title: Elevated levels of iC3b and C4d, but not Bb, complement fragments from plasma of persons infected with human T cell leukemia virus (HTLV) with HTLV-I-associated myelopathy/tropical spastic paraparesis.
abstract: Plasma levels of complement (C) fragments iC3b, C4d, and Bb from human T cell leukemia virus (HTLV)-positive subjects with HTLV-I-associated myelopathy (HAM)/tropical spastic paraparesis (TSP) were analyzed by EIA. Both iC3b and C4d levels were significantly elevated in persons with HAM/TSP. These levels were similar to those in patients with human immunodeficiency virus (HIV) infection or rheumatoid arthritis (RA), who are known to have increased C fragments. Bb levels in persons with HAM/TSP wer unaffected, suggesting that C activation occurred only via the classical pathway. This differed from findings in HIV-infected or RA patients, who had elevated levels of Bb. The results showed an increase in C activation in persons with HAM/TSP and activation via the classical pathway, likely mediated by virus or immune complexes. It is possible that the C activation observed in these subjects contributed to the inflammatory pathogenesis of HAM/TSP.
authors.affiliation: Department of Immunology/Microbiology, Rush Medical Center, Chicago, Illinois 60612, USA.
authors.forename: M N
authors.initials: MN
authors.lastname: Saarloos
authors.forename: R E
authors.initials: RE
authors.lastname: Koenig
authors.forename: G T
authors.initials: GT
authors.lastname: Spear
mesh_terms: D001172:Arthritis, Rheumatoid / Q000097:blood; D051561:Complement C3 Convertase, Alternative Pathway; D003179:Complement C3b / Q000032:analysis*; D003181:Complement C4 / Q000032:analysis*; D015935:Complement C4b; D006800:Deltaretrovirus Infections; D015658:HIV Infections / Q000097:blood; D015490:HTLV-I Infections; D006801:Humans; D015493:Paraparesis, Tropical Spastic / Q000097:blood*; D010446:Peptide Fragments / Q000032:analysis*
chemical_list: D003181:Complement C4; D010446:Peptide Fragments; D003179:Complement C3b; D015935:Complement C4b; C032261:complement C4d; D051561:Complement C3 Convertase, Alternative Pathway