Frequent severe liver iron overload after stem cell transplantation and its possible association with invasive aspergillosis

Iron overload: predictor of adverse outcome in hematopoietic stem cell transplantation

INTRODUCTION

Iron overload is an important problem in candidates for and survivors of hematopoietic stem cell transplantation (HSCT), and affects long-term outcome and survival. The objective of the present study was to determine the effect of iron overload on early toxic or infectious complications and survival.

PATIENTS AND METHODS

We retrospectively reviewed the medical records for 250 adult patients (162 men and 88 women; median [range] age, 34 [16-71] years who underwent HSCT between September 2003 and August 2008. The HSCT grafts were autologous in 102 patients, and allogeneic in 148.

RESULTS

Follow-up was 315 (1-1809) days. Mean (SD) pre-HSCT serum ferritin concentration was 1402.6 (5016.2) ng/mL in the entire group, 647.6 (1204.3 ng/mL in autologous recipients, and 1410.6 (2410.4) ng/mL in allogeneic recipients. Twenty-eight autologous graft recipients (27.4%) and 102 allogeneic recipients (68.9%) demonstrated serum ferritin concentrations of 500 ng/mL or greater, and were classified as the high-ferritin group. High ferritin concentrations were significantly associated with toxic or infectious complications including mucositis, fungal infections, pneumonia, and sinusoidal obstruction syndrome in the early post-HSCT setting. A significant effect of pre-HSCT ferritin concentration on overall survival and transplant-related mortality was observed. The effect of pre-HSCT ferritin on survival was independent of the comorbidity index at Cox regression analysis. In the entire study population, the probability of survival was significantly lower when ferritin concentration was greater than 500 ng/mL.

CONCLUSION

Transplant-related mortality has decreased substantially with the development of supportive treatments. Pretransplantation risk assessment and risk-adapted strategies such as decreasing iron overload might further improve transplant-related complications.

Iron overload in patients undergoing hematopoietic stem cell transplantation

Recipients of hematopoietic stem cell transplantation (HSCT) frequently have iron overload resulting from chronic transfusion therapy for anemia. In some cases, for example, in patients with myelodysplastic syndromes and thalassemia, this can be further exacerbated by increased absorption of iron from the gut as a result of ineffective erythropoiesis. Accumulating evidence has established the negative impact of elevated pretransplantation serum ferritin, a surrogate marker of iron overload, on overall survival and nonrelapse mortality after HSCT. Complications of HSCT associated with iron overload include increased bacterial and fungal infections as well as sinusoidal obstruction syndrome and possibly other regimen-related toxicities. Based on current evidence, particular attention should be paid to prevention and management of iron overload in allogeneic HSCT candidates, especially in patients with thalassemia and myelodysplastic syndromes. The pathophysiology of iron overload in the HSCT patient and optimum strategies to deal with iron overload during and after HSCT require further study.

Increased serum iron levels and infectious complications after liver transplantation

BACKGROUND

Elevated serum iron levels have been associated with infectious outcomes in various patient populations but, to our knowledge, have never been studied after liver transplantation.

METHODS

The relationship between serum iron levels and infectious outcomes after liver transplantation was evaluated in a nested case-control study using prospectively collected data and serum samples. Unadjusted and adjusted hazard ratios were calculated for each iron marker predictor variable (iron level, unsaturated iron-binding capacity, total iron-binding capacity, transferrin saturation, and ferritin level) and time to development of each of 6 outcomes (cytomegalovirus [CMV] disease, invasive fungal infection, bacteremia, invasive fungal infection or bacteremia, any infection, and 1-year mortality rate).

RESULTS

Serum measurements (n = 109) corresponding to increased levels of serum iron were independently associated with an increased risk of any infection and death. After adjusting for the number of red blood cell transfusions, donor CMV-seropositive status, and fungal colonization, ferritin level was independently associated with the development of any infection (hazard ratio, 1.09; 95% confidence interval, 1.04-1.14). After adjusting for the number of red blood cell transfusions, development of CMV disease, and administration of intravenous steroids for treatment of rejection, ferritin level was also was independently associated with death (hazard ratio, 1.11; 95% confidence interval, 1.04-1.18). Similar results were found for unsaturated iron binding capacity for the same 2 outcomes.

CONCLUSIONS

A better understanding of iron metabolism and its relationship to infection could help guide future infection prognosis, prevention, and management efforts in this high-risk population.

Serum ferritin: Past, present and future

BACKGROUND

Serum ferritin was discovered in the 1930s, and was developed as a clinical test in the 1970s. Many diseases are associated with iron overload or iron deficiency. Serum ferritin is widely used in diagnosing and monitoring these diseases.

SCOPE OF REVIEW

In this chapter, we discuss the role of serum ferritin in physiological and pathological processes and its use as a clinical tool.

MAJOR CONCLUSIONS

Although many aspects of the fundamental biology of serum ferritin remain surprisingly unclear, a growing number of roles have been attributed to extracellular ferritin, including newly described roles in iron delivery, angiogenesis, inflammation, immunity, signaling and cancer.

GENERAL SIGNIFICANCE

Serum ferritin remains a clinically useful tool. Further studies on the biology of this protein may provide new biological insights.

High ferritin levels are associated with hepatosplenic candidiasis in hematopoietic stem cell transplant candidates

OBJECTIVES

Invasive fungal infections (IFI) are a significant cause of morbidity and mortality in hematopoietic stem cell transplant (HSCT) recipients. Hepatosplenic candidiasis (HSC) is defined as a distinct form of invasive candidiasis, with liver, spleen, and kidney involvement, in patients with hematological disorders.

METHODS

The charts of 255 patients (male/female 168/87; median age 35 (range 16-71) years) who were evaluated pre-HSCT at the Gazi University Hospital Stem Cell Transplantation Unit between 2003 and 2008, were retrospectively reviewed.

RESULTS

HSC, which was demonstrated in six (2.3%) patients, was found to be more common in allogeneic HSCT recipients than in autologous HSCT recipients and in patients who had received two or more previous chemotherapy courses than in patients who had received fewer than two (p>0.05). Patients with HSC tended to have a worse performance status than patients without HSC according to the World Health Organization (p=0.001) and Karnofsky scale (p=0.007). Pre-transplantation ferritin (p=0.008) and acute phase reactant levels, including erythrocyte sedimentation rate (p=0.025) and C-reactive protein (p=0.007), were significantly higher in patients with HSC than in patients without HSC.

CONCLUSIONS

This study shows the predictive role of pre-transplantation ferritin levels in selecting a subset of patients at increased risk for HSC. Pre-transplantation risk assessment and targeted strategies might lower the morbidity and mortality of IFI in HSCT recipients.

Objectives of iron chelation therapy in myelodysplastic syndromes: more than meets the eye?

The role of iron chelation therapy in myelodysplastic syndrome (MDS) remains controversial. Averting cardiac dysfunction in low-grade MDS patients who have sufficient longevity to experience deleterious cardiac effects of iron overload has been the major argument in favor of iron chelation. Although there is significant evidence showing the adverse impact of transfusion dependency on survival in MDS, direct evidence linking tissue iron overload to poor survival or in particular to cardiac dysfunction is lacking. Given the heterogeneity of MDS, it is likely that the pathophysiology of iron overload is equally heterogeneous and complex in these patients. In this article, I argue that prevention of cardiac dysfunction in patients with lower grades of MDS may not be the major benefit of iron chelation therapy, and present evidence suggesting a potential benefit of iron chelation on 3 other outcomes, namely (1) lowering infection risk, (2) improving the outcome of allogeneic hematopoietic stem cell transplantation, and (3) delaying leukemic transformation. These outcomes have particular relevance for patients with higher grades of MDS and should be evaluated in future prospective clinical trials that include patients with all grades of MDS to fully evaluate the benefit of iron chelation therapy.

The iron chelator deferasirox enhances liposomal amphotericin B efficacy in treating murine invasive pulmonary aspergillosis

OBJECTIVES

Increased bone marrow iron levels in patients with haematological malignancies is an independent risk factor for developing invasive pulmonary aspergillosis (IPA), suggesting an important role for iron uptake in the pathogenesis of IPA. We sought to determine the potential for combination therapy with the iron chelator deferasirox + liposomal amphotericin B (LAmB) to improve the outcome of murine IPA compared with LAmB monotherapy.

METHODS

In vitro MIC and minimum fungicidal concentration (MFC) values of the iron chelator, deferasirox, for Aspergillus fumigatus were determined by microdilution assay. In addition, we studied the efficacy of deferasirox alone or combined with LAmB in treating immunocompromised mice infected with A. fumigatus via inhalation.

RESULTS

Deferasirox was cidal in vitro against A. fumigatus, with an MIC and MFC of 25 and 50 mg/L, respectively. Deferasirox monotherapy modestly prolonged survival of mice with IPA. Combination deferasirox + LAmB therapy synergistically improved survival and reduced lung fungal burden compared with either monotherapy alone.

CONCLUSIONS

Iron chelation therapy with deferasirox alone or in combination with LAmB is effective in treating experimental IPA. Further study of deferasirox is warranted as adjunctive therapy for IPA infections.

Impact of pre-transplant serum ferritin on outcomes of patients with myelodysplastic syndromes or secondary acute myeloid leukaemia receiving reduced intensity conditioning allogeneic haematopoietic stem cell transplantation

We report on a retrospective analysis examining the influence of pre-transplant serum ferritin on transplant outcomes of 99 MDS patients receiving reduced intensity conditioning (RIC) HSCT. The median pre-transplant ferritin value was 1992 ng/ml (range: 6-9580 ng/ml). No patients received iron chelation therapy preceding transplantation. On univariate analysis, there was a strong correlation between a higher pre-transplant serum ferritin (>1500 ng/ml) and a significantly inferior 3-year OS (64.6+/-7.5% vs 39.6+/-7.3%, p=0.01). However, pre-transplant serum ferritin did not influence 3-year TRM (20.2+/-7% vs 27.4+/-7%, p=0.24). There was no difference in infection-related mortality, and incidence of acute or chronic GvHD between cohorts. On multivariate analysis, a raised serum ferritin (HR: 2.00, 95% CI: 0.97-3.57, p=0.03), and the presence of >5% bone marrow blasts at time of transplantation (HR: 2.14, 95% CI: 0.84-4.58, p=0.06) were independent predictors of an inferior overall survival. However, pre-transplant serum ferritin was not a significant predictor of disease-free survival, relapse or TRM. When compared with myeloablative regimens, RIC regimens may attenuate the impact of iron overload related end-organ toxicity. Prospective studies incorporating alternative biomarkers of iron metabolism alongside serum ferritin levels are needed to improve our understanding of the significance of iron overload in MDS patients undergoing allogeneic transplantation.

The transplant iron score as a predictor of stem cell transplant survival

Recent studies have suggested that the presence of iron overload prior to stem cell transplantation is associated with decreased survival. Within these studies, the criteria used to define iron overload have varied considerably. Given the lack of consensus regarding the definition of iron overload in the transplant setting, we sought to methodically examine iron status among transplant patients. We studied 78 consecutive patients at risk for transfusion-related iron overload (diagnoses included AML, ALL, MDS, and aplastic anemia) who received either autologous or allogeneic stem cell transplant. Multiple measures of iron status were collected prior to transplantation and examined for their association with survival. Using this data, three potentially prognostic iron measures were identified and incorporated into a rational and unified scoring system. The resulting Transplant Iron Score assigns a point for each of the following variables: (1) greater than 25 red cell units transfused prior to transplantation; (2) serum ferritin > 1000 ng/ml; and (3) a semi-quantitative bone marrow iron stain of 6+. In our cohort, the score (range 0 to 3) was more closely associated with survival than any available single iron parameter. In multivariate analysis, we observed an independent effect of iron overload on transplant survival (p = 0.01) primarily attributable to an increase in early treatment-related deaths (p = 0.02) and lethal infections. In subgroup analysis, the predictive power of the iron score was most pronounced among allogeneic transplant patients, where a high score (> or = 2) was associated with a 50% absolute decrease in survival at one year. In summary, our results lend further credence to the notion that iron overload prior to transplant is detrimental and suggest iron overload may predispose to a higher rate of lethal infections.

Iron overload, hematopoietic cell transplantation, and graft-versus-host disease

Many patients who undergo hematopoietic cell transplantation (HCT) present with anemia and have received red blood cell transfusions before HCT. As a result, iron overload is frequent and appears to be particularly prominent in patients with myelodysplastic syndromes. There is evidence that peritransplant events contribute to further iron accumulation, although the mechanism that disrupts normal iron homeostasis remains to be determined. Recent studies suggest that iron overload, as determined by ferritin levels, a surrogate marker for iron, is a risk factor for increased non-relapse mortality after HCT. Iron overload is associated with an increased rate of infections, in particular with fungal organisms. Furthermore anecdotal data suggest that increased hepatic iron may mimic the clinical picture of (chronic) graft-versus-host-disease (GVHD). Whether excess iron contributes to GVHD and whether iron depletion, be it by phlebotomy or chelation, reduces the post-transplantation complication rate and improves transplant outcome is yet to be determined.

Ferritin for the clinician

Ferritin, a major iron storage protein, is essential to iron homeostasis and is involved in a wide range of physiologic and pathologic processes. In clinical medicine, ferritin is predominantly utilized as a serum marker of total body iron stores. In cases of iron deficiency and overload, serum ferritin serves a critical role in both diagnosis and management. Elevated serum and tissue ferritin are linked to coronary artery disease, malignancy, and poor outcomes following stem cell transplantation. Ferritin is directly implicated in less common but potentially devastating human diseases including sideroblastic anemias, neurodegenerative disorders, and hemophagocytic syndrome. Additionally, recent research describes novel functions of ferritin independent of iron storage.

Effect of iron overload and iron-chelating therapy on allogeneic hematopoietic SCT in children

Iron overload is known to increase complications of hematopoietic SCT (HSCT). We investigated the association of pre-transplant ferritin level with complications and survival after allogeneic HSCT, and evaluated the efficacy of iron-chelating therapy before HSCT. We retrospectively reviewed 101 patients who underwent allogeneic HSCT and divided these patients into three groups: F>1000, patients with ferritin level above 1000 ng/ml at the time of HSCT; F<1000, patients whose ferritin levels were maintained below 1000 ng/ml before HSCT without iron-chelating therapy; IC, patients with ferritin level decreased to less than 1000 ng/ml after iron-chelating therapy before HSCT. In the comparison between the F>1000 group and the F<1000 group, hyperbilirubinemia and treatment-related mortality (TRM) were significantly higher in the F>1000 group. The F>1000 group also showed decreased OS and EFS. In the comparison of the F<1000 and IC groups, there was no significant difference in complications and survival. When compared with the F>1000 group, the IC group showed lower TRM and higher survival. Elevated serum ferritin level was associated with increased TRM and decreased survival, and the analysis of the IC group suggested the benefit of iron-chelating therapy to improve the outcome of HSCT.

Antifungal activities of natural and synthetic iron chelators alone and in combination with azole and polyene antibiotics against Aspergillus fumigatus

Antifungal effects of iron chelators (lactoferrin, deferoxamine, deferiprone, and ciclopirox) were tested alone and in combination with antifungal drugs against Aspergillus fumigatus B5233 conidia. Lactoferrin, ciclopirox, and deferiprone inhibited whereas deferoxamine enhanced fungal growth. Antifungal synergy against conidia was observed for combinations of ketoconazole with ciclopirox or deferiprone, lactoferrin with amphotericin B, and fluconazole with deferiprone. Iron chelation alone or combined with antifungal drugs may be useful for prevention and treatment of mycosis.

Transplantation of allogeneic T cells alters iron homeostasis in NOD/SCID mice

Iron overload is common in patients undergoing allogeneic hematopoietic cell transplantation (HCT), but the mechanisms leading to overload are unknown. Here, we determined iron levels and the expression of iron regulatory proteins in the liver and gut of nonobese diabetic-severe combined immunodeficient (NOD/SCID) mice that underwent transplantation with syngeneic (histocompatible) or allogeneic (histoincompatible) T lymphocytes. Infusion of histoincompatible T cells resulted in a significant rise in serum iron levels and liver iron content. Iron deposition was accompanied by hepatocyte injury and intestinal villous damage. Feeding of low- or high-iron diet was associated with appropriate ferroportin 1 and hepcidin responses in mice given histocompatible T cells, whereas mice given histoincompatible T cells showed inappropriate up-regulation of duodenal ferroportin 1 and a loss of expression of hepatic hepcidin. These findings suggest that alloreactive T cell-dependent signals induced dysregulation of intestinal iron absorption, which contributed to liver iron overload after HCT.

Red blood cell transfusion dependence and outcome after allogeneic peripheral blood stem cell transplantation in patients with de novo myelodysplastic syndrome (MDS)

The prognosis of patients with de novo myelodysplastic syndrome (MDS) who are red blood cell transfusion-dependent (TD) and receive supportive care is inferior to that of patients who do not require transfusions. Whether TD also affects outcome after allogeneic transplantation is unknown. Consequently, in 172 de novo MDS patients (median age, 51 years), we analyzed the impact of TD on outcome after high-dose conditioning and allogeneic peripheral blood stem cell transplantation (PBSCT). With a median follow-up of 37 months, the probability of 3-year overall survival (OS) did not differ significantly between patients who were TD and those who were not TD before PBSCT (P=.1); however, transfusion burden, as reflected by ferritin levels, was correlated with a greater probability of severe acute graft-versus-host disease (aGVHD; P=.03) and a higher comorbidity index (P=.01), and OS was inferior in those patients with a ferritin level>1000 microg/L before PBSCT (P=.03). In multivariate analysis, only marrow myeloblast count (P=.01) and comorbidity index (P=.001) had a significant impact on OS. Our data do not identify TD as an independent negative prognostic factor for outcome after allogeneic PBSCT' however, iron overload (presumably transfusion-related) may contribute to poor transplantation success by adding to the overall comorbidities. Whether clinical intervention in the form of iron chelation can improve the outcome of allogeneic PBSCT in TD patients with MDS remains to be determined.

Anemia associated with impaired erythropoietin secretion after allogeneic stem cell transplantation: incidence, risk factors, and response to treatment

After allogeneic stem cell transplantation (allo-SCT) some patients develop persistent anemia in association with an inadequate erythropoietin (Epo) secretion. We determined the frequency and risk factors for this complication and the response to treatment with erythropoiesis stimulating proteins (ESP). Of 83 evaluable allo-SCT patients, 63 (76%) developed persistent anemia at a median of 34 (range: 30-244) days after allo-SCT. Forty-one (49%) patients had anemia considered as primary, and in all of them inadequate serum Epo levels (median 43.3, range: 2.5-134, mU/mL) were found. A high creatinine level during the first month after allo-SCT was associated with primary anemia (relative risk [RR] 2.5, P = .01). Of the 41 patients, 35 received ESP. Transfusion independence and an Hb level higher than 10 g/dL was achieved in 29 of 30 (97%) evaluable patients. Median ferritin levels at the beginning and at the end of the ESP treatment was 1628 (range: 168-5208) and 805 (range: 14-7443) ng/mL, respectively (P = .04). In conclusion, anemia associated with impaired Epo secretion after allo-SCT is more frequent than usually recognized and it is associated to early postransplantation renal damage. This complication easily reverts with ESP, which seems to contribute to reduce iron overload.

Iron overload adversely affects outcome of allogeneic hematopoietic cell transplantation

Iron overload is common in patients undergoing allogeneic hematopoietic cell transplantation (HCT) for hematologic disorders. Serum ferritin, a marker of tissue iron overload, was measured immediately before transplant in adult patients undergoing myeloablative HCT from matched sibling or unrelated donors. The effect of elevated pretransplant ferritin (defined as ferritin >or=1000 ng/ml) on day 100 mortality, overall survival, acute GVHD and infectious complications was assessed. Data on 190 patients were analyzed. In univariate analysis, the high-ferritin group had increased day 100 mortality (20 vs 9%, P=0.038), decreased overall survival (log-rank test: P-value=0.004), increased acute GVHD/death (63 vs 43%, P=0.009) and increased incidence of blood stream infections (BSIs)/death (60 vs 44%, P=0.042). In a multivariate analysis, high ferritin was associated with increased risk of death (Cox model: hazard ratio=2.28, P=0.004), increased day 100 mortality (generalized linear model (GLM) odds ratio=3.82, P=0.013), increased incidence of acute GVHD/death (GLM odds ratio=3.11, P=0.001) and increased risk of BSI/death (GLM odds ratio=1.99, P=0.032). The results remained similar when serum ferritin was considered a continuous variable. Elevated serum ferritin adversely impacts on overall survival and increases the likelihood of acute GVHD and BSI after allogeneic HCT.

Iron overload and unique susceptibility of liver transplant recipients to disseminated disease due to opportunistic pathogens

The propensity of liver transplant recipients to develop more fulminant disease presentation and a higher risk of disseminated disease due to a number of opportunistic infections, including invasive aspergillosis, cryptococcosis, zygomycosis, may be related to iron overload. Abnormalities in iron homeostasis may also be a contributor to severe manifestations due to other pathogens such as cytomegalovirus and Staphylococcus aureus in liver transplant recipients. Iron is essential not only for microbial pathogenesis, but directly impairs pivotal pathogen specific host defenses. Studies to assess iron homeostasis and the mechanisms by which iron overload contributes to the pathogenesis of opportunistic infections in liver transplant recipients are warranted.

The role of liver biopsy in the workup of liver dysfunction late after SCT: is the role of iron overload underestimated?

Abnormalities in liver function tests are common in hematopoietic SCT (HSCT) recipients. We retrospectively investigated the role of liver biopsy in determining the cause of elevated liver enzymes and its impact on the management of patients in the post-HSCT setting. A total of 24 consecutive liver biopsies were obtained from 20 patients from September 2003 to December 2007. A definite histopathologic diagnosis was obtained in 91.7% of the biopsies. Iron overload (IO) was found in 75% and GVHD in 54.2% of the patients. The initial clinical diagnosis of GVHD was confirmed in 56.5% and refuted in 43.5% of the allogeneic HSCT recipients. The median number of post transplant transfusions, percent transferrin saturation and ferritin levels were found to be higher in patients who had histologically proven hepatic IO (p1=0.007, p2=0.003 and p3=0.009, respectively). Regression analysis showed a significant correlation between serum ferritin levels and histological grade of iron in the hepatocytes. Our data suggest that hepatic IO is a frequent finding in the post-HSCT setting, which contributes to hepatic dysfunction and it should be considered in the differential diagnosis, particularly in patients with high serum ferritin levels.

Increased bone marrow iron stores is an independent risk factor for invasive aspergillosis in patients with high-risk hematologic malignancies and recipients of allogeneic hematopoietic stem cell transplantation

BACKGROUND

Invasive aspergillosis (IA) is a leading cause of death in patients with leukemia and those who have undergone hematopoietic stem cell transplantation. Laboratory studies have demonstrated that iron is essential for Aspergillus growth and virulence.

METHODS

In the current study, the authors retrospectively evaluated the bone marrow iron stores (BMIS) in patients with leukemia as well as recipients of allogeneic hematopoietic stem cell transplantation with IA (n = 33) and those without fungal infections (n = 33). The first available bone marrow biopsy specimens prior to the IA diagnosis or date of hospitalization (control group) were assessed in a blinded fashion using a standardized scoring system (0-4). Both groups were comparable with regard to clinical characteristics and classic risk factors for IA.

RESULTS

The majority of patients with IA (70%) were found to have increased BMIS (score >or=3) compared with the control patients (16%) (P < .0001). Increased BMIS was found to be an independent risk factor for IA on multivariate analysis (P < .0001).

CONCLUSIONS

The prospective validation of BMIS for risk stratification in patients with leukemia or those who undergo allogeneic hematopoietic stem cell transplantation is needed.

Human polymorphonuclear leukocytes inhibit Aspergillus fumigatus conidial growth by lactoferrin-mediated iron depletion

Aspergillus fumigatus, a common mold, rarely infects humans, except during prolonged neutropenia or in cases of chronic granulomatous disease (CGD), a primary immunodeficiency caused by mutations in the NADPH oxidase that normally produces fungicidal reactive oxygen species. Filamentous hyphae of Aspergillus are killed by normal, but not CGD polymorphonuclear leukocytes (PMN); however, the few studies on PMN-mediated host defenses against infectious conidia (spores) of this organism have yielded conflicting results, some showing that PMN do not inhibit conidial growth, with others showing that they do, most likely using reactive oxygen species. Given that CGD patients are exposed daily to hundreds of viable A. fumigatus conidia, yet considerable numbers of them survive years without infection, we reasoned that PMN use ROS-independent mechanisms to combat Aspergillus. We show that human PMN from both normal controls and CGD patients are equipotent at arresting the growth of Aspergillus conidia in vitro, indicating the presence of a reactive oxygen species-independent factor(s). Cell-free supernatants of degranulated normal and CGD neutrophils both suppressed fungal growth and were found to be rich in lactoferrin, an abundant PMN secondary granule protein. Purified iron-poor lactoferrin at concentrations occurring in PMN supernatants (and reported in human mucosal secretions in vivo) decreased fungal growth, whereas saturation of lactoferrin or PMN supernatants with iron, or testing in the presence of excess iron in the form of ferritin, completely abolished activity against conidia. These results demonstrate that PMN lactoferrin sequestration of iron is important for host defense against Aspergillus.

Early clinical impact of iron overload in stem cell transplantation. A prospective study

Toxic-infectious complications may be related with iron toxicity after a stem cell transplant (SCT). Eighty one patients who underwent SCT were prospectively evaluated over 3 months for mucositis, bacteraemia and febrile days. Pre-SCT transferrin saturation (TS), ferritin level and the number of days with TS >or= 80% after transplant were determined. A ferritin level >1,500 microg/l predicted the appearance of severe mucositis, bacteraemia and days with fever in univariate (P = 0.03, P = 0.03 and P = 0.03) and multivariate analysis (P = 0.03, P = 0.006 and P = 0.002). Nevertheless, further statistical studies revealed that the predictive value of pre-SCT ferritin levels was restricted to AUTO-transplanted patients in both univariate (P = 0.05, P = 0.05 and P < 0.001) and multivariate (P = 0.03, P = 0.05 and P < 0.001) analysis, in contrast with the ALLO-transplanted group where this variable did not reach statistical significance. In conclusion, iron burden seems to influence the appearance of toxic-infectious complications during the first 3 months after transplant in AUTO-transplanted patients.

Association of hepatic iron overload with invasive fungal infection in liver transplant recipients

Invasive fungal infection is a serious complication of orthotopic liver transplantation, but its risk factors remain incompletely defined. Iron overload has already been associated with increased risk of fungal infections, but it has not yet been assessed as a risk factor in liver transplantation. We retrospectively studied a cohort of 153 consecutive patients who underwent their first liver transplantation at a single center and who survived at least 7 days after transplantation. The association between various pretransplant patient characteristics, including hepatic explant iron and risk of invasive fungal infections, was analyzed by univariate and multivariate models. Iron in the hepatic explant was assessed by Perl's Prussian blue stain by a pathologist blinded to clinical outcome. During the first year after transplantation, 28 of 153 patients developed a total of 31 invasive fungal infections, of which 21 (68%) were caused by Candida, 7 (23%) by Aspergillus, 2 (6%) by Cryptococcus, and 1 (3%) by Saccharomyces. Stainable iron in the hepatic explant was found in 48 patients (31%). Stainable iron in the hepatic explant was found to be strongly and independently associated with posttransplantation fungal infections in multivariate analysis (hazard ratio 3.09; 95% confidence interval 1.45-6.56; P = 0.003). Hepatic iron overload is strongly and independently associated with posttransplantation invasive fungal infections. Studies to confirm this finding in other centers and define the mechanism are warranted.

Plasma antioxidants in subjects before hematopoietic stem cell transplantation

Chemo-irradiation induced oxidative damage to vascular endothelium may contribute to pulmonary complications of hematopoietic stem cell transplantation (HSCT). We measured antioxidants, markers of oxidative stress and plasma antioxidant capacity in plasma or serum from 24 subjects at day 7 before HSCT and 20 control subjects. The plasma concentration of extracellular glutathione peroxidase (GPX-3) was significantly reduced in the HSCT subjects compared with controls (HSCT: 98+/-42 microg/ml, control: 169+/-56 microg/ml, P<0.0001). The concentration of gamma-tocopherol was significantly higher in the HSCT subjects compared with controls (HSCT: 207+/-103 microg/dl;

CONTROL

98+/-52 microg/dl; P=0.0002). The plasma concentrations of protein carbonyl, nitrotyrosine, malondialdehyde, alpha-tocopherol, vitamin A, homocysteine, cysteine and cysteinylglycine did not differ between HSCT and control subjects. Plasma from HSCT subjects was as effective as control plasma in quenching menadione-induced intracellular reactive oxygen species production in human microvascular endothelial cells. In summary, subjects before HSCT have significantly reduced plasma concentrations of GPX-3, elevated plasma gamma-tocopherol yet retains the ability to quench an acute oxidative stress. These changes may play a role in chronic oxidative stress in the HSCT population.

Iron Overload Manifesting as Apparent Exacerbation of Hepatic Graft-versus-Host Disease after Allogeneic Hematopoietic Stem Cell Transplantation

Iron overload presenting as exacerbation of hepatic graft-versus-host disease (GVHD) after allogeneic hematopoietic stem cell transplantation has not been previously described. We report 6 patients with established hepatic GVHD in whom iron overload (median serum ferritin, 7231 mug/dL; median transferrin saturation, 77%) resulting from a lifetime median of 20 units of packed red blood cell transfusions was manifested by worsening of liver function. Liver biopsies performed in 4 patients confirmed severe iron overload and also hepatic GVHD. Analysis for the C282Y and H63D hemochromatosis gene mutation was negative for the homozygous state in all 6 patients. Erythropoietin-assisted phlebotomy resulted in normalization of liver function at a median of 7 months and of serum ferritin at a median of 11 months. Immunosuppressive therapy was successfully tapered in all 4 patients who completed the phlebotomy program, and this supported the impression that iron overload, rather than GVHD, was the principal cause of liver dysfunction. At a median follow-up of 50 months (range, 18-76 months) from the transplantation and 25 months (range, 5-36 months) from ferritin normalization, all 4 patients require maintenance phlebotomy. We conclude that iron overload can mimic GVHD exacerbation, thus resulting in unnecessary continuation or intensification of immunosuppressive therapy for GVHD, and that maintenance phlebotomy is necessary after successful iron-reduction therapy.

A murine model of invasive aspergillosis: variable benefit of interferon-gamma administration under in vitro and in vivo conditions

BACKGROUND

Interferon-gamma modulates host defense in a number of infectious diseases. Previous studies have shown that systemic administration of interferon-gamma (IFN-gamma) can enhance survival in experimental invasive aspergillosis (IA).

METHODS

Using a novel model of murine IA that is characterized by primary pulmonary infection, we investigated the role of IFN-gamma in the phagocytosis and killing of Aspergillus fumigatus by murine neutrophils and pulmonary alveolar macrophages in vitro and the impact of systemic and regional administration of IFN-gamma on the course of IA in glucocorticoid-treated mice.

RESULTS

In vitro, IFN-gamma significantly enhanced phagocytosis and killing function of both neutrophils and alveolar macrophages from normal animals, but not cortisone-treated animals. In vivo, intravenous administration of IFN-gamma did not improve phagocyte recruitment, in vivo killing, or mortality from IA. Regional (intranasal) administration of IFN-gamma to the lungs enhanced recruitment of phagocytic cells to the lungs and improved in vivo killing, but did not alter (and actually worsened) mortality from IA.

CONCLUSIONS

The in vitro and in vivo effects of IFN-gamma in IA are contingent on many variables, including the route of administration and the specific pathogenesis of infection.

Iron overload is a major risk factor for severe infection after autologous stem cell transplantation: a study of 367 myeloma patients

We evaluated the risk factors for infection of 367 consecutive myeloma patients who underwent high-dose melphalan and autologous stem cell transplantation (ASCT). Examination of bone marrow iron stores (BMIS) prior to ASCT was used to evaluate body iron stores. Other variables included age, sex, active smoking, myeloma remission status, severity of mucositis and duration of severe neutropenia post-ASCT (<100 absolute neutrophils counts (ANC)/microl). Median age was 56 years; 61% of patients were males. 140 episodes of severe infections occurred in 116 patients, including bacteremia (73), pneumonia (40), severe colitis (25) and bacteremia with septic shock (two). The infection incidence per 1,000 days at risk was 45.2. Pre-ASCT risk factors for severe infection by univariate analysis were increased BMIS (OR=2.686; 95% CI 1.707-4.226; P<0.0001), smoking (OR=1.565; 95% CI 1.005-2.437; P=0.0474) and male gender (OR=1.624; 95% CI 1.019-2.589; P=0.0414). Increased BMIS (OR=2.716; 95% CI 1.720-4.287; P<0.0001) and smoking (OR=1.714; 95% CI 1.081-2.718; P=0.022) remained significant by multivariate analysis. Duration of ANC <100 micro/l (OR=1.129; 95% CI 1.039-1.226; P=0.0069 and OR=1.127; 95% CI 1.038-1.224; P=0.0045 by both univariate and multivariate analysis, respectively) was the only post-ASCT risk factor for infection. Increased pre-transplant BMIS and smoking are significant predictors of severe infection after myeloablative chemotherapy followed by ASCT in myeloma patients.