Distribution of HLA-B*27 subtypes in Tunisians and their association with ankylosing spondylitis.
OBJECTIVE
The human leukocyte antigen HLA-B27 is a class I antigen of the major histocompatibility complex strongly associated with ankylosing spondylitis (AS) and other related spondyloarthropathies (SpAs). The mechanism of this association remains unknown. HLA-B27 is a serologic specificity that represents a family of at least 25 different HLA-B27 alleles (2701-2725). These alleles are closely related by nucleotide sequence homology, but differ in ethnic distribution. The purpose of the present study is to investigate the distribution of HLA-B27 alleles in healthy controls and in patients with ankylosing spondylitis (AS).


METHODS
We selected 160 HLA-B27-positive individuals (39 controls and 121 patients with ankylosing spondylitis). Typing of HLA-B27, and Cw alleles were performed by polymerase chain reaction amplification with sequence specific primers (PCR-SSP), and by serological typing (microlymphocytotoxicity).


RESULTS
Seven B27 subtypes were identified: B*2702, 03, 04, 05, 07, 09 and B*2714. The distribution of these alleles in the population of patients was B*2702 (47.1%) and B*2705 (47.1%). These subtypes were also detected in 16 (41%) and 16 (41%), respectively of the 39 control subjects. HLA-B*2707 was detected in 4 (3.31%) patients and in 3 (7.6%) controls. B*2704, 09 and B*2714 were relatively rare and were detected in one subject each. No significant differences were noticed in the frequencies and distribution of HLA-B27 alleles between patients and controls.


CONCLUSIONS
Our results show a restricted number of HLA B27 subtypes associated with AS. B*2702 and B*2705 were equally common in patients and controls. The most prominent B27/Cw haplotypes in the patient groups and controls were B*2702/Cw02022 and B*2705/Cw02022.
Ben Radhia
Karima
K
Department of Immunology, EPS Charles Nicolle, Boulevard 9 Avril, 1006 Tunis, Tunisia.
Ayed-Jendoubi
Saloua
S
Sfar
Imene
I
Ben Romdhane
Thouraya
T
Makhlouf
Mouna
M
Gorgi
Yousr
Y
Ayed
Khaled
K
D000328:Adult; D000483:Alleles; D016022:Case-Control Studies; D005260:Female; D020022:Genetic Predisposition to Disease; D015235:HLA-B Antigens / Q000235:genetics; D015796:HLA-B27 Antigen / Q000235:genetics*; D006239:Haplotypes / Q000235:genetics; D006801:Humans; D008297:Male; D008875:Middle Aged; D011110:Polymorphism, Genetic / Q000235:genetics*; D013167:Spondylitis, Ankylosing / Q000208:ethnology / Q000235:genetics* / Q000276:immunology; D014416:Tunisia
D015235:HLA-B Antigens; C464936:HLA-B*27:05 antigen; D015796:HLA-B27 Antigen