High levels of T lymphocyte activation in Leishmania-HIV-1 co-infected individuals despite low HIV viral load

• Published in: BMC infectious diseases Vol. 10; no. 1; p. 358
• Main Authors: Santos-Oliveira, Joanna R, Giacoia-Gripp, Carmem B W, Alexandrino de Oliveira, Priscilla, Amato, Valdir S, Lindoso, Jose Ângelo L, Goto, Hiro, Oliveira-Neto, Manoel P, Mattos, Marise S, Grinsztejn, Beatriz, Morgado, Mariza G, Da-Cruz, Alda M
• Format: Journal Article
• Language: English
• Published: England BioMed Central Ltd 20-12-2010; BioMed Central; BMC
• Subjects: Acquired immune deficiency syndrome; ADP-ribosyl Cyclase 1 - analysis; Adult; AIDS; Americas; CD4 Lymphocyte Count; CD4-CD8 Ratio; CD8-Positive T-Lymphocytes - chemistry; Comorbidity; Female; HIV; HIV infection; HIV Infections - complications; HIV Infections - immunology; HIV Infections - virology; HIV-1; Human immunodeficiency virus; Humans; Leishmaniasis; Leishmaniasis - complications; Leishmaniasis - immunology; Lymphocyte transformation; Lymphocytes; Male; Middle Aged; Parasitic diseases; Physiological aspects; Studies; T cells; T-Lymphocytes - immunology; Viral Load; Brazil
• ISSN: 1471-2334; 1471-2334
• DOI: 10.1186/1471-2334-10-358

Concomitant infections may influence HIV progression by causing chronic activation leading to decline in T-cell function. In the Americas, visceral (AVL) and tegumentary leishmaniasis (ATL) have emerged as important opportunistic infections in HIV-AIDS patients and both of those diseases have been implicated as potentially important co-factors in disease progression. We investigated whether leishmaniasis increases lymphocyte activation in HIV-1 co-infected patients. This might contribute to impaired cellular immune function.
To address this issue we analyzed CD4+ T absolute counts and the proportion of CD8+ T cells expressing CD38 in Leishmania/HIV co-infected patients that recovered after anti-leishmanial therapy.
We found that, despite clinical remission of leishmaniasis, AVL co-infected patients presented a more severe immunossupression as suggested by CD4+ T cell counts under 200 cells/mm3, differing from ATL/HIV-AIDS cases that tends to show higher lymphocytes levels (over 350 cells/mm3). Furthermore, five out of nine, AVL/HIV-AIDS presented low CD4+ T cell counts in spite of low or undetectable viral load. Expression of CD38 on CD8+ T lymphocytes was significantly higher in AVL or ATL/HIV-AIDS cases compared to HIV/AIDS patients without leishmaniasis or healthy subjects.
Leishmania infection can increase the degree of immune system activation in individuals concomitantly infected with HIV. In addition, AVL/HIV-AIDS patients can present low CD4+ T cell counts and higher proportion of activated T lymphocytes even when HIV viral load is suppressed under HAART. This fact can cause a misinterpretation of these laboratorial markers in co-infected patients.