Immunoglobulin A and C reactive protein levels in ankylosing spondylitis.

Correspondence: SIR, We read with interest the recent paper by Sanders et al on the correlation of immunoglobulin and C reactive protein (CRP) levels in 22 patients with ankylosing spondylitis (AS) and 20 patients with rheumatoid arthritis (RA).' The authors found that IgA serum levels, though raised in AS, do not correlate with CRP levels as they do in RA, suggesting that the mechanism of increase of IgA in the two diseases may be different. They conclude that production of IgA in AS is unrelated to the stimulation of acute phase reactants, reflecting a specific mucosal immune stimulation, possibly in the gut. Thus IgA may be a marker of the pathogenesis of AS

HLA class II antigens (DR, DQ loci) and peripheral arthritis in ankylosing spondylitis.

Fifty one patients with ankylosing spondylitis (AS) were typed for HLA-A, B, C, DR, and DQ antigens. The antigen frequencies were compared with those of a normal population and with a B27 positive control group. All but one of the patients with AS were HLA-B27 positive. A positive linkage disequilibrium between Cw1, Cw2, DR1, and the B27 antigen was observed. Patients with AS showed a significant increase in DQw2 antigen compared with the B27 positive control group. No differences in antigenic frequencies were observed in patients having peripheral arthritis and patients with only axial involvement. Seven out of nine patients (78%) with an erosive peripheral arthritis were DR7 positive, suggesting that DR7 or genes closely linked could be related with a more aggressive peripheral joint involvement in patients with AS

Prevalence of articular chondrocalcinosis in elderly subjects in a rural area of Catalonia.

OBJECTIVES--To undertake an epidemiological survey of the prevalence of radiological chondrocalcinosis in the elderly population of Osona, a rural area of Catalonia, north east Spain. METHODS--Knee and wrist radiographs were performed on 261 subjects (141 women, 120 men) aged at least 60 years, who attended a series of 35 general practitioners for various medical problems. RESULTS--Twenty seven subjects had articular chondrocalcinosis, which represents a crude prevalence of 10%. Articular chondrocalcinosis was more often observed in women than in men (14 v 6%). Articular chondrocalcinosis increases in occurrence with age, rising from 7% in subjects aged 60-69 years to 43% in subjects older than 80 years. A similar occurrence of articular chondrocalcinosis was noted in the indigenous population, in which several cases of familial chondrocalcinosis have previously been reported, and in subjects born in other areas of Spain. All but one subject with articular chondrocalcinosis had chondrocalcinosis of the knee. The occurrence of rheumatic disorders did not differ significantly between subjects with articular chondrocalcinosis and those without. CONCLUSIONS--Articular chondrocalcinosis is an age related disorder, which could partly explain the discrepancies in its prevalence reported in previous studies. In most subjects with articular chondrocalcinosis recruited from an unselected population the clinical manifestations are probably mild or even absent