Polymorphisms in the IL4 and IL4RA genes in Colombian patients with rheumatoid arthritis.
OBJECTIVE
Rheumatoid arthritis (RA) is considered a Th1-driven disease. Interleukin 4 (IL-4) binds to its receptor, promoting Th2 differentiation and limiting Th1 responses, but its role in the pathogenesis of RA is conflicting. We analyzed 2 polymorphisms of the IL4 gene and 4 polymorphisms of the IL4RA gene in patients with RA and in a control population, as well as rheumatoid factor (RF) seropositivity, titers of RF, and history of replacement joint surgery among patients with RA.


METHODS
The study population consisted of 102 patients with RA and 102 matched healthy controls. Genotyping of IL4 -590, IL4RA +148, +1124, +1218, and +1902 was determined by restriction fragment length polymorphism-polymerase chain reaction (PCR) and sequence-specific primer-PCR. IL4 variable number tandem repeat polymorphism was determined by direct amplification.


RESULTS
The IL4 -590TT genotype was significantly more frequent in patients with RA than in controls (p = 0.018, OR 3.34, 95% CI 1.08-11.04). The IL4RA +148A allele was significantly associated with the presence of RF (p = 0.0019, OR 2.55, 95% CI 1.55-4.86) and a history of articular joint replacement (p = 0.024, OR 2.08, 95% CI 1.04-4.18). The IL4RA +1902G allele was more frequently seen in patients with RA and high RF titers (p = 0.00067, OR 4, 95% CI 1.64-9.93).


CONCLUSIONS
Highly complex pathways lead to the development of RA and may not be similar in all patients. Our findings of higher frequency of IL4 and IL4RA genotypes and alleles with RA, presence of RF, RF titers, and history of articular joint replacement support the polygenic expression of RA and the likely role of IL-4 in influencing its initiation and development.
Moreno
Olga
O
Laboratorio de Inmunología y Biología Molecular, Grupo de Inmunología y Epidemiología Molecular, Facultad de Salud, Universidad Industrial de Santander, Bucaramanga, Spain.
González
Clara Isabel
CI
Saaibi
Diego Luis
DL
Otero
William
W
Badillo
Reynaldo
R
Martín
Javier
J
Ramírez
Gerardo
G
D000328:Adult; D001172:Arthritis, Rheumatoid / Q000097:blood / Q000208:ethnology / Q000235:genetics*; D016022:Case-Control Studies; D003105:Colombia / Q000208:ethnology; D005260:Female; D005787:Gene Frequency / Q000235:genetics; D006801:Humans; D015847:Interleukin-4 / Q000235:genetics* / Q000502:physiology; D053662:Interleukin-4 Receptor alpha Subunit / Q000235:genetics* / Q000502:physiology; D008297:Male; D008875:Middle Aged; D011110:Polymorphism, Genetic; D012217:Rheumatoid Factor / Q000097:blood
C504000:IL4R protein, human; D053662:Interleukin-4 Receptor alpha Subunit; D015847:Interleukin-4; D012217:Rheumatoid Factor