Three serological methods for streptococci grouping: latex agglutination after pronase extraction (LAP), latex agglutination after nitrous acid extraction (LAN) and counterimmunoelectrophoresis after nitrous acid extraction (CIEN) were evaluated in six laboratories with 310 strains of streptococci. To reduce the possible influence of a particular laboratory, each serological procedure was performed in two different laboratories with identical protocols and strains. Between the three procedures, a total agreement of 81.3% with six identical results was obtained. Since only one discordant result was obtained in 12.2% (CIEN 4.8%-LAN 5.8%-LAP 1.6%) and two discordant results with two different serological methods in 2.6%, it could be concluded that agreement between the three procedures was 96%. For B (99 strains tested) and D(100 strains tested) groups, total agreements of respectively 95% and 92% were achieved. In conclusion, LAP, LAN, and CIEN gave equivalent results for streptococci grouping, but LAN was the most simple needing no heating, centrifugation, or electrophoresis equipment and lacking cross-reactivity of group C antibody.

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HLA antigens (27 HLA alleles of the A and B loci) were determined in 20 subjects of the same family, covering three generations; 6 of them were suffering from hereditary hemorrhagic telangiectasia. The haplotype HLA A2, Bw17 was found in all the sufferers. The same haplotype was not found in clinically healthy members except two of the generation III, but a visceral angiomatosis without clinical evidence cannot be excluded. An association of hereditary hemorrhagic telangiectasia with the haplotype HLA A2, Bw17 can be suspected in this family.

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