Orbital immunoglobulin‐G4‐related disease: case series and literature review

Immunoglobulin‐G4‐related disease (IgG4‐RD) is a distinct group of diseases characterized by elevated serum IgG4 titres and infiltration of affected organs by IgG4‐positive plasma cells. IgG4‐RD can involve any ocular adnexal tissue. They have a distinct prognosis and pattern of tissue involvement and hence need to be differentiated from orbital lesions with similar clinicopathological features. We report three cases of IgG4‐RD and review the literature extensively discussing various aspects of this novel entity.     

Arachidonic acid metabolites and peroxide-induced inhibition of [3H]D-aspartate release from bovine isolated retinae

We have previously shown that hydrogen peroxide (H2O2) can inhibit K+-depolarization-evoked [3H]D-aspartate release from bovine isolated retinae. In the present study, we investigated the role of arachidonic acid metabolites in the inhibitory response elicited by H2O2 in the bovine retinae. Furthermore, we examined the direct effect of H2O2 on the production of prostaglandins and isoprostanes in this tissue. Isolated bovine retinae were prepared for studies of [3H]D-aspartate release using the Superfusion Method. Release of [3H]D-aspartate was elicited by Krebs solution containing an iso-osmotic concentration of KCl (50 mM). A direct action of H2O2 on prostaglandin E2 (PGE2) and 8-isoprostane F2alpha (8-iso-PGF2alpha) was also measured by enzyme-linked immunosorbant assay (ELISA). The cyclooxygenase inhibitor, flurbiprofen (3 microM), or the thromboxane-receptor antagonist, SQ 29548 (10 microM) had no significant (p > 0.05) effect on K+-evoked [3H]D-aspartate release. On the other hand, both flurbiprofen (3 microM) and SQ 29548 (10 microM) blocked the inhibition of K+-evoked [3H]D-aspartate induced by H2O2 (30 microM). In concentrations up to 100 microM, H2O2 caused an increase in PGE2 and 8-iso-PGF2alpha over basal levels. For instance, H2O2 (100 microM) increased PGE2 and 8-iso-PGF2alpha over basal levels by 348 +/- 41% and 185 +/- 26 (n = 4), respectively. We conclude that the peroxide-mediated inhibition of [3H]D-aspartate may involve the production of prostaglandins and isoprostanes in the bovine isolated retinae.     

Mycobacterium tuberculosis infection in health care workers in rural India: comparison of a whole-blood interferon gamma assay with tuberculin skin testing

Context  Mycobacterium tuberculosis infection in health care workers has not been adequately studied in developing countries using newer diagnostic tests. Objectives  To estimate latent tuberculosis infection prevalence in health care workers using the tuberculin skin test (TST) and a whole-blood interferon (IFN-) assay; to determine agreement between the tests; and to compare their correlation with risk factors. Design, Setting, and Participants  A cross-sectional comparison study of 726 health care workers aged 18 to 61 years (median age, 22 years) with no history of active tuberculosis conducted from January to May 2004, at a rural medical school in India. A total of 493 (68%) of the health care workers had direct contact with patients with tuberculosis and 514 (71%) had BCG vaccine scars. Interventions  Tuberculin skin testing was performed using 1-TU dose of purified protein derivative RT23, and the IFN- assay was performed by measuring IFN- response to early secreted antigenic target 6, culture filtrate protein 10, and a portion of tuberculosis antigen TB7.7. Main Outcome Measures  Agreement between TST and the IFN- assay, and comparison of the tests with respect to their association with risk factors. Results  A large proportion of the health care workers were latently infected; 360 (50%) were positive by either TST or IFN- assay, and 226 (31%) were positive by both tests. The prevalence estimates of TST and IFN- assay positivity were comparable (41%; 95% confidence interval [CI], 38%-45% and 40%; 95% CI, 37%-43%, respectively). Agreement between the tests was high (81.4%;  = 0.61; 95% CI, 0.56-0.67). Increasing age and years in the health profession were significant risk factors for both IFN- assay and TST positivity. BCG vaccination had little impact on TST and IFN- assay results. Conclusions  Our study showed high latent tuberculosis infection prevalence in Indian health care workers, high agreement between TST and IFN- assay, and similar association between positive test results and risk factors. Although TST and IFN- assay appear comparable in this population, they have different performance and operational characteristics; therefore, the decision to select one test over the other will depend on the population, purpose of testing, and resource availability.