Relationship between anti-hFVIII and anti-pFVIII inhibitors. (A) Correlation between initial anti-hFVIII and anti-pFVIII inhibitors. (B) Correlation between peak anti-hFVIII and anti-pFVIII titer. Initial titers did not correlate (A; Spearman coefficient: r = 0.4; P = .14), although peak human and porcine inhibitor titers had an observable correlation (Spearman coefficient: r = 0.71; P = .002).