Resistance to recombinant human granulocyte colony-stimulating factor in neonatal alloimmune neutropenia associated with anti-human neutrophil antigen-2a (NB1) antibodies

Neutrophil antigen antibodies affect engraftment and secondary graft failure in hematopoietic progenitor cell transplantation

BACKGROUND

Research is limited on the role of antibodies against human neutrophil antigen (HNA) in hematopoietic progenitor cell (HPC) transplantation outcomes.

STUDY DESIGN AND METHODS

A retrospective review was conducted on medical records of patients at the NIH Clinical Center enrolled in six research protocols. This case-control study included 21 patients tested for HNA antibodies from January 2010 to March 2022 who underwent HPC transplantation. In addition, 42 patients following the same research protocols were randomly selected as a control group.

RESULTS

The cumulative incidence of time to neutrophil engraftment was significantly impacted by the patients' anti-HNA status (p = .042), with the patients with anti-HNA experiencing delayed engraftment. Secondary graft failure occurred in 4 out of 42 patients (9.52%; 95% confidence interval [CI]: 3.7-22.1) of the control group, while 5 out of 9 patients (55.5%; 95% CI: 26.7-81.1) with anti-HNA experienced secondary graft failure (p = .005). Furthermore, patients with anti-HNA had a lower proportion (p = .008 for full and p = .002 for partial chimerism) and cumulative incidence (p = .016 for full and p = .010 for partial chimerism) of achieving donor chimerism compared to the control group.

DISCUSSION

The study reveals a potential link between anti-HNA and HPC transplantation outcomes not previously reported. Patients with anti-HNA had a lower proportion and cumulative incidence of achieving donor chimerism. Additionally, anti-HNA status affected the time for neutrophil engraftment, with a slower rate of neutrophil engraftment and increased risk of secondary failure in patients with anti-HNA.

The European Guidelines on Diagnosis and Management of Neutropenia in Adults and Children: A Consensus Between the European Hematology Association and the EuNet-INNOCHRON COST Action

Neutropenia, as an isolated blood cell deficiency, is a feature of a wide spectrum of acquired or congenital, benign or premalignant disorders with a predisposition to develop myelodysplastic neoplasms/acute myeloid leukemia that may arise at any age. In recent years, advances in diagnostic methodologies, particularly in the field of genomics, have revealed novel genes and mechanisms responsible for etiology and disease evolution and opened new perspectives for tailored treatment. Despite the research and diagnostic advances in the field, real world evidence, arising from international neutropenia patient registries and scientific networks, has shown that the diagnosis and management of neutropenic patients is mostly based on the physicians' experience and local practices. Therefore, experts participating in the European Network for the Innovative Diagnosis and Treatment of Chronic Neutropenias have collaborated under the auspices of the European Hematology Association to produce recommendations for the diagnosis and management of patients across the whole spectrum of chronic neutropenias. In the present article, we describe evidence- and consensus-based guidelines for the definition and classification, diagnosis, and follow-up of patients with chronic neutropenias including special entities such as pregnancy and the neonatal period. We particularly emphasize the importance of combining the clinical findings with classical and novel laboratory testing, and advanced germline and/or somatic mutational analyses, for the characterization, risk stratification, and monitoring of the entire spectrum of neutropenia patients. We believe that the wide clinical use of these practical recommendations will be particularly beneficial for patients, families, and treating physicians.

[Relevance of antibodies in hematopoietic stem cell transplantation: Antibodies anti-HLA, anti-platelets, anti-granulocytes, anti-erythrocytes and anti-MICA. Guidelines from the Francophone Society of Bone Marrow Transplantation and Cellular Therapy (SFGM-TC)]

The presence of allo-antibodies in the serum of a recipient awaiting hematopoietic stem cell transplantation (HSCT) may have an impact on transfusion efficiency and/or donor choice, especially in the absence of an identical sibling donor. Prior to transplantation, donor specific anti-HLA (Human Leukocyte Antigen) antibodies (DSA) have a recognized effect on transplant outcome, correlated with the increasing MFI value and with the ability of such antibody to fix the complement fraction. Anti-platelet antibodies (anti-HLA class I and anti-HPA [Human Platelet Antigen]) are better involved in transfusion inefficiency and can be responsible for refractory status. ABO incompatibilities require a specific treatment of the graft in presence of high titer to avoid hemolytic adverse effects. Investigations of these antibodies should be carried out on a regular basis in order to establish appropriate transfusion recommendation, select an alternative donor when possible or adapt the source of cells. After transplantation, in case of delayed recovery or graft rejection, long term aplasia, persistent mixed chimerism or late release, and after elimination of the main clinical causes, a biological assessment targeted on the different type of antibodies will have to be performed in order to orient towards the cause or the appropriate therapy. Further studies should be carried out to determine the impact of anti-MICA antibodies and recipient specific anti-HLA antibodies, on the outcome of the transplantation.

Neonatal Alloimmune Neutropenia

Neonatal alloimmune neutropenia (NAIN, NAIN or NIN) is a neutrophil blood group antagonism, analogous to hemolytic disease of the fetus and newborn (HDFN) and fetal/neonatal alloimmune thrombocytopenia (FNAIT). A limited number of prospective screening studies showed that granulocyte-specific antibodies were detectable in 0.35-1.1% of random postnatal maternal samples and that the incidence of NAIN was below 0.1%. Symptoms vary from none to mild skin infections, omphalitis or more severe infections like pneumonia, sepsis, and meningitis. Treatment of neonatal infection with antibiotics and granulocyte-colony stimulating factor is advised.

Prolonged neutropenia due to antihuman neutrophil antigen 2 (CD177) antibody after bone marrow transplantation

We describe a patient who presented with prolonged neutropenia due to anti-human neutrophil antigen (HNA)-2 (CD177) antibody after allogeneic bone marrow transplantation. A granulocyte immunofluorescence test showed bimodal expression of antineutrophil antibody that resulted from specific binding of anti-HNA-2 to CD177⁺ neutrophils from healthy donors. The patient did not respond to granulocyte colony stimulating factor, which is able to upregulate CD177 expression on neutrophils. The low percentage of CD177⁺ cells in the few remaining neutrophils supports the possibility of elimination of CD177-upregulated neutrophils. These findings might explain an inferior response to neutrophil growth factors in neutropenia secondary to anti-HNA-2 antibody.

Immune neutropenias of infancy and childhood

BACKGROUND

Anti-neutrophil antibodies are a well-recognized cause of neutropenia, producing a potential increase in risk of infection: in the majority of patients antibodies react against antigens located on the IgG Fc receptor type 3b (FcRIIIb), but other target antigens have been identified.

DATA SOURCES

In this review the most important papers of auto and alloimmune neutropenias of infancy and childhood were analyzed. PubMed, Google Scholar and Thompson ISI Web of Knowledge were searched for identifying relevant papers.

RESULTS

Primary autoimmune neutropenia of infancy is mostly a benign condition with self-limited course, whereas isolated alloimmune neonatal neutropenia or secondary autoimmune neutropenia may be occasionally complicated by severe infections.

CONCLUSION

Granulocyte colony stimulating factor is an effective therapy for patients affected by all types of autoimmune and alloimmune neutropenia, even though most of them do not need any therapy.

Neutropenia in the newborn

PURPOSE OF REVIEW

The aim is to review normal blood neutrophil concentrations and the clinical approach to neutropenia in the neonatal period. A literature search on neonatal neutropenia was performed using the databases PubMed, EMBASE, and Scopus, and the electronic archive of abstracts presented at the annual meetings of the Pediatric Academic Societies.

RECENT FINDINGS

The review summarizes current knowledge on the causes of neutropenia in premature and critically ill neonates, focusing on common causes such as maternal hypertension, neonatal sepsis, twin-twin transfusion, alloimmunization, and hemolytic disease. The article provides a rational approach to diagnosis and treatment of neonatal neutropenia, including current evidence on the role of recombinant hematopoietic growth factors.

SUMMARY

Neutrophil counts should be carefully evaluated in premature and critically ill neonates. Although neutropenia is usually benign and runs a self-limited course in most neonates, it can be prolonged, and it constitutes a serious deficiency in antimicrobial defense in some infants.

Evaluation of neutropenia and neutrophilia in preterm infants

OBJECTIVE

Neutrophil counts are used routinely as part of the sepsis evaluation in newborn infants. In this article, we review the normal blood neutrophil concentrations and the clinical approach to neutropenia and neutrophilia in the neonatal period.

METHODS

A literature search was performed using the databases PubMed, EMBASE, and Scopus, and the electronic archive of abstracts presented at the annual meetings of the Pediatric Academic Societies.

RESULTS

Neutropenia and neutrophilia are documented frequently in premature infants. Neutropenia can be seen in up to 8% of all infants admitted to neonatal intensive care. Neutrophilia is even more common, reported in up to 40% of all preterm infants.

CONCLUSIONS

Neutrophil counts should be carefully evaluated in premature neonates. Maternal and perinatal history, physical examination, and a limited laboratory assessment is usually adequate for making a diagnosis in most infants.

Neonatal alloimmune neutropenia: still a diagnostic and therapeutical challenge

OBJECTIVE

To describe a case of neonatal alloimmune neutropenia (NAN), a very rare disease of the newborn and the first ever reported in our neonatal intensive care unit, with emphasis in its management and outcome.

DESCRIPTION

We report a case of NAN due to anti-human neutrophil antigen-1b alloimmunization in a 29-week preterm admitted to our neonatal intensive care unit. In this case, the neutropenia was severe and persisted for almost 2 months. There was a good response to the administration of intravenous immunoglobulin.

COMMENTS

NAN is caused by maternal production of neutrophil-specific alloantibodies in response to antigens from paternal heritage present on the newborn neutrophiles. The course of the disease is usually mild and self-limiting. The optimal therapy is yet a debate, with some authors finding the use of intravenous immunoglobulin effective, prophylactic antibiotic therapy or recombinant human granulocyte colony-stimulating factor.

Granulocyte colony stimulating factor in neonatal alloimmune neutropenia: a possible association with induced thrombocytopenia

Neonatal alloimmune neutropenia (NAIN) is a rare cause of congenital neutropenia seen in <1% of births. Significant morbidity, usually infections, may result from this disease. The pathophysiology of NAIN, mediated by maternal antibodies crossing the placenta to destroy fetal cells expressing paternal antigens, is similar to that of neonatal alloimmune thrombocytopenia, as well as Rh/ABO hemolytic disease of the newborn. The use of high-dose granulocyte colony stimulating factor in patients with NAIN may cause a reversible thrombocytopenia in some patients.

A Case of Neonatal Neutropenia Due to Anti-Fc Gamma Receptor IIIb Isoantibodies Treated with Recombinant Human Granulocyte Colony Stimulating Factor

Alloimmunization to granulocyte-specific antigens can occur during pregnancy. Maternal antibodies of IgG class can cross the placenta to result in alloimmune neonatal neutropenia. Antibodies to human neutrophil antigens anti-HNA-1a, HNA-1b, and HNA-2a have been most commonly reported to cause alloimmune neonatal neutropenia. Isoantibodies to Fc gamma RIIIb (CD16) if mother is a HNA-null phenotype are rarely involved in neonatal neutropenia. We report on a case of severe neutropenia (440 neutrophils/μL) due to anti-Fc gamma RIIIb (CD16) isoimmunization. On day 14 severe omphalitis developed, which was treated for 7 days by an antibiotic (ceftriaxone in a dose of 80 mg/kg/d) according to umbilical swab finding. Omphalitis persisted for 10 days in spite of antibiotic therapy and only resolved upon the introduction of rhG-CSF therapy. Therapy with rh-GCSF proved efficient and led to neutrophil count increase to 1970/μL and cure of omphalitis. However, therapeutic effect on granulocyte count was of transient nature, as granulocyte count fell to 760 n/μL on day 4 of therapy discontinuation. Neutropenia persisted for 2 months. The newborn was discharged from the hospital on day 26 with normal clinical status with clinical and laboratory control examinations at 2-week intervals. No additional infections were observed during the course of neutropenia.

Disorders of the fetomaternal unit: hematologic manifestations in the fetus and neonate

Histoarchitectural characteristics of the human placenta place the fetus at a high risk of growth restriction, abnormal fetomaternal cell traffic, and vertical transmission of pathogens. These abnormalities of the fetomaternal unit are frequently associated with hematological abnormalities in the fetus/neonate and may be the first, most common, or the only clinical manifestations of these conditions. This article reviews the pathophysiology and characteristic hematological manifestations of these conditions in the fetus and the neonate.

Human neutrophil alloantigens

OBJECTIVE

This review describes alloantigens currently listed in the human neutrophil alloantigen (HNA) system.

MATERIAL AND METHODS

Review of the literature.

RESULTS

Neutrophil antigens are implicated in a variety of clinical conditions including neonatal immune neutropenia, transfusion-related acute lung injury, refractoriness to granulocyte transfusions, febrile transfusion reactions, immune neutropenia after bone marrow transplantation, autoimmune neutropenia and drug-induced immune neutropenia. Seven antigens have been listed in the HNA system that are assigned to five antigen groups. Six antigens have been characterized biochemically and molecularly so that their primary structure is now known. As shown by regularly performed international granulocyte immunology workshops, a combination of granulocyte agglutination and immunofluorescence tests together with a panel of typed cells is currently the best means of detection.

CONCLUSIONS

Most of the HNA antigens have been well-characterized so that HNA typing as well as the detection of the corresponding antibodies are now reliably possible. This will improve diagnostics of neutrophil antibody-mediated clinical conditions as well as the prevention of transfusion-related acute lung injury.

Alloimmune neonatal neutropenia due to anti-HNA-2a alloimmunization with severe and prolonged neutropenia but mild clinical course: two case reports

Alloimmunization to granulocyte-specific antigens can occur during pregnancy. Maternal IgG can cross the placenta and result in neonatal neutropenia. The clinical course of alloimmune neonatal neutropenia is usually self-limiting with only mild infection. However, in severe cases complicated with bacterial sepsis it is a potentially life-threatening disorder. The effect of intravenous (IV) immunoglobulin, prophylactic antibiotic therapy, and recombinant human granulocyte-colony stimulating factor is variable and may prove useful in some cases. Two cases of alloimmune neonatal neutropenia due to anti HNA-2a alloimmunization in two siblings are reported. The first neonate was administered IV gammaglobulins to increase the blood neutrophil count, at a standard dosage (0.4 g/kg body weight) for 5 days without response. The second neonate did not receive specific therapy for blood neutrophil count increase. Neutropenia persisted for 2 and 6 months, respectively. The choice and efficacy of specific therapy for neutrophil count increase in the management of alloimmune neonatal neutropenia have not yet been fully defined and require additional evaluation in the majority of cases.

Granulocyte antibodies in Korean neonates with neutropenia

Neonatal alloimmune neutropenia (NAN) is a disease that can cause severe and prolonged neutropenia in neonates. However, no report is available on the incidence of granulocyte antibody in neonates, the target antigen of this antibody, and the estimated incidence of NAN in Korea. Among a total of 856 neonates admitted to a neonatal intensive care unit (NICU) over a five year period, a total of 105 neonates with neutropenia were enrolled in this study. Positive reactions were observed in the sera of six neonates (5.7%, 6/105) by mixed passive hemagglutination assay (MPHA). To confirm the presence of NAN, MPHA and granulocyte antigen typing (HNA-1a, -1b, -2a, -4a, and -5a) were performed on neonatal and maternal blood. To differentiate granulocyte antibody and HLA antibody, MPHA was also performed using HLA antibody adsorbed serum. We confirmed three cases (2.9%, 3/105) of NAN among neonates with neutropenia in which granulocyte antibody specificities (two anti-HNA-1b and one anti-HNA-1a) and fetomaternal granulocyte antigen mismatches were identified. In this study, the estimated incidence of NAN was 0.35% (3/856) among neonates admitted to NICUs in Korea.

A case of neonatal alloimmune neutropenia associated with anti-human neutrophil antigen-1a (HNA-1a) antibody

Neonatal alloimmune neutropenia (NAN) is an uncommon disease of the newborn provoked by the maternal production of neutrophil-specific alloantibodies, whereby neutrophil IgG antibodies cross the placenta and induce the destruction of fetal neutrophils. Affected newborns are usually identified by the occurrence of bacterial infections. The most frequent antigens involved in NAN are the human neutrophil antigen-1a (HNA-1a), HNA-1b, and HNA-2a. We report a neonate who was delivered at 36 weeks and had a severe neutropenia but who responded well to recombinant human granulocyte colony-stimulating factor (rhG-CSF). Anti-HNA-1a antibody was identified by mixed passive hemagglutination assay in both the sera of the baby and the mother. The baby had HNA-1a and HNA-1b but the mother had only HNA-1b on granulocytes. This is the first Korean report of NAN in which the specificity of the causative antibody was identified.

Congenital neutropenia

The term "congenital neutropenia" signifies neutropenia that is present at birth. It includes a wide variety of disorders, some transient and others life long. Some varieties of congenital neutropenia are mild, with blood neutrophil concentrations below normal but not low enough to constitute a significant host defense deficiency. Other varieties of congenital neutropenia are characterized by low blood neutrophil concentrations and a predisposition to repeated infections.

Immune-mediated neutropenia in the neonate

Alloimmune neonatal neutropenia, neonatal autoimmune neutropenia and autoimmune neutropenia of infancy have remained nebulous entities with difficulties in both clinical and laboratory identification. These disorders are reviewed in this article.