Analysis of aqueous humour in ocular onchocerciasis.
The development of an onchocercal chorioretinopathy from the first detectable signs to a full blown oncho fundus is not fully understood. We investigated the intraocular humoral immune response against Onchocerca volvulus, human S-antigen, IRBP and crude retinal extract (using an ELISA) by examining paired aqueous humour and serum samples obtained from onchocerciasis patients (without [n = 10] and with ocular symptoms [n = 8]) and endemic controls [n = 14] from Sierra Leone (West Africa). A local intraocular anti-retinal IgG antibody production could not be demonstrated in onchocerciasis patients, whether they had ocular symptoms or not. A significantly higher level of O. volvulus antibodies and IgG was measured in the aqueous of onchocerciasis patients with ocular involvement, as compared to patients without ocular symptoms (Mann-Whitney ranksum test; p less than 0.001 and p less than 0.02 respectively). Since interleukin-6 (IL-6) plays an essential role in the differentiation of B cells into immunoglobulin producing plasma cells, we therefore measured this cytokine in paired aqueous and serum samples. Elevated IL-6 levels were found in the aqueous of two out of eight onchocerciasis patients tested. In view of these findings it seems improbable that retinal autoimmunity is a major factor in the pathogenesis of onchocercal chorioretinopathy. The high intraocular levels of antibodies against the parasite suggest a direct involvement of the parasite in the pathogenesis of onchocercal chorioretinopathy.
Van der Lelij
A
A
Department of Ophthalmology, Free University, Amsterdam, The Netherlands.
Rothova
A
A
De Vries
J P
JP
Vetter
J C
JC
Van Haren
M A
MA
Stilma
J S
JS
Kijlstra
A
A
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000818:Animals; D000909:Antibodies, Helminth / Q000032:analysis*; D001082:Aqueous Humor / Q000276:immunology*; D019393:Arrestin; D001323:Autoantibodies / Q000032:analysis*; D004797:Enzyme-Linked Immunosorbent Assay; D005136:Eye Proteins / Q000032:analysis*; D005260:Female; D006801:Humans; D007074:Immunoglobulin G / Q000032:analysis; D008297:Male; D008875:Middle Aged; D009854:Onchocerca / Q000276:immunology*; D015827:Onchocerciasis, Ocular / Q000276:immunology*; D012160:Retina / Q000276:immunology
D000909:Antibodies, Helminth; D019393:Arrestin; D001323:Autoantibodies; D005136:Eye Proteins; D007074:Immunoglobulin G