Implications of the accumulation of CXCR5+ NK cells in lymph nodes of HIV-1 infected patients.

BACKGROUND: B cell follicles are immune-privileged sites where intensive HIV-1 replication and latency occur, preventing a permanent cure. Recent study showed that CXCR5+ NK cells in B cell follicles can inhibit SIV replication in African green monkeys, but this has not been reported in HIV-1 infected patients. METHODS: Lymphocytes and tissue sections of lymph node were collected from 11 HIV-1 positive antiretroviral therapy (ART)-naive and 19 HIV-1 negative donors. We performed immunofluorescence and RNA-scope to detect the location of CXCR5+ NK cells and its relationship with HIV-1 RNA, and performed flow cytometry and RNA-seq to analyze the frequency, phenotypic and functional characteristics of CXCR5+ NK cells. The CXCL13 expression were detected by immunohistochemistry. FINDINGS: CXCR5+ NK cells, which accumulated in LNs from HIV-1 infected individuals, expressed high levels of activating receptors such as NKG2D and NKp44. CXCR5+ NK cells had upregulated expression of CD107a and ß-chemokines, which were partially impaired in HIV-1 infection. Importantly, the frequency of CXCR5+NK cells was inversely related to the HIV-1 viral burden in LNs. In addition, CXCL13-the ligand of CXCR5-was upregulated in HIV-1 infected individuals and positively correlated with the frequency of CXCR5+ NK cells. INTERPRETATION: During chronic HIV-1 infection, CXCR5+ NK cells accumulated in lymph node, exhibit altered immune characteristics and underlying anti-HIV-1 effect, which may be an effective target for a functional cure of HIV-1.

NLRP3 inflammasome induces CD4+ T cell loss in chronically HIV-1-infected patients.

Chronic HIV-1 infection is generally characterized by progressive CD4+ T cell depletion due to direct and bystander death that is closely associated with persistent HIV-1 replication and an inflammatory environment in vivo. The mechanisms underlying the loss of CD4+ T cells in patients with chronic HIV-1 infection are incompletely understood. In this study, we simultaneously monitored caspase-1 and caspase-3 activation in circulating CD4+ T cells, which revealed that pyroptotic and apoptotic CD4+ T cells are distinct cell populations with different phenotypic characteristics. Levels of pyroptosis and apoptosis in CD4+ T cells were significantly elevated during chronic HIV-1 infection, and decreased following effective antiretroviral therapy. Notably, the occurrence of pyroptosis was further confirmed by elevated gasdermin D activation in lymph nodes of HIV-1-infected individuals. Mechanistically, caspase-1 activation closely correlated with the inflammatory marker expression and was shown to occur through NLRP3 inflammasome activation driven by virus-dependent and/or -independent ROS production, while caspase-3 activation in CD4+ T cells was more closely related to T cell activation status. Hence, our findings show that NLRP3-dependent pyroptosis plays an essential role in CD4+ T cell loss in HIV-1-infected patients and implicate pyroptosis signaling as a target for anti-HIV-1 treatment.

[Clinicopathologic correlation between CD4-positive T lymphocyte counts and superficial lymphadenopathy in HIV-positive/AIDS patients].

OBJECTIVE: To explore the clinicopathological correlation between CD4(+) T lymphocyte count and superficial lymphadenopathy HIV/AIDS patients. METHODS: A total of 1066 HIV/AIDS patients were included in this study. The incidence of superficial lymphadenopathy, peripheral blood CD4(+) T lymphocyte counts and histological features of superficial lymphadenopathy were analyzed. RESULTS: Among 1066 patients, 126 cases (11.8%) presented with superficial lymphadenopathy. Of the 126 cases, there were 69 cases with CD4(+) T lymphocyte counts < 100/µl and clinical diagnoses including tuberculosis (37 cases), reactive hyperplasia (8 cases), AIDS-related lymphadenopathy (18 cases), penicillium diseases (12 cases), fungal infection (5 cases) and non-tuberculous mycobacterial infection (1 case). Twenty-six cases had CD4(+) T lymphocyte counts between 100/µl to 200/µl and clinical diagnosis including tuberculosis (12 cases), reactive hyperplasia (8 cases), AIDS-related lymphadenopathy(6 cases), penicillium disease (2 cases) and non-Hodgkin lymphoma (1 case). Twenty-nine cases had CD4(+) T lymphocyte counts > 200/µl and clinical diagnoses including tuberculosis (11 cases), reactive hyperplasia (12 cases), AIDS-related lymphadenopathy (3 cases), Penicillium diseases (1 case) and non-Hodgkin lymphoma (4 cases). The CD4(+) T lymphocyte counts among patients with tuberculosis, AIDS-related lymphadenopathy and Penicillium diseases were significantly different (χ(2) = 8.861, P = 0.012). A significant correlation between the incidence of superficial lymphadenopathy and CD4(+) T lymphocyte counts was found (χ(2) = 375.41, P = 0.000). CONCLUSIONS: The most common cause of superficial lymphadenopathy in HIV/AIDS patients is tuberculosis, followed by lymph node reactive hyperplasia, AIDS-related lymphadenopathy and Penicillium disease. Low CD4(+) T lymphocyte count correlates with an increased incidence of superficial lymphadenopathy and the risk of opportunity infection. Therefore, determination of peripheral blood CD4(+) T lymphocyte count should become an integral marker for the early diagnosis and treatment of superficial lymphadenopathy in HIV/AIDS patients.