A functional PTPN22 polymorphism associated with several autoimmune diseases is not associated with IgA deficiency in the Spanish population.
BACKGROUND
The 1858C/T SNP of the PTPN22 gene has been associated with many autoimmune diseases, suggesting the existence of an inflammatory process common to all of them. We studied the association of that polymorphism with immunoglobulin A deficiency (IgAD) following a double approach: a case-control and a TDT study.


METHODS
A total of 259 IgAD patients and 455 unrelated matched controls, and 128 families were used for each approach. Comparisons were performed using Chi-Square tests or Fisher's exact test when necessary.


RESULTS
No association between the PTPN22 1858C/T SNP and IgA deficiency was found in any case (allelic frequencies 8% vs. 6% in patients and controls, respectively, OR= 1.14 (0.72-1.79), p= 0.56; TDT p = 0.08).


CONCLUSIONS
The result obtained seems to reinforce the consideration of IgA deficiency as a primary immunodeficiency rather than an autoimmune disease.
Department of Clinical Immunology, Hospital Clínico San Carlos, Madrid, Spain. connunez@usc.es
Concepción
C
Núñez
Raquel
R
López-Mejías
Alfonso
A
Martínez
M Cruz
MC
García-Rodríguez
Miguel
M
Fernández-Arquero
Emilio G
EG
de la Concha
Elena
E
Urcelay
D001327:Autoimmune Diseases / Q000235:genetics; D016022:Case-Control Studies; D005787:Gene Frequency; D020022:Genetic Predisposition to Disease; D005838:Genotype; D006801:Humans; D017098:IgA Deficiency / Q000208:ethnology / Q000235:genetics*; D020641:Polymorphism, Single Nucleotide; D054596:Protein Tyrosine Phosphatase, Non-Receptor Type 22; D017027:Protein Tyrosine Phosphatases / Q000235:genetics*; D013030:Spain
C516765:PTPN22 protein, human; D054596:Protein Tyrosine Phosphatase, Non-Receptor Type 22; D017027:Protein Tyrosine Phosphatases