Identification of apparent dual ANCA specificities in a subset of patients with systemic vasculitis and crescentic glomerulonephritis.

23% of a random selection of ANCA (+) patients had dual, non-cross reactive autoantibody specificities. We found no clinical difference in such patients as compared to those having a single antibody. A second group of ANCA (+) patients had neither anti-MPO nor anti-PR3 autoantibody specificity. These findings suggest that multiple, coincident ANCA specificities occur more commonly than previously reported, and that additional, unidentified ANCA specificities are present in some patients.

Expression of IgA and IgM Fc receptors on murine T lymphocytes.

Fc receptors are induced on T cells following activation via the TCR. T cells that express Fc receptors transiently have the ability to use two different cognate systems: the TCR and immunoglobulins bound to the Fc receptors. The studies discussed in this article are focused on the Fc alpha and Fc mu receptors that can be induced on certain subsets of murine T lymphocytes. The article emphasizes the role of the T cell receptor for antigen in the expression of Fc alpha and Fc mu receptors on murine T cells and reviews experimental observations that suggest significant molecular heterogeneity of these Fc receptors. The finding that regulation of expression of Fc alpha receptors and Fc mu receptors on T lymphocytes is linked to cellular activation via the CD3/TCR complex implies that these Fc receptors might mediate important functions in the biology and pathology of T cells.