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In order to check the presence of anti-HCV in the blood of voluntary blood donors in four of the most active blood banks of Curitiba, PR, Brazil a third generation immunoassay (Murex--version III, ABBOTT AxSYM HCV version 3.0) was used. The study detected 347 positive cases, i.e. a median prevalence of 0.80% (range 0.64%-1.11%). Only 44 from the 347 anti-HCV positive blood donors had elevated values of serum aminotransferases (12.68%). Such low values of ALT suggest that the confirmatory RIBA should be applied to the remnant 303 anti-HCV positive cases (87.32%) which did not show elevation of ALT, with the expectation that 30% to 40% of them might be positive. The prevalence of anti-HCV in blood donors in Curitiba seems similar to published data in the Brazilian medical literature.

We describe here the genetic variability of C2, C4 and BF in 225 healthy adult individuals from southern Brazil, including 172 Caucasoids, 47 Mulattos, 3 Blacks and 1 Amerindian. C2 gene frequencies were in accordance with those described for other populations, and two rare variants were observed. The BF allotype frequencies were slightly different between the Caucasoids and Mulattos, the latter having a higher BF*F frequency. A new BF*S variant, identified as S05 was observed in a Caucasoid individual. The frequencies of C4A and C4B in the Caucasoids were similar to other reported Caucasoid populations; a decrease of the silent allele B*Q0, and several rare variants were observed. A higher C4A*3 frequency and a remarkable decrease of C4A*Q0 were observed in the Mulattos. In addition, several C4 heteroduplications and aberrant allotypes were observed. Considering the high genetic variability found in a limited number of individuals, one may conclude that due to genetic admixture much heterogeneity might be expected for the MHC class III region in different Brazilian populations.

The authors suggest the determination of antibody against HIV in vitreous humor as a screening technique for AIDS carriers, specially in cases of corneal transplantation when the eye bank could make the examinations required and in cases when drawing blood after death becomes difficult. Ten eyes of patients having died of AIDS-related causes were studied and 100% of the samples tested were found to be positive. False-positive results were eliminated by the study of a group of 90 eyes of patients dead from nonrelated causes; the results were all negative. Therefore, no discrepancy was noticed between the examination of the blood and the vitreous humor. A description is made of a technique which uses a special trocar that enables the examination to be made without contamination with blood. The authors conclude that the determination of antibodies in vitreous humor is a choice to be considered as a postmortem examination because it can be easily obtained and its results are reliable.