Infective complications of aplastic anaemia

Severe aplastic anemia patients with infection who received an allogeneic hematopoietic stem cell transplantation had a better chance: Long-term outcomes of a multicenter study

Background and aims

How to select the treatment is a challenge for the management of acquired patients with infections. This study aimed at comparing the outcomes of SAA with infections who had an allogeneic hematopoietic stem cell transplantation (allo-HSCT)with that of patients who had an infection and received non-HSCT therapy.

Methods

We retrospectively compared the outcomes of patients with acquired SAA and infections who had an allo-HSCT (n = 141) with that of patients who had an infection and received non-HSCT therapy (n = 186) between July 2004 and January 2020.

Results

The treatment-related mortality (TRM) of grade 1-2 infections in the HSCT and non-HSCT groups was 24.99% and 13.68%, respectively (P = 0.206), while the TRM of grade 3-4 infections was lower in the HSCT group than that observed in the non-HSCT group (18.54% vs. 33.33%, P = 0.036). At 6 months post-treatment, 91.30% patients in the HSCT group and 8.78% patients in the non-HSCT group had achieved a normal blood profile (P < 0.0001). The time required to discontinue transfusions of red blood cells and platelets in the non-HSCT group was longer than in the HSCT group (P < 0.0001). Estimated overall survival (OS) at 6 years was similar in the two groups (75.5% ± 3.9% vs. 76.3% ± 3.1%, P = 0.996), while the estimated failure-free survival (FFS) at 6 years was 75.2% ± 3.8% in the HSCT group and 48.9% ± 3.7% in the non-HSCT group (P < 0.0001). Multivariate analysis showed that younger age, lower grade of infection (grade 1-2), and SAA (vs. very SAA) were favorable factors for OS (P < 0.05), and that the choice of HSCT and younger age were favorable factors for FFS (P < 0.0001).

Conclusion

These results suggest that allo-HSCT has a better chance of a successful outcome than non-HSCT in SAA patients with an infection.

Risk factor analysis of bloodstream infection in pediatric patients after hematopoietic stem cell transplantation

Bloodstream infection (BSI) is a recognized cause of morbidity and mortality in children after hematopoietic stem cell transplantation (HSCT). However, there are limited reports on BSI after HSCT in pediatric patients in multiple centers. This study was a retrospective cohort analysis of consecutive patients who underwent allogeneic and autologous HSCT at the Department of Paediatrics, Hokkaido University Hospital, between 1988 and 2009; the Department of Paediatrics, Sapporo Hokuyu Hospital, between 2007 and 2009; and the Department of Paediatrics, Asahikawa Medical University, between 1989 and 2009. A total of 277 patients underwent HSCT during the study period. In this multicenter analysis, cases of BSI after HSCT were recorded in the early posttransplant period (within the first 100 d), and BSI was observed in 24 of 277 HSCT patients. Multivariate analysis showed that nonmalignant disease was an independent factor associated with BSI after HSCT (hazard ratio 6.3 for aplastic anemia or Wiskott-Aldrich syndrome patients; confidence interval, 1.4-12.8; P = 0.012). We conclude that aplastic anemia and Wiskott-Aldrich syndrome were the novel risk factors for BSI in pediatric patients after HSCT.

Abnormal immunity and stem/progenitor cells in acquired aplastic anemia

Acquired aplastic anemia (AA) is considered as an immune-mediated bone marrow failure syndrome, characterized by hypoplasia and pancytopenia with fatty bone marrow. Abnormal immunity is the major factor mediating the pathogenesis of acquired AA. Activated DCs might promote the polarization to Th1 cells, and activate CD8(+) T cells. A variety of immune molecules including IFN-gamma, TNF-alpha, MIP-1alpha and IL-2, 8, 12, 15, 17, 23, produced by them and stromal cells, compose a cytokine network to destruct stem/progenitor cells as well as hematopoietic stem/progenitor cells, mesenchymal stem cells (MSCs) and angioblasts/endothelial progenitor cells. Inversely, deficient MSCs, CD4(+)CD25(+) T cells, NK cells, NKT cells and early hematopoietic growth factors diminish the capacity of immune regulation and the support of hematopoiesis. As a result, stem/progenitor cells are significantly impaired to be disabled cells with markedly deficient proliferation, differentiation, induced apoptosis and dysfunctional response to growth factor stimuli, together with rare normal ones. Although some patients can be ameliorated by stem-cell transplantation or immunosuppressive therapy, more effective and convenient therapies such as patient-specific pluripotent iPS cells based on definite pathogenesis are expected.

Infections in patients with aplastic anemia: experience at a tertiary care cancer center

BACKGROUND

Infection is a significant cause of death in patients with aplastic anemia (AA). However, few recent studies have examined infectious complications in patients with AA.

METHODS

The authors retrospectively evaluated the type of infections, associated pathogens, and outcome of infectious episodes (IEs) in patients with AA who were treated at The University of Texas M. D. Anderson Cancer Center between July 1994 and June 2000.

RESULTS

Fifty-two patients with a median age of 37 years (range, 3-83 years) were identified. Overall, 104 IEs were documented in 42 patients (81%). The most common microbiologically documented infections were bacteremias (38%) followed by pneumonias (16%). Most patients (55%) had bacterial infections, mainly caused by gram-positive cocci. Multidrug-resistant, gram-negative bacilli also were not uncommon in this patient population. Five of 12 patients who died during the study period died of infection. All of these patients had invasive fungal infections, mostly due to molds. All five patients had prolonged and severe neutropenia.

CONCLUSIONS

Infections remain a major cause of death in patients with AA. Bacterial infections, especially those caused by gram-positive cocci, constitute the main cause of IE. Invasive mold infections, however, are the major cause of death in this patient population.

The incidence and significance of fevers during treatment with antithymocyte globulin for aplastic anaemia

Antithymocyte globulin (ATG) is a foreign protein used widely to treat aplastic anaemia (AA). Febrile reactions occurring during its administration may be impossible to distinguish clinically from fever due to sepsis, and are therefore routinely treated with intravenous antibiotics after collection of blood cultures. A statistically highly significant difference was found in positive blood cultures between 39 AA patients who developed fever during ATG therapy, and 38 febrile neutropenic patients with acute leukaemia. suggesting that most fevers developing during ATG treatment are not due to infection. It may therefore be reasonable to consider early discontinuation of intravenous antibiotics in patients who are clinically stable and have no proven sepsis.

Aplastic anaemia--aetiology and clinical features

Acquired aplastic anaemia remains a devastating and frustrating disease from which a proportion of patients still die as a result of failure of support measures. Its pathogenesis remains a mystery.