Aqueous chamber taps in toxoplasmic chorioretinitis.

The clinical value of the determination of toxoplasma antibodies in anterior chamber taps was evaluated in 12 posterior uveitis patients suspected of a toxoplasmic retinochoroiditis, in four patients with Fuchs's heterochromia and in 31 cataract patients. The posterior uveitis patients all had marked inflammation of the vitreous obstructing the examination of the fundus of the time of aqueous humour aspiration. The clinical diagnosis toxoplasmic uveitis (n = 9) was made after the inflammation of the vitreous had subsided and fundus examination became possible again. Paired serum and aqueous samples were tested for total immunoglobulin levels and toxoplasma antibodies. Eight of the nine clinical toxoplasmic uveitis patients had detectable toxoplasma antibodies in their aqueous, whereas none of the other seven uveitis patients were positive. All of these eight toxoplasmic uveitis patients had a coefficient above 1.5. Of the 31 control patients only one had a positive antibody titer at a dilution of 1/2 with a corresponding coefficient of 1.1. This study shows that aqueous humour examination for toxoplasma antibodies is a valuable diagnostic tool in a selected group of posterior uveitis patients.