Antibodies to collagen in patients with leprosy.

Abstract Antibodies to human collagen (ACA) were detected by hemagglutination assay in the serum of leprosy patients from two different geographic areas of Papua New Guinea. In the highland patients, the prevalence of elevated titers (1:4 or more) of ACA varied according to the clinical spectrum of leprosy. There was a significant gradient from high prevalence in the immunodeficient polar lepromatous patients (53%) to a low prevalence at the tuberculoid end of the clinical spectrum (9%). This gradient was not observed in coastal patients, who had a higher overall prevalence of ACA (53% compared with 37.5% in the highlanders), possibly caused by the many intercurrent infections endemic in the coastal region. It is not clear to what extent these antibodies are implicated either in the pathogenesis of the complications of leprosy, or in the prolongation and intensification of inflammatory reactions involving collagen at sites such as the skin, nerves, and glomerular basement membrane.