Successful Outcome in Patients with Fanconi Anemia Undergoing T Cell-Replete Mismatched Related Donor Hematopoietic Cell Transplantation Using Reduced-Dose Cyclophosphamide Post-Transplantation.

Allogeneic hematopoietic cell transplantation (HCT) has been shown to restore normal hematopoiesis in patients with Fanconi anemia (FA), with excellent results in matched related donor HCT. Outcomes of alternative donor HCT are less favorable, however. In patients without FA, several reports have documented stable engraftment and/or a low risk of graft-versus-host disease (GVHD) using unmanipulated HLA-mismatched related donors and post-HCT cyclophosphamide (PT-CY) for GVHD prophylaxis. Data on the use of this approach in patients with FA are scarce, and thus we launched a study of HLA-mismatched related donor HCT in these patient. Here we report our findings in 19 patients. The conditioning was fludarabine 30 mg/m2/day for 5 days, antithymocyte globulin 5 mg/kg/day for 4 days, and total body irradiation (total dose, 200 cGy). GVHD prophylaxis was cyclosporine and mycophenolate and reduced doses of PT-CY, 25 mg/kg, on days +3 and +5. All patients exhibited absolute neutrophil count recovery. Grade III-IV acute GVHD occurred in 3 patients, and chronic GVHD occurred in 1 patient. At a mean follow-up of 38.3 ± 5.8 months, the 5-year probability of overall survival for our patients was 89.2% ± 7.2%. The regimen was well tolerated; hemorrhagic cystitis occurred in 7 patients, and severe mucositis occurred in 5 patients. There were 2 deaths; the primary cause of death was severe GVHD in 1 patient and leukemia recurrence in the other. We conclude that in patients with FA lacking a matched related donor, the use of mismatched related HCT with low-dose PT-CY is a viable option; it is well tolerated, with a high rate of engraftment and an acceptable incidence of GVHD.

Risk factors affecting outcome of unrelated cord blood transplantation for children with familial haemophagocytic lymphohistiocytosis.

Allogeneic haematopoietic stem cell transplantation is still the only available curative option for Familial Haemophagocytic Lymphohistiocytosis (FHLH). Most studies report outcomes after bone marrow or peripheral blood stem cell transplantation. We analysed the outcomes of 118 children with FHLH undergoing single-unit umbilical cord blood transplantation performed from 1996 to 2014. Myeloablative conditioning regimen was given to 90% of the patients, and was mostly busulfan-based (n = 81, 76%), including anti-thymocyte globulin or alemtuzumab (n = 102, 86%). The cumulative incidence of Day 60 neutrophil engraftment was 85%; and that of non-relapse mortality and acute graft-versus-host disease (GvHD) was 21% and 33% at 100 days, respectively. The 6-year cumulative incidence of chronic GvHD was 17% and the 6-year probability of overall survival was 55%. In multivariate analysis, children receiving a graft with a total nucleated cell dose greater than 9·9 × 107 /kg had a better overall survival (hazard ratio [HR]: 0·49, 95% CI: 0·27-0·88, P = 0·02). Degree of human leucocyte antigen (HLA) matching was associated with improved disease-free survival (5/6 vs. 6/6 HR: 2·11, 95% confidence interval [CI]: 1·01-4·4, P = 0·05 and ≤4/6 vs. 6/6, HR: 2·82, CI: 1·27-6·23, P = 0·01). Umbilical cord blood transplantation with a high cell dose and good HLA match is a suitable alternative option to haematopoietic stem cell transplantation in children with FHLH who lack a HLA-matched donor.

Graft Versus Host Disease Following HLA-Matched Sibling Donor Compared with Matched Related Donor for Hematopoietic Stem Cell Transplantation for the Treatment of Severe Combined Immunodeficiency Disease.

BACKGROUND: One of the limiting factors for successful hematopoietic stem cell transplantation (HSCT) is graft versus host disease (GVHD). The EBMT/ESID guidelines for HSCT in severe combined immunodeficiency (SCID) recommend no GVHD prophylaxis for a matched sibling donor (MSD). OBJECTIVE: To determine the risk of GVHD in MSD HSCT for SCID patients compared to matched related donor (MRD). METHODS: This retrospective cohort study compares MSD with MRD and the outcome of GVHD in all SCID patients who underwent HSCT between 1993 and 2013. All statistical analyses were done using IBM SPSS statistics software. RESULTS: One hundred forty-five SCID patients underwent 152 HSCTs while 82 (54%) received GVHD prophylaxis. GVHD occurred in 48 patients (31.5%); 20/48 (42%) had GVHD prophylaxis compared to 28/48 (58%) that did not, P = 0.022. Acute GVHD occurred at a higher trend in MSD, 37/120 (30.8%), compared to MRD, 6/32 (18.8%), P = 0.17. We also analyzed the outcome according to the period of HSCT. The first period was 1993 to 2003, 48 HSCTs, 43 MSD, 5 MRD; all patients had GVHD prophylaxis, and there was no difference in GVHD. The second period was 2004 to 2013: of 104 HSCTs, 77 had MSD and 27 had MRD; GVHD prophylaxis was used in 22.1% of MSD and 63% of MRD, P = 0.000. GVHD was significantly higher in the MSD (40.2%) compared to MRD (18.5%) patients, P = 0.041. CONCLUSION: GVHD prophylaxis in MSD transplant should be considered in SCID patients.

Successful hematopoietic cell transplantation in Fanconi anemia patients with renal impairment using ultra-reduced doses of cyclophosphamide and fludarabine.

Hematopoietic cell transplantation (HCT) remains until now the only curative modality for hematological manifestations in patients with Fanconi anemia (FA). The doses of alkylating agents used in the conditioning of this patient population before HCT are usually significantly decreased due to the genomic instability of the FA cells. FA patients with renal impairment represent a dilemma because of the need to further modify the conditioning regimen according to the degree of renal impairment to avoid additional toxicity. At our institution, we successfully transplanted three FA patients using an ultra-modified regimen.

Factors Determining the Outcome of Hematopoietic Stem Cell Transplantation in Patients With Acute Lymphoblastic Leukemia at King Faisal Specialist Hospital and Research Center, Riyadh, Saudi Arabia.

Medical records of 82 patients with acute lymphoblastic leukemia (ALL) who underwent hematopoietic cell transplantation (HCT) at our institution from 2005 to 2011 were reviewed. Forty-five patients were male (54.8%). The median age at HCT was 7.46 years (range, 0.98 to 14.31 y), the median time to HCT after diagnosis was 12.56 months. Ten patients were below the age of 1 year (12%). All patients were in complete remission at the time of HCT. In 83 transplants, 64 patients received HCT from human leukocyte antigen-identical-related donors and 19 from other donors. Stem cell source was bone marrow in 65 (78%) and cord blood in 18 (22%). Five-year overall survival was 58.8% and event-free survival was 54.3%. The cumulative incidence of acute graft versus host disease was 4.8%±2.3% and of chronic graft versus host disease was 8.9%±3.2%. The median time to absolute neutrophil count and platelet recovery was 17 days (range, 12 to 43 d) and 28 days (range, 15 to 98 d), respectively. One patient acquired CMV infection after transplant. No one developed venoocclusive disease, hemorrhagic cystitis, or other complication. Patient's age at diagnosis, sex, donor's human leukocyte antigen status and sex, source of transplant and complete remission status at HCT did not affect overall survival and event-free survival. Our results show a favorable outcome to HCT for acute lymphoblastic leukemia patients comparable to published data, and no single factor was associated with superior outcome.

Hematopoietic stem cell transplant for hyper-IgM syndrome due to CD40L defects: A single-center experience.

HIGMI is a disease with a high risk for morbidity and mortality. HSCT has been shown to be a curative option. This study retrospectively reviewed and analyzed data from five patients who received HSCT at King Faisal Specialist Hospital & Research Centre (KFSH&RC) in Riyadh, Saudi Arabia, between 2005 and 2013. Five patients with HIGMI syndrome underwent HSCT at a median age of 41 months (range, 9-72 months). The median time from diagnosis to transplantation was 30 months (range, 5-58 months). For all five patients, the donors were HLA-identical siblings. In three patients, the conditioning regimen was composed of BU and CY. Fludarabine and melphalan with either ATG or alemtuzumab was used in two patients. For GVHD prophylaxis, cyclosporine was used in two patients, and the combination of cyclosporine and MTX was used in three patients. The survival rate was 100%, with a median follow-up of 69 months (range, 13-100 months). All patients engrafted. Two patients developed acute GVHD. Four patients showed complete immune recovery with positive CD40L expression in activated T cells and discontinued IVIG replacement. HSCT in early stage from an HLA-matched sibling donor is potentially effective at curing the disease.

Characterization of Crohn disease in X-linked inhibitor of apoptosis-deficient male patients and female symptomatic carriers.

BACKGROUND: Crohn disease is an inflammatory bowel disease (IBD) with a complex mode of inheritance. Although nucleotide binding and oligomerization domain containing 2 (NOD2) is the strongest risk factor, the cause of Crohn disease remains unknown in the majority of the cases. X-linked inhibitor of apoptosis (XIAP) deficiency causes X-linked lymphoproliferative syndrome type 2. IBD has been reported in some XIAP-deficient patients. OBJECTIVE: We characterize the IBD affecting a large cohort of patients with mutations in XIAP and examine the possible pathophysiologic mechanisms. METHODS: We performed a phenotypical and histologic analysis of the IBD affecting 17 patients with hemizygous mutations in XIAP, including 3 patients identified by screening 83 patients with pediatric-onset IBD. The X chromosome inactivation was analyzed in female carriers of heterozygous XIAP mutations, including 2 adults with IBD. The functional consequences of XIAP deficiency were analyzed. RESULTS: Clinical presentation and histology of IBD in patients with XIAP deficiency overlapped with those of patients with Crohn disease. The age at onset was variable (from 3 months to 41 years), and IBD was severe and difficult to treat. In 2 patients hematopoietic stem cell transplantation fully restored intestinal homeostasis. Monocytes of patients had impaired NOD2-mediated IL-8 and monocyte chemoattractant protein 1 (MCP-1) production, as well as IL-10, in response to NOD2 and Toll-like receptor 2/4 costimulation. Nucleotide binding and oligomerization domain containing 1 (NOD1)-mediated IL-6 and IL-8 production was defective in fibroblasts from XIAP-deficient patients. The 2 heterozygous female carriers of XIAP mutations with IBD displayed abnormal expression of the XIAP mutated allele, resulting in impaired activation of the NOD2 pathway. CONCLUSION: IBD in patients with XIAP deficiency is similar to Crohn disease and is associated with defective NOD2 function in monocytes. Importantly, we report that it is not restricted to male patients because we identified 2 symptomatic female heterozygous carriers of XIAP mutations.

Factors affecting the outcome of related allogeneic hematopoietic cell transplantation in patients with Fanconi Anemia.

Hematopoietic cell transplantation (HCT) can cure bone marrow failure in patients with Fanconi Anemia (FA), and it is generally accepted that these patients should receive low-intensity conditioning because of the underlying DNA repair defect in their cells. Outcomes for recipients of matched related HCT have generally been favorable, but only a few studies have scrutinized the factors that may affect the eventual outcome of these patients. This retrospective analysis of 94 pediatric patients with FA who underwent related HCT at King Faisal Specialist Hospital & Research Center was carried out to attempt to identify factors that may affect outcome. Results showed overall survival (OS) probabilities of 92.5%, 89%, and 86% at 1, 5, and 10 years, respectively. In univariate analysis, use of higher dose cyclophosphamide (CY) (60 mg/kg) conditioning was associated with a better 10-year OS than lower dose CY (20 mg/kg) conditioning (91% versus 82%, respectively; P = .035), and use of radiation-containing regimens was associated with a significantly lower 10-year OS than nonradiation regimens (76% versus 91%, respectively; P = .005). Of the 4 regimens used in this study, the fludarabine-based regimen was associated with the highest survival (95.2%; P = .034). The use of the higher dose CY (60 mg/kg) was associated with a significantly increased incidence of hemorrhagic cystitis (HC) (20% versus 5.6% respectively; P = .049). Three patients (3%) developed squamous cell carcinoma (2 oropharyngeal and 1 genitourinary), at 9.4, 5.4, and 13.3 years after HCT; 2 of them had radiation-containing conditioning. In conclusion, our data suggest that although using a higher dose CY (60 mg/kg) conditioning regimen may be associated with better survival, it is also associated with a significantly increased risk of HC. The addition of fludarabine to the low-dose CY (20 mg/kg) is associated with the best survival. On the other hand, radiation-containing regimens are associated with significantly lower survival.

Clinical characteristics and treatment outcome of childhood acute lymphoblastic leukemia in Saudi Arabia: a multi-institutional retrospective national collaborative study.

BACKGROUND: Treatment of childhood acute lymphoblastic leukemia (ALL) has been available in Saudi Arabia (SA) for over 30 years; however, only limited data have been published from there. This study was conducted to establish processes for collaborative data collection and provide clinical characteristics and outcome of children with ALL in SA. PROCEDURE: Clinical data for patients diagnosed from 2004 to 2008 were retrospectively collected at eight institutions and entered remotely into a custom-built database. Statistics regarding clinical and genetic characteristics and treatment outcome were calculated. RESULTS: The 594 evaluable patients had a median age of 4.37 years and 56.4% were boys. Majority of patients had B-precursor ALL while 10.7% had T-ALL. CNS leukemia was present in 5.2% of patients. The distribution of common genetic abnormalities was similar to that reported from western populations, with 24.6% hyperdiploidy, 21% RUNX1-ETV6 positivity, 4.2% BCR-ABL1 positivity, and 2.5% with MLL gene rearrangement. Patients received risk-adapted therapy according to various protocols, although treatment strategies for the majority were similar. Five-year OS, RFS and EFS were 86.9%, 79.1%, and 73.3%, respectively. The OS for patients with pre-B ALL was significantly higher than for T-ALL (88.0% vs. 71.8%; P = 0.019, Log-Rank test). Patients with pre-B ALL categorized as low-risk by NCI/Rome criteria and those with hyperdiploidy had OS of 93.4% and 95.8%, respectively. CONCLUSIONS: The characteristics of childhood ALL in SA are similar to those observed in developed countries. Future prospective studies utilizing unified national protocols are needed to further improve the outcome of our patients.

A green approach for preparation of chitosan/hydroxyapatite/graphitic carbon nitride hydrogel nanocomposite for improved 5-FU delivery.

Reducing the side effects of cancer treatment methods is an important issue. The loading efficiency and sustained release of 5-Fluorouracil (5-FU) have been significantly improved by creating a new method. A nanocarrier with pH sensitivity has been developed through the w/o/w emulsification method. It is loaded with 5-FU and comprises of chitosan (CS), hydroxyapatite (HAp), and graphitic carbon nitride (g-C3N4). g-C3N4 nanosheets were incorporated in CS/HAp hydrogel to improve the entrapment and loading efficiency. Drug loading efficiency and entrapment efficiency reached 48 % and 87 %, respectively, and the FTIR and XRD tests verified evidence of the formation of chemical bonds among the drug and nanocarrier. Structural analysis was done using FE-SEM. DLS and zeta potential were employed to obtain average size distribution and surface charge. The release profile of 5-FU in various conditions shows the nanoparticles' pH dependence, and the nanocomposite's controlled release is consistent with the Korsmeyer-Peppas kinetic model. Cell apoptosis and cytotoxicity were evaluated in vitro using flow cytometry and MTT analysis. The biocompatibility of CS/HAp/g-C3N4 against MCF-7 cells was shown by the MTT method and confirmed by flow cytometry. CS/HAp/g-C3N4@5-FU led to the highest apoptosis rate in MCF-7 cells, indicating the nanocarrier's efficiency in killing cancer cells. These data indicate that the designed CS/HAp/g-C3N4@5-FU can be a potential drug for treating cancer cells.

Cytogenetic abnormalities predict survival after allogeneic hematopoietic stem cell transplantation for pediatric acute myeloid leukemia: a PDWP/EBMT study.

Poor-risk (PR) cytogenetic/molecular abnormalities generally direct pediatric patients with acute myeloid leukemia (AML) to allogeneic hematopoietic stem cell transplant (HSCT). We assessed the predictive value of cytogenetic risk classification at diagnosis with respect to post-HSCT outcomes in pediatric patients. Patients younger than 18 years at the time of their first allogeneic HSCT for AML in CR1 between 2005 and 2022 who were reported to the European Society for Blood and Marrow Transplantation registry were subgrouped into four categories. Of the 845 pediatric patients included in this study, 36% had an 11q23 abnormality, 24% had monosomy 7/del7q or monosomy 5/del5q, 24% had a complex or monosomal karyotype, and 16% had other PR cytogenetic abnormalities. In a multivariable model, 11q23 (hazard ratio [HR] = 0.66, P = 0.03) and other PR cytogenetic abnormalities (HR = 0.55, P = 0.02) were associated with significantly better overall survival when compared with monosomy 7/del7q or monosomy 5/del5q. Patients with other PR cytogenetic abnormalities had a lower risk of disease relapse after HSCT (HR = 0.49, P = 0.01) and, hence, better leukemia-free survival (HR = 0.55, P = 0.01). Therefore, we conclude that PR cytogenetic abnormalities at diagnosis predict overall survival after HSCT for AML in pediatric patients.

Clofarabine in Pediatric Acute Relapsed or Refractory Leukemia: Where Do We Stand on the Bridge to Hematopoietic Stem Cell Transplantation?

Background: Despite pronounced improvement in overall survival (OS) in pediatric leukemia, a proportion of patients continue to suffer from lack of response or relapse, and the management of such patients is exceedingly difficult. Immunotherapy and engineered chimeric antigen receptor (CAR) T-cell therapy have shown promising results in the course of relapsed or refractory acute lymphoblastic leukemia (ALL). However, conventional chemotherapy continues to be utilized for re-induction purposes whether independently or in combination with immunotherapy. Methods: Forty-three pediatric leukemia patients (age < 14 years at diagnosis) consecutively diagnosed at our institution and got treated with clofarabine based regimen at a single tertiary care hospital between January 2005 and December 2019 were enrolled in this study. ALL comprised of 30 (69.8%) patients of the cohort while the remaining 13 (30.2%) were with acute myeloid leukemia (AML). Results: Post-clofarabine bone marrow (BM) was negative in 18 (45.0%) cases. Overall clofarabine failure rate was 58.1% (n = 25) with 60.0% (n = 18) in ALL and 53.8% (n = 7) in AML (P = 0.747). Eighteen (41.9%) patients eventually underwent hematopoietic stem cell transplantation (HSCT); 11 (61.1%) were from ALL group and remaining seven (38.9%) were AML (P = 0.332). Three- and 5-year OS of our patients was 37.7±7.6% and 32.7±7.3%. There was a trend of better OS for ALL patients compared to AML (40.9±9.3% vs. 15.4±10.0%, P = 0.492). Cumulative probability of 5-year OS was significantly better in transplanted patients (48.1±12.1% vs. 21.4±8.4%, P = 0.024). Conclusions: Though almost 90% of our patients proceeded to HSCT with complete response post-clofarabine treatment, yet clofarabine-based regimens are associated with the significant burden of infectious complications and sepsis-related deaths.

Is Mixed Chimerism Post-allogeneic Hematopoietic Stem Cell Transplantation in Pediatric Acute Lymphoid Leukemia a Prognostic Factor for Relapse?

Hematopoietic stem cell transplantation (HSCT) has been considered curative for children with high-risk acute leukemia (ALL), offering better survival. Short tandem repeat has been used as a marker of chimerism status after HSCT. The appearance of recipient cells >1% post-allogeneic stem cell transplant is defined as mixed chimerism (MC). Chimeric studies post-HSCT are dynamic. This study aimed to investigate the significance of recipient cells in post-HSCT pediatric ALL patients as a predictor of relapse of their primary disease. The rate of MC was 51.4% (19 out of 37 recipients). It was 48.6% (n = 18) during Day+100 and 12.9% (4 out of 31 recipients) during post-Day+100 follow-up until two years. No significant association was noted between MC and all grade overall acute graft-versus-host disease. A mortality rate of 35.1% (n = 13) and a median follow-up of 56.9 months (95% CI: 39.7-74.2) were observed for all but four (16.7%) of the survivors in remission. Regarding causes of death, transplant-related mortality was recorded in only 2 of 13 expired patients (15.4%); both succumbed to sepsis. No significant association was found between MC and primary causes of death. The cumulative probability of five-year overall survival and event-free survival was not found to be statistically significantly different for MC (≤1.0% vs. > 1.0%). In conclusion, our data did not show MC testing alone as an effective prognostic marker for detecting relapse; molecular and flow cytometric analyses should be considered in children with ALL post-HSCT for monitoring relapse.

The Saudi experience in fludarabine-based conditioning regimens in patients with Fanconi anemia undergoing stem cell transplantation: excellent outcome in recipients of matched related stem cells but not in recipients of unrelated cord blood stem cells.

Low-dose cyclophosphamide (CY) is now considered the backbone of many of the conditioning regimens used in patients with Fanconi anemia undergoing allogeneic stem cell transplantation (SCT). To reduce the risk of rejection and improve results, CY is usually used in combination with other agents/modalities, such as antithymocyte globulin (ATG), busulfan, radiation, and, more recently, fludarabine (Flu). In this study, we used a uniform Flu-based conditioning regimen (ie, CY, Flu, ATG) in 26 pediatric patients with Fanconi anemia undergoing SCT. The median patient age at the time of SCT was 7.8 years, and the stem cell source was an HLA-matched related donor in 19 patients and partially HLA-matched unrelated cord blood in 7 patients. The CY, Flu, ATG regimen was well tolerated overall, with a remarkably low incidence of graft-versus-host disease and hemorrhagic cystitis. All 19 patients in the matched related donor group engrafted and were alive and transfusion-independent at a median follow-up time of 19 months, compared with only 2 of 7 patients in the unrelated cord blood group. We conclude that the combination of CY, Flu, and ATG in the doses used in this study is well tolerated, and that the proclaimed positive effect of adding Flu to the conditioning regimens of patients with Fanconi anemia undergoing SCT is most pronounced in recipients of HLA-matched related transplants. Its value in unrelated cord blood transplantation probably depends on other factors, such as the degree of HLA matching and the cell dose.

Hematopoietic Stem Cell Transplantation Stabilizes Cerebral Vasculopathy in High-Risk Pediatric Sickle Cell Disease Patients: Evidence From a Referral Transplant Center.

Background: Severe sickle cell disease (SCD) can present with different vaso-occlusive manifestations with cerebral vasculopathy (CV) as one of the most serious complications. Hematopoietic stem cell transplant (HSCT) is the ultimate therapy for this complication. The aim of this study was to assess the outcome and impact of HSCT on severe SCD patients with CV complications. Methods: Twenty-five consecutive transplants-naive pediatric SCD patients with CV complications underwent HSCT at our institution between 1993 and 2015, using bone marrow as stem cells source from fully match related donors were included. Neurologic evaluation was done both clinically and radiologically before transplantation and regularly following the HSCT. Results: With a median follow-up of 52.2 ± 5.8 months, the cumulative probability of overall survival (OS) at 3 years was 92.0% and event-free survival (EFS) was 88%. Significant neurologic improvements were observed in most of the patients clinically. Different neurologic complications were assessed. The neurologic manifestations before and after HSCT were hemiparesis (11, 1), seizures (13, 8), focal neurologic deficit (4, 2), loss of conscious (2, 1) headache (6, 1), and psychological symptoms (5, 2). Post-HSCT radiological imaging was done in 15 patients, which showed stabilization of CV among all. Conclusions: Allogeneic HSCT in patients with severe SCD presenting with CV complications including moyamoya vasculopathy showed favorable outcome with significant clinical neurologic improvement and stabilization of the disease. None of the patients with severe vasculopathy underwent neurological vascular by-pass surgery prior to HSCT.

Use of Internet as a Source of Oral Health Information in Riyadh Region, Saudi Arabia.

Aim: This study aimed to assess the use of Internet as a source of oral health among adult population in Riyadh region, Saudi Arabia. Methodology: A self-administered questionnaire was distributed among adults aged above 18 years through Google Forms. Questionnaire consisting of demographic characteristics and questions related to use of Internet, reason for use of Internet, whether they use Internet for searching information related to oral health, which is the media they use more preferably to search oral health information, and does they found the information beneficial or not was asked. Results: Almost 98.2% of the participants uses Internet for one or the other reasons. About 71.3% of the participants use the Internet for searching oral health information. Google is the most common platform for searching oral health information on the Internet. Age and education wise, there was a statistically significant difference in many responses (P < 0.050). Conclusion: Majority of the study population have access to Internet, also search oral health information on the Internet. There is a need for regulations and guidelines so that oral health information available from the Internet can be used as a media to promote oral health.

Allogeneic hematopoietic stem cell transplantation in leukocyte adhesion deficiency type 1: a single center experience.

Leukocyte adhesion deficiency type 1 is a rare autosomal recessive immunodeficiency disorder. The severe phenotype is fatal unless hematopoietic stem cell transplantation (HSCT) is performed. A retrospective analysis was performed in 11 patients with leukocyte adhesion deficiency type 1 who underwent HSCT and monitoring over a period of 19 years at our institution. The median age at HSCT was 8.8 months. Stem cell sources were unmanipulated bone marrow from an HLA-matched related donor in 7 patients, unrelated umbilical cord blood in 3 patients, and a mismatched related donor in 1 patient. Three patients underwent a second HSCT. Conditioning was provided with a busulfan- and cyclophosphamide-based regimen, with anti-thymocyte immunoglobulin added for the cord blood transplant recipients. Graft-versus-host-disease prophylaxis consisted of cyclosporine A and methotrexate for related donor recipients (8 patients) and cyclosporine A and prednisone for cord blood transplant recipients (3 patients). The overall event-free survival rate was 91% with a median follow-up of 94 months (range, 15-223 months). Ten patients had immune reconstitution and demonstrated sustained engraftment that ranged from 11% to 100% for lymphoid lines and from 0% to 100% for myeloid lines. HSCT from a matched related donor or unrelated cord blood provided excellent outcome, and mixed chimerism appeared satisfactory to prevent recurrent infections.

Outcome of second allogenic stem cell transplantation in pediatric patients with non-malignant hematological and immune deficiency disorders.

BACKGROUND: Second stem cell transplantation (SCT) is usually associated with high morbidity and mortality and the data on its outcome in pediatric patients with non-malignant disorders are scarce. PATIENTS AND METHODS: We present 30 children with non-malignant conditions who underwent second SCT at our institution for graft failure after the first SCT; 20 had a non-malignant hematological disorder and 10 had an immune deficiency disorder. Median age at the second SCT was 6.1 years (range, 0.4-13 years) and median time from the first SCT to the second SCT was 6.2 months (range, 1.2-96 months). RESULTS: Twenty patients (70%) engrafted; severe acute GVHD developed in four patients (13%), and chronic GVHD developed in two patients of those at risk (10%). Thirteen deaths occurred and nine were considered treatment related. The 5-year overall (OS) and event free survival (EFS) for all patients were 53% and 47% respectively. The interval between the two transplants seemed to affect the outcome; patients who had the second SCT ≥ 6 months from the first SCT had better survival; the 5-year OS for the two groups (<6 months and ≥ 6 months) respectively were 30% and 74% (P = 0.004), and the 5-year EFS were 27% and 66% (P = 0.004). The underlying disease did not affect the outcome nor did the use of radiation in the conditioning regimen for the second SCT. CONCLUSIONS: Second SCT for graft failure should be considered for children with non-malignant hematological and immune deficiency disorders.

Genetic and clinical characteristics of pediatric patients with familial hemophagocytic lymphohistiocytosis.

BACKGROUND: Our study was designed to investigate the frequencies and distributions of familial hemophagocytic lymphohistiocytosis (FHL) associated genes in Saudi patients. METHODS: FHL associated gene screening was performed on 87 Saudi patients who were diagnosed with hemophagocytic lymphohistiocytosis (HLH) between 1995 and 2014. The clinical and biochemical profiles were also retrospectively captured and analyzed. RESULTS: Homozygous mutations and mono-allelic variants were identified in 66 (75.9%) and 3 (3.5%) of the study participants, respectively. STXBP2 was the most frequently mutated gene (36% of patients) and mutations in STXBP2 and STX11 accounted for 58% of all FHL cases and demonstrated a specific geographical pattern. Patients in the FHL group presented at a significantly younger age than those belonging to the unknown-genetics group (median, 3.9 vs. 9.4 mo; P=0.005). The presenting clinical features were similar among the various genetic groups and the 5-year overall survival (OS) was 55.4% with a 5.6 year median follow-up. Patients with PRF1 mutations had a significantly poorer 5-year OS (21.4%, P =0.008) and patients undergoing hematopoietic stem cell transplant (72.4%) had a significantly better 5-year OS (66.5% vs. 0%, P =0.001). CONCLUSION: Our study revealed the predominance of the STXBP2 mutations in Saudi patients with FHL. A genetic diagnosis was possible in 80% of the cohort and our data showed improved survival in FHL patients who underwent hematopoietic stem cell transplant.

Does Mixed Chimerism After Allogeneic Hematopoietic Cell Transplantation in Pediatric Patients With Fanconi Anemia Impact on Outcome?

Fanconi anemia (FA) cells are characterized by genomic instability, which places FA patients at risk for malignancies such as leukemia and oropharyngeal/urogenital cancers. The risk of development of leukemia is theoretically eliminated after hematopoietic cell transplantation (HCT). Mixed chimerism (MC) in FA patients might have a unique implication because the persistent existence of FA cells might give rise to a malignant clone. We have studied a large population of FA patients who underwent allogeneic HCT at our institution and report here the outcome according to chimerism status. Patients with FA who had evidence of progressive bone marrow failure and were blood products-transfusion dependent (packed red blood cells, platelets, or both) were included in the study. Those who had myelodysplasia (MDS) or an abnormal clone or evidence of leukemia were excluded. All but 3 patients had normal renal and cardiac function at the time of transplantation. In total, 160 patients with FA underwent allogeneic HCT at our center from January 1995 to December 2017; mean age at HCT was 8.4. Chimerism data at last follow-up visit were available on 97 patients who are the subjects of this analysis (no day +100 chimerism data on one of them). On day +100, 46 patients (47.9%) had full chimerism (FC) and 50 (52.1%) had MC, whereas at last follow-up 50 (51.5%) exhibited FC and the remaining 47 (48.5%) had MC. Cumulative incidence of all grades acute graft-versus-host disease (GVHD) was 13.4% and that of grade III to IV GVHD was 4.1%. Chronic GVHD was seen in eight (8.0%) patients. Incidence of severe acute GVHD (grade ≥ III) and that of chronic GVHD were not significantly associated with FC or MC measured at day +100 (P values = .347 and .254, respectively), nor at the last follow-up. Graft failure occurred in 2 patients; both from the MC at day +100 group. No graft failures occurred in the FC at day +100 group (P value = 1.00). At a median follow-up of 83.8 months (95% confidence interval, 51.0-116.6; range, 19.3-181.1 months) the cumulative probability of overall survival (OS) at 5 years was 95.7% ± 2.1%. Mean follow-up time in our cohort was 90.7 months. Five-year overall survival was not significantly associated with FC or MC evaluated at day +100 (95.7% ± 3.0% versus 95.6% ± 3.1%, P value = .908) nor at the last follow-up (96.0% ± 2.8% versus 95.4% ± 3.2%, P value = .925). No patient in either group developed MDS/leukemia during the follow-up period. We conclude that mixed chimerism in patients with FA appears to have no adverse effect on outcome in our follow-up period. A longer follow-up period is needed, however, to confirm the validity of this statement.