LETTERS

Group A Streptococcus is a common bacterium thatinduces tonsillitis, pharyngitis, and pyoderma, and,furthermore, its metabolic products cause scarlatina. It is suggested that the molecular mimicry and cross reactivity between human tissues and the micro-organism are associ-ated with immunogenic pathogenesis of well known post-streptococcal manifestations: acute rheumatic fever and acute glomerulonephritis.1 2 Recently, non-purulent arthritis after or during streptococcal infection, HLA-B27 unrelated “post-streptococcal reactive arthritis (PSReA)”, has been reported as another manifestation associated with streptococcal infection.3–5 The pathogenesis of PSReA is unknown, but it is likely that it is an immunogenic disorder similar to acute rheumatic fever. Anticardiolipin antibodies (aCL) are often detected in patients with autoimmune diseases, especially systemic lupus erythematosus, and they can induce antiphospholipid syn