Dynamic Trends in Surgical Oromaxillofacial Trauma Epidemiology: A Comparative Study of Pre-COVID-19 and COVID-19 Periods in Tertiary Referral Hospitals in Madrid.

Introduction: The COVID-19 pandemic has induced profound societal and healthcare transformations globally. Material and methods: This multicenter retrospective study aimed to assess potential shifts in the epidemiology and management of oromaxillofacial trauma requiring surgical intervention over a 1-year period encompassing the onset of the COVID-19 pandemic, in comparison to the preceding year. The parameters investigated included age, sex, injury mechanisms, fractured bones, and treatment modalities. The statistical significance was set at p < 0.05. Results: A notable 39.36% reduction in oromaxillofacial fractures was identified (p < 0.001), with no significant alterations in sex distribution, types of fractured bones, or treatment modalities. An appreciable increase in mean age was observed (35.92 vs. 40.26) (p = 0.006). Analysis of the causes of oromaxillofacial trauma revealed diminished incidents of interpersonal violence (41% vs. 35%) and sports-related injuries (14% vs. 8%), alongside an escalation in cases attributed to falls (27% vs. 35%), precipitation events (2% vs. 5%), and traffic accidents (12% vs. 13%). The mandible emerged as the most frequently fractured bone. Conclusion: In conclusion, the COVID-19 pandemic has decreased the number of maxillofacial fractures treated surgically and has changed the epidemiology and the etiology of facial traumas.

A retrospective analysis to evaluate if KIR B haplotype donors associate with a reduced risk of relapse in patients with haematological malignancies following haploidentical transplantation at the Blood and Bone Marrow Transplant Unit at Hammersmith Hospital ICHNHST.

Relapse is a major cause of treatment failure in haploidentical haematopoietic progenitor cell transplant (HPCT) with PTCy. Natural killer cells suppress graft versus host disease and mediate the graft versus leukaemia effect, driven by killer cell immunoglobulin-like receptors (KIRs). Emerging research suggests that donor KIR genotype may influence graft outcome in haploidentical transplants with varying impacts between patient cohorts. This study investigates whether donors with greater KIR B motifs associate with outcomes such as greater relapse-free survival (RFS), overall survival (OS), nonrelapse mortality (NRM), acute graft versus host disease (GvHD) and infection. The study cohort included 98 haploidentical donor-recipient (D/R) pairs (myeloablative n = 37, RIC n = 61) with various haematological malignancies, receiving primary T-cell replete haploidentical HSCT with PTCγ. Following KIR SSO genotyping, donors are categorised into neutral (n = 63) or better and best (n = 35), based on KIR B motif content. Kaplan-Meier and Cox regression survival functions are performed to investigate associations with outcomes. Our results show that the better and best category has significantly poorer RFS (p = 0.013; hazard ratio [HR] 3.16, 95% CI 1.21-8.24: p = 0.018). The greater risk of relapse associated with poorer OS (p = 0.011; HR 2.24, 95% CI 1.18-4.24: p = 0.01) in the better and best category. The competing KIR receptor-ligand and missing licensing proof models failed to predict transplant outcomes. Here, we show neutral donors associate with favourable outcomes in T-cell replete haplo-HPCT with PTCγ after categorisation using the KIR B content model, due to the increased risk of relapse associated with the use of better and best donors.

ALL-RIC trial protocol: a comparison of reduced dose total body irradiation (TBI) and cyclophosphamide with fludarabine and melphalan reduced intensity conditioning in adults with acute lymphoblastic leukaemia (ALL) in complete remission.

INTRODUCTION: The usage of a T-cell depleted, reduced intensity conditioning (RIC) approach to haematopoietic cell transplantation (HCT) in adult patients with acute lymphoblastic leukaemia (ALL) over 40 years of age and in first complete remission (CR) has resulted in encouraging rates of event-free and overall survival in a population of adults with high risk disease. However, relapse rates remain high-with disease progression being the major cause of treatment failure. Using different, more powerful conditioning approaches is the logical next step in examining the role of RIC allogeneic HCT in adult ALL. METHODS AND ANALYSIS: The ALL-RIC trial is a two-arm, phase II, multicentre, randomised clinical trial in adult patients with ALL in first or second CR, who are undergoing allogeneic HCT. Comparison of a novel RIC transplant conditioning regimen using reduced-dose total body irradiation (TBI), cyclophosphamide and alemtuzumab, is made against a standardised RIC approach using fludarabine, melphalan and alemtuzumab. The primary outcome of the study is disease-free survival at 3 years, defined as time from randomisation to the first of either relapse or death from any cause. Patients who are still alive and progression-free at the end of the trial will be censored at their last date known to be alive. Secondary outcomes include overall survival and non-relapse mortality. ETHICS AND DISSEMINATION: The protocol was approved by the East Midlands-Leicester Central Research Ethics committee (18/EM/0112). Initial approval was received on 12 June 2018. Current protocol version (V.6.0) approval obtained on 18 November 2019. The Medicines and Healthcare products Regulatory Agency (MHRA) also approved all protocol versions. The results of this trial will be disseminated through national and international presentations and peer-reviewed publications. TRIAL REGISTRATION NUMBER: EudraCT Number: 2017-004800-23.ISRCTN99927695.

Outcomes and toxicity of allogeneic hematopoietic cell transplantation in chronic myeloid leukemia patients previously treated with second-generation tyrosine kinase inhibitors: a prospective non-interventional study from the Chronic Malignancy Working Party of the EBMT.

Allogeneic hematopoietic cell transplantation (allo-HCT) remains a treatment option for patients with chronic myeloid leukemia (CML) who fail to respond to tyrosine kinase inhibitors (TKIs). While imatinib seems to have no adverse impact on outcomes after transplant, little is known on the effects of prior use of second-generation TKI (2GTKI). We present the results of a prospective non-interventional study performed by the EBMT on 383 consecutive CML patients previously treated with dasatinib or nilotinib undergoing allo-HCT from 2009 to 2013. The median age was 45 years (18-68). Disease status at transplant was CP1 in 139 patients (38%), AP or >CP1 in 163 (45%), and BC in 59 (16%). The choice of 2GTKI was: 40% dasatinib, 17% nilotinib, and 43% a sequential treatment of dasatinib and nilotinib with or without bosutinib/ponatinib. With a median follow-up of 37 months (1-77), 8% of patients developed either primary or secondary graft failure, 34% acute and 60% chronic GvHD. There were no differences in post-transplant complications between the three different 2GTKI subgroups. Non-relapse mortality was 18% and 24% at 12 months and at 5 years, respectively. Relapse incidence was 36%, overall survival 56% and relapse-free survival 40% at 5 years. No differences in post-transplant outcomes were found between the three different 2GTKI subgroups. This prospective study demonstrates the feasibility of allo-HCT in patients previously treated with 2GTKI with a post-transplant complications rate comparable to that of TKI-naive or imatinib-treated patients.

Fecal Microbiota Transplant Mitigates Adverse Outcomes Seen in Patients Colonized With Multidrug-Resistant Organisms Undergoing Allogeneic Hematopoietic Cell Transplantation.

The gut microbiome can be adversely affected by chemotherapy and antibiotics prior to hematopoietic cell transplantation (HCT). This affects graft success and increases susceptibility to multidrug-resistant organism (MDRO) colonization and infection. We performed an initial retrospective analysis of our use of fecal microbiota transplantation (FMT) from healthy donors as therapy for MDRO-colonized patients with hematological malignancy. FMT was performed on eight MDRO-colonized patients pre-HCT (FMT-MDRO group), and outcomes compared with 11 MDRO colonized HCT patients from the same period. At 12 months, survival was significantly higher in the FMT-MDRO group (70% versus 36% p = 0.044). Post-HCT, fewer FMT-MDRO patients required intensive care (0% versus 46%, P = 0.045) or experienced fever (0.29 versus 0.11 days, P = 0.027). Intestinal MDRO decolonization occurred in 25% of FMT-MDRO patients versus 11% non-FMT MDRO patients. Despite the significant differences and statistically comparable patient/transplant characteristics, as the sample size was small, a matched-pair analysis between both groups to non-MDRO colonized control cohorts (2:1 matching) was performed. At 12 months, the MDRO group who did not have an FMT had significantly lower survival (36.4% versus 61.9% respectively, p=0.012), and higher non relapse mortality (NRM; 60.2% versus 16.7% respectively, p=0.009) than their paired non-MDRO-colonized cohort. Conversely, there was no difference in survival (70% versus 43.4%, p=0.14) or NRM (12.5% versus 31.2% respectively, p=0.24) between the FMT-MDRO group and their paired non-MDRO cohort. Collectively, these data suggest that negative clinical outcomes, including mortality associated with MDRO colonization, may be ameliorated by pre-HCT FMT, even in the absence of intestinal MDRO decolonization. Further work is needed to explore this observed benefit.

Autologous Hematopoietic Stem Cell Transplantation in Active Multiple Sclerosis: A Real-world Case Series.

OBJECTIVE: To examine outcomes in people with multiple sclerosis (PwMS) treated with autologous hematopoietic stem cell transplantation (AHSCT) in a real-world setting. METHODS: This was a retrospective cohort study of PwMS treated with AHSCT at 2 centers in London, UK, consecutively between 2012 and 2019 who had ≥6 months of follow-up or died at any time. Primary outcomes were survival free of multiple sclerosis (MS) relapses, MRI new lesions, and worsening of Expanded Disability Status Scale (EDSS) score. Adverse events rates were also examined. RESULTS: The cohort includes 120 PwMS; 52% had progressive MS (primary or secondary) and 48% had relapsing-remitting MS. At baseline, the median EDSS score was 6.0; 90% of the evaluable cases showed MRI activity in the 12 months preceding AHSCT. Median follow-up after AHSCT was 21 months (range 6-85 months). MS relapse-free survival was 93% at 2 years and 87% at 4 years after AHSCT. No new MRI lesions were detected in 90% of participants at 2 years and in 85% at 4 years. EDSS score progression-free survival (PFS) was 75% at 2 years and 65% at 4 years. Epstein-Barr virus reactivation and monoclonal paraproteinemia were associated with worse PFS. There were 3 transplantation-related deaths within 100 days (2.5%), all after fluid overload and cardiac or respiratory failure. CONCLUSIONS: Efficacy outcomes of AHSCT in this real-world cohort are similar to those reported in more stringently selected clinical trial populations, although the risks may be higher. CLASSIFICATION OF EVIDENCE: This study is rated Class IV because of the uncontrolled, open-label design.

Evidence for HIV-1 cure after CCR5Δ32/Δ32 allogeneic haemopoietic stem-cell transplantation 30 months post analytical treatment interruption: a case report.

BACKGROUND: The London patient (participant 36 in the IciStem cohort) underwent allogeneic stem-cell transplantation with cells that did not express CCR5 (CCR5Δ32/Δ32); remission was reported at 18 months after analytical treatment interruption (ATI). Here, we present longer term data for this patient (up to 30 months after ATI), including sampling from diverse HIV-1 reservoir sites. METHODS: We used ultrasensitive viral load assays of plasma, semen, and cerebrospinal fluid (CSF) samples to detect HIV-1 RNA. In gut biopsy samples and lymph-node tissue, cell-copy number and total HIV-1 DNA levels were quantified in multiple replicates, using droplet digital PCR (ddPCR) and quantitative real-time PCR. We also analysed the presence of intact proviral DNA using multiplex ddPCR targeting the packaging signal (ψ) and envelope (env). We did intracellular cytokine staining to measure HIV-1-specific T-cell responses. We used low-sensitive and low-avidity antibody assays to measure the humoral response to HIV-1. We predicted the probability of rebound using a mathematical model and inference approach. FINDINGS: HIV-1 viral load in plasma remained undetectable in the London patient up to 30 months (last tested on March 4, 2020), using an assay with a detection limit of 1 copy per mL. The patient's CD4 count was 430 cells per µL (23·5% of total T cells) at 28 months. A very low-level positive signal for HIV-1 DNA was recorded in peripheral CD4 memory cells at 28 months. The viral load in semen was undetectable in both plasma (lower limit of detection [LLD] <12 copies per mL) and cells (LLD 10 copies per 106 cells) at 21 months. CSF was within normal parameters at 25 months, with HIV-1 RNA below the detection limit (LLD 1 copy per mL). HIV-1 DNA by ddPCR was negative in rectum, caecum, and sigmoid colon and terminal ileum tissue samples at 22 months. Lymph-node tissue from axilla was positive for the long-terminal repeat (33 copies per 106 cells) and env (26·1 copies per 106 cells), negative for ψ and integrase, and negative by the intact proviral DNA assay, at 27 months. HIV-1-specific CD4 and CD8 T-cell responses have remained absent at 27 months. Low-avidity Env antibodies have continued to decline. Mathematical modelling suggests that the probability of remission for life (cure) is 98% in the context of 80% donor chimerism in total HIV target cells and greater than 99% probability of remission for life with 90% donor chimerism. INTERPRETATION: The London patient has been in HIV-1 remission for 30 months with no detectable replication-competent virus in blood, CSF, intestinal tissue, or lymphoid tissue. Donor chimerism has been maintained at 99% in peripheral T cells. We propose that these findings represent HIV-1 cure. FUNDING: Wellcome Trust and amfAR (American Foundation for AIDS Research).

ATIR101 administered after T-cell-depleted haploidentical HSCT reduces NRM and improves overall survival in acute leukemia.

Overcoming graft-versus-host disease (GvHD) without increasing relapse and severe infections is a major challenge after allogeneic hematopoietic stem-cell transplantation (HSCT). ATIR101 is a haploidentical, naïve cell-enriched T-cell product, depleted of recipient-alloreactive T cells to minimize the risk of GvHD and provide graft-versus-infection and -leukemia activity. Safety and efficacy of ATIR101 administered after T-cell-depleted haploidentical HSCT (TCD-haplo + ATIR101) without posttransplant immunosuppressors were evaluated in a Phase 2, multicenter study of 23 patients with acute leukemia and compared with an observational cohort undergoing TCD-haplo alone (n = 35), matched unrelated donor (MUD; n = 64), mismatched unrelated donor (MMUD; n = 37), and umbilical cord blood (UCB; n = 22) HSCT. The primary endpoint, 6-month non-relapse mortality (NRM), was 13% with TCD-haplo + ATIR101. One year post HSCT, TCD-haplo + ATIR101 resulted in lower NRM versus TCD-haplo alone (P = 0.008). GvHD-free, relapse-free survival (GRFS) was higher with TCD-haplo + ATIR101 versus MMUD and UCB (both P < 0.03; 1-year rates: 56.5%, 27.0%, and 22.7%, respectively) and was not statistically different from MUD (1 year: 40.6%). ATIR101 grafts with high third-party reactivity were associated with fewer clinically relevant viral infections. Results suggest that haploidentical, selective donor-cell depletion may eliminate requirements for posttransplant immunosuppressors without increasing GvHD risk, with similar GRFS to MUD. Following these results, a randomized Phase 3 trial versus posttransplant cyclophosphamide had been initiated.

Role of Age and Hematopoietic Cell Transplantation-Specific Comorbidity Index in Myelodysplastic Patients Undergoing an Allotransplant: A Retrospective Study from the Chronic Malignancies Working Party of the European Group for Blood and Marrow Transplantation.

Allogeneic hematopoietic stem cell transplantation (HSCT) remains the only potentially curative option for myelodysplastic syndromes (MDSs) but is severely limited by nonrelapse mortality (NRM), especially in this mostly older population. Comorbidity assessment is crucial to predict NRM and often assessed with the Hematopoietic Cell Transplantation-Specific Comorbidity Index (HCT-CI). Moreover, the impact of age on NRM still remains a matter of debate. In recent years, the age at which transplants are made has been progressively increasing, and patients with comorbidities have become more common. Extricating the respective roles of age and comorbidities in toxic mortality is all the more important. This study by the European Group for Blood and Marrow Transplantation registry included 1245 adult patients who underwent a first allogeneic stem cell transplantation for MDSs between 2003 and 2014. Overall, 4-year NRM and overall survival were 32% and 47%, respectively. When considered as continuous predictors, HCT-CI score and age were associated with an increased hazard ratio (HR) for NRM. In multivariate analysis, age band (HR, 1.13; 95% CI, 1.02 to 1.25; P= .016), HCT-CI ≥3 (HR, 1.34; 95% CI, 1.04 to 1.73; P = .022), and Karnofsky Performance Status ≤80 (HR, 2.03; 95% CI, 1.52 to 2.73; P< .0001) were significantly predictive of a worse NRM. In our large cohort, both comorbidities, evaluated by the original HCT-CI score, and chronological age significantly affected NRM. Thus, age should be part of the transplant decision-making process and should be integrated in future scoring systems predicting outcomes of HSCT in MDSs.

HIV-1 remission following CCR5Δ32/Δ32 haematopoietic stem-cell transplantation.

A cure for HIV-1 remains unattainable as only one case has been reported, a decade ago1,2. The individual-who is known as the 'Berlin patient'-underwent two allogeneic haematopoietic stem-cell transplantation (HSCT) procedures using a donor with a homozygous mutation in the HIV coreceptor CCR5 (CCR5Δ32/Δ32) to treat his acute myeloid leukaemia. Total body irradiation was given with each HSCT. Notably, it is unclear which treatment or patient parameters contributed to this case of long-term HIV remission. Here we show that HIV-1 remission may be possible with a less aggressive and toxic approach. An adult infected with HIV-1 underwent allogeneic HSCT for Hodgkin's lymphoma using cells from a CCR5Δ32/Δ32 donor. He experienced mild gut graft-versus-host disease. Antiretroviral therapy was interrupted 16 months after transplantation. HIV-1 remission has been maintained over a further 18 months. Plasma HIV-1 RNA has been undetectable at less than one copy per millilitre along with undetectable HIV-1 DNA in peripheral CD4 T lymphocytes. Quantitative viral outgrowth assays from peripheral CD4 T lymphocytes show no reactivatable virus using a total of 24 million resting CD4 T cells. CCR5-tropic, but not CXCR4-tropic, viruses were identified in HIV-1 DNA from CD4 T cells of the patient before the transplant. CD4 T cells isolated from peripheral blood after transplantation did not express CCR5 and were susceptible only to CXCR4-tropic virus ex vivo. HIV-1 Gag-specific CD4 and CD8 T cell responses were lost after transplantation, whereas cytomegalovirus-specific responses were detectable. Similarly, HIV-1-specific antibodies and avidities fell to levels comparable to those in the Berlin patient following transplantation. Although at 18 months after the interruption of treatment it is premature to conclude that this patient has been cured, these data suggest that a single allogeneic HSCT with homozygous CCR5Δ32 donor cells may be sufficient to achieve HIV-1 remission with reduced intensity conditioning and no irradiation, and the findings provide further support for the development of HIV-1 remission strategies based on preventing CCR5 expression.

Impact of route and adequacy of nutritional intake on outcomes of allogeneic haematopoietic cell transplantation for haematologic malignancies.

BACKGROUND: Allogeneic haematopoietic cell transplantation (HCT) is often associated with poor oral intake due to painful mucositis and gastrointestinal sequalae that occur following a preparative regimen of intensive chemotherapy and/or total body radiation. Although attractive to assume that optimal nutrition improves HCT outcomes, there are limited data to support this. It is also unclear whether artificial nutrition support should be provided as enteral tube feeding or parenteral nutrition (PN). METHODS: We analysed day-100 non-relapse mortality (NRM), incidence of acute graft-versus-host disease (GvHD), acute gastrointestinal GvHD, 5-year survival and GvHD-free/relapse-free survival (GRFS) according to both route and adequacy of nutritional intake prior to neutrophil engraftment, together with other known prognostic factors, in a retrospective cohort of 484 patients who underwent allogeneic HCT for haematologic malignancy between 2000 and 2014. RESULTS: Multivariate analyses showed increased NRM with inadequate nutrition (hazard ratio (HR) 4.1; 95% confidence interval (CI) 2.2-7.2) and adequate PN (HR 2.9; 95% CI 1.6-5.4) compared to adequate enteral nutrition (EN) both P < .001. There were increased incidences of gastrointestinal GvHD of any stage and all GvHD ≥ grade 2 in patients who received PN (odds ratio (OR) 2.0; 95% CI 1.2-3.3; P = .006, and OR 1.8; 95% CI 1.1-3.0; P = .018, respectively), compared to adequate EN. Patients who received adequate PN and inadequate nutrition also had reduced probabilities of survival and GRFS at 5 years. CONCLUSION: Adequate EN during the early transplantation course is associated with reduced NRM, improved survival and GRFS at 5 years. Furthermore, adequate EN is associated with lower incidence of overall and gut acute GvHD than PN, perhaps because of its ability to maintain mucosal integrity, modulate the immune response to intensive chemo/radiotherapy and support the gastrointestinal tract environment, including gut microflora.

Family Mismatched Allogeneic Stem Cell Transplantation for Myelofibrosis: Report from the Chronic Malignancies Working Party of European Society for Blood and Marrow Transplantation.

This analysis included 56 myelofibrosis (MF) patients transplanted from family mismatched donor between 2009 and 2015 enrolled in the European Society for Blood and Marrow Transplantation database. The median age was 57years (range, 38 to 72); 75% had primary MF and 25% had secondary MF. JAK2 V617F was mutated in 61%. Donors were HLA mismatched at 2 or more loci. Stem cells were sourced from bone marrow in 66% and peripheral blood in 34%. The median CD34+ cell dose was 4.8 × 106/kg (range, 1.7 to 22.9; n = 43). Conditioning was predominantly myeloablative in 70% and reduced intensity in the remainder. Regimens were heterogeneous with thiotepa, busulfan, fludarabine, and post-transplant cyclophosphamide used in 59%. The incidence of neutrophil engraftment by 28days was 82% (range, 70% to 93%), at a median of 21days (range, 19 to 23). At 2years the cumulative incidence of primary graft failure was 9% (95% CI 1% to 16%) and secondary graft failure was 13% (95% CI 4% to 22%). The cumulative incidence of acute graft-versus-host disease (GVHD) grades II to IV and III to IV was 28% (95% CI 16% to 40%) and 9% (95% CI 2% to 17%) at 100days. The cumulative incidence of chronic GVHD at 1 year was 45% (95% CI 32% to 58%), but the cumulative incidence of death without chronic GVHD by 1 year was 20% (95% CI 10% to 31%). With a median follow-up of 32 months, the 1- and 2-year overall survival was 61% (95% CI 48% to 74%) and 56% (95% CI 41% to 70%), respectively. The 1- and 2- year progression-free survival was 58% (95% CI 45% to 71%) and 43% (95% CI 28% to 58%), respectively, with a 2-year cumulative incidence of relapse of 19% (95% CI 7% to 31%). The 2-year nonrelapse mortality was 38% (95% CI 24% to 51%). This retrospective study of MF allo-SCT using family mismatched donors demonstrated feasibility of the approach, timely neutrophil engraftment in over 80% of cases, and acceptable overall and progression-free survival rates with relapse rates not dissimilar to the unrelated donor setting. However, strategies to minimize the risk of graft failure and the relatively high nonrelapse mortality need to be used, ideally in a multicenter prospective fashion.

Allogeneic stem cell transplantation from unrelated donors in acute leukaemia.

PURPOSE OF REVIEW: To summarize the past and current knowledge of the use of unrelated donors (URDs) in allogeneic stem cell transplantation for patients with acute leukaemia. RECENT FINDINGS: The outcome of URD stem cell transplants in terms of treatment-related mortality, relapse rates, disease free survival and overall survival is comparable to sibling donors. SUMMARY: Haematopoietic stem cell transplantation (HSCT) is the therapy of choice in many haematological malignant diseases but only one-third of the patients will have an HLA-matched sibling. The possibility of finding a matched URD is more than 70% because of recent advances in HLA typing and continuous expansion of URD registries around the world. The use of URD as a source of stem cells in adult patients are steadily increasing and in the last 8 years, superseded the matched sibling donors and became the most commonly used stem cell source. There is also an increasing trend of using peripheral blood stem cells than bone marrow stem cells. Outcomes following URD transplants depend mainly upon the indication and urgency of transplant, age and comorbidities of recipients, cytomegalovirus matching/mismatching between donor and the recipient and degree of HLA matching.

Outcome of patients with Myelofibrosis relapsing after allogeneic stem cell transplant: a retrospective study by the Chronic Malignancies Working Party of EBMT.

Allogeneic Haematopoietic Stem Cell Transplant (allo-HSCT) remains the only curative approach for Myelofibrosis (MF). Scarce information exists in the literature on the outcome and, indeed, management of those MF patients who relapse following transplant. We hereby report on the management and outcome of 202 patients who relapsed post allo-HSCT for MF.

Correction to: An analysis of the kinetics of molecular response during the first trimester of treatment with nilotinib in newly diagnosed chronic myeloid leukemia patients in chronic phase.

Correction to: J Cancer Res Clin Oncol (2017) 143:2059-2066 DOI 10.1007/s00432-017-2445-z.