Efficacy of prophylactic use of trimethoprim-sulfamethoxazole in autoimmune neutropenia in infancy

Clinical significance of human neutrophil antigen-1 antibodies in children with neutropenia

Primary autoimmune neutropenia in young children is characterized by chronic neutropenia and positivity for antibodies against human neutrophil antigens (HNAs). This study analyzed the clinical characteristics of 402 children with neutropenia to identify differences between those with and without HNA-1 antibodies (HNA1abs). HNAabs in sera were detected by granulocyte immunofluorescence testing using flow cytometry. Relative fluorescence intensity (RFI) values were used to divide patients into positive (PG, n = 302), borderline (BG, n = 34), and negative (NG, n = 66) groups. The antibodies reacted to HNA-1a alone (59%), HNA-1b alone (1%), and HNA-1a/1b (40%). The PG had a significantly lower absolute neutrophil count before definitive diagnosis and a 1.6- to 2-times greater risk of hospitalization during neutropenia than the other groups. The median duration of neutropenia was longest in the PG at 25 months, followed by 20 months in the BG and 14 months in the NG. This large-scale cohort characterizes clinically distinct groups using the RFI value for HNA1abs in young children with neutropenia. Detection of HNA1abs may aid in understanding the clinical characteristics of children with neutropenia.

Pediatric Benign Neutropenia: Assessing Practice Preferences in Canada

Pediatric benign neutropenia is a self-limited condition with a benign clinical course. An approach to this condition is not well-defined in the literature. Our objective was to use a case-based survey to elucidate trends in the diagnosis and management of benign neutropenia among pediatric hematology/oncology practitioners in Canada. We received 46 completed surveys (response rate 66%). At initial presentation with fever and neutropenia, 67% of respondents recommended partial septic workup but 11% recommended no investigations. Nearly 70% recommended admission for empiric intravenous antibiotics, while 24% would discharge home without antibiotics. In a patient with fever and known neutropenia, respondents were more likely to pursue outpatient antibiotic therapy. For investigation of chronic neutropenia, most respondents (60%) do not use antineutrophil antibody testing. Common indications for bone marrow biopsy were severe infection, prolonged neutropenia, or before initiating granulocyte colony stimulating factor. Indications for granulocyte colony stimulating factor were based on severity and frequency of infection. Most respondents (84%) would not recommend antibiotic prophylaxis. Results demonstrate the considerable variability in management of benign neutropenia among pediatric hematology/oncology practitioners in Canada and highlight the need for prospective studies to establish diagnostic criteria for benign neutropenia and evaluate management of fever in this population.

Diagnosis of autoimmune neutropenia in a 10-month-old boy - a case report

Neutropenia, congenital or acquired, is related to impaired granulocyte production in the bone marrow or increased destruction by antibodies. Autoimmune neutropenia of infancy (AIN) is associated with the occurrence of antineutrophil antibodies. AIN is the most common cause of neutropenia in infants and young children. However, its incidence is low. Detection of anti-neutrophil antibodies is an important step in confirming the diagnosis of AIN, although their detection is difficult due to low titer and poor avidity. In differential diagnosis, another cause of neutropenia should be considered, such as a drug-induced mechanism, viral infection, autoimmune and metabolic disease, hematological conditions or immune deficiency syndromes. Despite the benign course of AIN, serious infectious complications can occur. Spontaneous remission of neutropenia was observed in 95% of patients during 24 months of follow-up. We present a case of a 10-month-old boy with deafness, heart defect and Morgagni-Larrey hernia diagnosed in our department because of formation of a skin abscess due to autoimmune neutropenia.

Efficacy of using trimethoprim-sulfamethoxazole prophylaxis in an adult patient with autoimmune neutropenia

A 63-year-old man was admitted for pneumonia with neutropenia. After the pneumonia resolved with administration of antibiotics and granulocyte colony-stimulating factor, he was diagnosed with autoimmune neutropenia (AIN) on the basis of bone marrow findings and positive antineutrophil antibodies. He had recurring high fever once or twice a month with productive cough and an elevated serum C-reactive protein level. However, after the initiation of treatment with oral trimethoprim-sulfamethoxazole (TMP/SMX), the respiratory tract infection no longer recurred. The standard management for adults with AIN has not been established. In our case, the recurrent infection was resolved with TMP/SMX prophylaxis. Thus, TMP/SMX prophylaxis may be beneficial for managing adults with AIN.

Chronic Neutropenia in Children With Abscess Forming Cervical Lymphadenitis Caused by Staphylococcus aureus

BACKGROUND

Suppurative cervical lymphadenitis is rare in children with limited information about the frequency of neutropenia in any series.

METHODS

We conducted a retrospective review of pediatric patients in whom suppurative cervical lymphadenitis was diagnosed between April 2011 and March 2016 at a tertiary children's hospital in Tokyo, Japan. Microbiologically confirmed cases of cervical lymphadenitis with abscess formation were included in the analysis.

RESULTS

Twenty-five patients (median age, 1 yr old; 64% female) with abscess formation caused by Staphylococcus aureus were identified. Among these 25 patients, 5 (20%) met the criteria for chronic neutropenia and 4 (80%) received the final diagnosis of autoimmune neutropenia based on the identification of the serum anti-CD16 antibodies.

CONCLUSIONS

Chronic neutropenia and autoimmune neutropenia were relatively common among infants with suppurative cervical lymphadenitis caused by S. aureus.

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.

Diagnosis and management of primary autoimmune neutropenia in children: insights for clinicians

Autoimmune neutropenia of infancy (AIN), also called primary autoimmune neutropenia, is a disease in which antibodies recognize membrane antigens of neutrophils, mostly located on immunoglobulin G (IgG) Fc receptor type 3b (FcγIIIb receptor), causing their peripheral destruction. It is the most frequent type of neutropenia in children under 3-4 years of age and in most cases shows a benign, self-limited course. The diagnosis is based on evidence of indirect antineutrophil antibodies, whose detection frequently remains difficult. In this review we have analyzed the literature regarding AIN and present our personal experience in diagnosis and management.

An infant with chronic severe neutropenia

Neutropenia in infancy and childhood poses a diagnostic challenge as the aetiology ranges from acute life-threatening conditions to chronic benign diseases. Chronic benign neutropenia of infancy is a rare disorder occurring in 1:100,000. The neutrophil count continues to be low for a prolonged period until spontaneous resolution by the age of 3-4 years. Such infants are having higher incidences of minor infections requiring treatment with antibiotics and rare incidences of meningitis and sepsis. The authors describe an infant presenting with fever and cervical lymphadenitis, who was found to have isolated severe neutropenia and its persistence posing a diagnostic challenge. The prolonged course with minor infections and absence of serious underlying conditions finally confirmed chronic benign neutropenia of infancy.

Ela2 mutations and clinical manifestations in familial congenital neutropenia

PURPOSE

Three familial cases of each of severe congenital neutropenia (SCN) and cyclic neutropenia (CN) in addition to 3 sporadic cases of SCN were analyzed for neutrophil elastase (Ela2) gene mutation. The contents of the neutrophil-specific granule proteins cathelicidin antimicrobial peptide and neutrophil gelatinase-associated lipocalin were also analyzed in SCN.

METHODS

Genomic DNA was extracted from the patients' peripheral blood or bone marrow, and the coding sequence of the Ela2 gene was amplified by polymerase chain reaction and subjected to direct sequencing. The contents of antimicrobial peptides were analyzed by flow cytometry.

RESULTS

Three cases of familial SCN (P13L, R52P, and S97L), 2 of familial CN (W212stop and P110L), and 1 of sporadic SCN (V72M) were shown to have heterozygous mutations in the Ela2 gene. W212stop found in a familial CN case was a novel mutation of Ela2. Prophylactic treatment for growth factors or antibiotic prophylaxis against bacterial infection was useful for lowering the frequency of infectious episodes. Adult patients tended to have less frequent infections compared with minors in the same family. The contents of both cathelicidin antimicrobial peptide and neutrophil gelatinase-associated lipocalin were significantly reduced in SCN compared with healthy controls.

CONCLUSIONS

Prophylaxis by growth factor or antibiotics is useful for decreasing risks of bacterial infections in SCN and CN. Adults were likely to have less frequent infections than children in familial cases of SCN and CN with the same mutation of Ela2.

[Autoimmune thrombocytopenia, neutropenia and hemolysis]

Autoantibodies reduce the life span of platelets, granulocytes, and red blood cells. This may result in thrombocytopenia with bleeding, in neutropenia with infection, and in anemia, respectively. Immune-hemocytopenias can manifest as primary disease without another cause, or they are associated with other underlying morbidities such as autoimmune diseases, lymphoproliferative diseases, immune defects, or viral infections. Diagnosis is confirmed by laboratory tests showing autoantibodies against the respective blood cells. Indication for treatment is the clinical manifestation of symptoms: bleeding in autoimmune thrombocytopenia, infections in neutropenia, and symptomatic anemia, respectively. Especially in case of thrombocytopenia patients should not be treated because of abnormal laboratory values, only. To date steroids are the basic treatment in autoimmune thrombocytopenia and hemolytic anemia, while prophylactic antibiotics are the main treatment in autoimmune neutropenia. Growth factors like the new thrombopoietin receptor agnonists in autoimmune thrombocytopenia or G-CSF in autoimmune neutropenia, and anti-CD20 antibodies are new options for treatment.

Primary autoimmune neutropenia in children: a study of neutrophil antibodies and clinical course

BACKGROUND AND OBJECTIVES

Primary autoimmune neutropenia (AIN) in children is characterized by severe neutropenia, but mild bacterial infections and a spontaneous resolution. Neutrophil autoantibodies are involved in the disease. The precise relationship between the specificity and level of reactivity of the antibodies with the absolute neutrophil count and frequency of infections is not known. To obtain a better insight into this relationship, we performed a follow-up study in 15 patients with primary AIN. In addition, we performed two different neutrophil antibody tests to evaluate their sensitivity and specificity.

MATERIALS AND METHODS

Blood samples from 15 children were tested for neutrophil antibodies, at different time-points during the disease, by using the indirect granulocyte immunofluorescence test (GIFT) and the monoclonal antibody-specific immobilization of granulocyte antigens (MAIGA) assay. Clinical data related to the occurrence of bacterial infections and treatment, and neutrophil counts were collected.

RESULTS

Early in the disease, antibodies with pan-FcRIIIb specificity were detected, and HNA-1a or HNA-1b specificity of the antibodies developed over time. The sensitivity and specificity of neutrophil antibody detection tests were higher in the GIFT than in the MAIGA assay. Variables predicting time of recovery from neutropenia were not found. Prophylactic antibiotics led to the almost complete disappearance of infections.

CONCLUSIONS

In patients with primary neutropenia, neutrophil antibody specificity changes over time. Prophylactic antibiotics do benefit the patients.