To investigate retinal involvement in chronic Chagas' disease, we performed electroretinography and retinal fluorescein angiography studies in chagasic patients. Our results demonstrated a dissociated electrophysiological response characterized by both an abnormal reduction of the electroretinographic b-wave amplitude and a delayed latency, under the dark-adaptated condition. These alterations are compatible with a selective dysfunction of the rods. Antibodies raised against Trypanosoma cruzi that also interact with beta1-adrenergic receptor blocked light stimulation of cGMP-phosphodiesterase in bovine rod membranes. The specificity from the antibody-rhodopsin interaction was confirmed by Western blot analysis and antigenic competition experiments. Our results suggest an immunomediated rhodopsin blockade. T. cruzi infection probably induces an autoimmune response against rhodopsin in the chronic phase of Chagas' disease through a molecular mimicry mechanism similar to that described previously on cardiac human beta1-adrenergic and M2-cholinergic receptors, all related to the same subfamily of G-protein-coupled receptors.

The presence of anti-zona pellucida antibodies in the follicular fluid of 11 women who underwent in-vitro fertilization (IVF) and embryo transfer was analysed. Only infertile couples with tubal or unexplained pathologies were included in our study, which was aimed at investigating the relationship between anti-zona pellucida antibodies in follicular fluid and failed fertilization. Whether or not these antibodies were present in some or all follicles in the same patient was also investigated. Out of 55 follicular fluids analysed, 36.3% were positive to the test and no fertilization was observed in oocytes from these follicles, while 63.6% were negative, and the oocyte fertilization rate associated with these was 51.4%. The presence of anti-zona pellucida antibodies was positively correlated with the degree of fertilization failure (P < 0.001 chi 2 test).