The objective of our study was to determine the prevalence of anti-infectious agent
antibodies and
autoantibodies in a unique non-Westernized population from Kitava, Papua New Guinea (PNG), compared to Western populations. We matched 120 serum samples from Kitavans with 437 samples from four healthy control groups. Sera were tested for the presence of anti-infectious agent
antibodies (treponema, toxoplsmosis, Epstein-Barr virus, cytomegalovirus,
rubella) and autoantiobodies [anti-double-stranded (
ds)DNA, anti-
chromatin, anti-
ribonucleoprotein (RNP), anti-SSB, anti-SSA, anti-Scl-70, anti-Smith, anti-centromer, anti-SmRNP, anti-Jo-1, and anti-ribosomal-P] using the Bio-Rad
BioPlex 2200. Antitreponemal
antibodies were detected in 87% of PNG sera versus 0-6% of controls (P < 0.0001).
Anti-dsDNA antibodies were detected in 31% of PNG samples, which was significantly higher than in three of the control groups (<10%). The outstanding high rate of antitreponemal
antibodies detected in Kitavans possibly represents prior
yaws disease. A low prevalence of
cardiovascular disease was previously documented in Kitavans and has been attributed, in addition to their diet, to the high prevalence of natural cardioprotective
autoantibodies (the
IgM-antiphosphorylcholine
antibodies) in this population.
Treponemal infection has been shown to induce the appearance of antiphosphorylcholine
antibodies. These protective
autoantibodies may cross-react with the pathogenic
anti-dsDNA antibodies. Thus, it is suggested that
infection with treponema is associated with the presence of protective as well as pathogenic
autoantibodies.