Autoantibodies in HIV-infected patients that modulate the cholinergic activity of heart and gut tissue

In human immune deficiency virus (HIV) disease, direct infection of heart tissue with HIV and repeated intestinal infections with opportunistic pathogens are thought to be the main cause of cardiac disease and diarrhoea respectively. A role for autoimmune phenomena may also be involved in the pathogeny of HIV disease. In this study, we demonstrate that immunoglobulins from the A and G classes from HIV positive patients are able to interfere with the function of the muscarinic cholinergic receptors from heart and gut. Both IgA and IgG HIV+ preparations decreased the tension of isolated atria and increased the tension of isolated ileum. The mechanical effect of carbachol was inhibited in both atria and ileum preparations, when they were preincubated with either IgA or IgG HIV+ fractions. An inhibitor of muscarinic cholinergic receptors (atropine) impaired the negative inotropic action of HIV+ immunoglobulins (Ig) on the heart and prevented the positive inotropic effect of HIV+ Igs on ileum. HIV+ IgA fraction was approximately ten fold more potent to interfere with the cholinergic function as compared to the IgG fraction. These results suggest that antibodies present in HIV+ serum may also modulate muscle's cholinergic activity in the heart and ileum from HIV+patients.