Influence of HLA-B*5703 and HLA-B*1403 on susceptibility to spondyloarthropathies in the Zambian population.

Objective: To analyze the distribution of HLA-B alleles and to investigate their contribution in the susceptibility to spondyloarthropathies (SpA) in a sample population from Zambia, in order to determine a relationship between some HLA-B alleles and development of ankylosing spondylitis (AS), reactive arthritis (ReA), or undifferentiated SpA (uSpA).

Methods: . We selected 72 patients with SpA and found that 46 had uSpA, 23 ReA, and 3 AS. We also selected 92 matched controls; 55 of these had human immunodeficiency virus type I (HIV-I) infection.

Results: We found a significant increase in the rate of uSpA and ReA with features of Reiter's syndrome (RS) in HIV-positive individuals who carried the HLA-B*5703 allele (pc < 0.0001 and pc < 0.001, respectively). Among the significant new findings identified were the presence of B*1403 in 2 of the 3 AS patients (pc < 0.05, OR 47), confirming previous data in the Togolese population.

Conclusion: The presence of B*5703 and HIV infection may not affect susceptibility to AS and ReA, but they do show an important influence in uSpA and RS. Our findings confirm that HLA-B*1403 is the only factor to increase the risk of AS in a sub-Saharan African population, whereas HLA-B27 was virtually absent in patients with AS.