Cytokine analysis at the single cell level and lymphoproliferative responses to mycobacterial antigens in HIV-1 patients with successful virologic response to potent antiretrovirals

Deficient in vitro anti-mycobacterial immunity despite successful long-term highly active antiretroviral therapy in HIV-infected patients with past history of tuberculosis infection or disease

We evaluated the anti-Mycobacterium tuberculosis (Mtb) immune responses of HIV patients after long-term successful HAART, presenting >500 TCD4+ cells/microl, undetectable viral load, and past history of tuberculosis infection (HIV+PPD+, n=14) or disease (HIV+CTB, n=17). Their lymphoproliferative and IFN-gamma responses were compared with those from HIV-uninfected controls either PPD+ (HIV-PPD+, n=17) or with past history of pulmonary tuberculosis (n=15). Most HIV-infected patients presented normal PHA responses while responses to the Mtb recombinant polypeptides ESAT-6 and Ag85B were markedly reduced. Responses to a whole Mtb lysate (S-Mtb) in HIV+PPD+ patients were lower than in HIV-PPD+ controls, while in HIV+CTB patients these responses were similar to that of past-tuberculosis controls. Comparison between the two HIV groups also suggested better S-Mtb responses in those cured from tuberculosis. Thus, while immune responses to single Mtb proteins are depressed even after successful HAART, reactivity to S-Mtb is high, specially in those cured from tuberculosis, possibly as a result of the survival of higher numbers of mycobacteria-specific T cell clones during the immunosuppression phase, which may afford sufficient protection against new Mtb challenges.

Clinical tolerance and immunologic effects after single or repeated administrations of the synthetic immunomodulator murabutide in HIV-1-infected patients

Correction of the virus-induced deficits in innate immunity of HIV-infected subjects could well contribute to enhanced immune recovery and efficacious control of viral replication. The safe synthetic immunomodulator Murabutide (ISTAC Biotechnology, Lille, France) has been found to regulate the function of antigen-presenting cells and to selectively activate CD4 lymphocytes leading to dramatic suppression of HIV replication, in vitro. Therefore, as a first step toward the evaluation of the immunotherapeutic potential of Murabutide in HIV disease, we have conducted two phase 1/2 clinical trials to address the safety and the immunologic effects of Murabutide administration into HIV-infected subjects receiving antiretroviral therapy. The first study revealed that single administration of 5, 7, or 9 mg of Murabutide, to 6 patients per dose, was well tolerated. This was accompanied by a selective induction of cytokines and chemokines detectable in the serum, and the levels appeared to plateau at the 7-mg dose. The second study then evaluated the safety and biological effects of repeated administrations of 7 mg Murabutide, on 5 consecutive days, in 12 HIV-1-infected patients. A good clinical tolerance was noted throughout the study. Moreover, changes in several immune parameters, including downregulation of coreceptor expression on lymphocytes and improved lymphoproliferative responses, were detected during or/and up to 3 weeks after Murabutide administration. These encouraging results warrant further evaluation of longer periods or cycles of immunotherapy with Murabutide in HIV-infected subjects.