1Abd Al-Rehiem G. Ads, 2Farha A. El-Chennawi, 1Mohamed I. Abd El-Hamid, 3Mostafa A. Abo-Farrag and 1Azza M. Hassan
Departments of 1Microbiology, and 3Pediatric Faculty of Medicine, Tanta University, Tanta and department of 2Clinical Pathology, Faculty of Medicine, Mansoura University, Mansoura, Egypt.
The aim of the present study
is to analyze the immunogenetic features of juvenile rheumatoid arthritis (JRA)
in Egyptian children and to investigate the role of human leukocytic antigen
(HLA) class I and II alleles as well as T cell receptors (TCRs) polymorphism in
susceptibility to JRA.
Subjects were 25 Egyptian patients
with JRA and 20 controls were included in this study. Rheumatoid factor (RF)
was performed using latex test, while antinuclear antibodies (ANA) were
estimated by immunofluorescent assay. For HLA-class I typing, lymphocyte
cytotoxicity technique was performed, while for HLA class II typing; DR, DQA,
and DQB as well as TCRVB6.1 polymorphism DNA techniques were used. We studied
two groups of patients with JRA having different disease prognosis and course;
pauciarticular and polyarticular groups. Each JRA subset was characterized by a
distinct distribution of HLA class I and class II alleles. In pauciarticular
group and its early onset subset, there were positive associations with HLA-A2,
B5, DRB 1*0801 and 1301, DQA1*01 as well as DQB 1*02, while in late onset
subset there was positive association with HLA-B27. In polyarticular group and
its seronegative subset, the significant positive associations were mainly with
HLA-B13, DRB1 *01 and *0801 as well as DQA1 *01. DRB1 *0401 was the only HLA
allele that was significantly frequent in seropositive subset. Unique protective
effect of HLA-DRRB 1*1001 was observed in JRA patients. TCRVB6.1 polymorphism
was not associated with any of JRA groups except in those with or without
chronic iridocyclitis, ANA or both. Immunogenetic profile of JRA in Egyptian
children appears to be somewhat different from that reported for other
populations and the role of TCRVB6.1 polymorphism needs to be reevaluated.