[Measurement of total IgE in tears : the adaptation of an immunoenzyme technique and the value of investigating locally produced IgE in the diagnosis of chronic conjunctivitis].

The measurement of total IgE in tears could be useful to confirm the diagnosis of allergic conjunctivitis, particularly in chronic forms when the etiology is difficult to determine solely on clinical criteria and allergologic anamnesis. Since the level of IgE is normally very low in tears, the adaptation of a fluorescent enzyme immunoassay of total IgE (Unicap, Pharmacia-Upjohn) reduces the detection limit from 0.35 to 0.15 kU/l. Satisfactory results are obtained for accuracy, within-run precision (CV < 5%) and between-run precision (CV < or =11%). During allergic reactions, the local synthesis of IgE is evaluated by the ratio between the measured lacrimal IgE and the lacrimal IgE that have been filtered through the hemato-lacrimal barrier. The serum and tear albumin allows to quantify the permeability of the barrier and thus the amount of filtered tear IgE.