Immunological study in three families of juvenile ankylosing spondylitis

Three patients, all exhibiting symptoms before 15 years of age, were diagnosed as juvenile ankylosing spondylitis (JAS) by stigma of JAS. The families of these three patients--a total of fifteen first-degree relatives--had clinical, radiologic and laboratory examinations. All three patients and four family members (26%) had positive HLA-B27 and ankylosing spondylitis (AS). Five (33%) of these three family members had positive HLA-B27 but were asymptomatic; six members(40%) were HLA-B27 negative and symptom-free. A high positive rate of HLA-B27 was found among the patients (100%) and the family members (60%). The rheumatoid factor, antinuclear antibody, and anti-native DNA antibody were negative for all patients and family members. Significant elevation of IgG, IgA, and C3 were noted in the AS group. The CD3 cell was lower, and the ratio of CD4/CD8 was decreased in the AS group. Lympho-proliferative responses to phytomitogens (Con A, LPS and PHA) were also done in our study. There was no significant difference in Con A and LPS stimulation index among the AS group, symptom-free family members and normal controls.