Immunological Aspects of Kabuki Syndrome: A Retrospective Multicenter Study of the Italian Primary Immunodeficiency Network (IPINet)

Kabuki Syndrome (KS) is a multisystemic genetic disorder. A portion of patients has immunological manifestations characterized by increased susceptibility to infections and autoimmunity. Aiming to describe the clinical and laboratory immunological aspects of KS, we conducted a retrospective multicenter observational study on patients with KS treated in centers affiliated to the Italian Primary Immunodeficiency Network.Thirty-nine patients were enrolled, with a median age at evaluation of 10 years (range: 3 m-21y). All individuals had organ malformations of variable severity. Congenital heart defect (CHD) was present in 19/39 patients (49%) and required surgical correction in 9/39 (23%), with associated thymectomy in 7/39 (18%). Autoimmune cytopenia occurred in 6/39 patients (15%) and was significantly correlated with thymectomy (p < 0.002), but not CHD. Individuals with cytopenia treated with mycophenolate as long-term immunomodulatory treatment (n = 4) showed complete response. Increased susceptibility to infections was observed in 22/32 patients (69%). IgG, IgA, and IgM were low in 13/29 (45%), 13/30 (43%) and 4/29 (14%) patients, respectively. Immunoglobulin substitution was required in three patients. Lymphocyte subsets were normal in all patients except for reduced naïve T-cells in 3/15 patients (20%) and reduced memory switched B-cells in 3/17 patients (18%). Elevated CD3 + TCRαβ + CD4-CD8-T-cells were present in 5/17 individuals (23%) and were correlated with hematological and overall autoimmunity (p < 0.05).In conclusion, immunological manifestations of KS in our cohort include susceptibility to infections, antibody deficiency, and autoimmunity. Autoimmune cytopenia is correlated with thymectomy and elevated CD3 + TCRαβ + CD4-CD8-T-cells, and benefits from treatment with mycophenolate.

Mesenchymal Stem Cell-Derived Exosomes and Their Potential Agents in Hematological Diseases

Mesenchymal stem cells (MSCs) are the most exploited stem cells with multilineage differentiation potential and immunomodulatory properties. Numerous lines of findings have reported their successful applications in a multitude of inflammatory conditions and immune disorders. However, it is currently discovered that these effects are mainly mediated in a paracrine manner by MSC-exosomes. Moreover, MSC-exosomes have been implicated in a wide variety of biological responses including immunomodulation, oxidative stress, tumor progression, and tissue regeneration. Meanwhile, they are reported to actively participate in various hematological diseases by the means of transferring different types of exosomal components to the target cells. Therefore, in this review, we briefly discuss the sources and biological features of MSCs and then illustrate the biogenesis and biological processes of MSC-exosomes. Of note, this paper especially highlights the latest research progress of MSC-exosomes in hematological diseases.

The rheumatology/hematology interface: CAPS and MAS diagnosis and management

Catastrophic antiphospholipid antibody syndrome (CAPS) and macrophage activation syndrome (MAS) are both life-threatening hematologic disorders that infrequently afflict patients with rheumatologic disease. CAPS is characterized by fulminant multiorgan damage related to small vessel thrombosis in the setting of persistent antiphospholipid antibodies. It can occur in patients with rheumatologic diseases such as systemic lupus erythematosus but can also affect patients who do not have rheumatologic disease. By contrast, the term MAS is applied when patients with rheumatologic disease develop hemophagocytic lymphohistiocytosis (HLH); therefore, patients with MAS have an underlying rheumatologic disease by definition. Similar to CAPS, HLH/MAS can have a fulminant presentation, but the pathogenesis and manifestations are different. In both CAPS and MAS, management generally includes but is not limited to immunosuppression with steroids. Fatalities are relatively common and morbidity is often significant. Early recognition of these disorders and initiation of timely treatment are important. More effective therapies for both syndromes are urgently needed.

Defining success with cellular therapeutics: the current landscape for clinical end point and toxicity analysis

Cellular therapies play a major and expanding role in the treatment of hematologic diseases. For each of these therapies, a narrow therapeutic window exists, where efficacy is maximized and toxicities minimized. This review focuses on one of the most established cellular therapies, hematopoietic stem cell transplant, and one of the newest cellular therapies, chimeric antigen receptor-T cells. In this review, I will discuss the current state of the field for clinical end point analysis with each of these therapeutics, including their critical toxicities, and focus on the major elements of success for each of these complex treatments for hematologic disease.

Molecular characterization and multidisciplinary management of Gerbich hemolytic disease of the newborn

Gerbich (Ge) antigens are high frequency red cell antigens expressed on glycophorin C (GYPC) and glycophorin D. Hemolytic disease of the fetus and newborn (HDFN) due to Gerbich antibody is rare and presents a clinical challenge, as Gerbich negative blood is scarce. We report a case of HDFN due to maternal Ge3 negative phenotype and anti-Ge3 alloimmunization, successfully managed by transfusion of maternal blood. Molecular testing revealed that the mother has homozygous deletion of exon 3 of GYPC, the father is homozygous wildtype for GYPC, and the infant is obligate heterozygote expressing Ge3.

Dose-Dependent Effect of Granulocyte Transfusions in Hematological Patients with Febrile Neutropenia

It is still under debate whether granulocyte transfusions (GTs) substantially increase survival in patients with febrile neutropenia. We retrospectively examined data relative to 96 patients with hematological malignancies receiving 491 GTs during 114 infectious episodes (IE). Patients were grouped according to the median doses of granulocytes transfused during the infectious episode (low-dose group: <1.5-x10⁸ cells/Kg; standard-dose group: 1.5–3.0x10⁸ cells/Kg and high-dose group: >3.0x10⁸ cells/Kg). The impact of clinical, microbiological and GT-related variables on the infection-related mortality (IRM) was investigated. The IRM was not influenced by the number of GTs or by the total amount of granulocytes received, whereas a dose-related effect of the median dose received for IE was detected at univariate analysis (IRM of 18.4% in the standard-dose group, 44.4% in the low-dose group and 48.4% in the high-dose group, p = 0.040) and confirmed at multivariate analysis (OR 3.7, IC 95% 1.5–8.9; 0.004 for patients not receiving standard doses of GTs). Moreover, patients receiving GTs at doses lower or greater than standard had increased risk for subsequent ICU admission and reduced overall survival. The dose-related effect of GTs was confirmed in bacterial but not in fungal infections. Preliminary findings obtained from a subgroup of patients candidate to GTs revealed that levels of inflammatory response mediators increase in a dose-related manner after GTs, providing a possible explanation for the detrimental effect exerted by high-dose transfusions. GTs can constitute a valuable tool to improve the outcome of infections in neutropenic patients, provided that adequate recipient-tailored doses are supplied. Further investigations of the immunomodulatory effects of GTs are recommended.

Nonredundant Roles of Interleukin-17A (IL-17A) and IL-22 in Murine Host Defense against Cutaneous and Hematogenous Infection Due to Methicillin-Resistant Staphylococcus aureus

Staphylococcus aureus is the leading cause of skin and skin structure infections (SSSI) in humans. Moreover, the high frequency of recurring SSSI due to S. aureus, particularly methicillin-resistant S. aureus (MRSA) strains, suggests that infection induces suboptimal anamnestic defenses. The present study addresses the hypothesis that interleukin-17A (IL-17A) and IL-22 play distinct roles in immunity to cutaneous and invasive MRSA infection in a mouse model of SSSI. Mice were treated with specific neutralizing antibodies against IL-17A and/or IL-22 and infected with MRSA, after which the severity of infection and host immune response were determined. Neutralization of either IL-17A or IL-22 reduced T cell and neutrophil infiltration and host defense peptide elaboration in lesions. These events corresponded with increased abscess severity, MRSA viability, and CFU density in skin. Interestingly, combined inhibition of IL-17A and IL-22 did not worsen abscesses but did increase gamma interferon (IFN-γ) expression at these sites. The inhibition of IL-22 led to a reduction in IL-17A expression, but not vice versa. These results suggest that the expression of IL-17A is at least partially dependent on IL-22 in this model. Inhibition of IL-17A but not IL-22 led to hematogenous dissemination to kidneys, which correlated with decreased T cell infiltration in renal tissue. Collectively, these findings indicate that IL-17A and IL-22 have complementary but nonredundant roles in host defense against cutaneous versus hematogenous infection. These insights may support targeted immune enhancement or other novel approaches to address the challenge of MRSA infection.

Immunologic and Hematological Abnormalities in Necrotizing Enterocolitis

Necrotizing enterocolitis (NEC) is a leading cause of mortality in preterm infants. This article reviews the immunologic and hematological abnormalities typically seen in infants with NEC, such as elevated plasma cytokine levels, thrombocytopenia, increased or decreased neutrophil counts, low monocyte counts, and anemia. Some of these findings may provide important diagnostic and prognostic information.

Anti-HLA antibody testing in hematology patients

Anti-human leukocyte antigens (HLA) antibodies can adversely impact the care of hematology patients. In particular, HLA antibody testing provides important information for optimal stem cell and platelet donor selection in the management of stem cell recipients and platelet refractory patients. Current testing methods for HLA antibodies are briefly reviewed, with particular emphasis on laboratory and clinical issues associated with solid-phase multiplex assays.

[Integration of Internal and Clinical Laboratory Medicine]

The mission of our department is to contribute to diagnostic improvement in medicine in order to promote better outcomes. We have clinical expertise in internal medicine including primary care medicine, hematology, allergy, rheumatology, and nephrology. We also have expertise in clinical laboratory medicine and hospital infection control. Specific areas of academic interest include immune-mediated hematological diseases, allergic diseases, autoimmune diseases, and chronic kidney disease. Immune recovery following hematopoietic stem cell transplantation and the immunopathophysiology of bone marrow failure syndrome have been our main topics of interest, and we have been applying our knowledge of T-cell receptor diversity to these areas in order to explore the mechanisms of immunodeficiency and autoimmunity in hematological disorders. We have found that the peripheral expansion of mature T cells in grafts plays an important role in immune reconstitution after stem cell transplantation in humans, and have also found altered T-cell repertoires in immune-mediated chronic acquired pure red cell aplasia. Thus, quantitative and qualitative analyses of immune receptors could be a promising method for assessing immunocompetence and exploring the pathophysiology of autoimmune diseases. Research and development of novel approaches in this field should be intensively conducted.

Transfusion-related adverse events in the Platelet Dose study

BACKGROUND

How platelet (PLT) product characteristics such as dose, source (whole blood derived [WBD] vs. apheresis), storage duration, and ABO matching status affect the risks of transfusion-related adverse events (TRAEs) is unclear. Similarly, more information is needed to define how recipient characteristics affect the frequency of TRAEs after PLT transfusion.

STUDY DESIGN AND METHODS

In the multicenter Platelet Dose ("PLADO") study, pediatric and adult hematology-oncology patients with hypoproliferative thrombocytopenia were randomized to receive low-dose (LD), medium-dose (MD), or high-dose (HD) PLT prophylaxis for a pretransfusion PLT count of not more than 10 × 10(9) /L. All PLT units (apheresis or WBD) were leukoreduced. Post hoc analyses of PLADO data were performed using multipredictor models.

RESULTS

A total of 5034 PLT transfusions to 1102 patients were analyzed. A TRAE occurred with 501 PLT transfusions (10.0%). The most common TRAEs were fever (6.6% of transfusions), allergic or hypersensitivity reactions (1.9%), and sinus tachycardia (1.8%). Patients assigned HD PLTs were more likely than LD or MD patients to experience any TRAE (odds ratio for HD vs. MD, 1.50; 95% confidence interval, 1.10-2.05; three-group comparison p = 0.02). PLT source and ABO matching status were not significantly related to overall TRAE risk. Compared to a patient's first PLT transfusion, subsequent PLT transfusions were less likely to have a TRAE reported, primarily due to a lower risk of allergic or hypersensitivity reactions.

CONCLUSION

The most important PLT unit characteristic associated with TRAEs was PLT dose per transfusion. HD PLTs may increase the risk of TRAEs, and LD PLTs may reduce the risk.

Immunoglobulins and their use in children

Immunoglobulin preparations are one of the products of the human plasma fractionation, where the plasma is obtained, in accordance with WHO guidelines from at least 1,000 donors. These preparations contain all IgG subclasses with various antigen characteristics. In clinical practice these drugs are used as replacement therapy in patients with primary and secondary immunodeficiencies as well as immunomodulatory therapy in many autoimmune diseases and systemic inflammatory diseases. Here we present characteristics of i.v. polyvalent, human immunoglobulin preparations available on the Polish market and the possibilities of their use in clinical practice, in children with hematological diseases. Considering the very low consumption of immunoglobulin preparations in our country as compared to other European countries, we would like to draw the attention of medical professionals, especially pediatricians and haematologists, to the benefits that stem from the use of these drugs in the therapy of children with haematological diseases. Our work will also facilitate the choice of an optimal polyvalent human immunoglobulin preparation for a particular patient.

The seroprevalence of hepatitis C virus antibodies among transfused patients with haematological disorders

AIMS AND OBJECTIVES

This study was undertaken to determine the prevalence of hepatitis C virus antibodies (anti- HCV) among transfused patients with haematological disorders. and correlate this with the units of blood or blood products received

PATIENTS AND METHODS

This was a cross sectional study. Patients with haematological disorders who had received two or more units of blood or blood products and healthy blood donors who had not received blood transfusion were screened for ant-HCV using Enzyme Linked Immunosorbent Assay (ELISA) kits.

RESULTS

A total of 480 subjects comprising 146 patients with haematological disorders and 334 blood donor controls were recruited for this study. The patients comprised 78 (53.4%) males and 68 (46.6%) females with age range from 14-65 years and a mean of 39.5. The prevalence of anti-HCV was 6 (4.1%) among transfused patients and 7 (2.1%) among untransfused blood donors. The risk of anti- HCV positivity among patients was higher with increasing units of received blood or blood products. A significant statistical association was observed between the number of pints of blood or blood products received and anti-HCV positivity among patients p=0.008 CONCLUSION: This study suggests that patients who had received blood or blood products are at higher risk of HCV infection than the untransfused individuals. The risk of infection is higher with increasing units of blood or blood products received by transfused patients.

[Clinical manifestations of Legionella pneumonia in hematology patients]

AIM

To detect the most common clinical manifestations of Legionella pneumonia (LP) in immunocompromized patients.

SUBJECTS AND METHODS

Clinical manifestations, the results of investigation of bronchoalveolar lavage fluid (BALF) and urine, and the data of lung computed tomography (CT) were studied in patients with blood system diseases and acute respiratory failure (ARF).

RESULTS

The diagnosis of LP was verified in 8 (10.5%) of 76 patients with blood system diseases and ARF. The disease manifested as fever, higher concentrations of inflammatory markers (procalcitonin, fibrinogen), ARF, hypoxemia, and infiltrative lung injury. Six of the 8 patients were switched to mechanical ventilation. Lung CT showed no pathognomonic signs. Five of the 8 patients were observed to have renal dysfunction. The diagnosis of LP was made on the basis of the results of BALF examination in 7 patients and urinary antigen detection in 1. The disease was caused by Legionella pneumophila serogroup 1 in 3 patients and by L. pneumophila of other serogroups in the other patients. Therapy with respiratory fluoroquinolones was performed in 5 patients. Three patients died from progressive ARF and hypoxemia. BALF results were obtained after their death and therapy for legionellosis was not initiated.

CONCLUSION

The incidence of LP is 10.5% in hematology patients. The clinical manifestations of legionellosis are nonspecific; its diagnosis requires bacteriological and/or serological evidence. Due to the high risk of death, it is reasonable to preuse respiratory fluoroquinolones or macrolides in immunocompromized patients with progressive ARF and suspected Legionella pneumonia before diagnosis.

[Selection of an unrelated donor for hematopoietic stem cell transplantation. HLA haplotypes in patients with blood system diseases]

AIM

To study the distribution of HLA-A*-B*-C*-DRB1 *-DQB1 * haplotypes in patients with blood system diseases, to establish the most common HLA haplotypes, and to compare the findings with the data on the frequency and distribution of the highest-frequency HLA haplotypes in donors of a number of leading registries.

SUBJECTS AND METHODS

In 2008-2012, the Hematology Research Center, Ministry of Health of the Russian Federation, examined 203 patients with blood system diseases who needed allogeneic hematopoietic stem cell transplantation (allo-HSCT) and their 386 blood relatives. Typing ascertained the kind of HLA haplotype in all the patients. Among the patients, there were 97 men who were aged 17 to 64 years (median 38 years) and 106 women who were aged 18 to 59 years (median 40 years).

RESULTS

The examinees were found to have 265 different HLA haplotypes. There were 21 high-frequency HLA haplotypes; of them 7 belonged to 10 HLA haplotypes that are most frequent in the representatives of the Caucasoid race. Nearly 30% of the patients who needed allo-HSCT and had no HLA-identical siblings had HLA haplotypes out of the 10 ones that are most common in the representatives of the Caucasoids and thus could expect to find a compatible unrelated donor for a short time. The examinees were found to have a wide variety of HLA haplotypes (265 types in 203 persons). This variety, as well as the extreme polymorphism of HLA alleles, shows that there should be large registries of HLA-typed bone marrow donors in the country. These registries increase the chance to find a HLA-compatible unrelated donor for a short time for a patient with blood disease who has an indication for hematopoietic stem cell transplantation. The performed study supported that there were regional features in the distribution of HLA haplotypes within the same ethnic group.

CONCLUSION

The chance to find a HLA-compatible donor for Russian patients in the large national registry that accumulates donors from different regional populations is substantially higher than that in the foreign registries. To create large cohorts of HLA-typic bone marrow donors from different regions of the country will substantially increase the chance of patients with blood system diseases to find a HLA-compatible unrelated donor.

[Secondary osteoporosis or secondary contributors to bone loss in fracture. Bone metabolism in hematological disorders]

Bone marrow provides a microenvironment responsible for hematopoiesis, in which osteoclasts and osteoblasts interact with each other to maintain bone remodeling. Multiple myeloma and a portion of lymphoid tumors have a unique propensity to expand in bone. Such tumors have been demonstrated to perturb bone metabolism and skew a microenvironment in bone suited for their growth and survival. However, a bone metabolic state remains largely unknown in most of hematological disorders without apparent bone disease, although hematopoiesis and bone metabolism appear to have a link. Also, the skeletal effects of treatment for hematological disorders should be clarified further.

[The efficacy and safety of unmanipulated haploidentical peripheral blood stem cell transplantation on hematologic diseases]

OBJECTIVE

To evaluate the efficacy and safety of unmanipulated haploidentical allogeneic peripheral blood stem cells transplantation (PBSCT) on hematologic diseases.

METHODS

Patients who underwent unmanipulated HLA-mismatched/haploidentical PBSCT from July 2007 to December 2011 were investigated retrospectively.

RESULT

Forty-nine patients with hematologic diseases underwent unmanipulated human leukocyte antigen (HLA)-mismatched/haploidentical PBSCT with myeloablative conditioning. All patients were mismatched at the allele level for HLA-A, HLA-B, HLA-Cw, HLA-DRB1 and HLA-DQ1. Fifteen patients were mismatched in 5 loci, 11 patients in 4 loci, 7 patients in 3 loci, 5 patients in 2 loci, and 11 patients in 1 locus. The median numbers of mononuclear cells and CD₃₄⁺ cells infused at transplantation were 10.01(7.05-25.34) × 10⁸/kg and 4.51 (2.01-11.47) × 10⁶/kg, respectively. Patients achieved myeloid and platelet engraftment at a median of 14 (10-25) days and 22 (10-135) days, respectively. The cumulative incidence of acute graft versus host disease (aGVHD) on day 100 was (61.6 ± 7.3)%, and the 2-year cumulative incidence of chronic graft versus host disease (cGVHD) was (42.6 ± 8.5)%. One hundred-day transplantation related mortality (TRM) rate and 2-year cumulative TRM rate were (14.7 ± 5.1)% and (30.9 ± 8.8)%, respectively. The 2-year cumulative incidence estimate of relapse was (25.4 ± 7.0)%. The 2-year cumulative overall survival rate was (58.1 ± 8.8)% and 2-year disease-free survival rate was (53.9 ± 8.4)% with an 11.5-months median follow-up.

CONCLUSION

Unmanipulated PBSCT is a promising protocol for patients with hematologic diseases in HLA-mismatched/haploidentical transplant settings.

Regulatory T cells: a review

Regulatory T cells (Tregs) play a pivotal role in the homeostasis of the immune system and in the modulation of the immune response. Tregs have emerged as key players in the development and maintenance of peripheral immune tolerance. Broadly speaking, CD4+ T cells possessing the ability to suppress immune responses can be divided into two types: naturally occurring (nTreg) and inducible (iTreg) or adaptive regulatory cells. Naturally occurring thymus-derived CD4+CD25+ Tregs are a subset of T cells which have immunosuppressive properties and are 5%-10% of the total peripheral CD4+ T cells. In normal conditions, Tregs regulate ongoing immune responses and prevent autoimmunity. Imbalanced function or number of these cells, either enhanced or decreased, might lead to tumour development and autoimmunity, respectively. These cells thus play a major role in autoimmune diseases, transplantation tolerance, infectious diseases, allergic disease and tumour immunity. These natural properties make Tregs attractive tools for novel immunotherapeutic approaches. The in vivo manipulation or depletion of Tregs may help devise effective immunotherapy for patients with cancer, autoimmunity, graftversus-host disease, infectious diseases and allergic diseases. It is crucial to understand the biology of Tregs before attempting therapies, including (i) the injection of expanded Tregs to cure autoimmune disease or prevent graft-versus-host disease or (ii) the depletion or inhibition of Tregs in cancer therapy. Recent findings in murine models and studies in humans have opened new avenues to study the biology of Tregs and their therapeutic potential. This overview provides a framework for integrating these concepts of basic and translational research.

Late onset neonatal anaemia due to maternal anti-Kp(b) induced haemolytic disease of the newborn

BACKGROUND

Alloanti-Kp(b) is a rare, clinically significant antibody against high frequency red cell antigen Kp(b) of Kell blood group system. We report here a case of Haemolytic disease of newborn (HDN) due to anti-Kp(b), which manifested as severe anaemia at the age of 1 month.

AIM

To diagnose and successfully manage anti-Kp(b) induced HDN.

METHODOLOGY

Direct antiglobulin test (DAT), antigen typing, irregular antibody screening and identification were done by polyspecific LISS Coombs Gel card and standard methods.

RESULTS

At presentation the neonate had severe anemia with reticulocytopenia. Blood group was B, Rh D positive and DAT was 2+. Anti-Kp(b) was detected in mother's serum. Due to unavailability of Kp(b) negative red cells and incompatible blood group of mother (A(1)B Rh D positive) infant was transfused group B Rh D, Kp(b) positive PRBCs under steroid cover. He was symptom free at 4 months of age and DAT became negative at 6 months.

CONCLUSION

Anti-Kp(b) is capable of causing severe late HDN. Infants born to irregular antibody positive mothers should be investigated and closely monitored for several weeks after birth for immune HDN even if asymptomatic at birth.

[Cytomegalovirus-specific T cells immune reconstitution after human leukocyte antigen matched sibling donor allogeneic bone marrow plus peripheral blood hematopoietic stem cell transplantation]

OBJECTIVE

To investigate the regular pattern of Cytomegalovirus (CMV)-specific T cells (CTL) immune reconstitution after human leukocyte antigen (HLA) matched sibling donor allogeneic bone marrow(BM) plus peripheral blood hematopoietic stem cell (PBSC) transplantation.

METHODS

CTL from seventeen patients after transplantation was detected by flow cytometry, the IFN-γ secretion ability of CTL by enzyme-linked immunospot (ELISPOT) assay, and clonal analysis of TCR Vβ subfamily by gene scan assays. The relationship between CTL reconstitution and CMV infection was studied.

RESULTS

Both number and function of recipients CTL reached to normal control level at 30 d post-transplantation. The recipients achieved a high frequency CTL with IFN-γ response and restoration of T-cell receptor β (TCR Vβ) repertoire at one year post-transplantation. CTL with the central memory CD45RO(+)CD62L(+) cell phenotype expanded in PB when CMV was reactivated. The incidence of CMV reactivation was 35.83% (17.91% - 63.10%) after transplantation, and none of them developed CMV disease.

CONCLUSION

After HLA matched related donor transplantation using mixed grafts, immune recovery to CMV seems to be early and fast. The incidence of CMV infection and disease are low.

The use of monoclonal antibodies in immune-mediated hematologic disorders

In this article, the evidence on the clinical use of monoclonal antibodies in the treatment of immune-mediated hematologic disorders is described. Insights into pathogenic mechanisms have revealed a major role of both B and T cells. Controlled trials have shown conflicting results, necessitating further research regarding pathogenesis, mechanism of action, and resistance. Although the use of more potent and specific monoclonal antibody therapy, mainly targeting costimulation signals, may improve response rates and long-term outcome, its use should be carefully balanced against potential side effects.

Outcomes after major or bidirectional ABO-mismatched allogeneic hematopoietic progenitor cell transplantation after pretransplant isoagglutinin reduction with donor-type secretor plasma with or without plasma exchange

BACKGROUND

Major ABO mismatch in hematopoietic progenitor cell transplantation (HPCT) is associated with a range of immunohematologic consequences including progenitor cell infusion (PCI)-related hemolysis, delayed red blood cell engraftment, and pure red cell aplasia (PRCA). Although pretransplant (recipient) isoagglutinin reduction may be associated with decreased immunohematologic complications in this setting, there is no consensus with respect to strategies for isoagglutinin reduction.

STUDY DESIGN AND METHODS

This observational study assessed the efficacy of a standardized pretransplant isoagglutinin reduction strategy incorporating donor-type secretor plasma infusions with or without plasma exchange to prevent PCI-associated hemolysis and PRCA in major or bidirectional ABO-mismatched peripheral blood HPCT. All major or bidirectional ABO-mismatched HPCTs performed between 1999 and 2010 were identified from an institutional database. Immunohematologic outcomes were determined retrospectively by review of individual medical records.

RESULTS

In total 110 major or bidirectional ABO-mismatched HPCTs had been performed. No patient developed hemolysis after PCI. With respect to PRCA incidence, 16 patients (15%) were excluded due to early mortality and three (3%) due to incomplete data; of the remaining 91 patients, five (5%) developed PRCA. Patients with PRCA had significantly higher pretransplant isoagglutinin titers (p = 0.0001) compared to those who did not develop PRCA.

CONCLUSIONS

Use of a standardized pretransplant isoagglutinin reduction strategy including donor-type secretor plasma infusions is both safe and efficient in preventing PCI-associated hemolysis and is associated with low rates of posttransplant PRCA.

CD4+CD25highFoxP3+ regulatory T-cells in hematologic diseases

BACKGROUND

CD4+CD25+ regulatory T-cells (Tregs) play a critical role in immune responses. We explored the status of Tregs in neoplastic and autoimmune hematologic diseases. We also evaluated the technical aspects of Treg measurement in terms of sample type and detection markers.

METHODS

A total of 68 subjects were enrolled: 11 with AML, 8 with MDS, 10 with autoimmune diseases, and 39 controls. Tregs were analyzed in peripheral blood (PB) and bone marrow (BM) samples from each subject. Flow cytometry and the Human Regulatory T cell Staining Kit (eBioscience, USA) for CD4, CD25, and FoxP3 (forkhead box P3) were used.

RESULTS

The CD4+CD25(high)/CD4 and CD4+CD25(high)FoxP3+/CD4 populations were significantly correlated (P<0.0001). The AML and high-risk MDS groups had significantly larger CD4+CD25(high)/CD4 and CD4+CD25(high)FoxP3+/CD4 populations in PB than the autoimmune (P=0.007 and 0.012, respectively) and control groups (P=0.004 and 0.006, respectively). Comparable findings were observed in BM. The CD4+CD25(high)FoxP3+/CD4 population was significantly larger in PB than in BM (P=0.0003).

CONCLUSIONS

This study provides comparison data for Tregs in AML, MDS, and autoimmune hematologic diseases, and would be helpful for understanding the different immunologic bases of various hematologic diseases. Treg measurement using CD4, CD25, and/or FoxP3 in PB rather than in BM seems to be practical for routine hematologic purposes. Large-scale analysis of the diagnostic role of Treg measurement is needed.

Rituximab therapy for autoimmune haematological diseases

Autoimmune haematological diseases are characterized by the production of antibodies against blood proteins or cells, and comprise primary immune thrombocytopenia, autoimmune haemolytic anaemia, acquired haemophilia, and thrombotic thrombocytopenic purpura. Current treatments for these disorders include corticosteroids, cytotoxic drugs and splenectomy, which may be associated with significant systemic toxicity and/or morbility. B cells play a key role in both the development and perpetuation of autoimmunity, since they produce autoantibodies but also function as antigen-presenting cells, and release immunomodulatory cytokines. Rituximab, an anti-CD20 monoclonal antibody that specifically depletes B cells, may be an effective treatment strategy for patients with autoimmune disorders. This article reviews data of the literature, showing that patients with autoimmune haematological diseases can respond to rituximab irrespective of age and number or type of prior treatments. These data suggest that rituximab provides an effective and well-tolerated treatment option for these conditions.

[Comparison of curative efficacy after G-CSF-mobilized sibling HLA-matched peripheral blood hematopoietic stem cell transplantation versus that combined with BMT for patients with hematologic malignancies in a single center]

This study was aimed to retrospectively analyze and compare the clinical curative efficacy of patients with hematologic malignancies after G-CSF-mobilized sibling HLA-matched (sm) peripheral blood hematopoietic stem cell transplantation (sm-allo-PBHSCT) and sm-allo-PBHSCT combined with bone marrow transplantation (BMT). 100 patients received sm-allo-HSCT in a single center from October 2001 to October to 2010, included 38 patients received sm-allo-PBHSCT and 62 patients received sm-allo-PBHSCT combined with BMT. The myeloablative or reduced intensity conditioning regimens were chosen according to the condition of patients. All patients received standard cyclosporine (CsA) and mycophenolate mofetil (MMF) as prophylaxis for GVHD. The results showed that the rapid hematopoietic reconstitution was observed in all patients. The median time of ANC ≥ 0.5 × 10(9)/L in both groups were 12 days, the median time of platelet count ≥ 20 × 10(9)/L was 15 days in sm-allo-PBHSCT group and 16 days in sm-allo-PBHSCT + BMT group. The incidence of acute GVHD, acute GVHD of III-IV grade and chronic GVHD in sm-allo-PBHSCT and sm-allo-PBHSCT + BMT groups were 37.1% and 34.2%, 7.89% and 8.06%, 36.11% and 41.38% respectively, there were no statistical differences. The relapse rates were similar in two groups (sm-allo-PBHSCT 13.16% vs sm-allo-PBHSCT + BMT 12.9%). The 3-year disease-free survivals in sm-allo-PBHSC and sm-allo-PBHSCT + BMT groups were 57.1 ± 8.7% and 61.3 ± 6.4% respectively (p = 0.852). The 2-year overall survival of high-risk patients was 41.4 ± 12.8% in sm-allo-PBHSCT group, while 60.9 ± 9.6% in sm-allo-PBHSCT + BMT group (p = 0.071). It is concluded that the rhG-CSF mobilized sibling matched allo-PBHSCT + BMT is superior to the rhG-CSF mobilized sibling matched allo-PBHSCT in increasing the overall survival of high-risk hematologic malignancies.

Innate immunity as orchestrator of stem cell mobilization

Hematopoietic stem and progenitor cells (HSPCs), as well as other types of stem cells, circulate under steady-state conditions at detectable levels in peripheral blood (PB), with their numbers increasing in response to stress, inflammation and tissue/organ injury. This mobilization process may be envisioned as a danger-sensing response mechanism triggered by hypoxia or mechanical or infection-induced tissue damage that recruits into PB different types of stem cells that have a role in immune surveillance and organ/tissue regeneration. Mobilization is also significantly enhanced by the administration of pharmacological agents, which has been exploited in hematological transplantology as a means to obtain HSPCs for hematopoietic reconstitution. In this review we will present mounting evidence that innate immunity orchestrates this evolutionarily conserved mechanism of HSPC mobilization.

How I treat common variable immune deficiency

Common variable immunodeficiency is a rare immune deficiency, characterized by low levels of serum immunoglobulin G, A, and/or M with loss of antibody production. The diagnosis is most commonly made in adults between the ages of 20 and 40 years, but both children and older adults can be found to have this immune defect. The range of clinical manifestations is broad, including acute and chronic infections, inflammatory and autoimmune disease, and an increased incidence of cancer and lymphoma. For all these reasons, the disease phenotype is both heterogeneous and complex. Contributing to the complexity is that patient cohorts are generally small, criteria used for diagnosis vary, and the doses of replacement immune globulin differ. In addition, routines for monitoring patients over the years and protocols for the use of other biologic agents for complications have not been clarified or standardized. In the past few years, data from large patient registries have revealed that both selected laboratory markers and clinical phenotyping may aid in dissecting groups of subjects into biologically relevant categories. This review presents my approach to the diagnosis and treatment of patients with common variable immunodeficiency, with suggestions for the use of laboratory biomarkers and means of monitoring patients.

[Paraneoplastic autoimmune disorders]

Paraneoplastic syndrome is defined as tumor-associated symptoms and signs not related to the physical effects of primary or metastatic tumors. The mechanisms of this syndrome include the production of bioactive soluble factors by tumor cells and autoimmune diseases elicited by the immune responses against tumors. Production of bioactive soluble factors causes endocrinologic symptoms. The paraneoplastic autoimmune process may affect the nervous system, cutaneous tissue, musculoskeletal system, hematopoietic cells or kidneys. Paraneoplastic rheumatic diseases show symptoms similar to inflammatory myopathy, polyarthritis, vasculitis, cryoglobulinemia and polymyalgia rheumatica. Rapid onset, unusual age, asymmetrical involvement of joints or refractoriness to standard immunosuppressive therapy suggests the presence of paraneoplastic autoimmune diseases. Autoimmune hematopoietic disorders include pure red cell aplasia, autoimmune hemolytic anemia and thrombocytopenia. Unexplained anemia or thrombocytopenia may indicate the presence of lymphoid neoplasms. Membranous nephropathy is a well-known glomerular disease associated with malignancy, and membranoproliferative glomerulonephritis, minimal change nephrotic syndrome, and antineutrophil cytoplasmic antibody(ANCA)-associated crescentic glomerulonephritis may be seen in cancer patients. Age and sex-appropriate cancer screening should be performed in patients with nephrotic syndrome due to membranous nephropathy.

Allogeneic hematopoietic cell transplantation: the state of the art

Allogeneic hematopoietic cell transplantation (HCT) is a potentially curative procedure for a variety of hematologic malignancies. The field has evolved substantially over the past decade, with advances in patient and donor selection, stem cell sources, supportive care, prevention of complications and reduced-toxicity preparative regimens. As a result, the indications for HCT and the pool of eligible patients have expanded significantly. In this article, we provide an overview of the major aspects of allogeneic HCT, and focus specifically on areas of active research and on novel approaches to challenges in the field. Specifically, we will discuss approaches to reduce the toxicity of the preparative regimen, with the goal of increasing the safety and applicability of HCT. The availability of suitable donors may be an obstacle to wider application of HCT. We review three major approaches to broadening the donor pool: the use of HLA-mismatched unrelated donors, umbilical cord blood and HLA-haploidentical family donors. Graft-versus-host disease remains a major cause of morbidity and mortality after HCT. We review recent advances in the understanding of this phenomenon, and novel prophylactic and therapeutic approaches that hold the promise of further improving the safety of the procedure. We conclude with a speculative outline of the next 5 years of research in the field of HCT.

[Comparison of immunological reconstitution and related complications after HLA-matched and HLA haploidentical peripheral blood hematopoietic stem cell transplantation]

OBJECTIVE

To explore the difference of immune function and relationship with main complications after HLA-matched and HLA haploidentical allogeneic peripheral blood hematopoietic stem cell transplantation (allo-PBSCT).

METHODS

Sixty-seven patients undergoing HLA-matched (n = 33) or HLA haploidentical (n = 34) allo-PBSCT during the same time period in our hospital from June 2004 to December 2007 were included in this study. Indirect immunofluorescence assay was employed to detect lymphocyte subsets before transplantation and on month 1, 3, 6, 12 and 18 after transplantation and the lymphocyte subsets of 100 healthy people were used as normal control. The comparison of immunological reconstitution and relationship with main complications was carried out with statistical analysis.

RESULTS

(1) Comparison of the 67 patients with normal controls showed that CD(3)(+), CD(4)(+), CD(4)(+)/CD(8)(+) at month 1, CD(4)(+), CD(4)(+)/CD(8)(+) at month 3 and CD(4)(+) at month 6 after PBSCT were lower. CD(8)(+) at month 3 and month 6 were higher. (2) The immune function was not statistically different between HLA haploidentical and HLA-matched allo-PBSCT (P > 0.05). (3) The immune function of patients with and without severe infection was not statistically different (P > 0.05). (4) The immune function of patients with chronic graft-versus-host disease (cGVHD) between HLA haploidentical and HLA-matched allo-PBSCT groups was not statistically different. The immune function of patients without cGVHD in two groups was not statistically different (P > 0.05). (5) The immune function of patients with or without relapse was not statistically different (P > 0.05).

CONCLUSIONS

HLA-haploidentical PBSCT conditioning including antithymocyte globulin without in vitro T cell depletion is feasible and safe. The immunological reconstitution, incidence of severe infection, incidence of relapse and treatment-related mortality are not significantly different between HLA-matched and HLA haploidentical allo-PBSCT.

Adverse drug reactions affecting blood cells

Numerous medications and other xenobiotics are capable of producing adverse reactions (ADRs) affecting red cells, platelets or neutrophils. Occasionally, more than one blood element is affected simultaneously. As with all drug reactions, some side effects are a direct consequence of a known pharmacologic action of the drug and are dose-dependent; others occur sporadically and relatively independent of dose. The latter ("idiosyncratic") reactions are unpredictable and, in general, have no known underlying genetic basis. Many are antibody-mediated, as would be expected since cellular immune effector cells have little direct access to circulating blood cells. In this chapter, we will discuss idiosyncratic drug reactions affecting blood and blood forming tissues with an emphasis on those thought to be immune-mediated.

CXCR4 in clinical hematology

Pharmacological manipulation of CXCR4 has proven clinically useful for mobilization of stem and progenitor cells and in several preclinical models of disease. It is a key component in the localization of leukocytes and stem cells. For patients with multiple myeloma and non-Hodgkin's Lymphoma, treatment with plerixafor, an inhibitor of CXCL12 binding to CXCR4, plus G-CSF mobilizes stem cells for autologous transplantation to a greater degree than the treatment with G-CSF alone, and in some cases when patients could not be mobilized with cytokines, chemotherapy, or the combination. Stem cells from healthy donors mobilized with single agent plerixafor have been used for allogeneic transplantation in acute myelogenous leukemia (AML) patients, although this is still in the early phase of clinical development. Plerixafor is also undergoing evaluation to mobilize tumor cells in patients with AML and chronic lymphocytic leukemia (CLL) to enhance the effectiveness of chemotherapy regimens. Plerixafor's effect on neutrophils may also restore circulating neutrophil counts to normal levels in patients with chronic neutropenias such as in WHIMs syndrome. Other areas where inhibition of CXCR4 may be useful based upon preclinical or clinical data include peripheral vascular disease, autoimmune diseases such as rheumatoid arthritis, pulmonary inflammation, and HIV.

The ratio between CD4 + and CD8 + cells in the peripheral blood of patients with hematological malignancies is not altered by thalidomide

Thalidomide is thought to have anti-angiogenic and immunomodulatory properties, including suppression of tumor necrosis factor-alpha, effects on interleukins and interferons, down-regulation of some cell adhesion molecules, and changes in the proportion of lymphocyte subsets. It is unclear whether the clinical response to thalidomide in patients with multiple myeloma (MM), idiopathic myelofibrosis (IM), and myelodysplastic syndromes (MDS) is related to its ability to inhibit angiogenesis or its immunomodulatory effects. We examined the effect of thalidomide on T-lymphocyte subsets in 18 patients with MDS, 6 patients with MM, 4 patients with IM, and 3 patients with angioimmunoblastic lymphoma (AILD). These patients had either a relapse or progressive disease following cytotoxic chemotherapy including high-dose chemotherapy with autologous stem cell support. Thalidomide was first administered at 100 mg/day p.o. and increased to 400 mg/day. T-lymphocyte subsets (CD4+, CD8+) were measured by fluorescence-activated cell sorter (FACS) before and during treatment with thalidomide. Twenty-six of 31 patients responded to thalidomide, most of them achieving partial remission. The median concentration of CD4+ cells was 443/microl, the median of CD8+ cells was 359/microl (CD3 992/microl). In our cohort, no significant changes in absolute numbers or proportions of CD3+ (P = 0.12), CD4+ (P = 0.668), or CD8+ (P = 0.143) cells were observed following the treatment with thalidomide. Although the CD4/CD8 ratio declined from 1.6 to 1.0 during 3 months of thalidomide treatment, this had no statistical significance (P = 0.1). Our findings show that an effect of thalidomide on the T lymphocytes studied is unlikely to be of major importance for the clinical effects.

[Factors influencing engraftment in hematological patients after human leukocyte antigen matched sibling allogeneic blood and marrow transplantation]

OBJECTIVE

To investigate the factors influencing engraftment in patients with hematological diseases after human leukocyte antigen matched sibling allogeneic blood and marrow transplantation.

METHODS

One hundred and fifty-seven patients with hematological diseases who underwent allogeneic blood and marrow transplantation were enrolled in this study. The cell compositions in allografts were determined using multi-color flow cytometry.

RESULTS

The median time for the engraftment of neutrophil and platelet was 15 (11-25) days and 12 (7-78) days, respectively. Univariate analyses demonstrated that the source of allografts (P = 0.049) and allograft-infused cell doses of CD34+ cells (P = 0.001) was correlated with neutrophil engraftment. The duration from diagnosis to transplantation (P = 0.043) and allograft-infused cell doses of CD cells (P < 0.001) were correlated with platelet engraftment. Multivariate analysis showed that allograft-infused cell doses of CD34+ cells were associated with a rapid neutrophil recovery (RR: 1.222, 95% CI: 1.063-1.405, P = 0.005) and platelet reconstitution (RR: 1.228, 95% CI: 1.090-1.382, P = 0. 001), the duration from diagnosis to transplantation was associated with platelet recovery (RR: 1.000, 95% CI: 0.999-1.000, P = 0.065). A significantly faster recovery of neutrophils (14.5 d) and platelets (11 d) was found in patients infused > 2.45 x 10(6)/kg CD34+ cells as compared with those (16 d and 14 d) infused < or = 2.45 x 10(6)/kg CD34+ cells (P = 0.021, 0.010, respectively).

CONCLUSION

The absolute number of CD34+ cell in allografts was a main factor influencing the engraftment of neutrophil and platelet after HLA-matched sibling allogeneic blood and marrow transplantation. Duration from diagnosis to transplantation was another factor influencing engraftment of platelet.

Anti‐N‐Like and Anti‐Form Red Cell Antibodies in Chronic Hemodialysis Patients

Allogeneic red blood cell (RBC) transfusions and the use of reusable dialyzers sterilized with formaldehyde can lead to RBC alloimmunization in chronic hemodialysis patients. The formed RBC alloantibodies have been implicated in immediate kidney allograft failure and decreased RBC survival observed in these patients. Using indirect antiglobulin test, direct antiglobulin test (DAT), and direct Polibrene test (DPT), we detected an RBC alloimmunization rate of 17.2% (11/64) in transfused hemodialysis patients, and found the presence of anti-N-like and anti-Form antibodies in 5 (5.7%) and 53 (60.9%) individuals, respectively. The sensitivity rate of the DPT was significantly higher than that of the DAT in detecting anti-Form, but the DAT showed a higher specificity rate compared with the DPT. We conclude that patients treated with reusable dialyzers sterilized with formaldehyde may develop specific RBC alloantibodies that could increase the potential risk of hemolysis, decrease survival of RBCs, and increase the need of blood supply.

Pneumococcal vaccination in splenectomized patients with hematological disorders

Seventy splenectomized patients were vaccinated with Pneumovax, a pneumococcal polysaccharide vaccine. Twenty-four of the patients had a malignant and 30 a nonmalignant hematological disorder. The remaining 16 were patients with no known hematological disorder, seven with intra-abdominal carcinomas and nine with non-malignant reasons for splenectomy. About 90% of the patients with non-malignant hematological disorders responded to vaccination with a rise in antibody titres, which was significantly higher than in the other two groups studied. Malignant hematological disorders lowered the response rate to 61-67%. Patients with no known hematological disorder but with intra-abdominal carcinomas also responded less frequently, while those in this group with other surgical reasons for splenectomy had a response rate comparable to healthy individuals. No serious side-effects were reported and we therefore conclude that all splenectomized patients should be vaccinated with a pneumococcal vaccine. However, it must always be born in mind that one third of the patients with malignant disease did not respond to vaccination.

[Objectives and organization of a reference center for autoimmune cytopenia in adults]

French public health legislation passed in August 2004 made orphan diseases one of five major priorities. The main aims were to improve healthcare access and quality. One hundred thirty-two centers were certified. In 2005, our group was certified for the treatment of adult patients with autoimmune cytopenia, and for related research. Our reference center consists of eight teams located in the Paris area (6 teams), Lille and Caen, and 19" centers of competence" covering the whole of France. The reference and competence centers' main tasks are to provide expertise, referral, research and healthcare organization in the field of purp autoimmune cytopenias.

New treatment options for immune-mediated hematological disorders

In recent years, there has been a tremendous increase in the number of clinical studies with monoclonal antibodies and small molecules in the treatment of hematological malignancies. Clinical observations have shown that some of these molecules may also aid in the treatment of immune-mediated hematological disorders. Moreover, immunotherapy has become an important treatment cornerstone in other, non-hematological, auto-immune diseases. This paper reviews the current state of the use of these new molecules in the treatment of the most frequently encountered immune-mediated hematological disorders: auto-immune hemolytic anemia (AIHA), idiopathic thrombocytopenic purpura (ITP), and thrombotic thrombocytopenic purpura (TTP).

[Auto-immune serological disorders in chronic viral C hepatitis: prevalence and clinical significance]

BACKGROUND

Hepatitis C viral (HCV) infection has been shown to lead to auto-immune phenomena.

AIMS

We review the prevalence of serological auto-immune disorders associated to HCV infection and to clarify their clinical significance.

METHODS

Literature review.

RESULTS

The serological immune response to HCV infection may include the development of cryoglobulinemia, rheumatoid factor, anticardiolipin, antinuclear, anti-liver-kidney-microsome 1 and anti-smooth muscle antibodies. Serological auto-immune manifestations were explained by the lymphotropism of HCV and the polyclonal activation of B cells. Interferon-based treatment of HCV infection may precipitate or exacerbate the associated auto-immune disease.

CONCLUSION

In patients with serological auto-immune disorders associated with HCV infection, a very careful analysis of clinical and biological features is needed. Application of classification criteria of systemic auto-immune diseases and testing more specific antibodies can resolve this point.

Abbreviated dose rituximab for immune-mediated hematological disorders

As rituximab, a monoclonal antibody targeting CD20, depletes B cells, there is considerable interest in its use in immune-mediated disorders. The majority of studies employ a four-dose regimen based on practice in lymphoma therapy. We describe our experience with one or two doses of 375 mg/m(2) of rituximab in 12 patients with relapsed and refractory immune-mediated hematological disorders. Eleven patients (92%) achieved a complete remission that has been sustained in 7 for a median of 14.5 (10.5-22) months. Four patients (36%) relapsed after responses of 1-18.5 months. This preliminary experience suggests that one or two doses of rituximab may have response and relapse rates comparable to multidose regimens while potentially providing considerable cost savings. Further prospective studies are planned.

[Characteristics of chronic active Epstein-Barr virus infection-associated hematological disorders in children]

The aim of this study was to analyze characteristics of chronic active Epstein-Barr virus (CAEBV) infection associated hematological disorders in children. Clinical characteristics were summarized; the morphology of hematopoietic cells in bone marrow was observed by microscopy; the lymphocyte subpopulations were analyzed by flow cytometry; the immunophenotype of liver biopsies was assayed by immunohistochemistry; EBV-related antibodies were measured by ELISA; serum EBV-DNA loads were detected by real-time quantitative PCR; EBV-encoded small RNA 1-positive cells in peripheral blood mononuclear cells were identified by in situ hybridization. The results indicated that the clinical manifestations in patients included persistent or recurrent fever, hepatosplenomegaly, liver dysfunction, anemia, thrombocytopenia, systemic inflammatory reaction. Bone marrow presented as hypocellularity, dysmaturation, myelodysplasia and hemophagocytosis. CD8(+) cell high counts were demonstrated in all 4 patients, one of them developed into a T cell lymphoma. Serum EBV-DNA load was 3.26 x 10(3) copies/ml in one patient, EBER1(+) cells were detected at a frequency of 1.7% in PBMNCs from another patient; the titers of IgG to EBV-VCA were >or= 1:5120 in the rest 2 patients. All 4 patients described above were diagnosed as CAEBV infection. In conclusion, the immune-related cytopenia, macrophage activation syndrome and lymphoproliferative disorders are characteristics of CAEBV infection associated hematological disorders in these 4 children patients.

[Atypical lymphocytes]

Atypical lymphocytes or reactive are cells that become large as a result of antigen stimulation. This cells usually are associated with viral illnesses, however they can also be present as result of drug reactions, immunisations, humoral diseases and auto-immune disorders.

Safety, efficacy, and immune reconstitution after rituximab therapy in pediatric patients with chronic or refractory hematologic autoimmune cytopenias

BACKGROUND

Autoimmune hematologic cytopenias in children often require therapeutic intervention. We report a prospective pediatric multicenter trial of rituximab for refractory or steroid-dependent patients.

METHODS

Four doses of rituximab (375 mg/m(2)/dose) were administered weekly. Patients without response after three doses were offered dose escalation to 750 mg/m(2)/dose/week x 3. Safety, efficacy, and immunologic tests were evaluated after therapy.

RESULTS

Twenty-nine of 30 children (2-18 years) with thrombocytopenia (21), hemolytic anemia (6), Evans syndrome (2), and neutropenia (1) received at least four doses of rituximab. One developed anaphylaxis with the first dose. One patient was subsequently diagnosed with monosomy 7 myelodysplasia. Of 28 remaining patients, 9 received dose escalation. Responders discontinued other therapy following rituximab. The overall response rate was 72% with median follow-up of 18 months. Complete remission was observed in 14 (50%); all received four doses of rituximab. Partial remission (PR) was observed in six (22%); five had received dose escalation. Of four relapses, 4-24 months after therapy, two were retreated with rituximab and achieved second remission. No major infections were encountered. Circulating B-cells were depleted by 1 month and normalized by 1 year. IgM, Ig A, and IgG levels decreased 6, 9, and 12 months after therapy, respectively, but remained near normal range. Tetanus toxoid antibody titers remained detectable.

CONCLUSIONS

Rituximab was well tolerated, and induced sustained remissions in children with refractory immune cytopenias. Dose escalation and re-treatment after relapse elicited additional responses. Rituximab therapy should be considered prior to potential interventions with higher toxicity.

Transfusion support for a patient with McLeod phenotype without chronic granulomatous disease and with antibodies to Kx and Km

BACKGROUND AND OBJECTIVES

Kell antigens are encoded by the KEL gene on the long arm of chromosome 7. Kx antigen is encoded by the XK gene on the short arm of the X chromosome. Kell and Kx proteins in the red cell membrane are covalently linked by a disulphide bond. The McLeod phenotype is characterized by weakened expression of antigens in the Kell blood group system, absence of Km and Kx antigens, and acanthocytosis. It has an X-linked mode of inheritance with transmission through carrier females. Some males with the McLeod syndrome also have chronic granulomatous disease (CGD). It is generally believed that patients with non-CGD McLeod may develop anti-Km but not anti-Kx, but that those with CGD McLeod can develop both anti-Km and anti-Kx.

MATERIALS AND METHODS

We present serological data, DNA genotyping and gene sequencing, monocyte monolayer assay and neutrophil oxidative burst test from a patient with the McLeod phenotype without clinical evidence of CGD.

RESULTS

We report here the second example of a patient with non-CGD McLeod who developed anti-Kx in addition to anti-Km. Sequencing of our patient's XK gene confirmed the presence of a mutation resulting in a premature stop codon and lack of Kx protein in the red cell membrane, which is consistent with the diagnosis of McLeod syndrome. Neutrophil oxidative burst test was normal, indicating that our patient did not have CGD. The challenge of providing 10 compatible blood units for multiple surgeries was met.

CONCLUSION

The second case of a rare entity, a patient with non-CGD McLeod who developed anti-Kx and anti-Km, was managed successfully with a combination of autologous donations and procurement of compatible units from national and international sources.