The aim of this study was to investigate the association of different
groups and subgroups of juvenile chronic arthritis (JCA) with HLA class
II (DR, DI: DQ) alleles and/or haplotypes. Groups and subgroups were
mainly distinguished on the basis of the type of onset, the course and
complications of the disease, and some predefined disease markers
according to the criteria proposed by the ILAR Standing Committee
(Chile, 1994). On the basis of these criteria the following five JCA
groups and their subgroups were included in the study: (1) definite
systemic onset (n = 25) and systemic progressing to persistent arthritis
(n = 14); (2) JCA of oligoarthritis onset (O-JCA, n = 124) and of
oligoarthritis onset and course (n = 98), O-JCA of early (< 6 years) or
late (> 6 years) onset (EOO-JCA n = 71 and LOO JCA n = 44), O-JCA with
ANA positive (n = 69) or negative (n = 55) and O-JCA progressing to
extended arthritis (n = 22); (3) JCA of polyarthritis onset (P-JCA) with
rheumatic factor (RF) negative (n = 29), and P-JCA RF negative with
antinuclear antibodies (ANA) positive (n = 13) or negative (n = 16); (4)
JCA complicated with chronic anterior uveitis (CAU, n = 32); (5)
juvenile psoriatic arthritis (n = 20). To assess the HLA allele
frequencies in the above 223 Greek children with JCA, these frequencies
were compared to those of 98 age-matched and 250 adult controls. The
main findings were the following. A common HLA-DRB1* allele was not
involved in the JCA groups and subgroups studied; on the other hand, the
DQA1*0501 allele was found to be associated with different JCA
groups/subgroups (Q-JCA, P-JCA RF-negative ANA-positive, JCA with CAU),
probably suggesting a closer relationship of this locus with the
immunogenetic background of JCA. The DPB1*0201 allele was associated
with the development of either EOO-JCA or CAU. Susceptibility to CAU was
stronger when the DPB1*0201 was combined with the presence of
DRB1*13. Another allele, DQB1*0301, was also associated with O-JCA
and CAU. Finally, no specific HLA class II allele was found to be
related to the presence of ANA or psoriatic lesions or to the severity
of the arthritis. Our findings suggest that the wide clinical and
laboratory spectrum of JCA is associated with an immunogenetic
background that is linked with HLA alleles of more than one locus. Some
of them, such as the DPB1*0201 allele, confer susceptibility to
certain clinical onsets and courses or complications of the disease. The
rapidly advancing techniques of typing of DNA profiles may lead to more
definite conclusions