Pathogenetic and diagnostic aspects of siliconosis

Immunization with vaccines and Sjögren's syndrome

Sjögren's syndrome (SjS) is a systemic autoimmune disease with complex pathogenesis and still unknown etiology. Infections are listed among the main environmental factors triggering the disease in genetically predisposed individuals. Among other environmental factors, the role of immunization with vaccines in the etiopathogenesis of SjS has not yet been elucidated. Although immunization with vaccines is safe for the majority of subjects, in rare cases it can trigger or exacerbate autoimmune and rheumatic inflammatory conditions. In this paper we investigate the possible links between immunization with vaccines and the pathogenesis of SjS. The current scientific evidence about safety and efficacy of vaccines in the course of SjS are also reviewed.

To clot or not to clot: are there predictors of clinically significant thrombus formation in patients with gastroparesis and prolonged IV access?

Some patients with gastroparesis (GP) require sustained central intravenous access for hydration, medication and/or nutrition, leaving them at risk for venous thrombosis. We studied a group of 53 patients with gastroparesis for identifiable risk factors of clinically significant thrombosis. Patients requiring prolonged central IV access fell into two groups: those who had clinical incidence of IV catheter-related thrombosis confirmed radiologically (CLOT, n = 14), and those who did not form IV catheter thrombosis (NOCLOT, n = 39). We analyzed and compared clinical symptoms, serum/plasma coagulation studies, and autoimmune antibodies in the CLOT and NOCLOT groups. Patients in the CLOT group had statistically more Scl 70 antibodies than did the NOCLOT group, and another autoantibody, Ku 66, was found in higher titers in the NOCLOT group than the CLOT group. Other autoimmune and coagulation factors were not statistically different between the two groups, although a subgroup of CLOT patients had lower plasma Protein S levels. We conclude that the presence of Scl 70 autoantibodies is associated with increased clotting risk in this group of GP patients, and that the Ku 66 antibody may be associated with decreased risk of thrombosis in patients with GP. These findings, coupled with lower Protein S levels in some CLOT patients, suggests that autoimmune factors may be associated with GP patients who thrombose IV access versus patients who do not.

Surface and cytoplasmic immunoglobulin expression in B-cell chronic lymphocytic leukemia (CLL)

Flow cytometric analysis of abnormal lymphocyte populations in chronic lymphocytic leukemia (CLL) has been widely reported to show weak expression of surface immunoglobulin (sIg). The international scoring system to help discriminate between CLL and other B-cell lymphoproliferative disorders lists this as the first of 5 criteria worth 1 point each. In the present study, 30 cases of CLL were studied for surface and cytoplasmic Ig expression. 23 of these 30 (76.7%) cases were positive for sIg. Of these 23, 14 cases (60.9%) showed moderate to bright sIg expression. All of these 23 cases were positive for CD5 and CD23; all were negative for CD10 and only 6 (26.1%) were positive for FMC7. 27 of 30 (90.0%) cases expressed cytoplasmic immunoglobulin (cIg) compared to 5% reported by others. This shows that cytoplasmic Ig occurs in a much greater percentage of cases than reported previously. 23 of 30 (76.7%) cases showed positivity for both surface and cytoplasmic Ig, with 15 showing kappa light chain restriction and 8 showing lambda light chain restriction. Six expressed cytoplasmic Ig only, with 4 showing kappa light chain restriction and 2 showing lambda light chain restriction. One case expressed neither cytoplasmic nor surface Ig. CD38 positivity portends a worse prognosis. Of the 29 cases tested for CD38, 13 (44.8%) were positive. Of these 13 cases, 12 were in the surface Ig/cytoplasmic Ig+ group and 1 in the cytoplasmic Ig+ group only. Also, of the 23 cases tested for CD22 expression, 16 (69.6%) were positive. These data question the use of both "weak" surface Ig expression and lack of CD22 expression as valid scoring criteria for CLL.

Kinetics of T lymphocyte responses to persistent antigens

Long term sequential study of immune responses in the same individuals is difficult from the time commitment required and the problem of maintaining enough subjects to provide for comparative analysis. We closely studied one hundred women with silicone mammary devices through cross sectional analysis up to 26 years post implantation and a similar sample of women to 6 years post explantation. The T cell index, calculated from tritiated thymidine incorporation during lymphoblast transformation, rose to a post implant peak at 10.5-12.0 years, falling progressively over the next 14.0-15.5 years to values indicative of probable immune quiescence. Post explantation, the index rose over the first 3 years and then sharply declined to within the range for unexposed controls. The shape of these time curves contains considerable information referent cell dynamics for both stimulatory and inhibitory factors and for demonstrating net group effects, appropriate to analysis in the cross sectional perspective. When a subset of four women was studied frequently and sequentially up to 8 years, an internal oscillatory pattern emerged, focusing attention on both the stimulatory and the inhibitory aspects of long term clonal expansion. IL-2 has stimulatory and inhibitory properties at different levels of production and is considered a prime candidate as the essential cytokine. The equations have details, however, which require exploration beyond any such provisional conclusion. The analytic process was aided by normalization of oscillatory data to eliminate subject variability and by Pareto optimization to assess the trend shown by normalization. Pareto analysis revealed two minimally coordinated oscillations, one over time and the other along net clonal expansion or decline of the siloxane specific T lymphocyte clone. The segments of the time related oscillation greatly exceeded the reaction times of cytokines currently known to be active in T cell regulation. Although the ultimate controlling factor(s) may be cytokine or chemokine combinations, the data are compatible with some more basic regulatory factor(s) of cell integrity, including limits on the number of cell divisions which can be sustained in long term immunopathic lesions, among other processes.