Spondyloarthritis (SpA) is generally uncommon in sub-Saharan Africa, in part because of the rarity of
HLA-B27 in this region. However, the relationship between
HLA-B27 and SpA, particularly
ankylosing spondylitis (AS), is complex. Despite the
HLA-B 27:05 risk allele occurring in some West African populations, associated AS is not seen. In fact, most patients with AS are HLA-B27-negative, although there is emerging evidence that another class I HLA molecule,
HLA-B 14:03, is associated with AS in black Africans. The Assessment of SpondyloArthritis International Society criteria for detecting early axial disease are of limited value in sub-Saharan Africa, because of both the rarity of
HLA-B27 and very limited access to magnetic resonance imaging.
Reactive arthritis (ReA),
psoriatic arthritis, and undifferentiated SpA are seen mainly in the context of
HIV infection, although the exact effect of the virus in the pathogenesis of
arthritis is unclear. In Zambia, ReA is associated with the
HLA-B*57:03 allele, which is paradoxically also associated with slow progression of
HIV infection. HIV-associated ReA has a more protracted and aggressive course than standard ReA. Enthesitis-related
arthritis is more common in children infected with HIV by vertical mother-to child transmission. Use of
TNF inhibitors for axial disease is problematic, mainly because of cost, but also because of potential safety problems, especially reactivation of
tuberculosis.