Reversal of Immunoglobulin A Deficiency in Children.

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. 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). 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. 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.