Spondyloarthropathy and human immunodeficiency virus infection in Zambia

OBJECTIVE: To explore the relationship between spondyloarthropathy (SpA) and infection with the human immunodeficiency virus (HIV) in black Zambians. METHODS: Consecutive patients attending an arthritis clinic in a 30 month period were assessed clinically and tested for the presence of antibodies to HIV. HLA-B27 gene was investigated by polymerase chain reaction and T cell subsets were tested in selected subgroups. RESULTS: Of 595 new attendees, 272 were diagnosed with SpA [130 reactive arthritis (ReA), 128 undifferentiated SpA (uSpA), 13 psoriatic arthritis (PsA), 1 ankylosing spondylitis] and 146 with a reactive type arthritis alone (AA) without preceding clinical trigger infection or SpA features. HIV seroprevalence was 98% in uSpA, 94% PsA, 87% ReA, 64% AA; vs approximately 50% among hospital outpatients and 30% of the adult urban population. Prevalence of SpA is calculated at approximately 180/100,000 in HIV positive and approximately 15/100,000 in HIV negative in the general population. Dysentery was the most common identified trigger. Positive HIV status correlated strongly with SpA features and aggressive sustained disease. At onset 80% of patients were in WHO clinical stage 1 (no disease or lymphadenopathy alone), with a mean CD4+ count of 279/microl. Stage 4 patients had a mean CD4+ count of 60/microl and inactive arthritis. The B27 gene was absent in 30 patients tested. CONCLUSION: ReA is the most common inflammatory joint disorder in black Zambians and is closely linked to HIV infection and not B27, even though our subjects had clinical and radiological characteristics similar to those reported in HLA-B27 positive Caucasians. The changing epidemiology of SpA in this region has important practical and educational implications.