[IL1/IL1 Ra, CTLA-4 and Apo1/Fas genes polymorphisms and susceptibility to IgA nephropathy in Tunisian patients].
BACKGROUND
The IgA nephropathy (IgA-N) is considered the most common form of primary glomerulonephritis and its pathogenic mechanisms are very complex. The study of several genes which encode for immunoregulator molecules in inflammatory and immunological responses during the disease, allowed to describe some number of polymorphisms would be involved in the molecular expression, the road marking, the synthesis and\or the binding to the receptors. So an abnormality of the molecular function associated with its polymorphism would be suggested in the genetic predisposition to the disease.


OBJECTIVE
To determine interleukin 1 (IL1), interleukin1 receptor antagonist (IL1 Ra), CTLA-4 and Apo1/Fas genes polymorphisms frequencies in IgA-N in order to estimate the impact of these polymorphisms in the disease susceptibility.


METHODS
The polymorphism of a single nucleotide (SNP) at (-889) IL1 a of 21 IgA-N patients and 100 healthy blood donors, as controls, was studied by PCRSSP. The SNPs of the IL1 ß (+3954), CTLA-4 (+49) and l'Apo1/Fas were analyzed by PCR RFLP and finally the polymorphism of the IL1 Ra gene was determined by a PCR VNTR (variable number tandem repeat).


RESULTS
Investigation of IL1a/ß and Apo1/Fas polymorphisms showed no differences in genotypes and alleles frequencies between IgA-N patients and controls. However, genotype AA of CTLA-4 exon1 (+49) was significantly higher in patients (47.62%) than in controls (9.1%) p<0.001. Nevertheless, the clinical, histological and biological characteristics of IgA-N were similar in AA CTLA-4 genotype patients compared to AG or GG genotype patients. We fund also, a significant increased frequency of 1/1 IL1 Ra genotype in IgA-N patients (95.24%) compared to controls (54%) (p<0.001) (p<0.001).


CONCLUSIONS
We conclude that the susceptibility to IgA-N seems to be associated with the presence of CTLA-4 AA and IL1 Ra 1/1 genotypes in Tunisian population. However, the lack of association between IL1 a/ß and Apo1/fas genes polymorphisms should be further investigated by large population based studies.
Laboratoire de Recherche d'Immunologie de la Transplantation Rénale et d'Immunopathologie LP03SP01, Hôpital Charles Nicolle, Tunis.
Yosr
Y
Gorgi
Imene
I
Sfar
Rym
R
Goucha
Houda
H
Aouadi
Mohamed
M
Amri
Mouna
M
Makhlouf
Thouraya
T
Ben Romdhane
Mejda
M
Cherif
Salwa
S
Jendoubi-Ayed
Taïeb
T
Ben Abdallah
Khaled
K
Ayed
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015703:Antigens, CD / Q000235:genetics; D060908:CTLA-4 Antigen; D005260:Female; D020022:Genetic Predisposition to Disease; D005922:Glomerulonephritis, IGA / Q000235:genetics*; D006801:Humans; D053590:Interleukin 1 Receptor Antagonist Protein / Q000235:genetics; D007375:Interleukin-1 / Q000235:genetics; D008297:Male; D008875:Middle Aged; D020641:Polymorphism, Single Nucleotide; D014416:Tunisia; D019014:fas Receptor / Q000235:genetics
D015703:Antigens, CD; D060908:CTLA-4 Antigen; C556706:CTLA4 protein, human; C491901:FAS protein, human; D053590:Interleukin 1 Receptor Antagonist Protein; D007375:Interleukin-1; D019014:fas Receptor