No abstract

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LETTERSmeasure reflecting biologically important features of a crystal surface.These experiments confirm and extend Mandel's work. The results re-emphasize the problems inherent in all experimental work on crystal-induced inflammation; crystal structure and surfaces are clearly susceptible to widely used laboratory manipulations, and much previous work on "treated" crystals must be interpreted with caution.

Results of HLA‐A, B and C typing as well as haplotype frequencies in the Nahuas, who are the predominant Indian group in Mexico are presented. ABO and Rh blood groups show the genetic homogeneity of this population, since all of them were group O and Rh+. The most frequent antigens and haplotype are in general, the same as in some, but not all Amerindian tribes (Papago, Pimas, Zuñi from North America and Ixils from Guatemala). When‐compared to other Mongoloids, the HLA pattern is very close to the Japanese population. Antigens Bw39 and Cw4 look like markers of Nahuas and because Bw16 cells from four individuals could not be assigned either as Bw38 or Bw39, and 6 subjects did not type for any of the Bw22 splits, new subtypes of these antigens are probable.