Granulocyte antibodies in Korean neonates with neutropenia

Phenotyping and Genotyping of HNA: Prevalence, Risk of Alloimmunization, and HNA Incompatibilities in Indians

Background

Antibodies to human neutrophil alloantigens (HNA) are involved in the pathophysiology of several clinical conditions including transfusion-related acute lung injury (TRALI), alloimmune and autoimmune neutropenia, and febrile nonhemolytic transfusion reactions leading to neutropenia. The cognate antigens are polymorphic structures expressed on several glycoproteins on the neutrophils, i.e., antigens HNA-1a, -1b, -1c, and -1d on Fc-γ-receptor IIIb; HNA-2 on CD177; HNA-3a and -3b on choline transporter-like protein 2; HNA-4a and -4b on CD11b/αM subunit of the αMβ2-integrin (CD11b/CD18, Mac-1, CR3); and HNA-5a and -5b on αL-subunit (CD11a) of the αLβ2 integrin (CD11a/CD18), leukocyte function associated molecule (LFA)-1. Currently, there is a lacuna of diagnostic methods for detection of HNA in India. This study aimed to determine the HNA frequencies in Indians, estimate the risk of alloimmunization, and prepare typed neutrophil panels, which can be used to detect HNA antibodies in neutropenia cases.

Material and Methods

EDTA blood samples were collected from random 1,054 blood donors. HNA-2 was phenotyped on fresh EDTA samples using FITC labelled monoclonal anti-CD177 by flowcytometry. HNA-1 (FCGR3B) genotyping was carried out by DNA sequencing and PCR-RFLP. Antigens of HNA-3 (SLC44A2) and HNA-5 (ITGAL) were genotyped by PCR-RFLP using TaqαI and Bsp1286I restriction enzymes, respectively, while HNA-4 (ITGAM) was genotyped by PCR-SSP.

Results

Allele frequencies of FCGR3B*01, FCGR3B*02, and FCGR3B*03 were found to be 0.433, 0.444, and 0.087, respectively. FCGR3B*01+*02+*03- was the most common genotype (33.78%). Ten individuals showed deficiency of FCGR3B individuals, while 23 showed hyperexpression, i.e., FCGR3B*01+*02+*03+. FCGR3B*04and *05 occurred with a frequency of 0.002 and 0.024. HNA-2 was found to be a high frequency antigen occurring in 98.8% population. Four percent individuals showed atypical expression of CD177 on their neutrophils. Allele frequencies of SLC44A2*01 and SLC44A2*02were 0.812 and 0.188, respectively, and that of ITGAM*01, ITGAM*02, ITGAL*01, and ITGAL*02 were 0.9546, 0.0454, 0.2372, and 0.7628, respectively.

Conclusion

This is the first study in India to report the frequencies of HNA among blood donors. Typed neutrophil panels identified in the present study will enable us to investigate suspected cases of immune neutropenia in future.

Neonatal alloimmune neutropaenia: Experience from an Australian paediatric health service

AIM

To describe the presenting features and investigation findings in infants diagnosed with neonatal alloimmune neutropaenia (NAIN) within an Australian paediatric health network. The secondary aim was to describe the management and resolution of neutropaenia in infants with NAIN.

METHODS

A retrospective cohort study was conducted at Monash Children's Hospital, Melbourne, Australia. Infants referred to the Victorian Transplantation and Immunogenetics Service for evaluation of NAIN were identified and medical records were reviewed. Descriptive statistical analysis of infants' clinical outcomes, investigation findings and management was performed.

RESULTS

Nine infants were diagnosed with NAIN between December 2004 and June 2017. Overall incidence of NAIN was around 1 per 10 000 births. Median gestational age was 38 (range 35-40) weeks and birthweight was 2920 (2300-4445) g. Median age at NAIN work-up was 7 (2-33) days. Prior to investigation for NAIN, median absolute neutrophil count was 0.2 (0.01-0.6) × 10⁹ cells/L. The post-natal ward was the source of presentation in most infants (78%). All except one infant were admitted to a neonatal unit and commenced on intravenous antibiotics (89%). Six infants were asymptomatic but received antibiotics for risk of infection (75%). Granulocyte-colony stimulating factor was administered to 44% of infants due to neutropaenia with presumed or confirmed infection. NAIN resolved at median age of 32 (6-200) days.

CONCLUSIONS

Infants with NAIN frequently presented with severe, unexpected neutropaenia without major infection. Intravenous antibiotic therapy and granulocyte-colony stimulating factor use was common in this cohort.

Idiopathic neutropenia of infancy: Data from the Italian Neutropenia Registry

Autoimmune neutropenia of infancy (AIN) is characterized by low risk of severe infection, tendency to spontaneously resolve and typically onset at ≤4-5 years of age; it is due to auto-antibodies whose detection is often difficult. In case of negativity of 4 antineutrophils autoantibody tests, after having excluded ethnic, postinfection, drug induced, or congenital neutropenia, according to the Italian guidelines the patients will be defined as affected by "idiopathic neutropenia" (IN). We describe the characteristics of 85 IN patients enrolled in the Italian neutropenia registry: they were compared with 336 children affected by AIN. The 2 groups were clinically very similar and the main differences were detection age (later in IN), length of disease (longer in IN) and, among recovered patients, age of spontaneous recovery: the median age at resolution was 2.13 years in AINs and 3.03 years in INs (P = .00002). At bivariate analysis among AIN patients earlier detection age (P = .00013), male sex (P = .000748), absence of leucopenia (P = .0045), and absence of monocytosis (P = .0419) were significantly associated with earlier recovery; in the IN group only detection age (P = .013) and absence of monocytosis (P = .0333) were significant. At multivariate analysis detection age and absence of monocytosis were independently significant (P = 6.7e-05 and 4.4e-03, respectively) in the AIN group, whereas in the IN group only detection age stayed significant (P = .013).

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.

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.

FCGR3B gene frequencies among ethnic Thai blood donors from a regional hospital in Eastern Thailand

The FCGR3B gene encodes three human neutrophil antigens which consist of HNA-1a, HNA-1b, and HNA-1c. These antigens are encoded by three alleles in the FCGR3B locus: FCGR3B*01, FCGR3B*02, and FCGR3B*03 alleles, respectively. The frequencies of FCGR3B alleles have been reported in different ethnic populations. This study compared the FCGR3B gene frequencies among 230 unrelated healthy Eastern Thai blood donors in Rayong hospital with the previously published studies. The polymerase chain reaction-sequence-specific primers method was performed to determine FCGR3B genotypes. The results showed that the allele frequencies of FCGR3B*01, FCGR3B*02, and FCGR3B*03 were 0.722, 0.274, and 0.009, respectively. The FCGR3B*01 and FCGR3B*02 frequencies found in the Eastern Thais were similar to the previous reports investigating in Northern Thais, Chinese Han, Taiwanese, and Japanese populations. Interestingly, our data showed statistically significant difference (P < 0.05) to Central Thais, Korean, Indian, Turkish, Australian, Tunisian, American, German, and Italian populations. In addition, one FCGR3Bnull , which represents a gene deletion, was also found in this study. This information is important not only for the assessment of neutrophil antibody-mediated clinical conditions and for disease association studies but also for anthropological studies.

Management and outcome of 35 cases with foetal/neonatal alloimmune neutropenia

AIM

The aim of this study was to provide an overview of foetal/neonatal alloimmune neutropenia (FNAIN), together with advice on the clinical management.

METHODS

Neutrophil serology in the Netherlands is centralised at Sanquin Diagnostic Services. We examined FNAIN cases between January 1, 1991, and July 1, 2013, to determine the number of cases diagnosed, the relationship with human neutrophil antigen (HNA) antibody, the clinical presentation and therapeutic interventions.

RESULTS

We identified 35 FNAIN cases. The detected HNA antibodies were as follows: anti-HNA-1a (n = 7), anti-HNA-1b (n = 12), anti-HNA-1c (n = 2), anti-HNA-2 (n = 8), anti-HNA-3a (n = 1), anti-HNA-5a (n = 1) and anti-FcγRIIIb (n = 4). No infections were diagnosed in 14 neonates, and the other 21 neonates suffered from omphalitis (n = 6), urinary tract infection (n = 1), candida mucositis (n = 1), fever of unknown origin (n = 6) and sepsis (n = 7, 20%). Parity, gestational age, birthweight, neutrophil counts and antibody specificity were not significantly different for cases with, and without, infections. All the infected children were treated with antibiotics. No children died.

CONCLUSION

More than half (21) of the 35 cases of FNAIN presented with infections and most implicated were HNA-1a, HNA-1b and HNA-2. Treatment with antibiotics seemed adequate. A neonatal neutropenia workflow model for use in neonatal intensive care units is presented.

Alloimmune neonatal neutropenia in Croatia during the 1998-2008 period

PROBLEM

The aim of this study was to estimate the incidence of the disease and to analyze laboratory data of 23 newborns undergoing serologic testing for alloimmune neonatal neutropenia (ANN) during the 1998-2008 period in Croatia.

METHOD OF STUDY

Laboratory data on 23 newborns undergoing serologic testing for ANN during the 1998-2008 period and epidemiologic data on the number of live births in Croatia were analyzed. Laboratory testing for ANN included serologic screening of maternal and neonatal sera and granulocytes (neutrophils) by immunofluorescence (IF) method. The monoclonal antibody immobilization of neutrophil antigens (MAINA) was employed to determine anti-HNA antibody specificity.

RESULTS

Anti-HNA antibodies were detected in seven (54%) of 13 cases of serologically positive ANN. Only anti-HLA class I antibodies were demonstrated in four (31%) of 13 cases In the 2007-2008 period of prospective data collection, the number of serologically verified ANN cases was one case per 17,323 live births. Results of the prospective study conducted at Maternity Ward, Department of Gynecology and Obstetrics, Sestre milosrdnice University Hospital Center yielded the ANN incidence of one case per 2843 live births.

CONCLUSION

Monitoring of neutrophil count in neonatal blood and serologic testing for ANN in case of isolated neutropenia in the newborn contributed considerably to timely detection of ANN.

DESCRIPTORS

Neonatal alloimmune neutropenia-incidence, serologic diagnosis, antineutrophil antibodies, anti-HNA, anti-HLA class I, Croatia.

Antibiotic-induced severe neutropenia with multidrug-dependent antineutrophil antibodies developed in a child with Streptococcus pneumoniae infection

Drug-induced neutropenia (DIN), particularly that in which antibiotic-dependent antineutrophil antibodies have been detected, is a rare disorder. We report the case of a child with pneumococcal pneumonia, who experienced severe neutropenia during various antibiotic treatments. We detected 4 kinds (cefotaxim, augmentin, vancomycin, and tobramycin) of antibiotic-dependent antineutrophil antibodies by using the mixed passive hemagglutination assay (MPHA) technique with this child.

Comparison of acute non-haemolytic transfusion reactions in female and male patients receiving female or male blood components

To study the relationship between antibodies detected in patients’ and/or donors’ sera and the clinical features of acute non-haemolytic transfusion reactions (ANHTRs), and to determine any gender-related difference. ANHTRs range from urticaria to transfusion-related acute lung injury (TRALI). Antibodies to human leukocyte antigen (HLA), granulocytes, platelets, and/or plasma proteins are implicated in some of the ANHTRs. A higher antibody positivity is expected for females than for males. A comparative study of ANHTRs for antibody positivity and their clinical features between females and males for both patients and donors is helpful for characterizing ANHTRs including TRALI more clearly, but such studies are few and outdated. Two hundred and twenty-three ANHTR cases reported by 45 hospitals between October 2000 and July 2005 were analysed. The patients and 196 donors of suspect blood products were screened for antibodies to HLA Class I, HLA Class II, granulocytes, and platelets. The patients were also screened for anti-plasma protein antibodies. The types and severity of ANHTR did not differ significantly between female and male patients. The frequency of the anti-HLA antibodies, but not that of the non-HLA antibodies, was significantly higher in females. Non-HLA antibodies were significantly associated with severe reactions in females. All the TRALI cases had predisposing risk factors for acute lung injury, and 60% of the cases showed anti-leucocyte antibodies. Although the anti-HLA antibodies were detected more frequently in females than males, no significant association of ANHTRs including TRALI with gender, not only for patients, but also for donors, could be shown in this study.

Neutrophil-specific antigen HNA-2a, NB1 glycoprotein, and CD177

PURPOSE OF REVIEW

Several advances have been made in characterization of the molecule that carries human neutrophil antigen (HNA)-2a, NB1 glycoprotein, the gene that encodes NB1 glycoprotein, CD177, and the role of antibodies to HNA-2a in transfusion reactions.

RECENT FINDINGS

NB1 glycoprotein binds to the endothelial cell adhesion molecule, platelet endothelial cell adhesion molecule-1 (PECAM-1), and participates in neutrophil transmigration. The overexpression of neutrophil CD177 mRNA has become a useful, but nonspecific biomarker of myeloproliferative diseases, especially polycythemia vera. CD177 mRNA overexpression is also a biomarker of a subset of patients with essential thrombocythemia who are at increased risk of thromboembolic complications. In patients with myeloproliferative disorders CD177 mRNA overexpression is secondary to a gain-of-function mutation in JAK2, JAK2 V617F. NB1 glycoprotein is co-localized on neutrophil plasma membranes with proteinase 3 and a complex of NB1 glycoprotein and proteinase 3 may initiate the activation of neutrophils by antineutrophil cytoplasmic antibodies in patients with Wegener's granulomatosis. The inadvertent transfusion of antibodies to HNA-2a with blood components frequently causes pulmonary transfusion reactions.

SUMMARY

The expression of CD177 is an important biomarker of myeloproliferative diseases, NB1 glycoprotein is a ligand for PECAM-1 and it may have a role in Wegener's granulomatosis, and antibodies to HNA-2a frequently cause pulmonary transfusion reactions.