Lack of known hepatitis virus in hepatitis-associated aplastic anemia and outcome after bone marrow transplantation

Exploring strategies to optimise outcomes in hepatitis-associated aplastic anaemia patients following haematopoietic stem cell transplantation

This study aimed to assess haematopoietic stem cell transplantation (HSCT) safety and efficacy while exploring strategies for optimising outcomes in patients with hepatitis-associated aplastic anaemia (HAAA). We retrospectively reviewed 35 HAAA patients who underwent HSCT at a large Chinese blood disease hospital between 2008 and 2022. HAAA patients receiving HSCT typically presented with severe (28.6%) and very severe (65.7%) AA. Male patients predominated (68.6%), with a median onset age of 23 years (range, 9-44). Haploidentical donor-HSCT and matched sibling donor-HSCT were in comparable proportions. The 5-year overall survival (OS) rate was 74.0%, with cumulative incidences of grade II-IV acute and chronic graft-versus-host disease (GVHD) at 37.1% and 22.4%, respectively. A diagnosis-to-HSCT interval ≥ 75 days, acute GVHD, and post-HSCT liver events (e.g., hepatic GVHD and a three-fold increase in aminotransferase or bilirubin) significantly worsened 5-year OS. In the multivariate models, recipients with sex-matched grafts had better OS, and those with younger male donors had a lower incidence of II-IV aGVHD. Higher HLA matching degree (HLA > = 7/10) was an independent prognostic factor associated with better OS and GFFS. A diagnosis-to-HSCT interval ≥ 75 days was predictive of post-transplant liver events in HAAA patients. In conclusion, HSCT was a safe and effective treatment for HAAA. Early transplantation, careful donor selection and improving post-transplant liver events were crucial to optimise outcomes.

A case of hepatitis-associated aplastic anaemia following living-donor liver transplantation for fulminant hepatitis showing loss of heterozygosity in the 6p chromosome in the affected liver

The mechanisms underlying hepatitis-associated aplastic anaemia (HAAA) that occurs several weeks after the development of acute hepatitis are unknown. A 20-year-old male developed HAAA following living-donor liver transplantation for fulminant hepatitis. The patient's leucocytes lacked HLA-class I due to loss of heterozygosity in the short arm of chromosome 6p (6pLOH). Interestingly, the patient's liver cells resected during the transplantation also exhibited 6pLOH that affected the same HLA haplotype as the leucocytes, suggesting that CD8+ T cells recognizing antigens presented by specific HLA molecules on liver cells may have attacked the haematopoietic stem cells of the patient, leading to the HAAA development.

Comparison of hematopoietic stem cell transplantation and immunosuppressive therapy as the first-line treatment option for patients with severe hepatitis−associated aplastic anemia

Hepatitis-associated aplastic anemia (HAAA) is a rare variant of acquired aplastic anemia characterized with a syndrome of bone marrow failure after hepatitis. We retrospectively analyzed the outcomes of consecutive severe HAAA patients who received immunosuppressive therapy (IST, n = 70), matched-sibling donor hematopoietic stem cell transplantation (MSD-HSCT, n = 26) or haploidentical-donor (HID) HSCT (n = 11) as the first-line treatment. In the IST group, the hematologic response (HR) rate was 55.71% at 6 months. In contrast, HSCT recipients exhibited significantly more rapid and sustained hematopoiesis (HR 76.92%, 96.15% and 96.15% at 3, 6 and 12months, respectively). The 5-year overall survival (OS) was not different among IST (83.7 ± 4.9%), MSD-HSCT (93.3 ± 6.4%) and HID-HSCT group (80.8 ± 12.3%). Compared with IST, MSD and HID-HSCT demonstrated a trend of superiority in the estimated 5-year failure-free survival rates (93.3 ± 6.4% vs 64.3 ± 6.0%, p = 0.05; 80.8 ± 12.3% vs 64.3 ± 6.0%, p = 0.57). In subsequent stratified analysis on age, we found that HID-HSCT showed its efficacy and safety among young patients. In sum, MSD-HSCT remains first-line treatment choice for HAAA, whereas HID-HSCT represents an alternative treatment choice in addition to IST for young patients (< 40 years) without a matched sibling donor.

Hepatitis-associated Aplastic Anemia

Hepatitis-associated aplastic anemia (HAAA) accounts for 4% of autoimmune hepatitis in children. An episode of seronegative autoimmune hepatitis is followed a few days or months later by aplastic anemia or full aplasia. This autoimmune disease could be due to a regulation defect in the immune response to a viral trigger, in a genetically predisposed individual. Other causes of hepatitis or aplastic anemia have to be ruled out. Steroids and azathioprine usually control the liver damage but do not prevent the development of aplastic anemia. Aplastic anemia is treated with either hematopoietic stem cell transplantation in patients with a sibling donor or anti-thymocyte globulins and cyclosporine. We propose guidelines to explore and treat this rare disease. We emphasize on the necessary close collaboration between hepatologists and hematologists.

Assessment of Hepatic Profile in Acquired Aplastic Anemia: An Experience From Pakistan

Introduction: Aplastic anemia (AA) is characterized by pancytopenia and hypocellular marrow in the absence of an abnormal infiltrate or increase in reticulin fibrosis. The diagnosis of AA is challenging at times due to decreased cellularity and overlapping morphological features with other bone marrow failure syndromes. Hepatitis-associated aplastic anemia (HAAA) is a rare variant in which patients typically present with jaundice and hepatitis followed by pancytopenia almost within 6 months. Post-hepatitis AA accounts for approximately 1-5% of cases, and invariably such cases are negative for the known hepatitis virus as well. There is limited literature available to understand the correlation of AA with hepatitis with none reported at the national level in our region. As AA is relatively more prevalent in Southeast Asia as compared to the western world and hepatitis is a prevalent disease in our population, the main purpose of this study was to assess the hepatic profile and determine the association of hepatitis in AA at the time of diagnosis.

Materials and methods: A cross-sectional study was carried out at the National Institute of Blood Disease and Bone Marrow Transplantation, Karachi, from November 2019 to December 2020 after the informed consent from patients. The study included all treatment-naïve patients of acquired AA with no prior history of taking steroids, immunosuppressive treatment, or chemoradiation therapy. Liver function tests, complete blood count, prothrombin time (PT), and activated partial thromboplastin time were performed, along with viral profiles (HAV, Hep B, Hep C, and HIV). SPSS version 23 (IBM Corp., Armonk, NY) was used for statistical analysis. Mean and standard deviations were computed for quantitative variables while percentages and frequencies were reported for qualitative variables. T-test was used to observe the main difference between groups and a p-value <0.05 was considered to be significant.

Results: Out of a total of 351 patients, 29 (8.2%) patients with AA tested positive for viral hepatitis. Hepatitis A was the most prevalent hepatitis (4.0%), followed by hepatitis C (3.7%). The comparison of platelet counts in patients with and without hepatitis was reported to be of statistical significance (p-value < 0.05). A significant statistical difference (p-value < 0.0001) was found in platelet count and PT in patients of AA with and without hepatitis.

Conclusion: Overall, this study revealed that <10% of patients of AA had a positive screening for hepatitis A, B, and C and low platelet count, and PT was statistically significant when compared between the patients with and without hepatitis. Hepatitis being prevalent in our part of the world might have an important causal association with AA. Patients with AA should be screened for liver functions and viral hepatitis at the time of diagnosis. In addition to hepatitis A, B, and C and HIV, other causes of hepatitis should also be screened such as parvovirus B19, human herpes virus 16, and adenovirus which are not included in routine diagnostic viral testing panel.

Changes in bone marrow and peripheral blood lymphocyte subset findings with onset of hepatitis-associated aplastic anemia

RATIONALE

Hepatitis-associated aplastic anemia (HAAA) is a rare illness that results in bone marrow failure following hepatitis development. The etiological agent remains unknown in most HAAA cases. However, clinical features of the disease and immunotherapy response indicate that immune-mediated factors play a central role in the pathogenesis of HAAA. Activation of cytotoxic T cells and increase in CD8 cells could exert cytotoxic effects on the myelopoietic cells in the bone marrow.

PATIENT CONCERNS

A 15-month-old boy was brought to our hospital with complaints of generalized petechiae and purpura observed a week prior to hospitalization. His liver was palpated 3 cm below the costal margin, platelet count was 0 × 104/μL, and alanine aminotransferase level was 1346 IU/L. A blood test indicated cytomegalovirus infection, and 3 bone marrow examinations revealed progressive HAAA. As the disease progressed to the 3rd, 6th, and 9th week after onset, CD4+ T cells were markedly decreased, CD8+ T cells were markedly increased, and the CD4/CD8 ratio was significantly decreased. The number of B cells and natural killer cells decreased with time, eventually reaching 0.0%.

DIAGNOSIS

HAAA.

INTERVENTIONS

Rabbit antithymocyte globulin and eltrombopag olamine (a thrombopoietin receptor agonist) were administered.

OUTCOMES

The patient's platelet count returned to normal, and bone marrow transplantation was avoided. The peripheral blood lymphocytes (PBLs) improved as the patient's general condition recovered.

LESSONS

This case demonstrates that HAAA induced by cytomegalovirus infection features decreasing CD4+ and increasing CD8+ PBLs as the bone marrow hypoplasia progresses. The PBLs return to their normal levels with the recovery from the disease. Our case findings thus support the involvement of immunological abnormality in HAAA.

Hemolytic Anemia after Acute Hepatitis B Virus Infection: A Case Report and Systematic Review

Hemolytic anemia and pure red cell aplasia are rare hematological complications of hepatitis B virus infection. We herein report a 24-year-old man who was diagnosed with hemolytic anemia and possible transient pure red cell anemia eight weeks after a severe episode of acute hepatitis B virus infection. Rapid recovery was observed with conservative management. Hemoglobin returned to baseline within three months. As the clinical features of hemolytic anemia associated with hepatitis B virus have not yet been elucidated, we conducted a systematic review and present an analysis of the 20 reported cases, including our present case.

Comparative metavirome analysis in polytransfused patients

Due to the high transfusion volume, polytransfused patients with sickle cell disease (SCD) and beta-thalassemia are constantly exposed to parenterally transmitted infections. Currently, we have little information about the virome of such patients and how the virological composition might be influenced by the hemotherapy procedures that these patients receive. The objective of this study was to compare the viral diversity between these two groups with respect to the viral abundance and how it might be affected by the specific conditions of these groups. We sequenced by next-generation sequencing (NGS) and compared the virome of 30 patients with beta-thalassemia major, 45 with SCD, and 16 blood donors from the Blood Center of Ribeirão Preto, Brazil. Predominantly, commensal viruses including Torque teno virus (TTV) genotypes and human pegiviris-1 (HPgV-1) were identified in each group. Strikingly, while HPgV-1 reads were dominant in the SCD group, thalassemic patients showed high TTV abundance, expressed both in viral reads and genotypes. We speculated that the commensal virome of polytransfused patients might be influenced by the transfusion frequency and disease characteristics and that commensal viruses might be used as important genetic biomarkers for these hematological disturbances. Nevertheless, more specific studies are necessary to confirm a relationship between blood virome and transfusion treatment.

Seronegative autoimmune hepatitis in children: a single-center experience

BACKGROUND

Seronegative autoimmune hepatitis (AIH) is a diagnostic challenge with unclear prognosis. This study describes the features and outcomes of seronegative AIH in children.

PATIENTS AND METHODS

Patients under 18 years of age, who had been diagnosed with AIH between April 2014 and April 2020, were retrospectively evaluated. Seronegative AIH was identified by the absence of the three conventional non-organ-specific autoantibodies (anti-nuclear antibody [ANA], anti-smooth muscle antibody [ASMA], and anti-liver kidney microsomal [anti-LKM] type 1 antibody), alongside the characteristic AIH liver histopathology and a positive response to immunosuppressive therapy in the absence of other liver diseases.

RESULTS

The study included 54 patients with AIH. 15 (27.77%) were seronegative at the time of diagnosis. 13 of the 15 seronegative patients presented with acute hepatitis or acute liver failure (ALF). Mean follow-up duration was 27.48 months in seronegative patients. Two seronegative patients had lymphocytopenia on admission, and, although the liver disease improved after corticosteroid treatment, they developed aplastic anemia (AA). Other seronegative patients responded well to immunosuppressive therapy.

CONCLUSIONS

Patients with seronegative AIH present frequently with acute hepatitis or ALF. AIH diagnosis can be confirmed by observing the effects of corticosteroid therapy in seronegative patients with characteristic AIH liver histopathological features. However, the presence of lymphocytopenia in seronegative patients is a sign of bone marrow failure.

Outcomes of Severe Seronegative Hepatitis-associated Aplastic Anemia: A Pediatric Case Series

OBJECTIVES

Hepatitis-associated aplastic anemia (HAAA) is a potentially life-threatening diagnosis without clear treatment guidelines. The goal of the study was to characterize the presentation, evaluation, histopathology, and outcomes of therapy in children with HAAA to guide future research and to develop standardized care guidelines for this rare disease.

METHODS

Retrospective chart review of 4 patients with HAAA who presented to Children's Hospital Colorado between 2016 and 2019 was conducted. Patient presentation, evaluation, bone marrow and liver pathology, interventions, and clinical course were collected. Immunohistochemistry of liver biopsies was performed.

RESULTS

We treated 4 patients with HAAA without liver failure. All had evidence of systemic hyperinflammation and CD8+ T cell predominant liver tissue infiltration. One had a genetic mutation predisposing him to immune-mediated disease, but all other genetic testing was negative. In 3 of the 4 patients, hepatitis was poorly responsive to standard therapy with steroids, azathioprine, or tacrolimus; however, sustained biochemical remission of hepatitis was induced after more aggressive immunosuppressive therapies including Anti-Thymocyte Globulin (ATG) at standard immunosuppressive therapy (IST) dosing for severe Aplastic Anemia (sAA). Two patients underwent hematopoietic stem cell transplant (HSCT); 1 as first line therapy and 1 for refractory sAA.

CONCLUSIONS

We found that ATG-based IST induced remission of hepatitis in patients with steroid-refractory HAAA. This is also an appropriate initial treatment for severe Aplastic Anemia, though may not prevent the need for HSCT. We propose that equine ATG based IST at standard dosing regimen for sAA is a therapy that in select cases can be considered early on in the treatment course and could lead to a sustained remission of both hepatitis and sAA. This should be considered in collaboration with a pediatric hematologist.

Hepatitis-associated aplastic anemia

Hepatitis-associated aplastic anemia (HAAA) is a rare illness, characterized by onset of pancytopenia with a hypoplastic bone marrow that traditionally occurs within 6 months of an increase in serum aminotransferases. HAAA is observed in 1% to 5% of all newly diagnosed cases of acquired aplastic anemia. Several hepatitis viruses have been linked to the disease, but in many cases no specific virus is detected. The exact pathophysiology is unknown; however, immune destruction of hematopoietic stem cells is believed to be the underlying mechanism. HAAA is a potentially lethal disease if left untreated. Management includes immunosuppression with antithymocyte globulin and cyclosporine and allogeneic hematopoietic stem cell transplantation.

Hepatitis-associated Aplastic Anemia with Rapid Progression of Liver Fibrosis Due to Repeated Hepatitis

Hepatitis-associated aplastic anemia (HAAA) is a variant of acquired aplastic anemia and characterized by bone marrow failure that follows the development of acute hepatitis. We herein report a rare case of HAAA with rapid progression of liver fibrosis due to repeated hepatitis. A pathological examination of liver specimens revealed liver fibrosis progression over a short period. Immunosuppressive therapy with cyclosporine effectively cured both the pancytopenia and hepatitis. Our case suggests that the pathological examination of the liver tissue is useful for determining a treatment plan and that immunosuppressive therapy is a promising treatment for both aplastic anemia and persistent hepatitis.

Hepatitis-associated aplastic anemia from workout supplement: Rare but potentially fatal entity

Hepatitis-associated aplastic anemia (HAAA) is a rare clinical syndrome characterized by bone marrow failure 1–3 months after development of hepatitis. Untreated, hepatitis-associated aplastic anemia has poor outcome and the mainstay of treatment remains either bone marrow transplant or immunosuppressive therapy. A previously healthy 21-year-old man presented with a 1-week history of right upper quadrant pain and jaundice. Admission labs revealed mixed hyperbilirubinemia and elevated transaminases ranging in 2000s IU/dl. Extensive workup for etiologies of acute hepatitis including viruses, autoimmune, toxins etc. were negative. He admitted to taking “Dust V2,” a workout supplement, for 4 months prior to the presentation. His liver function tests started to improve after conservative treatment. Two months after his discharge, he was found to have severe pancytopenia on routine labs. Bone marrow biopsy revealed hypocellular marrow consistent with aplastic anemia. Extensive workup for etiologies of aplastic anemia were negative. On literature review, none of the components of the supplement were found to cause aplastic anemia. A diagnosis of hepatitis-associated aplastic anemia was made as there was a lag time before development of anemia. His counts failed to improve despite treatment with filgrastim and he was referred for hematopoietic cell transplant.

Hepatitis-associated Aplastic Anemia: A Report of 3 Cases Associated With HAV

Aplastic anemia is a rare complication of viral hepatitis. We present 3 cases of hepatitis-associated aplastic anemia after hepatitis A virus infection. One of our cases is the first reported case of hepatitis-associated aplastic anemia after fulminant hepatitis A infection. Patient characteristics were consistent with older reports with regard to age and sex. All 3 patients were male individuals under the age of 20. In addition, all 3 patients had A+ blood group. Outcomes in our series were poor because of the unavailability of antithymocyte globulin and bone marrow transplantation.

Cynomolgus monkeys (Macaca fascicularis) experimentally and naturally infected with hepatitis E virus: The bone marrow as a possible new viral target

Hepatitis E virus (HEV) transmission through infected blood and blood products has already been described. However, little is known about the bone marrow (BM) as source of HEV infection. Our study aimed to investigate the presence of HEV antigen (Ag) and histological changes in BM of cynomolgus monkeys (Macaca fascicularis) experimentally and naturally infected with HEV. Four cynomolgus monkeys with acute, and two with chronic hepatitis E ─ after immunosuppressive therapy with tacrolimus ─ were compared with one colony-bred animal naturally infected. Both, natural and experimental infections were characterized by anti-HEV IgG seroconversion detected by ELISA, and viral RNA isolation confirmed by RT-qPCR and qualitative nested RT-PCR. BM biopsies were collected from all animals, submitted to histology and indirect immunofluorescence techniques and observed, respectively, by light and confocal microscopy. The HEV Ag-fluorescent-labeled cells were detected from BM biopsies obtained from three monkeys with acute and one with chronic hepatitis E, and also from the naturally infected monkey. In the experimentally infected animals with acute hepatitis, HEV Ag detection occurred at 160 days post-infection, even after viral clearance in serum, feces, and liver. Double-stranded RNA, a replicative marker, was detected in BM cells from both acute and chronically infected animals. Major histological findings included vacuolization in mononuclear and endosteal cells, an absence of organized inflammatory infiltrates, and also some fields suggesting displasic focal BM disease. These findings support the hypothesis of BM cells as secondary target sites of HEV persistence. Further experimental studies should be carried out to confirm the assumption of HEV transmission through BM transplantation.

Resolution of acute hepatitis B-associated aplastic anaemia with antiviral therapy

A previously healthy 44-year-old woman presented with 3 days of worsening petechial rash, epistaxis and fatigue. Admission labs revealed pancytopenia, low reticulocyte index and elevated liver enzymes. Bone marrow biopsy demonstrated a profoundly hypocellular bone marrow without dysplasia and additional testing demonstrated an acute hepatitis B infection. In the context of an acute hepatitis B infection, elevated liver enzymes and aplastic anaemia, our patient was diagnosed with severe hepatitis-associated aplastic anaemia due to an acute hepatitis B infection. She was initiated on antiviral therapy with tenofovir and briefly received immunosuppressive therapy with a robust sustained improvement in her blood counts. Acute hepatitis B-associated aplastic anaemia is an exceptionally rare presentation of aplastic anaemia. We present acute hepatitis B-associated aplastic anaemia that resolved with antiviral therapy, which to our knowledge is the second such case reported in the literature and the first using tenofovir.

Severe Aplastic Anemia following Parvovirus B19-Associated Acute Hepatitis

Human parvovirus (HPV) B19 is linked to a variety of clinical manifestations, such as erythema infectiosum, nonimmune hydrops fetalis, and transient aplastic anemia. Although a few cases have shown HPVB19 infection as a possible causative agent for hepatitis-associated aplastic anemia (HAAA) in immunocompetent patients, most reported cases of HAAA following transient hepatitis did not have delayed remission. Here we report a rare case of severe aplastic anemia following acute hepatitis with prolonged jaundice due to HPVB19 infection in a previously healthy young male. Clinical laboratory examination assessed marked liver injury and jaundice as well as peripheral pancytopenia, and bone marrow biopsy revealed severe hypoplasia and fatty replacement. HPVB19 infection was diagnosed by enzyme immunoassay with high titer of anti-HPVB19 immunoglobulin M antibodies. Immunosuppressive therapy was initiated 2 months after the onset of acute hepatitis when liver injury and jaundice were improved. Cyclosporine provided partial remission after 2 months of medication without bone marrow transplantation. Our case suggests that HPVB19 should be considered as a hepatotropic virus and a cause of acquired aplastic anemia, including HAAA.

Microbe-Induced Inflammatory Signals Triggering Acquired Bone Marrow Failure Syndromes

Acquired bone marrow failure syndromes encompass a unique set of disorders characterized by a reduction in the effective production of mature cells by the bone marrow (BM). In the majority of cases, these syndromes are the result of the immune-mediated destruction of hematopoietic stem cells or their progenitors at various stages of differentiation. Microbial infection has also been associated with hematopoietic stem cell injury and may lead to associated transient or persistent BM failure, and recent evidence has highlighted the potential impact of commensal microbes and their metabolites on hematopoiesis. We summarize the interactions between microorganisms and the host immune system and emphasize how they may impact the development of acquired BM failure.

Features of Hepatitis in Hepatitis-associated Aplastic Anemia: Clinical and Histopathologic Study

OBJECTIVES

Hepatitis-associated aplastic anemia (HAA) is a rare variant of aplastic anemia in which patients present with severe pancytopenia after an episode of acute hepatitis. The marrow failure is often rapid, severe, and usually fatal if untreated. The preceding hepatitis is largely under-studied.

METHODS

Retrospective study of the clinical and histopathologic features of hepatitis in pediatric patients who subsequently developed aplastic anemia and comparison with consecutive cases of acute liver failure and random cases of autoimmune hepatitis during the same time frame.

RESULTS

All 7 patients of HAA had significant elevations in aminotransferases and conjugated hyperbilirubinemia at initial presentation. Echoing liver function indices, cholestatic hepatitis with sinusoidal obstruction-type endothelial injury was seen histomorphologically. Autoimmune hepatitis serology such as anti-F-actin, anti-liver/kidney microsome, and hypergammaglobulinemia was negative in all patients. Five of 7 patients (71.4%) had, however, elevated antinuclear antibody, all with a speckled pattern. Hepatitis virus serology was negative in all patients. By immunohistochemical staining, the lobular CD8/CD4 lymphocyte ratio was markedly elevated in all of the initial samples with significant reduction in this ratio (P = 0.03) in 3 patients post treatment (ursodiol, antibiotics, and/or immunosuppressive therapy).

CONCLUSIONS

Hepatitis preceding HAA is characterized by marked elevation of aminotransferases, conjugated hyperbilirubinemia, elevated antinuclear antibody with a speckled pattern, cholestatic hepatitis with sinusoidal obstruction morphology, and CD8 dominant lobular infiltrates. The present study suggests HAA may result from cytotoxic T-cell-mediated sinusoidal endothelial and hepatocytic injury.

Aplastic anemia and dental implant rehabilitation: a clinical trial

The purpose of this study was to investigate implant-supported restoration as a technique for restoring missing teeth in patients with aplastic anemia. Recurrent bleeding from wound sites leads to persistent release of iron in the tissue. Excessive iron in tissue is related to clinical findings, including fibrosis, poor wound healing, and high level of angiogenesis, which are possible etiological factors of reduced osseointegration. A 44-year-old female patient with aplastic anemia was treated with multiple endosseous implants throughout the mandible and in the posterior region of the maxilla. After 14 implants were placed, radiological and clinical parameters were assessed during the follow-up period. Marginal bone did not change significantly during the follow-up period. The fine trabecular bone in intimate contact and enclosing the implant fixture was sufficient for successful osseointegration. None of the 14 implants were associated with compilations during the seven-year experimental period. This study suggests that dental implant procedures are a safe and reliable treatment option for restoration of missing dentition in patients with aplastic anemia.

Human anelloviruses: an update of molecular, epidemiological and clinical aspects

Human torque teno viruses (TTVs) are new, emerging infectious agents, recently assigned to the family Anelloviridae. The first representative of the genus, torque teno virus (TTV), was discovered in 1997, followed by torque teno mini virus (TTMV) in 2000, and torque teno midi virus (TTMDV) in 2007. These viruses are characterized by an extremely high prevalence, with relatively uniform distribution worldwide and a high level of genomic heterogeneity, as well as an apparent pan-tropism at the host level. Although these viruses have a very high prevalence in the general population across the globe, neither their interaction with their hosts nor their direct involvement in the etiology of specific diseases are fully understood. Since their discovery, human anelloviruses, and especially TTV, have been suggested to be associated with various diseases, such as hepatitis, respiratory diseases, cancer, hematological and autoimmune disorders, with few arguments for their direct involvement. Recent studies have started to reveal interactions between TTVs and the host's immune system, leading to new hypotheses for potential pathological mechanisms of these viruses. In this review article, we discuss the most important aspects and current status of human TTVs in order to guide future studies.

Successful treatment of a 3-year-old boy with hepatitis-associated aplastic anemia with combination of auto-umbilical cord blood transplantation and immunosuppressive therapy

In this work we describe a 3-year-old boy with hepatitis-associated aplastic anemia (HAAA) treated successfully with autologous cord blood transplantation combined with immunosuppressive therapy. There is little previous experience in the utility of autologous cord blood transplantation in the treatment of HAAA. Nowadays, for patients born after 1980, an HLA matched sibling donor is not usually available because of the family planning policy in our country. So more and more parents choose to preserve the umbilical cord blood for their children. We consider it a new effective choice for the treatment of HAAA, especially for the pediatric patients.

Severe Aplastic Anemia following Acute Hepatitis from Toxic Liver Injury: Literature Review and Case Report of a Successful Outcome

Hepatitis associated aplastic anemia (HAAA) is a rare syndrome in which severe aplastic anemia (SAA) complicates the recovery of acute hepatitis (AH). HAAA is described to occur with AH caused by viral infections and also with idiopathic cases of AH and no clear etiology of liver injury. Clinically, AH can be mild to fulminant and transient to persistent and precedes the onset SAA. It is assumed that immunologic dysregulation following AH leads to the development of SAA. Several observations have been made to elucidate the immune mediated injury mechanisms, ensuing from liver injury and progressing to trigger bone marrow failure with the involvement of activated lymphocytes and severe T-cell imbalance. HAAA has a very poor outcome and often requires bone marrow transplant (BMT). The findings of immune related myeloid injury implied the use of immunosuppressive therapy (IST) and led to improved survival from HAAA. We report a case of young male who presented with AH resulting from the intake of muscle building protein supplements and anabolic steroids. The liver injury slowly resolved with supportive care and after 4 months of attack of AH, he developed SAA. He was treated with IST with successful outcome without the need for a BMT.

Up-regulation of the monocyte chemotactic protein-3 in sera from bone marrow transplanted children with torquetenovirus infection

BACKGROUND

Torquetenovirus (TTV) represents a commensal human virus producing life-long viremia in approximately 80% of healthy individuals of all ages. A potential pathogenic role for TTV has been suggested in immunocompromised patients with hepatitis of unknown etiology sustained by strong proinflammatory cytokines.

OBJECTIVES

The aim of this study was to investigate the sera immunological profile linked to TTV infection in bone marrow transplant (BMT) children with liver injury.

STUDY DESIGN

TTV infection was assessed in sera from 27 BMT patients with altered hepatic parameters and histological features, by the use of quantitative real-time PCR, along with TTV genogroups and coinfection with HEV. The qualitative and quantitative nature of soluble inflammatory factors was evaluated studying a large set of cytokines using the Bioplex platform. As controls, sera from 22 healthy children negative for serological and molecular hepatitis markers including TTV and HEV, and for autoimmune diseases, were selected.

RESULTS AND CONCLUSIONS

TTV was detected in 81.4% of BMT patients with a viral load ranging from 10(5) to 10(9) copies/mL. All samples were HEV-RNA negative. A pattern of cytokines, IFN-γ, TNF-α, FGF-basic (p<0.01) and MCP-3 (p<0.001) was found significantly highly expressed in TTV-positive patients compared to TTV-negative and controls. Of note, MCP-3 chemokine showed the highest sera concentration independently of the amount of TTV load and the status of immune system deregulation (p<0.001). In this pilot study for the first time, a positive association was found between TTV and increased level of MCP-3 suggesting a indirect role of TTV in liver injury.

The clinical and immune characteristics of patients with hepatitis-associated aplastic anemia in China

Hepatitis-associated aplastic anemia (HAAA) is a variant of severe aplastic anemia (SAA) in which bone marrow failure follows an acute attack of hepatitis. Its pathogenesis is poorly understood. We investigated the prevalence of HAAA among cases of newly diagnosed SAA presenting to our hospital between January 1998 and February 2013, and analyzed the clinical and immune characteristics of HAAA and non-hepatitis-associated SAA (non-HASAA) patients. The prevalence of HAAA among cases of SAA was 3.8% (36/949), and the majority of patients (33/36) were seronegative for a known hepatitis virus. Compared with non-HASAA patients, HAAA patients had a larger proportion of CD8+ T cells, a lower ratio of CD4+/CD8+ T cells, and a smaller proportion of CD4+CD25+ regulatory T cells. There was no significant difference in peripheral blood count, bone marrow cellularity, or the number of blood transfusions received between HAAA and non-HASAA patients. HAAA patients had a higher early infection rate and more infection-related mortality in the first 2 years after diagnosis than non-HASAA patients, and their 2-year survival rate was lower. The results demonstrate that HAAA patients have a more severe T cell imbalance and a poorer prognosis than non-HASAA patients.

A marked decrease in CD4-positive lymphocytes at the onset of hepatitis in a patient with hepatitis-associated aplastic anemia

A 10-year-old Japanese boy developed acute hepatitis with high levels of serum Torque teno virus DNA and marked lymphocytopenia, especially CD4 T-lymphocytopenia. Although the total lymphocyte counts rose as the patient recovered from hepatitis, this was largely because of a marked rise in CD8 cells. In contrast, CD4 cells recovered poorly, resulting in a further striking fall in the CD4/8 ratio. Two months later, the patient developed hepatitis-associated aplastic anemia. He was successfully treated with immunosuppressive therapy, which normalized the lymphocyte subset proportions. T-cell subsets analysis at the onset of hepatitis might be useful for predicting development of hepatitis-associated aplastic anemia.

Bilateral macular haemorrhages secondary to hepatitis-associated aplastic anaemia, treated with Nd:YAG laser posterior hyaloidotomy

Hepatitis-associated aplastic anaemia (HAAA) is an uncommon but distinct variant of aplastic anaemia in which pancytopenia and bone marrow failure appears 2-3 months after an acute attack of hepatitis. Although bilateral vision loss may rarely be the initial presentation of aplastic anaemia, no such report is known in HAAA. Here the authors report such a case presenting with large premacular subhyaloid haemorrhages secondary to severe anaemia and thrombocytopenia. Anaemic hypoxic damage to the vessel wall together with increased cardiac output and low platelet counts are interacting causal factors in the development of bleeding. Though these haemorrhages are benign and usually improve spontaneously, the presence of blood may cause permanent macular changes before it resolves. Posterior hyaloidotomy enabled rapid resolution of premacular subhyaloid haemorrhage thereby restoring vision and preventing need for vitreo-retinal surgery. These patients should be advised to refrain from valsalva manoeuvres, ocular rubbing and vigorous exercise to prevent ocular morbidity.

Hepatitis associated aplastic anemia: a review

Hepatitis-associated aplastic anemia (HAAA) is an uncommon but distinct variant of aplastic anemia in which pancytopenia appears two to three months after an acute attack of hepatitis. HAAA occurs most frequently in young male children and is lethal if leave untreated. The etiology of this syndrome is proposed to be attributed to various hepatitis and non hepatitis viruses. Several hepatitis viruses such as HAV, HBV, HCV, HDV, HEV and HGV have been associated with this set of symptoms. Viruses other than the hepatitis viruses such as parvovirus B19, Cytomegalovirus, Epstein bar virus, Transfusion Transmitted virus (TTV) and non-A-E hepatitis virus (unknown viruses) has also been documented to develop the syndrome. Considerable evidences including the clinical features, severe imbalance of the T cell immune system and effective response to immunosuppressive therapy strongly present HAAA as an immune mediated mechanism. However, no association of HAAA has been found with blood transfusions, drugs and toxins. Besides hepatitis and non hepatitis viruses and immunopathogenesis phenomenon as causative agents of the disorder, telomerase mutation, a genetic factor has also been predisposed for the development of aplastic anemia. Diagnosis includes clinical manifestations, blood profiling, viral serological markers testing, immune functioning and bone marrow hypocellularity examination. Patients presenting the features of HAAA have been mostly treated with bone marrow or hematopoietic cell transplantation from HLA matched donor, and if not available then by immunosuppressive therapy. New therapeutic approaches involve the administration of steroids especially the glucocorticoids to augment the immunosuppressive therapy response. Pancytopenia following an episode of acute hepatitis response better to hematopoietic cell transplantation than immunosuppressive therapy.

Hepatitis-associated aplastic anemia during a primary infection of genotype 1a torque teno virus

A 12-year-old Japanese boy suffered from severe acute hepatitis and pancytopenia. The patient underwent successful bone marrow transplantation from an HLA-identical sister. Torque teno virus (TTV) DNA of genotype 1a and IgM-class antibody against the virus were detected in sera at the onset of hepatitis. TTV/1a DNA and anti-TTV/1a IgM antibody levels were undetectable on the 16th and 46th days after the onset of illness, respectively. Anti-TTV/1a IgG antibody was positive throughout the observation period. Sequential viral load and anti-TTV/1a IgM antibody suggested a primary infection of TTV/1a. Genomic sequence of the virus coincided with that of the original strain first isolated from human. TTV DNA was quantified at 130 copies in 10(5) bone marrow mononuclear cells, which suggested that infection of hematopoietic cells might be the cause of aplasia. This is the first report of TTV hepatitis-associated aplastic anemia assessed by the anti-TTV antibodies and viral load in peripheral blood and bone marrow.

Aplastica anemia and viral hepatitis

Acquired aplastic anemia (aAA) is a severe and rare disease, characterized by hematopoietic bone marrow failure and peripheral cytopenia. The pathophysiology is immune mediated in most cases, activated T1 lymphocytes have been identified as effector cells. The disease can be successfully treated with combined immunosuppressive therapy or allogeneic hematopoietic stem cell transplantation. Hepatitis-associated aplastic anemia (HAA) is a syndrome of bone marrow failure following the development of acute seronegative hepatitis. HAA syndrome most often affects young males who presented severe pancytopenia two to three months after an episode of acute hepatitis. The clinical course of hepatitis is more frequently benign but a fulminant severe course is also described. The bone marrow failure can be explosive and severe and it is usually fatal if untreated, no correlations have been observed between severity of hepatitis and AA. In none of the studies a specific virus could be identified and most cases are seronegative for known hepatitis viruses. The clinical characteristics and response to immunotherapy indicate a central role for immune-mediated mechanism in the pathogenesis of HAA. The initial target organ of the immune response is the liver as suggested by the time interval between hepatitis and the onset of bone marrow failure. Liver histology is characterized by T cell infiltrating the parenchyma as reported in acute hepatitis. Recently in HAA it has been demonstrated intrahepatic and blood lymphocytes with T cell repertoire similar to that of confirmed viral acute hepatitis. The expanded T cell clones return to a normal distribution after response to immunosuppressive treatment, suggesting the antigen or T cell clearance. Therapeutic options are the same as acquired aplastic anemia.

A hospital-based case control study of aplastic anemia in Shanghai, China

We report results of a hospital-based case control study of 137 consecutive patients diagnosed with aplastic anemia (AA) in participating hospitals over a 4-year period. Diagnoses were made by a single laboratory, subjects were age- and gender-matched to two controls and interviewed concerning previous disease, work histories and exposures to potential etiologic agents. Analysis was conducted on two distinct subgroups: severe aplastic anemia (SAA) and moderate aplastic anemia (MAA). In univariate regression models, the strongest associations were observed for exposure to benzene and SAA (OR=3.12, 95% CI=1.12-8.65) and life on a farm and MAA (OR=3.08, 95% CI=1.44-6.56). Benzene exposure did not show a strong dose-response relationship with either subtype. When accounting for all of the potential confounders we considered in conditional regression models, the previous relationships persisted. Other explanatory variables included hair-dye use for MAA and farm exposures, such as livestock for SAA, although most of these additional variables fell just short of statistical significance. Adjusted R-squared values were only 10% for each subtype, leaving 90% of AA occurrence unexplained. Our results suggest that: (a) benzene exposure is more strongly related to SAA than MAA, (b) farm and livestock exposures are related to both forms of AA, confirming some previous results, and (c) a large percentage of AA remains unexplained, which may indicate that individual susceptibility has a major influence on AA occurrence.

Aplastic anaemia in childhood. Description of two cases and review of the literature

Childhood aplastic anaemia (AA) is an uncommon but potentially fatal haematological disorder. Patients with AA receive supportive care based on transfusions and timely treatment of opportunistic infections, along with specific therapies, which may be bone marrow transplantation and immunosuppressive therapy. Early diagnosis and supportive therapy are required to prevent fatal complications like overwhelming sepsis or life threatening haemorrhages. We report two cases of aplastic anaemia having a different aetiology. The diagnostic work-up and the therapeutic management for each case are described below.

Systematic review: hepatitis-associated aplastic anaemia--a syndrome associated with abnormal immunological function

BACKGROUND

Hepatitis-associated aplastic anaemia is a syndrome in which marrow failure follows the development of hepatitis.

AIM

To review systematically the aetiology, immunopathogenesis, clinical presentation, diagnosis and treatment of hepatitis-associated aplastic anaemia.

METHODS

Literature searches were undertaken on the MEDLINE electronic database up to December 2008. Twenty-four relevant studies were identified. The clinical and laboratory characteristics of the patients were analysed and reviewed.

RESULTS

Hepatitis-associated aplastic anemia is a variant of acquired aplastic anemia in which an episode of hepatitis precedes the onset of aplastic anemia. The hepatitis may be acute and severe, even fulminant; it may be self-limiting or chronic. The pathology is often not attributable to a recognized cause of viral hepatitis. The syndrome occurs in 28 percent of young adults after liver transplantation for non-A, non-B, non-C hepatitis. Several features of the syndrome suggest that the marrow aplasia is mediated by immunological mechanisms, possibly mediated by gamma interferon or the cytokine cascade. Survival of patients treated with hematopoietic cell transplantation has been 82%, and the response rate to immunosuppressive therapy 70%.

CONCLUSIONS

Hepatitis-associated bone marrow aplasia is mediated by immunological mechanisms. Treatment options include hematopoietic cell transplantation and immunosuppressive therapy.

History of discoveries and pathogenicity of TT viruses

Since 1997, groups of novel nonenveloped DNA viruses with a circular, single-stranded (negative sense) DNA genome of 3.6-3.9 kb, 3.2 kb, or 2.8-2.9 kb in size have been discovered and designated Torque teno virus (TTV), Torque teno midi virus (TTMDV), and Torque teno mini virus (TTMV), respectively, in the floating genus Anellovirus. These three anelloviruses frequently and ubiquitously infect humans, and the infections are characterized by lifelong viremia and great genetic variability. Although TTV infection has been epidemiologically suggested to be associated with many diseases including liver diseases, respiratory disorders, hematological disorders, and cancer, there is no direct causal evidence for links between TTV infection and specific clinical diseases. The pathogenetic role of TTMV and TTMDV infections remains unknown. The changing ratio of the three anelloviruses to each other over time, relative viral load, or combination of different genotype(s) of each anellovirus may be associated with the pathogenicity or the disease-inducing potential of these three human anelloviruses. To clarify their disease association, polymerase chain reaction (PCR) systems for accurately detecting, differentiating, and quantitating all of the genotypes and/or genogroups of TTV, TTMDV, and TTMV should be established and standardized, as should methods to detect past infections and immunological responses to anellovirus infections.

Recurrence of hepatitis-associated aplastic anemia after a 10-year interval

Hepatitis-associated aplastic anemia (HAA) has been reported to show a successful outcome following immunosuppressive treatment. On the other hand, the long-term prognosis of HAA has not been sufficiently clarified. Herein we report a patient with HAA who had been treated with cyclosporine for one year, and maintained complete remission without treatment. Ten years later, acute non-A, non-B, and non-C hepatitis reccurred followed by bone marrow aplasia. A second immunosuppressive treatment with antithymocyte globulin and cyclosporine was effective. This case might provide useful information for the long-term follow-up of patients with HAA.

Treatment of hepatitis-associated aplastic anemia with high-dose cyclophosphamide

OBJECTIVE

Demonstrate that high-dose cyclophosphamide (CY) is effective therapy for hepatitis-associated aplastic anemia (HAA).

BACKGROUND

HAA is a sequence of seronegative hepatitis followed by aplastic anemia. Optimal treatment is matched-sibling allogeneic bone marrow transplantation (BMT). The combination of antithymocyte globulin (ATG) and cyclosporine (CSA) has also been studied, but there are scarce data regarding treatment of HAA.

PROCEDURE

Five patients (median age 14 years; range 6-17 years) with HAA and without an HLA-matched sibling were treated with high-dose CY (50 mg/kg/day IV x 4 days) followed by granulocyte-colony stimulation factor (G-CSF).

RESULTS

After at least 1 year of follow-up, four of five patients are in remission without further immune suppression beyond high-dose CY. Of the 4 responders, median time to absolute neutrophil count (ANC) >500 microl(-1) was 51 days (range 44-369). Median time to transfusion independence for erythrocytes and platelets was 109 (range 57-679) and 160 (range 48-679) days, respectively. The fifth patient did not respond and proceeded to an unrelated donor transplant. One patient met criteria for autoimmune hepatitis (AIH) in addition to HAA. In this case, high-dose CY successfully induced remission of both diseases.

CONCLUSIONS

High-dose CY induces durable remissions in HAA and may be an effective treatment for AIH.

Acquired aplastic anaemia in seven children with severe hepatitis with or without liver failure

AIM

Aplastic anaemia following hepatitis may develop in as many as 1 of 3 patients with non-A, non-B and non-C hepatitis. Several causative factors have been discussed, such as viral infections and autoimmunity. Here we describe the natural history of this condition in 7 children and investigate possible hepatitis-causing agents.

METHODS

We reviewed the medical records, bone marrow and liver biopsies of 7 children with severe hepatitis, with or without liver failure, who subsequently had developed aplastic anaemia.

RESULTS

The median time from onset of hepatic symptoms until diagnosed onset of aplasia was 54 days. No associated viral infections could be identified. On liver biopsy, a majority had lobular inflammation but lacked signs of autoimmune hepatitis, findings compatible with a viral aetiology. Three of 6 children had low reticulocyte counts already at onset of hepatitis. All, but one patient is alive at median follow-up of 8 years.

CONCLUSION

The unknown pathogenetic mechanism appears to target liver and bone marrow simultaneously, because half of the children concomitantly had low reticulocyte counts and severe liver failure.

Immune-mediated hepatitis-associated aplastic anemia caused by the emergence of a mutant hepatitis B virus undetectable by standard assays

Hepatitis-associated aplastic anemia (HAA) is characterized by marrow failure developing after acute seronegative hepatitis. A patient with agammaglobulinemia developed HAA in association with HBsAg-negative, hepatitis B virus (HBV) DNA-positive acute hepatitis. Sequence analysis showed several substitutions in the major antigenic determinant of HBsAg, potentially affecting the detection by diagnostic immunoassays. Viral mutants may therefore be implicated as etiologic agents of HBsAg-negative HAA. HBV DNA determination may be necessary to exclude mutant HBV as a cause of HAA, particularly in categories at high risk of mutant selection such as agammaglobulinemic and transplanted patients.

Lamivudine reverses severe acute hepatitis B and pancytopenia after renal transplantation: a case report

Pancytopenia is rare after acute hepatitis B infection. The use of lamivudine in the treatment of acute hepatitis B-associated pancytopenia in renal transplant recipients has not been documented. Herein we reported a 21-year-old woman who was infected with acute hepatitis B 6 months after renal transplantation, a condition complicated by pancytopenia. Lamivudine reversed the acute hepatitis in 1 month and the pancytopenia after 3 months, without a change in renal function. Lamivudine was maintained for 2 years without a hepatitis flare-up after 4 years.

The epidemiology of aplastic anemia in Thailand

Aplastic anemia has been linked to environmental exposures, from chemicals and medical drugs to infectious agents. The disease occurs more frequently in Asia than in the West, with incidence rates 2- to 3-fold higher. We report updated results of an epidemiologic study conducted in Thailand from 1989 to 2002, in which 541 patients and 2261 controls were enrolled. Exposures were determined by in-person interview. We observed significantly elevated relative risk estimates for benzene (3.5) and other solvents (2.0) and for sulfonamides (5.6), thiazides (3.8), and mebendazole (3.0). Chloramphenicol use was infrequent, and no significant association was observed. Agricultural pesticides were implicated in Khonkaen (northeastern Thailand). There were significant associations with organophosphates (2.1), DDT (6.7), and carbamates (7.4). We found significant risks for farmers exposed to ducks and geese (3.7) and a borderline association with animal fertilizer (2.1). There was a significant association in Khonkaen with drinking other than bottled or distilled water (2.8). Nonmedical needle exposure was associated in Bangkok and Khonkaen combined (3.8). Most striking was the large etiologic fraction in a rural region accounted for by animal exposures and drinking of water from sources such as wells, rural taps, and rainwater, consistent with an infectious etiology for many cases of aplastic anemia in Thailand.

Hepatitis-associated aplastic anaemia treated successfully with antilymphocyte globulin

Aplastic anaemia may occur following an acute attack of hepatitis. This is a rare condition, which if not recognized and promptly treated, may be fatal. Antilymphocyte globulin and allogeneic bone marrow transplantation have been used in the treatment of this condition. We report the case of a young man who developed severe aplastic anaemia following nonviral hepatitis.

Immune Pathophysiology of Aplastic Anemia

Acquired aplastic anemia (AA) is considered an immune-mediated disease because approximately 70% of AA patients improve with immunosuppressive therapy. However, little is known about the inciting antigens or the mechanisms responsible for the destruction of hematopoietic stem cells by immune system attack. Recent advances in immunologic techniques have promoted our understanding of the pathogenesis of AA and have provided evidence that AA is an organ-specific T-cell-mediated disease localized in the bone marrow. Moreover, antibody screening of patients' serum with a complementary DNA library derived from hematopoietic cells has identified several proteins as candidate autoantigens in AA.

Mutation of chicken anemia virus VP2 differentially affects serine/threonine and tyrosine protein phosphatase activities

Novel dual-specificity protein phosphatases (DSPs), which catalyse the removal of phosphate from both phosphotyrosine and phosphoserine/phosphothreonine substrates, have recently been identified in two viruses within the familyCircoviridae. Viral protein 2 (VP2) of chicken anemia virus (CAV) and ORF2 of TT virus have been shown to possess DSP activityin vitro. CAV VP2 is unusual in possessing two vicinal cysteines within the protein phosphatase signature motif. The first cysteine residue (C95) within the motif has been identified by mutagenesis as the essential catalytic cysteine. In this study, it was shown that virus mutated at this residue displayed a marked inhibition of growth, with titres reduced 104-fold, and reduced cytopathogenic effect in cell culture, indicating that viral DSP activity may be significant during infection. As with virus mutated at the first cysteine residue, mutation of the second cysteine (C97) within the motif resulted in a marked reduction in viral growth and attenuation of cytopathogenicity in infected cell cultures. However, mutagenesis of this second cysteine only reduced phosphotyrosine phosphatase activity to 70 % of that of wild-type VP2, but increased phosphoserine/phosphothreonine phosphatase activity by as much as 700 %. The differential effect of the C97S mutation on VP2 activity does not appear to have parallels in other DSPs and suggests a unique role for the second cysteine in the function of these viral proteins, particularlyin vivo.

Analysis of T-cell repertoire in hepatitis-associated aplastic anemia

Hepatitis-associated aplastic anemia (HAA) is a syndrome of bone marrow failure following an acute attack of seronegative hepatitis. Clinical features and liver histology suggest a central role for an immune-mediated mechanism. To characterize the immune response, we investigated the T-cell repertoire (T-cell receptor [TCR] Vβ chain subfamily) of intrahepatic lymphocytes in HAA patients by TCR spectratyping. In 6 of 7 HAA liver samples, a broad skewing pattern in the 21 Vβ subfamilies tested was observed. In total, 62% ± 18% of HAA spectratypes showed a skewed pattern, similar to 68% ± 18% skewed spectratype patterns in 3 of 4 patients with confirmed viral hepatitis. Additionally, the T-cell repertoire had similarly low levels of complexity. In the peripheral blood lymphocytes (PBLs) of a separate group of HAA patients prior to treatment, 60% ± 15% skewed spectratypes were detected, compared with only 18% ± 8% skewed spectratypes in healthy controls. After successful immunosuppressive treatment, an apparent reversion to a normal T-cell repertoire with a corresponding significant increase in T-cell repertoire complexity was observed in the HAA samples. In conclusion, our data suggest an antigen-driven T-cell expansion in HAA and achievement of a normal T-cell repertoire during recovery from HAA. (Blood. 2004;103:4588-4593)