Autoimmune neutropenia
Autoimmune neutropenia (AIN) is a form of neutropenia which is most common in infants and young children[1] where the body identifies the neutrophils as enemies and makes antibodies to destroy them.
| Autoimmune neutropenia | |
|---|---|
| Other names | Autoimmune neutropenia of infancy and Primary autoimmune neutropenia |
| Pronunciation |
|
| Specialty | Hematology |
| Symptoms | Weak immune system, mouth ulcers, sore throat, lethargy, high fever and chills |
| Usual onset | Present from Birth |
| Duration | Disappears or weakens by age three |
| Causes | Autoimmune abnormality |
| Diagnostic method | Blood tests |
| Treatment | Granulocyte colony-stimulating factors (G-CSF) |
| Medication | Corticosteroids and antibiotics |
| Prognosis | Disappears or weakens by age three |
| Frequency | In the U.s: 1 per 100,000 newborns |
| Deaths | None Recorded |
Primary autoimmune neutropenia, another name for autoimmune neutropenia, is an autoimmune disease first reported in 1975 that primarily occurs in infancy.[2] In autoimmune neutropenia, the immune system produces autoantibodies directed against the neutrophilic protein antigens in white blood cells known as granulocytic neutrophils, granulocytes, segmented neutrophils, segs, polysegmented neutrophils, or polys. These antibodies, IgG antibodies, destroy granulocytic neutrophils.[3] Consequently, patients with autoimmune neutropenia have low levels of granulocytic neutrophilic white blood cells causing a condition of neutropenia. Neutropenia causes an increased risk of infection from organisms that the body could normally fight easily.
Primary autoimmune neutropenia has been reported as early as the second month of life although most cases are diagnosed in children between 5 and 15 months of age.[3] Girls have a slightly higher risk of developing AIN than boys as well as do people of Caucasian background.[4] In neutropenia discovered at birth or shortly after birth, a diagnosis of allo-immune neutropenia (from maternal white blood cell antibodies passively transferred to the infant) is more likely.
In infants neutropenia is defined by absolute neutrophil counts less than 1000/uL. After the first year of life neutropenia is defined by absolute counts less than 1500/uL. Neutropenia may be primary in which it is the only blood abnormality seen. In secondary neutropenia, other primary conditions occur, including other autoimmune diseases, infections, and cancers. Neutropenia is considered chronic when it persists for more than 6 months.
Signs and symptoms
Neutropenia, which may be discovered on routine blood tests, typically causes benign infections even when the condition is severe. Ear infections (otitis media) are the most common infection seen in autoimmune neutropenia and typically infection responds to antibiotic treatment alone. Infections associated with primary AIN are usually mild and limited, including skin infections such as impetigo, gastroenteritis, upper respiratory tract infections, and ear infections. Rarely, cellulitis and abscesses may occur.[5] Studies of children studied for up to six years showed that most cases of autoimmune neutropenia resolved spontaneously after a median of 17 months. In 95 percent of patients, neutropenia persisted for 7 to 24 months.[1]
Diagnosis
The diagnosis of autoimmune neutropenia is based on blood tests demonstrating neutropenia and the presence of granulocyte-specific antibodies. In some cases, tests for granulocyte-specific antibodies must be repeated several times before a positive result is seen. Bone marrow aspiration, if performed, is typically normal or it can show increased cell production with a variably diminished number of segmented granulocytes.[2]
An association with prior parvovirus B19 has been made, but this hasn’t been confirmed.[1]
Treatment
Treatment consists of corticosteroids to reduce autoantibody production and antibiotics to prevent infection.
Granulocyte colony-stimulating factor (G-CSF) is recommended to temporarily increase neutrophil counts in patients with absolute neutrophil counts (ANC) of less than 0.5 x 109/l and recurrent fever or infections.[6][7]
In cases of severe infection or the need for surgery, intravenous immunoglobulin therapy may be used.[8]
Prognosis
This form of neutropenia disappears in two to three years of a child's life in 95% of cases.[3]
The use of prophylactic antibiotics has been successfully demonstrated to reduce infection incidence without causing adverse effects among the 5% of children whose condition does not resolve itself.[9][10]
References
- Bux J, Behrens G, Jaeger G, Welte K (January 1998). "Diagnosis and clinical course of autoimmune neutropenia in infancy: analysis of 240 cases". Blood. 91 (1): 181–6. doi:10.1182/blood.V91.1.181. PMID 9414283.
- Farruggia P, Dufour C (February 2015). "Diagnosis and management of primary autoimmune neutropenia in children: insights for clinicians". Therapeutic Advances in Hematology. 6 (1): 15–24. doi:10.1177/2040620714556642. PMC 4298488. PMID 25642312.
- Capsoni F, Sarzi-Puttini P, Zanella A (2005). "Primary and secondary autoimmune neutropenia". Arthritis Research & Therapy. 7 (5): 208–14. doi:10.1186/ar1803. PMC 1257445. PMID 16207350.
- Ancliff P. "Neutropenia (Severe Chronic)".page=2&f=N&page=2&f=N
- Mayo Clinic staff. "Neutropenia symptoms". mayoclinic.org.
- Newburger PE (December 2016). "Autoimmune and other acquired neutropenias". Hematology. American Society of Hematology. Education Program. 2016 (1): 38–42. doi:10.1182/asheducation-2016.1.38. PMC 5380382. PMID 27913460.
- Dale DC (August 2017). "How I manage children with neutropenia". British Journal of Haematology. 178 (3): 351–363. doi:10.1111/bjh.14677. PMID 28419427. S2CID 44046950.
- Susumu I (29 April 2021). "Pediatric Autoimmune and Chronic Benign Neutropenia Treatment & Management".
- Kobayashi M, Sato T, Kawaguchi H, Nakamura K, Kihara H, Hiraoka A, et al. (July 2003). "Efficacy of prophylactic use of trimethoprim-sulfamethoxazole in autoimmune neutropenia in infancy". Journal of Pediatric Hematology/Oncology. 25 (7): 553–7. doi:10.1097/00043426-200307000-00011. PMID 12847323. S2CID 26673564.
- Bruin M, Dassen A, Pajkrt D, Buddelmeyer L, Kuijpers T, de Haas M (January 2005). "Primary autoimmune neutropenia in children: a study of neutrophil antibodies and clinical course". Vox Sanguinis. 88 (1): 52–9. doi:10.1111/j.1423-0410.2005.00585.x. PMID 15663723. S2CID 22952792.