title: Reversal of Immunoglobulin A Deficiency in Children.
abstract: OBJECTIVE
  Immunoglobulin A deficiency (IgAD) is the most common primary immunodeficiency in the general population. It is defined as a serum IgA level below or equal to 0.07 g/l with normal IgM and IgG levels in children over the age of 4. However, a few cases of reversal of IgAD at later ages have been observed previously, especially in pediatric patients. This study aimed at investigating the frequency of reversal in a large cohort of children and young adults in order to evaluate the present definition of IgAD.
  
  
  METHODS
  Clinical laboratory records from 654 pediatric IgA deficient patients, 4-13 years of age, were retrieved from five university hospitals in Sweden. Follow up in the children where IgA serum levels had been routinely measured was subsequently performed. In addition, follow up of the IgA-levels was also performed at 4, 8 and 16 years of age in children who were IgA deficient at the age of 4 years in a Swedish population-based birth cohort study in Stockholm (BAMSE).
  
  
  RESULTS
  Nine out of 39 (23.1%) children who were identified as IgAD at 4 years of age subsequently increased their serum IgA level above 0.07 g/L. The average age of reversal was 9.53 ± 2.91 years. In addition, 30 out of the 131 (22.9%) children with serum IgAD when sampled between 5 and 9.99 years of age reversed their serum IgA level with time. The BAMSE follow up study showed a reversal of IgAD noted at 4 years of age in 8 out of 14 IgAD children at 16 years of age (5 at 8 years of age) where 4 were normalized their serum IgA levels while 4 still showed low serum levels of IgA, yet above the level defining IgAD. The results indicate that using 4 years of age, as a cut off for a diagnosis of IgAD may not be appropriate.
  
  
  CONCLUSIONS
  Our findings suggest that a diagnosis of IgAD should not be made before the early teens using 0.07 g/L of IgA in serum as a cut off.
authors.affiliation: Division of Clinical Immunology (F79), Department of Laboratory Medicine, Karolinska Institutet at Karolinska University Hospital Huddinge, SE 14186, Stockholm, Sweden.|Department of Clinical Research, Singapore General Hospital, Academia Discovery Tower Level 9, Research Office 2, 20 College Road, Singapore, 169856, Singapore.
authors.forename: Che Kang
authors.initials: CK
authors.lastname: Lim
authors.affiliation: Department of Clinical Immunology and Transfusion Medicine, Linköping University, SE 58185, Linköping, Sweden.|Department of Clinical and Experimental Medicine, Linköping University, SE 58185, Linköping, Sweden.
authors.forename: Charlotte
authors.initials: C
authors.lastname: Dahle
authors.affiliation: Department of Medicine, Clinical Immunology and Allergy Unit, Karolinska Institutet, SE 17176, Stockholm, Sweden.
authors.forename: Kerstin
authors.initials: K
authors.lastname: Elvin
authors.affiliation: Department of Clinical Immunology and Transfusion Medicine, Sahlgrenska University Hospital, SE 41345, Gothenburg, Sweden.
authors.forename: Bengt A
authors.initials: BA
authors.lastname: Andersson
authors.affiliation: Department of Immunology, Genetics and Pathology, Uppsala University, SE 75185, Uppsala, Sweden.
authors.forename: Johan
authors.initials: J
authors.lastname: Rönnelid
authors.affiliation: Institute of Environmental Medicine, Karolinska Institutet, SE 17176, Stockholm, Sweden.|Sachs' Children and Youth Hospital, Stockholm South General Hospital, SE 11883, Stockholm, Sweden.
authors.forename: Erik
authors.initials: E
authors.lastname: Melén
authors.affiliation: Institute of Environmental Medicine, Karolinska Institutet, SE 17176, Stockholm, Sweden.
authors.forename: Anna
authors.initials: A
authors.lastname: Bergström
authors.affiliation: Department of Laboratory Medicine, Section of Microbiology, Immunology and Glycobiology, Lund University, SE 22185, Lund, Sweden.
authors.forename: Lennart
authors.initials: L
authors.lastname: Truedsson
authors.affiliation: Division of Clinical Immunology (F79), Department of Laboratory Medicine, Karolinska Institutet at Karolinska University Hospital Huddinge, SE 14186, Stockholm, Sweden. Lennart.Hammarstrom@ki.se.
authors.forename: Lennart
authors.initials: L
authors.lastname: Hammarström
mesh_terms: D000293:Adolescent; D000367:Age Factors; D002648:Child; D002675:Child, Preschool; D015331:Cohort Studies; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D017098:IgA Deficiency / Q000175:diagnosis / Q000276:immunology*; D007070:Immunoglobulin A / Q000097:blood; D008297:Male; D012075:Remission, Spontaneous; D013548:Sweden
chemical_list: D007070:Immunoglobulin A
keywords: IgA deficiency; diagnostic definition; reversal