APOH and rheumatic heart disease: In fact, the clinical and experimental study published by Blank et al., which evaluated the serum of 90 patients with RF and of 42 patients with APS, showed that 24% of patients with rheumatic heart disease had positivity for anti-β2GPI (antibeta-2-glycoprotein I) and that patients with APS had antistreptococcal activity, recognizing the M protein in 16.6% of cases.