ABSTRACT:The major elements of bone pathology in Gaucher disease are a failure of osteoclast and osteoblast function, resulting in osteopenia and also osteonecrosis. T lymphocytes have recently been found to be involved in the regulation of osteoblast/osteoclast activity in vitro. In the present report the peripheral blood T major lymphocyte subsets were investigated in a group of genotyped type 1 Gaucher disease patients. A total of 31 patients were studied: 21 non-splenectomized (5 N370S homozygotes) and 10 splenectomized (of whom 1 was a N370S homozygote). The results show that non-splenectomized patients present a decrease in absolute numbers of peripheral blood T lymphocytes, specially the CD4 ϩ T subset. However, when patients were analyzed with respect to the presence of bone disease, the number of CD8 ϩ T lymphocytes was found to be statistically significantly lower in patients presenting bone involvement. Furthermore, lower numbers of CD8 ϩ T lymphocytes were significantly correlated with higher levels of plasma tartrate resistant acid phosphatase (TRAP) activity, a putative marker of osteoclast cell activity. These in vivo findings are in agreement with the results reached in vitro by others.

A protocol for the statistical and graphical evaluation of erythrocyte volume distributions has been developed using expectation-maximization methods for distribution parameter estimation. In a reference sample group of 50 healthy individuals, none of the red cell volume distributions determined by an aperture impedance method differed significantly from a log normal model. Measurements in 211 patients with anemia provided evidence that similar statistical methods could be used for the characterization of abnormal red cell volume distributions. Graphical displays accurately summarize the quantitative information derived from the analysis of volume distributions and show a reference distribution fitted to the observed distribution against the range of distributions found in healthy individuals. This protocol provides a specific, statistically valid implementation of the general principles for the analysis of cell volume distributions proposed by the International Committee for Standardization in Hematology.

We compared initial screening transferrin saturation (TfSat) and serum ferritin (SF) phenotypes and HFE C282Y and H63D genotypes of 645 Native American and 43,453 white Hemochromatosis and Iron Overload Screening Study participants who did not report a previous diagnosis of hemochromatosis or iron overload. Elevated measurements were defined as TfSat >50% in men and >45% in women and SF >300 ng/ml in men and >200 ng/ml in women. Mean TfSat was 31% in Native American men and 32% in white men (p = 0.0337) and 25% in Native American women and 27% in white women (p < 0.0001). Mean SF was 153 µg/l in Native American and 151 µg/l in white men (p = 0.8256); mean SF was 55 µg/l in Native American women and 63 µg/l in white women (p = 0.0015). The C282Y allele frequency was 0.0340 in Native Americans and 0.0683 in whites (p < 0.0001). The H63D allele frequency was 0.1150 in Native Americans and 0.1532 in whites (p = 0.0001). We conclude that the screening TfSat and SF phenotypes of Native Americans are similar to those of whites. The allele frequencies of HFE C282Y and H63D are significantly lower in Native Americans than in whites.

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