George Vartholomatos

THE 2003 MARSHALL R. URIST AWARD PAPER: Genetic Background of Osteonecrosis: Associated with Thrombophilic Mutations?

Intravascular coagulation is considered a major pathogenetic mechanism for nontraumatic osteonecrosis. The aim of our study was to evaluate the association of thrombophilic factor V G1691A mutation (factor V Leiden) and G20210A prothrombin mutation with the disease. Mutation presence was investigated by polymerase chain reaction techniques in a study population of 72 adult Caucasian patients with osteonecrosis of the femoral head and 300 healthy Caucasian control subjects. The disease was considered idiopathic in 23 patients and secondary in 49. The factor V Leiden mutation was present in 18% of patients, compared with 4.6% of control subjects, resulting in a statistically significant odds ratio of 4.5. The prothrombin mutation was not significantly increased in the idiopathic osteonecrosis subgroup (8.7% versus 2.6%) with an odds ratio of 3.5. Overall, either of these coagulation disorders was present in 22.2% of patients and in 7.3% of control subjects resulting in a significant odds ratio of 3.6. Factor V Leiden, a genetic risk factor for venous thrombosis, is associated with nontraumatic osteonecrosis of the femoral head, supporting the hypothesis that intravascular coagulation is a major pathogenetic mechanism of the disease.

HLA-DR Expressing Peripheral T Regulatory Cells in Newly Diagnosed Patients with Different Forms of Autoimmune Thyroid Disease

BACKGROUND Several reports have claimed a role for T regulatory cells (Tregs) in the pathogenesis of various autoimmune diseases, including autoimmune thyroid disease (AITD). The aim of the present study was to examine whether changes in the number of peripheral CD4 + CD25highHLA-DR + lymphocytes, a subpopulation of Tregs, occur in patients with AITD. METHODS Three-color flow cytometry was used to detect the proportion of CD4 cells expressing CD25, CD25high, and HLA-DR in 70 newly diagnosed and untreated AITD patients and 20 controls. The intensity of CD25 expression on these cells was also examined. RESULTS The proportion of CD4 + CD25 + cells as well as the proportion of CD4 + CD25high cells among the population of CD4 lymphocytes was not different in AITD patients relative to controls. However, a significant increase in the proportion of CD4 + CD25highHLA-DR + cells among the population of CD4 lymphocytes was found in patients with Hashimotos thyroiditis (HT) compared to controls. CONCLUSIONS In HT patients there is a quantitative increase of CD4 + CD25highHLA-DR + cells that may indicate a compensatory expansion of this subpopulation of Tregs in an attempt to suppress the immune response.

Serum levels of soluble fas in patients with multinodular goiter.

Objective: Fas is a cell-surface receptor responsible for induction of apoptosis in human thyrocytes upon interaction with Fas Ligand. Fas protein expression on thyroid cells and Fas-mediated apoptosis is decreased in multinodular goiter (MNG) resulting in thyroid cell proliferation. The soluble form of Fas (sFas) produced by alternative mRNA splicing may inhibit Fas-Fas Ligand binding and apoptosis. The aim of this study was to examine whether sFas is differentially expressed in multinodular goiter (MNG), which is associated with decreased Fas-mediated apoptosis. Method: We determined serum sFas levels using enzyme-linked immunosorbent assay (ELISA) in 42 patients with MNG and 23 normal controls. Results: Serum sFas levels were increased in patients with MNG (7.47 ± 2.55 ng/ml) compared to normal controls (2.26 ± 0.9 ng/ml). Levels of sFas were not significantly correlated with age, sex or clinical parameters, such as serum levels of FT4 or TSH. Discussion: Increased sFas in MNG may indicate increased expression of alternatively spliced Fas mRNA variant and decreased expression of cell-surface Fas protein, and may enhance thyroid cell proliferation by protecting thyroid cells from Fas-mediated apoptosis.

Genetic Risk Factors Associated With Thrombosis in Children With Congenital Neurologic Disorders

Thromboembolic events during the perinatal period are responsible for irreversible brain damage owing to cerebral hypoxia and neuronal necrosis. We investigated the presence of thrombophilia risk factors in children with congenital neurologic disorders. Nineteen children (9 males and 10 females), aged 1 to 14 years (median 4.5 years), who had presented with symptoms and signs of congenital neurologic disorders were studied. Thirty-five age-matched healthy children recruited from the same geographic area served as controls. Three patients of 19 (15.8%) were carrying the factor V Leiden mutation compared with 2 children among the controls (5.7%). One patient was heterozygous for the prothrombin G20210A variant (5.2%) compared with one child who was heterozygous among the controls. Three patients were homozygous (15.8%) and 11 were heterozygous (57.9%) for the C677T 5,10-methylenetetrahydrofolate reductase gene mutation compared with 4 (11.5%) and 18 (51.4%), respectively, among the controls. Three patients of 19 (15.8%) were carrying more than one mutation. We found 18 mutations in 79% (15/19) of the patients and 25 mutations in 69% (24/35) of the healthy children. Among the individuals carrying the homozygous 677TT 5,10-methylenetetrahydrofolate reductase genotype, we found 7 mutations in 32% (6/19) of the patients and 7 mutations in 20% (7/35) of the healthy children (P > .05). In one patient, lupus anticoagulant and antiphospholipid antibodies of IgG isotype were detected. Reduced activities of protein C, protein S, or antithrombin III were not observed in either the patient or the control group. Although, among our cases, we found some well-known risk factors associated with thrombosis in adults, the pathogenesis of these clinical entities remains obscure. (J Child Neurol 2005;20:509—512).