Page 99 - Recognizing axial spondyloarthritis - Janneke de Winter

Figure 1. mRNA expression of A) HLA-B, B) Beta-2 microglobulin, C) HLA-C using the Hs00740298_g1 assay and D) HLA-C using the Hs03044135_m1 assay
Lower frequency of HLA-C*07 in AS
As one potential explanation for the complete absence of HLA-C*07 mRNA in a majority of the analyzed AS samples is the absence of the HLA-C*07 genotype, we hypothesized that (the absence of) HLA-C*07 is associated with genetic susceptibility for AS and axSpA. Therefore, we first explored the frequency of HLA-C*07 in a relatively small exploratory cohort of 24 AS patients versus 40 healthy controls. Nineteen out of 24 AS patients were HLA-C*07 negative compared to 14 of the 40 healthy controls (79.2% vs. 35.0%, p<0.001, Figure 2). These results correlated perfectly with our hypotheses: all individuals with mRNA expression of HLA-C using probe Hs00740298_g1 had at least 1 HLA-C*07 allele.
Figure 2. Prevalence of HLA-C*07 negativity in
A) patients with AS (n=24) and healthy controls (n=40)
B) patients with AS (n=113) from GESPIC and healthy potential donors (n=135,160)
C) patients with axSpA (n=196) and chronic back pain controls (n=216) from the
SPACE Cohort
Confirmation of the association between the absence of HLA-C*07 and AS/axSpA
To confirm this finding, we tested the prevalence of HLA-C*07 in AS patients of GESPIC. Of the 113 AS patients, 82 were HLA-C*07 negative compared to 67,043 of the 135,168 donor controls (72.6% vs. 49.6%, p<0.0001, Figure 2). As the axSpA disease spectrum consists not only of AS but also of non-radiographic axSpA
HLA-C*07 IN AXIAL SPA
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