Cytomegalovirus reactivation is associated with an increased risk of late-onset invasive aspergillosis independently of grade II-IV acute graft-versus-host disease in allogeneic hematopoietic stem cell transplantation: JSTCT Transplant Complications Working Group

Expansion of effector memory Vδ2neg γδ T cells associates with cytomegalovirus reactivation in allogeneic stem cell transplant recipients

Background

Cytomegalovirus (CMV) reactivation is a significant concern following allogeneic stem cell transplantation. While previous research has highlighted the anti-CMV reactivation effect of γδ T cells in immunocompromised transplant patients, their characterization in recipients at high risk of CMV reactivation remains limited.

Methods

This study focused on D+/R+ recipients (where both donor and recipient are CMV seropositive) at high risk of CMV reactivation. We analyzed 28 patients who experienced CMV recurrence within 100 days post-allogeneic hematopoietic stem cell transplantation, along with 36 matched recipients who did not experience CMV recurrence. Clinical data from both groups were compared, and risk factors for CMV reactivation were identified. Additionally, CMV viral load was measured, and flow cytometric analysis was conducted to assess changes in peripheral blood γδ T cell proportions, subpopulation distribution, and differentiation status. We also analyzed the CDR3 repertoire of the TCR δ chain in different γδ T cell subsets. Functional analysis was performed by measuring the lysis of CMV-infected cells upon stimulation.

Results

CMV reactivation post-transplantation was associated with acute graft-versus-host disease (aGvHD) and reactivation of non-CMV herpesviruses. Notably, CMV reactivation led to sustained expansion of γδ T cells, primarily within the Vδ2neg γδ T cell subpopulation, with a trend toward differentiation from Naive to effector memory cells. Analysis of the δ chain CDR3 repertoire revealed a delay in the reconstitution of clonal diversity in Vδ2neg γδ T cells following CMV reactivation, while Vδ2pos T cells remained unaffected. Upon stimulation with CMV-infected MRC5 cells, the Vδ2neg γδ T cell subpopulation emerged as the primary effector cell group producing IFN-γ and capable of lysing CMV-infected cells. Moreover, our findings suggest that NKG2D is not necessary involved in Vδ2neg γδ T cell-mediated anti-CMV cytotoxicity.

Conclusion

This study provides novel insights into the role of γδ T cells in the immune response to CMV reactivation in transplantation recipients at high risk of CMV infection. Specifically, the Vδ2neg γδ T cell subpopulation appears to be closely associated with CMV reactivation, underscoring their potential role in controlling infection and reflecting CMV reactivation in HSCT patients.

Risk factors for invasive fungal infections after haematopoietic stem cell transplantation: a systematic review and meta-analysis

BACKGROUND

Invasive fungal infections (IFIs) are common infectious complications after haematopoietic stem cell transplantation (HSCT), seriously threatening the survival of patients.

OBJECTIVES

This systematic review aimed to investigate risk factors associated with IFIs following HSCT.

METHODS

Two authors independently conducted the selection of studies and extraction of data. Risk factors for IFIs, invasive aspergillosis or invasive mould infections and invasive candida infection after HSCT were compiled separately by meta-analysis using RevMan 5.4 and R language 4.1.2.

DATA SOURCES

Pubmed, EMBASE, Web of Science, and the Cochrane Library until April 2023.

STUDY ELIGIBILITY CRITERIA

Case-control or cohort studies that assessed risk factors for IFIs among HSCT recipients were included.

PARTICIPANTS

Patients experiencing HSCT.

TEST/S

None.

REFERENCE STANDARD

The IFIs were defined according to the European Organisation for Research and Treatment of Cancer/Mycosis Study Group (EORTC/MSG) criteria, or a similar definition.

ASSESSMENT OF RISK OF BIAS

A modified version of the Newcastle-Ottawa Scale was used.

METHODS OF DATA SYNTHESIS

A random-effects model with the Mantel-Haenszel method was used to pool results from primary studies.

RESULTS

Out of 1637 studies screened, 51 studies involving 109 155 patients were included, with 45 studies providing adequate data for meta-analysis. Identified risk factors for IFIs included prolonged neutropenia, intensified therapy for graft-versus-host disease (GVHD), previous transplantation, previous proven or probable IFI, acute GVHD ≥ grade II, extensive or severe chronic GVHD, use of anti-thymocyte globulin during transplantation, haploidentical transplantation, high-dose glucocorticoids, Epstein-Barr virus infection, cytomegalovirus infection or reactivation, and lower albumin. Conversely, antifungal prophylaxis emerged as the sole preventive factor. For invasive aspergillosis or invasive mould infections, the top risk factors were extensive or severe chronic GVHD, respiratory viral infection, high-dose glucocorticoids, acute GVHD ≥ grade II, and human leukocyte antigen mismatch. Cord blood transplantation was the sole significant risk factor for invasive candidiasis. However, there was likely a high degree of interdependence among various risk factors.

DISCUSSION

This meta-analysis provides a thorough review of risk factors for IFIs infection after HSCT. The achieved insights can aid in stratifying patients who are at an elevated risk of IFIs and promoting antifungal preventive strategies.

Impact of Early Cytomegalovirus Reactivation After Allogeneic Hematopoietic Stem Cell Transplantation on Relapse in Patients With Myelodysplastic Syndrome: A Nationwide Retrospective Study From Adult Myelodysplastic Syndrome Working Group of the JSTCT

Cytomegalovirus (CMV) reactivation is a prominent complication associated with adverse outcomes in allogeneic hematopoietic stem cell transplantation (HSCT). However, CMV reactivation after allogeneic HSCT may be associated with a lower incidence of relapse in some hematological malignancies. This study analyzed the Japanese registry data from 1082 patients with myelodysplastic syndrome (MDS) who underwent their first allogeneic HSCT and survived for 100 days after transplantation without graft failure or disease relapse to investigate this association. Patients who received cord blood transplants, demonstrated in vivo T cell depletion, underwent prophylactic anti-CMV treatment, or diagnosed with secondary MDS were excluded. CMV reactivation measured by pp65 antigenemia within 100 days after allogeneic HSCT was observed in 57.5% of patients, with a median time of 46 days from transplant. The 5-yr overall survival and cumulative incidence of relapse (CIR) in the cohort were 60.5% and 15.6%, respectively. The 5-yr CIR showed no significant difference between patients with and without CMV reactivation (14.4% versus 17.2%; P = .185). Interestingly, CMV reactivation within 100 days was significantly associated with a lower 5-yr CIR (7.6% versus 16.4%; P = .002) in patients with <5% myeloblasts in the bone marrow (BM) just before HSCT. Furthermore, this relevancy confirmed even when excluding patients with Grade II to IV acute GVHD (Hazard ratio: 0.38; 95% confidential intervals: 0.18-0.801; P = .011). Our findings indicate a correlation between early CMV reactivation and MDS relapse, based on the proportion of myeloblasts in the BM. These results may contribute to the development of effective CMV prophylaxis post-HSCT.

Incidence and Impact of Fungal Infections in Post-Transplantation Cyclophosphamide-Based Graft-versus-Host Disease Prophylaxis and Haploidentical Hematopoietic Cell Transplantation: A Center for International Blood and Marrow Transplant Research Analysis

Fungal infection (FI) after allogeneic hematopoietic cell transplantation (HCT) is associated with increased morbidity and mortality. Neutropenia, HLA mismatch, graft-versus-host disease (GVHD), and viral infections are risk factors for FI. The objectives of this Center for International Blood and Marrow Transplant Research registry study were to compare the incidence and density of FI occurring within 180 days after HCT in matched sibling (Sib) transplants with either calcineurin inhibitor (CNI)-based or post-transplantation cyclophosphamide (PTCy)-based GVHD prophylaxis and related haploidentical transplants receiving PTCy, and to examine the impact of FI by day 180 on transplantation outcomes.

METHODS

Patients who underwent their first HCT between 2012 and 2017 for acute myeloid leukemia, acute lymphoblastic leukemia, and myelodysplastic syndrome and received a related haploidentical transplant with PTCy (HaploCy; n = 757) or a Sib transplant with PTCy (SibCy; n = 403) or CNI (SibCNI; n = 1605) were analyzed. The incidence of FI by day 180 post-HCT was calculated as cumulative incidence with death as the competing risk. The associations of FI with overall survival, transplant-related mortality, chronic GVHD, and relapse at 2 years post-HCT were examined in Cox proportional hazards regression models. Factors significantly associated with the outcome variable at a 1% level were kept in the final model.

RESULTS

By day 180 post-HCT, 56 (7%) HaploCy, 24 (6%), SibCy, and 59 (4%) SibCNI recipients developed ≥1 FI (P < .001). The cumulative incidence of yeast FI was 5.2% (99% confidence interval [CI], 3.3% to 7.3%) for HaploCy, 2.2% (99% CI, .7% to 4.5%) for SibCy, and 1.9% (99% CI, 1.1% to 2.9%) for SibCNI (P = .001), and that of mold FI was 2.9% (99% CI, 1.5% to 4.7%), 3.7% (99% CI, 91.7% to 6.6%), and 1.7% (99% CI, 1.0% to 2.6%), respectively (P = .040). FI was associated with an increased risk of death, with an adjusted hazard ratio (HR) of 4.06 (99% CI, 2.2 to 7.6) for HaploCy, 4.7 (99% CI, 2.0 to 11.0) for SibCy, and 3.4 (99% CI, 1.8 to 6.4) for SibCNI compared with SibCNI without FI (P < .0001 for all). Similar associations were noted for transplantation-related mortality. FI did not impact rates of relapse or chronic GVHD.

CONCLUSIONS

Rates of FI by day 180 ranged between 1.9% and 5.2% for yeast FI and from 1.7% to 3.7% for mold FI across the 3 cohorts. The use of PTCy was associated with higher rates of yeast FI only in HaploHCT and with mold FI in both HaploHCT and SibHCT. The presence of FI by day 180 was associated with increased risk for overall mortality and transplant-related mortality at 2 years regardless of donor type or PTCy use. Although rates of FI were low with PTCy, FI is associated with an increased risk of death, underscoring the need for improved management strategies.

Approach to the diagnosis of invasive fungal infections of the respiratory tract in the immunocompromised host

PURPOSE OF REVIEW

The burden of invasive fungal infection is increasing worldwide, largely due to a growing population at-risk. Most serious human fungal pathogens enter the host via the respiratory tract. Early identification and treatment of invasive fungal respiratory infections (IFRIs) in the immunocompromised host saves lives. However, their accurate diagnosis is a difficult challenge for clinicians and mortality remains high.

RECENT FINDINGS

This article reviews IFRIs, focussing on host susceptibility factors, clinical presentation, and mycological diagnosis. Several new diagnostic tools are coming of age including molecular diagnostics and point-of-care antigen tests. As diagnosis of IFRI relies heavily on invasive procedures like bronchoalveolar lavage and lung biopsy, several novel noninvasive diagnostic techniques are in development, such as metagenomics, 'volatilomics' and advanced imaging technologies.

SUMMARY

Where IFRI cannot be proven, clinicians must employ a 'weights-of-evidence' approach to evaluate host factors, clinical and mycological data. Implementation studies are needed to understand how new diagnostic tools can be best applied within clinical pathways. Differentiating invasive infection from colonization and identifying antifungal resistance remain key challenges. As our diagnostic arsenal expands, centralized clinical mycology laboratories and efforts to ensure access to new diagnostics in low-resource settings will become increasingly important.

Attenuated humoral response against SARS-CoV-2 mRNA vaccination in allogeneic stem cell transplantation recipients

Antibody persistence several months after severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) mRNA vaccination in allogeneic stem cell transplantation recipients remains largely unknown. We sequentially evaluated the humoral response to two doses of mRNA vaccines in 128 adult recipients and identified the risk factors involved in a poor response. The median interval between stem cell transplantation and vaccination was 2.7 years. The SARS-CoV-2 S1 Ab became positive after the second vaccination dose in 87.6% of the recipients, and the median titer was 1235.4 arbitrary units (AU)/ml. In patients on corticosteroid treatment, the corticosteroid dose inversely correlated with Ab titer. Multivariate analysis identified risk factors for poor peak response such as an interval from stem cell transplantation ≤1 year, history of clinically significant CMV infection, and use of >5 mg/day prednisolone at vaccination. Six months after vaccination, the median titer decreased to 185.15 AU/ml, and use of >5 mg/day prednisolone at vaccination was significantly associated with a poor response. These results indicate that early vaccination after stem cell transplantation (<12 months) and CMV infection are risk factors for poor peak response, while steroid use is important for a peak as well as a persistent response. In conclusion, although humoral response is observed in many stem cell transplantation recipients after two doses of vaccination, Ab titers diminish with time, and factors associated with persistence and a peak immunity should be considered separately.