HUMAN INTESTINAL ALKALINE PHOSPHATASE-BINDING IGG IN PATIENTS WITH SEVERE BACTERIAL-INFECTIONS

Patterns of alkaline phosphatase (AP)-binding proteins were observed i n the alkaline pH range of 6.5-9.5 upon isoelectric focusing and blott ing of serum from patients with inflammatory diseases. After isolation using affinity chromatography on protein A or immunoaffinity chromato graphy on AP coupled to cyanogen bromide (CNBr)-activated Sepharose, t he AP-binding protein was identified as IgG on Western blots and in EL ISA using human IgG-specific antibodies. It was shown that this IgG bi nds to AP from both calf(bovine) and human intestine. However, it bind s neither to the human liver-bone-kidney (LBK) isoform nor to bacteria l AP. Moderate reaction was observed with human placental AP. Comparin g patients with various diagnoses (n=284), AP-binding antibodies were mainly found in severe bacterial infections. They were not detected in serum from healthy blood donors (n=300). The presence of AP-binding I gG was independent of the infected organ and the bacterial species cau sing infection. This antibody may be useful for discriminating bacteri al from viral infection and for indicating severe bacterial inflammati on.