Autoimmune neutropenia associated with influenza virus infection in childhood: a case report

Abstract

Background Although neutropenia is relatively frequent in infants and children and is mostly a benign condition with a self-limited course, it can lead to life-threatening severe infections. Autoimmune neutropenia is a relatively uncommon hematological disorder characterized by the autoantibody-induced destruction of neutrophils. It is usually triggered by viral infections with very few documented cases after influenza virus. Case presentation An 8-month-old male infant presented at the emergency room with a 5-days history of fever up to 39.7 °C, cough and runny nose. In the blood test performed, severe neutropenia was diagnosed (neutrophils 109/μL). A nasopharyngeal aspirate revealed a positive rapid test for Influenza A. Serum antineutrophil antibodies were determined with positive results. Neutropenia targeted panel showed no mutations. Despite maintenance of severe neutropenia for 9 months the course was uneventful without treatment. Conclusions When severe neutropenia is diagnosed and confirmed, it is essential to rule out some potential etiologies and underlying conditions, since the appropriate subsequent management will depend on it. Although autoimmune neutropenia triggered by viral infections has been widely reported, it has seldom been reported after influenza infection. The benign course of the disease allows a conservative management in most cases.

HNA specificity and association to HLA-DRB1 and -DQB1 in patients with autoimmune neutropenia of early childhood

“…In the case of AIN, there is not yet enough data to propose a genetic or environmental cause. A possible event trigger- n = number of cases † One sample was inconclusive ing AIN is viral infection [4] , initiating the activation of autoreactive B cells and CD4 + T cells, but research also points to a general deficiency in peripheral self-tolerance, mediated by an alteration in either the function or number of CD4 + Tregs cells [26] . Activation of Tregs is HLA restricted, and certain HLA genotypes protect or increase susceptibility to autoimmune diseases through Tregs cells.…”

“…Information regarding the cause of this disease is limited due to the scarce data on the triggering etiology. Viral infections have been suggested as a possible trigger [4] .…”

Neutrophils in Inflammatory Diseases: Unraveling the Impact of Their Derived Molecules and Heterogeneity

“…These viruses can cause neutrophil apoptosis by a variety of complex mechanisms/pathways, including the secretion of ROS and cytokines [78][79][80]. When these viruses cause enhanced apoptosis of neutrophils, they can induce neutropenia, potentially weakening the immune response to infection [81,82]. In contrast, delaying neutrophil apoptosis has the potential to worsen tissue damage and accelerate viral clearance.…”

Pathogenesis of Autoimmune Cytopenias in Inborn Errors of Immunity Revealing Novel Therapeutic Targets

“…Spontaneous resolution is frequently observed in most cases within months. Children with AIN rarely suffer from severe or invasive or life-threatening infections despite severe neutropenia ( 14 ), because circulating neutrophils, although low in number, can display normal anti-microbial activity and they often increase in number during the acute event ( 18 ).…”