02242nas a2200361   4500000000100000008004100001260001300042653002500055653001900080653002500099653003600124653004000160653001100200653001200211653001600223653002500239100001600264700001600280700001800296700001400314700001500328700001100343700002000354700001800374700001500392245012000407856005900527300001000586490000700596050003200603520123100635022001401866       1991                            d  c1991 Mar10aAntibody Specificity10aAutoantibodies10aBinding, Competitive10aCytotoxicity Tests, Immunologic10aHistocompatibility Antigens Class I10aHumans10aleprosy10aLymphocytes10aBeta 2-Microglobulin1 aRasheed F N1 aLocniskar M1 aMcCloskey D J1 aHasan R S1 aChiang T J1 aRose P1 aDe Soldenhoff R1 aFestenstein H1 aMcAdam K P00aSpecificity of lymphocytotoxic autoantibodies (LCAbs) found in the serum of leprosy patients: class I MHC antigens.  uhttp://leprev.ilsl.br/pdfs/1991/v62n1/pdf/v62n1a02.pdf  a13-200 v62  aInfolep Library - available3 a<p>Lymphocytotoxic autoantibodies (LCAbs) of the IgM class have been identified in patients with borderline tuberculoid (BT) and borderline lepromatous (BL) leprosy with Type I reactions (I) as well as lepromatous leprosy (LL) patients with erythema nodosum leprosum reactions (ENL). The observation that lymphocytotoxic activity (LCA) was reduced in the presence of platelets led us to determine whether LCAbs had specificities for Class I Major Histocompatibility Complex (MHC) determinants. Absorption of LCA positive sera with platelets, classically used to deplete Class I specific lymphocytotoxic antibodies, reduced LCA towards autologous as well as allogeneic target cells. This was true for LCA positive sera from all patient classifications (group BT in the autologous system, p less than 0.01; in all other patient groups, p less than 0.001). Introducing B-2m to cytotoxicity assays only marginally reduced LCA when added at high concentrations (5 mg/ml). An anti-Class I MHC antiserum which blocked the lytic activity. The data indicate that LCAbs while absorbed by platelets, are not specific for the Class I MHC antigens. The autoantigen recognized by these autoantibodies therefore remains to be identified.</p>  a0305-7518