Anti-IgG autoantibodies in HIV-infected hemophilia patients.

Sera of 76 HIV-negative hemophilia patients, 103 HIV-positive (HIV+) hemophilia patients free of AIDS or AIDS related complex (ARC), and 32 HIV+ hemophilia patients with AIDS/ARC were tested for four different anti-IgG activities. IgG-anti-F(ab')2 gamma, IgM-anti-F(ab')2 gamma, and IgG-anti-Fc gamma serum activities were significantly associated with the clinical stage of HIV infection, whereas IgM-anti-Fc gamma was not. IgG-anti-F(ab')2 gamma activity was found to be caused by cross-reaction of anti-HIV antibody with an epitope within the constant CH1 domain of human IgG. HIV+ hemophilia patients with severe thrombocytopenia (less than 50,000/microliters platelet counts) had significantly higher IgM-anti-IgG activity than patients with greater than 50,000/microliters platelets. Because anti-IgG antibodies possess immunoregulatory properties, our results may serve as a possible explanation for the frequent B cell disorders encountered in HIV-infected patients.

Allergy treatment with a peptide vaccine.

An antiserum, obtained by immunising rabbits with a human peptide-protein conjugate, was shown to inhibit histamine release from rat mast cells both in vitro and in vivo. Immunisation of sensitised rats with the same peptide reduced IgE antibody formation and serum histamine concentration, and abolished systemic anaphylactic reactions in response to allergen challenge. This peptide may form the basis of a vaccine in a new approach to the immunotherapy of atopic disease.

Anti-viral antibodies in HIV (HTLV-III) infection possess auto-antibody activity against a CH1 domain determinant in human IgG: possible immunological consequences.

Two regions of the envelope glycoprotein gp120 of the human immunodeficiency virus were shown to have a significant degree of homology to human immunoglobulin-gamma heavy-chain constant domains. We have now synthesized three short linear peptides, the first representing a sequence within the CH1 domain, the second an analogue of it, and the third representative of a region within the viral gp120. Polyclonal antibodies against these peptides were raised in rabbits and used to demonstrate that they all reacted well with human native IgG. Vice-versa, we observed the reaction of these antisera to the virus in an ELISA system. The proportion of sera reacting with the human gamma-chain peptide was significantly higher in HIV-positive individuals than in HIV-negative individuals, suggesting production of anti-viral antibodies in AIDS patients with auto-antibody activity against a CH1 domain determinant in human IgG.

Sulphasalazine therapy in ankylosing spondylitis: its effect on disease activity, immunoglobulin A and the complex immunoglobulin A-alpha-1-antitrypsin.

Serum levels of immunoglobulin A (IgA) and the complex immunoglobulin A-alpha 1 antitrypsin (IgA-alpha 1AT) were measured at the commencement and after 3 months of a double-blind, placebo-controlled trial of sulphasalazine (SAS) in patients with active ankylosing spondylitis (AS). Twenty-eight patients were evaluated, 15 on sulphasalazine, 13 on placebo. Significant falls were seen in both IgA (p less than 0.01) and IgA-alpha 1AT (p less than 0.001) in the actively treated patients. In addition, significant improvement in clinical and laboratory measures of disease were observed. It is concluded that SAS is effective in AS and modulates the immune response.

IgA-alpha 1 antitrypsin complexes in ankylosing spondylitis.

A study of 95 serum samples from 61 patients with ankylosing spondylitis (AS) showed that 21 patients (34%) had raised levels of IgA-alpha 1 antitrypsin complexes. These were associated with active disease as measured by a clinical index and also with erythrocyte sedimentation rate, C reactive protein, and serum IgA. In particular, an association was noted between 'extraspinal' manifestations of AS such as synovitis, uveitis, and active inflammatory properties of these complexes. It is suggested that these complexes may have a role in the pathogenesis of such clinical manifestations.

The relationship between the complex of immunoglobulin A and alpha-1-antitrypsin, its constituent components and the acute-phase response as measured by C-reactive protein in rheumatoid arthritis treated with gold or D-penicillamine.

Serum levels of immunoglobulin A (IgA), alpha 1-antitrypsin (AT), their complex (IgA-alpha 1AT) and C-reactive protein (CRP) were measured prior to treatment and at 6 months, in 45 rheumatoid arthritis (RA) patients. Twenty-five patients were treated with D-penicillamine (DPA) and 20 patients with gold (sodium aurothiomalate). The level of circulating complex was reduced by both treatments (p less than 0.001). There was a significant correlation between the circulating levels of IgA-alpha 1AT complex and serum IgA (p less than 0.05). No relationship was observed between the level of circulating complex and CRP. These findings suggest that formation of IgA-alpha 1AT complex in RA is dependent on the level of IgA. The complex is reduced by gold and DPA but it does not reflect an acute phase response as measured by CRP.