DEFECTIVE OPSONIZATION IN RECURRENT INFECTIONS

Deficient opsonization of yeasts, assessed by a microscopic method, has been reported as a frequent occurrence in children with recurrent infections (Soothill & Harvey, Arch. Dis. Childh. 51: 91, 1976) and in atopic patients (Turner et al.Clin. exp.Immunol.34: 253, 1978).We have studied opsonization spectrophotometrically by the stimulation, induced by serum, of the reduction of nitrobluetetrazolium which accompanies the phagocytosis of zymosan by PMN leucocytes. In 44 normal adults, half-maximal stimulation (S 0.5) was observed with a serum concentration of 3.1% ± 0.6 (mean ± St. dev.) Opsonization was considered deficient when S 0.5 was increased above 4.3% (+ 2 st.dev.).In accordance with Soothill et al., defective opsonization was occasionally found in healthy adults (3/47). Opsonization was studied in 91 children divided in 4 groups. In 22 children with various non-infectious diseases, including 6 with eczema, opsonization was normal. Deficient opsonization was found in 4 ( 14.3%,n.s.) out of 28 children hospitalized for a single acute infection, in 9 (50%, X2=13.7,p < 0.001) out of 18 children with a history of 3 or more severe infections (pneumonia, meningitis, sepsis) and in 2 (8.7%,n.s.)out of 23 children with frequent more benign infections (otitis, bronchitis). These results confirm the association of defective opsonization with an increased susceptibility to severe recurrent infections.