To investigate the changes in the percentages of CD4⁺ T lymphocyte subsets and the homeostasis of T lymphocytes among MSM (men who have sex with men) population with different stages of HIV-1 infection.

A total of 166 untreated MSM with HIV infection were enrolled and divided into three groups including early HIV infection (EHI, n=38) , HIV (n=94) and AIDS (n=34) groups. Sixty-two MSM negative for anti-HIV antibody were selected as healthy controls. Blood samples were collected into EDTA tubes and detected to analyze the changes in the distribution of CD4⁺ T cells and CD8⁺ T lymphocyte subsets (CD4⁺ CD45RA⁺ , CD8⁺ CD28⁺ , CD4⁺ CD25⁺ CD127^-) and the percentages of activated (CD38, HLA-DR) and apoptotic cells (CD95) with disease progression by flow cytometry.

The expression of CD4⁺ CD45RA⁺ T lymphocytes gradually decreased with the progression of AIDS. The percentage of CD4⁺ CD45RA⁺ T lymphocytes in HIV group was lower than that of the control group, but higher than that of the AIDS group (P=0.015, P=0.000). No significant difference was found between the EHI and the control groups (P>0.05). CD8⁺ CD28⁺ T cells were significantly reduced in the EHI group and remained at a low level with disease progression. No significant difference in the proportion of CD4⁺ CD25⁺ CD127^- T cells was observed among all groups (P>0.05). The percentage of CD4⁺ CD38⁺ HLA-DR⁺ T cells increased gradually and the highest level was detected in the AIDS group, followed by those in the HIV, EHI and control groups (P<0.01). The percentages of CD8⁺ CD38⁺ , CD8⁺ HLA-DR⁺ , CD8⁺ CD38⁺ HLA-DR⁺ and CD8⁺ CD95⁺ T cells in the EHI, HIV and AIDS groups were significantly higher than those in the control group (P<0.01), but there was no significant difference among the former three groups (P>0.05).

HIV infection caused the changes in the numbers and functions of T lymphocyte subsets and accelerated the activation and apoptosis of T lymphocytes, which aggravated the T lymphocyte immune dysfunction even further. A comprehensive analysis of the alterations in different T cell subsets would be conducive to reflect the immune deficiency and the severity of disease. CD4⁺ and CD8⁺ T cells were activated in the early stage of HIV infection, which indicated that studying the immune response during that stage might help to understand their roles in disease progression.

Human immunodeficiency virus; Early HIV infection; Activation; T cell homeostasis; Disease progression