Restoration of T Cell Responses to Toxoplasma gondii after Successful Combined Antiretroviral Therapy in Patients with AIDS with Previous Toxoplasmic

Clin Infect Dis. 2011 Mar;52(5):662-670.

Restoration of T Cell Responses to Toxoplasma gondii after Successful Combined Antiretroviral Therapy in Patients with AIDS with Previous Toxoplasmic Encephalitis

Lejeune M, Miró JM, De Lazzari E, García F, Claramonte X, Martínez E, Ribera E, Arrizabalaga J, Arribas JR, Domingo P, Ferrer E, Plana M, Valls ME, Podzamczer D, Pumarola T, Jacquet A, Mallolas J, Gatell JM, Gallart T; the Spanish Toxoplasma gondii Study Group.

Immunology Service, Hospital Clinic-Institut d'Investigacions Biomèdiques Augustí Pi i Suñer.

Abstract
Background. It is unknown whether a Toxoplasma gondii-specific T cell response is restored after successful combined antiretroviral therapy (cART) in patients with AIDS and current or previous toxoplasmic encephalitis (TE). Methods. We performed a multicenter cross-sectional study with 17 healthy T. gondii-positive human immunodeficiency virus (HIV)-1-uninfected individuals and 90 patients coinfected with HIV-1 and T. gondii distributed in 5 groups according to their CD4(+) T cell counts and T. gondii infection (with or without current or previous TE). We investigated the lymphocyte proliferative response (LPR) and interferon (IFN)-γ production in response to T. gondii soluble antigen extract (SATg) and as CD4(+) and CD8(+) T cell subsets. Results. SATg-specific LPR and IFN-γ production were not observed in many of the most immunosuppressed patients (CD4(+) T cell count, <200 cells/μL, with or without current or previous TE). By contrast, these responses occurred in a considerable percentage (LPR, 43%; IFN-γ production, 80%) of patients receiving successful cART (CD4(+) T cell count, >200 cells/μL) who presented with TE and had already stopped secondary TE prophylaxis. Similar results were found in immunocompetent asymptomatic patients who did not receive TE prophylaxis. The predictors of SATg-specific T cell responses and IFN-γ production were a cART-mediated increase in CD4(+) T cell count and LPR to phytohemagglutinin and viral suppression and a decrease in the activated (CD38(+)) CD8(+) T cell count, respectively. Conclusions. cART restores T. gondii-specific CD4 T cell responses in most patients with AIDS who had previous TE. Our data support the safety of withdrawing TE prophylaxis when the CD4(+) T cell count returns to levels >200 cells/μL.

PMID: 21292671 [PubMed - as supplied by publisher]