pMSC co-culture increased the surface expression of major histocompatibility complex (MHC-II) molecules on iDCs but decreased MHC-II expression on mDCs. Moreover, pMSC co-culture with iDCs or mDCs increased the expression of immunosuppressive molecules [B7H3, B7H4, CD273, CD274 and indoleamine-pyrrole 2,3-dioxygenase (IDO). Additionally, the secretion of IL-12 and IL-23 by iDCs and mDCs co-cultured with pMSCs was decreased. Furthermore, pMSC co-culture with mDCs decreased the secretion of IL-12 and INF-γ whilst increasing the secretion of IL-10 in a T cell proliferation experiment. Finally, pMSC co-culture with iDCs induced the phagocytic activity of iDCs.

CONCLUSIONS

We have shown that pMSCs have an inhibitory effect on the differentiation, maturation and function of DCs, as well as on the proliferation of T cells, suggesting that pMSCs can control the immune responses at multiple levels.

Stem cell research and regenerative medicine at King Abdullah International Medical Research Center

Translation of stem cell research from bench to bedside opens up exciting new therapeutic options for patients. Although stem cell research has progressed rapidly, its clinical applications have not kept pace. We report on the establishment of a stem cell research and regenerative medicine program at King Abdullah International Medical Research Center (KAIMRC). The purpose of this unit is to coordinate advanced stem cell research and translational outcomes with the goal of treating chronic human diseases, such as cancer, diabetes, cardiovascular, neurological, immunological, and liver diseases. Our first step in achieving this goal was to integrate the stem cells and regenerative medicine unit with our umbilical cord blood bank and bone marrow registry. This organizational structure will provide different sources for stem cells for research and clinical purposes, and facilitate our stem cell research and stem cell transplantation program. We are at an early and exciting stage in our program, but we believe that our progress to the international stage will be rapid and have a significant impact.

Three new HLA-C alleles (HLA-C*14:02:13, HLA-C*15:72 and HLA-C*15:74) in Saudi bone marrow donors

Three new HLA-C alleles were identified by sequence-based typing method (SBT) in donors for the Saudi Bone Marrow Donor Registry (SBMDR). HLA-C*14:02:13 differs from HLA-C*14:02:01 by a silent G to A substitution at nucleotide position 400 in exon 2, where lysine at position 66 remains unchanged. HLA-C*15:72 differs from HLA-C*15:22 by a nonsynonymous C to A substitution at nucleotide position 796 in exon 3, resulting in an amino acid change from phenylalanine to leucine at position 116. HLA-C*15:74 differs from HLA-C*15:08 by a nonsynonymous C to T substitution at nucleotide position 914 in exon 3, resulting in an amino acid change from arginine to tryptophan at position 156.

Screening panel-reactive antibody negative, single-antigen positive: a case report

Sensitized patients remain a challenge for successful transplant. Virtual crossmatch is used to determine the presence or absence of donor-specific antibodies. A 60-year-old woman with a negative screening for panel-reactive antibodies (PRA) received an A*11, A*68 type kidney with a negative anti-human globulin/complement-dependent cytotoxicity (AHG-CDC) crossmatch. Her transplant course was complicated by delayed graft function, and she required hemodialysis. On day 8 after receiving the transplant, she had a kidney biopsy that showed features of antibody-mediated rejection/severe acute tubular necrosis, which was treated by plasmapheresis for 5 sessions and intravenous immunoglobulin (2 g/kg). Her serum level of creatinine decreased from 6.7 to 3.6 mg/dL (600-320 μmol/L). Panel-reactive antibody by Luminex was repeated and again was negative. Single-antigen detection was tried next. Surprisingly, A*11:02 came up positive with a mean fluorescence intensity of 9500. High-resolution donor HLA type was A*68:01 and A*11:01. A*11:02 is not part of the screening Luminex PRA whereas the 11:01 allele is. Serologically, HLA-A11 has 2 defined splits, A11.1 and A11.2, which encode A*11:01 and A*11:02, respectively. In this case, the A*11:02 antibody does not seem to be responsible for the increasing creatinine level. However, if the donor had been A*11:02, a humeral rejection would have occurred and been missed by a virtual crossmatch. Thus virtual crossmatch may not work at all times. Screening for PRA by single antigens is suggested even in PRA-negative cases, if only virtual crossmatch is to be used.

Improving cord blood unit quantity and quality at King Abdullah International Medical Research Center Cord Blood Bank

BACKGROUND

Public cord blood banks (CBBs) store cord blood unit (CBU) donations for anyone in need. However, strict regulations need to be followed to build up high-quality bank products that can be used worldwide. We established a public CBB at a tertiary hospital in Saudi Arabia. Here, we investigated the reasons behind rejecting or not collecting CBUs over 2 years (2011-2012) and which steps were implemented to improve the number and quality of storable units.

STUDY DESIGN AND METHODS

A total of 2891 mothers were evaluated. Reasons for rejecting donors, not collecting, and rejecting units before or after collection were analyzed and compared for the years 2011 and 2012.

RESULTS

A total of 1157 (40%) CBUs were not collected, mainly due to staff availability, and 564 (20%) CBUs were rejected. The main reason for rejecting donations was the mother's or neonate's health. Rejecting CBUs after collection was due to low volume. A total of 1170 (40%) CBUs were successfully collected for potential banking and sent for processing; however, 58% were rejected in the laboratory due to low total nucleated cell counts. Several changes were implemented during the 2 years including physician education and awareness, in utero collection, cesarean collection, and staff recruitment. These changes positively affected the numbers of our collected units. Out of the initially eligible mothers in 2011, only 17% were banked; this was increased to 33% in 2012.

CONCLUSIONS

We identified the problems with collecting CBUs for banking and will keep improving our selection process of recruiting more CBUs of high quality.

A need to adopt new strategies for organ donation in Saudi Arabia

BACKGROUND

HLA matching in kidney transplantation is a major factor in long-term survival of the graft. In Saudi Arabia, most deceased donors are non-Saudi, making it difficult to achieve minimal HLA mismatches between donor and recipient.

OBJECTIVE

To analyze HLA types of 200 deceased donors and compare them with the Saudi population's HLA types.

MATERIALS AND METHODS

In a retrospective study analyzing HLA types of the last 398 deceased donors processed in a tertiary hospital in Riyadh, Saudi Arabia, HLA types of all donors were compared with HLA types from a control group of healthy Saudi persons.

RESULTS

HLA types were significantly different between the deceased donor group and the Saudi population. In all deceased donors, zero mismatches was never achieved. The major differences in HLA types were in HLA-A*02, HLA-B*15, B*40, B*50, HLA-DRB1*14, DRB1*15, and DRB1*04.

CONCLUSIONS

As most of our deceased donors are non-Saudis, it is difficult to match for HLA-A, HLA-B, and HLA-DR. HLA matching should be attempted nationwide by adopting different strategies, including typing donors centrally and distributing results to all centers, agreeing on a national point system for allocating organs from deceased donors, and making HLA matching a priority, especially for highly sensitized patients.

Two novel alleles HLA-A*02:433 and HLA-A*02:434 identified in Saudi bone marrow donors using sequence-based typing

In this report, we present two novel HLA-A alleles: HLA-A*02:433 and HLA-A*02:434. These alleles were identified by sequence-based typing method (SBT), in two donors for the Saudi Bone Marrow Donor Registry (SBMDR). Allele A*02:433 is identical to A*02:05:01G except for a G to A substitution at nucleotide position 449 in exon 2. This substitution results in glycine to serine substitution at position 83. Whereas, allele A*02:434 is identical to A*02:01:01G except for a C to A substitution at nucleotide position 245 in exon 2, which results in phenylalanine to threonine substitution at position 15. The generation of both alleles appears to be the result of nucleotide point mutation involving 02:01:01 and 02:05:01.

Human placental mesenchymal stem cells (pMSCs) play a role as immune suppressive cells by shifting macrophage differentiation from inflammatory M1 to anti-inflammatory M2 macrophages

BACKGROUND

Mesenchymal stem cells (MSCs) have a therapeutic potential in tissue repair because of capacity for multipotent differentiation and their ability to modulate the immune response. In this study, we examined the ability of human placental MSCs (pMSCs) to modify the differentiation of human monocytes into macrophages and assessed the influence of pMSCs on important macrophage functions.

METHODS

We used GM-CSF to stimulate the differentiation of monocytes into the M1 macrophage pathway and then co-cultured these cells with pMSCs in the early stages of macrophage differentiation. We then evaluated the effect on differentiation by microscopic examination and by quantification of molecules important in the differentiation and immune functions of macrophages using flow cytometry and ELISA. The mechanism by which pMSCs could mediate their effects on macrophage differentiation was also studied.

RESULTS

The co-culture of pMSCs with monocytes stimulated to follow the inflammatory M1 macrophage differentiation pathway resulted in a shift to anti-inflammatory M2-like macrophage differentiation. This transition was characterized by morphological of changes typical of M2 macrophages, and by changes in cell surface marker expression including CD14, CD36, CD163, CD204, CD206, B7-H4 and CD11b, which are distinctive of M2 macrophages. Co-culture with pMSCs reduced the expression of the costimulatory molecules (CD40, CD80 and CD86) and increased the expression of co-inhibitory molecules (CD273, CD274 and B7-H4) as well as the surface expression of major histocompatibility complex (MHC-II) molecules. Furthermore, the secretion of IL-10 was increased while the secretion of IL-1β, IL-12 (p70) and MIP-1α was decreased; a profile typical of M2 macrophages. Finally, pMSCs induced the phagocytic activity and the phagocytosis of apoptotic cells associated with M2- like macrophages; again a profile typical of M2 macrophages. We found that the immunoregulatory effect of pMSCs on macrophage differentiation was mediated by soluble molecules acting partially via glucocorticoid and progesterone receptors.

CONCLUSIONS

We have shown that pMSCs can transition macrophages from an inflammatory M1 into an anti-inflammatory M2 phenotype. Our findings suggest a new immunosuppressive property of pMSCs that may be employed in the resolution of inflammation associated with inflammatory diseases and in tissue repair.