Impact of early cyclosporine A levels on acute graft-versus-host disease in allogeneic hematopoietic stem cell transplantation using in vivo T-cell depletion

BACKGROUND AIMS

Cyclosporin A (CsA) remains a major component of immunosuppressive regimens applied in allogeneic hematopoietic stem cell transplantation (HSCT). The impact of CsA trough levels during the first weeks after HSCT has not yet been investigated specifically in anti-T-lymphocyte globulin (ATLG)-based HSCT from matched related and unrelated donors.

METHODS

To address this issue, we have retrospectively examined 307 consecutive matched related (n = 145) and unrelated (n = 162) HSCTs, using peripheral blood stem cells or bone marrow. HSCTs for active, uncontrolled malignancies were excluded. The initial three weeks' average mean CsA trough levels were analyzed in landmark and multi-state models, using a cut-off of 200 ng/mL.

RESULTS

CsA levels >200 ng/mL were associated with a reduced risk of acute graft-versus-host disease (GVHD) grade 3-4 at the first-week landmark (subdistribution hazard ratio [SHR] 0.59, P = 0.03) and the second-week landmark (SHR 0.48, P = 0.004), whereas there was no impact at the third-week landmark (HR 0.87, P = 0.69). This was supported by a multi-state model, in which week 1 (hazard ratio [HR] 0.53, P = 0.006) and week 2 (HR 0.48, P = 0.003), but not week 3 (HR 0.80, P = 0.44) CsA levels >200 ng/mL were associated with a reduced acute GVHD 3-4 risk. Relapse incidence was not significantly affected by week 1 through 3 CsA levels. Despite ATLG's inherent GVHD-preventive properties, week 1 CsA trough levels >200 ng/mL following ATLG-based HSCT (n = 220) were associated with a significantly reduced risk of non-relapse mortality (SHR 0.52, P = 0.02) and improved overall survival (HR 0.61, P = 0.02).

CONCLUSIONS

Our findings emphasize the continuing importance of ensuring CsA levels ≥200 ng/mL immediately post-transplant in the setting of ATLG-based HSCT.

Allogeneic Stem Cell Transplantation in Multiple Myeloma: Risk Factors and Outcomes in the Era of New Therapeutic Options-A Single-Center Experience

BACKGROUND

Despite major treatment advances, multiple myeloma remains incurable. The outcome of patients who are refractory to immunomodulatory agents, proteasome inhibitors, and anti-CD38 monoclonal antibodies is poor, and improved treatment strategies for this difficult-to-treat patient population are an unmet medical need.

METHODS

This retrospective, unicentric analysis included 38 patients with relapsed/refractory multiple myeloma or plasma cell leukemia who underwent allogeneic stem cell transplantation (allo-HSCT) between 2013 and 2022. Survival outcomes, relapse incidence, and non-relapse mortality were calculated according to remission status, date of allo-HSCT, cytogenetic risk status, timing, and number of previous autologous HSCTs.

RESULTS

The median PFS was 13.6 months (95% CI, 7.7-30.4) and the median OS was 51.4 months (95% CI, 23.5-NA) in the overall cohort. The cumulative incidence of relapse at 3 years was 57%, and non-relapse mortality was 16%. The median PFS and OS were significantly longer in patients with very good partial remission (VGPR) or better compared to patients with less than VGPR at the time of allo-HSCT (mPFS 29.7 months (95% CI, 13.7-NA) vs. 6.5 months (95% CI, 2.6-17.0); p = 0.009 and mOS not reached vs. 18.6 months (95% CI, 7.0-NA); p = 0.006).

CONCLUSION

For selected patients, allo-HSCT may result in favorable overall survival, in part by providing an appropriate hemato-immunological basis for subsequent therapies.

Impact of the Recipient's Pre-Treatment Blood Lymphocyte Count on Intended and Unintended Effects of Anti-T-Lymphocyte Globulin in Allogeneic Hematopoietic Stem Cell Transplantation

Background: In allogeneic hematopoietic stem cell transplantation (HSCT), Anti-T-Lymphocyte Globulin (ATLG) may be used for the prevention of severe graft-versus-host disease (GVHD). ATLG targets both the recipient's lymphocytes and those transferred with the graft. Assuming an inverse relation between the recipient's absolute lymphocyte count (ALC) and exposure of remaining ATLG to the graft, we aim to evaluate the impact of the recipient's ALC before the first ATLG administration on the benefits (prevention of GVHD and GVHD-associated mortality) and potential risks (increased relapse incidence) associated with ATLG. Methods: In recipients of HLA-matched, ATLG-based HSCT (n = 311), we assessed the incidence of acute GVHD, GVHD-related mortality and relapse, as well as other transplant-related outcomes, in relation to the respective ALC (divided into tertiles) before ATLG. Results: The top-tertile ALC group had a significantly increased risk of aGVHD (subhazard ratio (sHR) 1.81; [CI 95%; 1.14-2.88]; p = 0.01) and aGVHD-associated mortality (sHR 1.81; [CI 95%; 1.03-3.19]; p = 0.04). At the highest ATLG dose level (≥45 mg/kg), recipients with lowest-tertile ALC had a trend towards increased relapse incidence (sHR 4.19; [CI 95%; 0.99-17.7]; p = 0.05, n = 32). Conclusions: ATLG dosing based on the recipient's ALC may be required for an optimal balance between GVHD suppression and relapse prevention.

Adverse impact of a high CD4/CD8 ratio in the allograft may be overcome by methotrexate- but not mycophenolate- or posttransplant cyclophosphamide-based graft versus host disease prophylaxis

INTRODUCTION

A high CD4/CD8 T cell ratio in hematopoietic stem cell transplant (HSCT) allografts was observed to predict graft-versus-host disease (GVHD) and non-relapse mortality (NRM) but has not been comparatively examined in settings of various GVHD-prophylaxis regimens.

METHODS

This retrospective monocentric study included all consecutive HSCT performed with peripheral blood stem cells (PBSC) between January 2000 and June 2021. The impact of the graft CD4/CD8 ratio was analyzed in three cohorts with different GVHD-prophylaxis platforms.

RESULTS

In the cyclosporine/mycophenolate-mofetil (CSA/MMF) cohort (n = 294, HLA-matched HSCT), a high (> 75^th percentile) CD4/CD8 ratio was associated with increased overall mortality (HR 1.56; P=0.01), increased NRM (HR 1.85; P=0.01) and GVHD-associated mortality (HR 2.13; P=0.005). In the post-transplant cyclophosphamide (PTCy)/tacrolimus/MMF cohort (n = 113, haploidentical-related or mismatched-unrelated HSCT), a high CD4/CD8 ratio was associated with increased overall mortality (HR 2.07; P=0.04) and aGVHD3-4 (HR 2.24; P=0.02). By contrast, in the CSA/methotrexate (CSA/MTX) cohort (n = 185, HLA-matched HSCT) the CD4/CD8 ratio had no significant impact on any of the investigated endpoints.

CONCLUSION

A high CD4/CD8 ratio in the allograft has an adverse impact on GVHD and survival in CSA/MMF- and PTCy-based HSCT, while MTX-based prophylaxis may largely alleviate this important risk factor.

A H2O2-producing glyoxal oxidase is required for filamentous growth and pathogenicity in Ustilago maydis

In the phytopathogenic fungus Ustilago maydis the mating-type loci control the transition from yeast-like to filamentous growth required for pathogenic development. In a large REMI (restriction enzyme mediated integration) screen, non-pathogenic mutants were isolated in a haploid strain that had been engineered to be pathogenic. In one of these mutants, which showed a specific morphological phenotype, the tagged gene, glo1 , was found to encode a product that is highly homologous to a glyoxal oxidase gene from the wood-rot fungus Phanerochaete chrysosporium. Glyoxal oxidase homologues are found in human, plant pathogenic fungi and in plants, but not in other mammals or yeasts. To confirm the function of the glo1 gene, null mutations were generated in compatible haploid U. maydis strains. In crosses null mutants were unable to generate filamentous dikaryons, and were completely non-pathogenic. Using a Glo1-overproducing strain we demonstrated that Glo1 is membrane bound, oxidizes a series of small aldehydes (< C4) and produces H2O2. The enzyme needs to be activated, presumably by auto-oxidation, to show full activity. A potential role for Glo1 during filamentous growth and pathogenic development of U. maydis is proposed.

Identification of plant-regulated genes in Ustilago maydis by enhancer-trapping mutagenesis

To identify plant-induced genes in the maize pathogenic fungus Ustilago maydis we have developed a genetic screen that combines REMI (restriction enzyme mediated integration) mutagenesis with enhancer trapping using the gene for Green Fluorescent Protein (GFP) as vital reporter. Of 2,350 insertion mutants isolated, three were shown to express GFP only after the fungus had come into contact with the host maize plant. One of the genes tagged was mfa1, which encodes the pheromone precursor, while the second gene, pig2, codes for a product that showed similarity to protein disulfide isomerase. The third integration event had occurred in a locus which we designated the p -locus. This locus contains 11 genes in a 24-kb stretch. Of these, pig3, 4, 5, 6 and 7 show a plant-regulated expression pattern, while the other genes found at the locus (designated npi) do not. Of the plant-regulated genes only two were found to be similar to database entries: the pig4 product is related to membrane transporters of the major facilitator family, while the pig6 protein shows similarity to multidrug transporters. Detailed expression studies revealed that the five plant-regulated genes at the p -locus differ in their expression profiles. Mutants deleted for each of them showed no apparent phenotype, while the npi1 gene appeared to be essential. A viable deletion encompassing the entire p -locus could be generated when npi1 function was provided ectopically. This deletion mutant also showed no obvious alteration in virulence.

The MAP kinase kpp2 regulates mating and pathogenic development in Ustilago maydis

In the phytopathogenic fungus Ustilago maydis, fusion of compatible haploid cells is a prerequisite for infection. This process is genetically controlled by the biallelic a locus, encoding pheromone precursors and receptors. These are presumed to be coupled to a heterotrimeric G protein and a MAP kinase cascade, leading to activation of the HMG domain transcription factor Prf1. Here, we have demonstrated that putative MAP kinase sites in Prf1 are required for its activity during mating. In addition, we have identified a gene, kpp2, which encodes a putative MAP kinase related to Pmk1 of Magnaporthe grisea and Fus3p of Saccharomyces cerevisiae. kpp2 deletion mutants are attenuated in several steps of development: cell fusion, induction of pheromone-responsive genes and pathogenicity. Epistasis analysis shows that kpp2 does not affect pheromone gene expression through the cAMP signalling cascade. Pathogenicity of kpp2 mutants can be partially restored by overexpressing the b genes, indicating a regulation of Prf1 by Kpp2. These data support the hypothesis that the MAP kinase Kpp2 transmits the pheromone signal.

A MADS-box homologue in Ustilago maydis regulates the expression of pheromone-inducible genes but is nonessential

Mating and pathogenic development in the smut fungus Ustilago maydis are controlled by a pheromone/receptor system and two homeodomain proteins, bEp and bWp, which form heterodimers in nonallelic combinations. We describe the isolation of a gene, umc1, encoding a MADS-box protein, which displays significant similarity to the Saccharomyces cerevisiae MCM1 gene. umc1 complemented the viability defect of yeast mcm1 mutants. In U. maydis, umc1 deletion mutants were viable and pathogenic development was unaffected. Nevertheless, the basal expression levels of several pheromone-inducible genes were significantly reduced leading to an attenuated mating reaction. In contrast to S. cerevisiae, where Mcm1p plays a crucial role in the cell-type specific expression of a- and alpha-specific genes, the U. maydis umc1 gene appears to have only a modulatory effect on the expression of mating type-specific genes.