Seronegative spondarthritides: a clinical and genetic study with particular reference to the histocompatibility antigens
Eastmond, Clifford John
In a clinical, radiological and histocompatibility typing study of 3 60 patients the association between individual types of seronegative spondarthritis and HLA-B27 is confirmed. HLA-B27 was associated with recurrent acute anterior uveitis in 119 patients with ankylosing spondylitis, but not with severity of the spinal disease. HLA-B27 negative patients had a later mean age of onset and more dactylitis of the toes. In 77 patients with Reiter's syndrome the presence of HLA-B27 was associated with the occurrence of keratoderma blenorrhagica, acute anterior uveitis and radiological sacroiliitis but not with conjunctivitis. No particular pattern of peripheral psoriatic arthritis was associated with HLA-B27 in the 79 patients studied. The frequency of HLA-B27 was highest in psoriatic patients with spinal arthritis. In 22 patients with peripheral psoriatic arthritis in addition to spinal arthritis the frequency of HLA-B27 was significantly less than in 8 psoriatic patients with spinal arthritis alone and in 119 patients with ankylosing spondylitis alone. In patients with chronic inflammatory bowel disease and ankylosing spondylitis the frequency of HLA-B27 was significantly less than in 119 patients with ankylosing spondylitis alone. These results were confirmed by a combined analysis with other series and suggest the possible role of genetic factors predisposing to chronic inflammatory bowel disease and peripheral psoriatic arthritis also predisposing to ankylosing spondylitis in HLA-B27 negative individuals. In a study of 36 selected families only 2 examples of seronegative spondarthritis in HLA-B27 negative relatives were seen. In both families there was evidence of the possible role of genes predisposing to chronic inflammatory bowel disease. In a study of 23 unselected families of probands with ankylosing spondylitis this disease was found in 28.6% of HLA-B27 positive fathers, none of the mothers and none of the HLA-B27 negative parents. Comparison with the frequency of ankylosing spondylitis in blood donors and of reactive arthritis in infected individuals suggests that additional genetic factors may be necessary for the occurrence of disease. A study of three pairs of identical twins showed discordance for ankylosing spondylitis in two suggesting the necessity of environmental factors in addition to genetic ones for the development of disease.