Activation profile of CXCL8-stimulated neutrophils and aging.

Neutrophils are pivotal effector cells of innate immunity representing the first line of defense against aggression. They are the first cells to arrive at the site of the aggression, where they can directly eliminate the invading microorganisms. Their activation and recruitment into peripheral tissues is indispensable for host defense. With aging, there are alterations of the receptor by driven functions of human neutrophils as a decrease in the functional changes in signaling elicited by specific receptors, as CXCR1. We investigated the activation of neutrophils from elderly after the cells were cultivated with CXCL8. Although, CXCL8 induced elastase (ELA) secretion, data showed neither myeloperoxidase (MPO) activity nor production of IL-6, IL-10, GM-CSF by neutrophils from elderly compared with young individuals. On the other hand, in the presence of only LPS or LPS associated with CXCL8 neutrophils from elderly individuals, there were significant levels of IL-6, IL-10, GM-CSF but not MPO. These results indicate that neutrophils from elderly do not respond to CXCL8 stimulus, but they are activated by LPS to produce cytokines. However, MPO activity from elderly individuals was not different in the presence or absence of LPS and CXCL8.

Fcγ receptors on aging neutrophils.

OBJECTIVE: Neutrophils are key effector cells of the innate immune system. They recognize antigens through membrane receptors, which are expressed during their maturation and activation. Neutrophils express FcγRII (CD32), FcγRIII (CD16), and FcγRI (CD64) after being activated by different factors such as cytokines and bacterial products. These receptors are involved with phagocytosis of IgG-opsonized microbes and enhance defense mechanisms. Based on that, our study seeks to compare the expression of FcγRII, FcγRIII, FcγRI, and CD11b on neutrophils from elderly and young subjects and their expression after in vitro activation with cytokines and LPS. METHODOLOGY: Neutrophils were isolated from human peripheral blood and from mice bone marrow by density gradient. After isolation, FCγRs expression was immediately analyzed by flow cytometry or after in vitro stimulation. RESULTS: In freshly isolated cells, the percentage of FcγRIIIb+ and CD11b+ neutrophils were higher in samples from young individuals; FcγRIIIa expression was more prominent on aged neutrophils; FcγRIA expression was similar in all samples analyzed. Exposure to CXCL8 and LPS resulted in a higher percentage of FcγRIa+ neutrophils on elderly individuals' samples but lower when compared with neutrophils from young donors. We observed that LPS caused an increase in FcγRIIa expression on aging human neutrophils. In contrast, FcγRIIIb expression in response to CXCL8 and LPS stimulation was not altered in the four groups. CD11b expression was lower in neutrophils from elderly individuals even in response to LPS and CXCL8. In mice, we observed differences only regarding CD11b expression, which was increased on aged neutrophils. LPS exposure caused an increase in all FcγRs. CONCLUSIONS: Our results suggest that, in humans, the overall pattern of FcγR expression and integrin CD11b are altered during aging and immunosenescence might contribute to age-related infection.

Fcγ receptors on aging neutrophils

Abstract Objective Neutrophils are key effector cells of the innate immune system. They recognize antigens through membrane receptors, which are expressed during their maturation and activation. Neutrophils express FcγRII (CD32), FcγRIII (CD16), and FcγRI (CD64) after being activated by different factors such as cytokines and bacterial products. These receptors are involved with phagocytosis of IgG-opsonized microbes and enhance defense mechanisms. Based on that, our study seeks to compare the expression of FcγRII, FcγRIII, FcγRI, and CD11b on neutrophils from elderly and young subjects and their expression after in vitro activation with cytokines and LPS. Methodology Neutrophils were isolated from human peripheral blood and from mice bone marrow by density gradient. After isolation, FCγRs expression was immediately analyzed by flow cytometry or after in vitro stimulation. Results In freshly isolated cells, the percentage of FcγRIIIb+ and CD11b+ neutrophils were higher in samples from young individuals; FcγRIIIa expression was more prominent on aged neutrophils; FcγRIA expression was similar in all samples analyzed. Exposure to CXCL8 and LPS resulted in a higher percentage of FcγRIa+ neutrophils on elderly individuals' samples but lower when compared with neutrophils from young donors. We observed that LPS caused an increase in FcγRIIa expression on aging human neutrophils. In contrast, FcγRIIIb expression in response to CXCL8 and LPS stimulation was not altered in the four groups. CD11b expression was lower in neutrophils from elderly individuals even in response to LPS and CXCL8. In mice, we observed differences only regarding CD11b expression, which was increased on aged neutrophils. LPS exposure caused an increase in all FcγRs. Conclusions Our results suggest that, in humans, the overall pattern of FcγR expression and integrin CD11b are altered during aging and immunosenescence might contribute to age-related infection.

Antiretroviral drug resistance among patients with human immunodeficiency virus who act as sources or potential sources in occupational accidents involving healthcare workers.

OBJECTIVE: To determine human immunodeficiency virus (HIV) type 1 genotypic antiretroviral drug resistance profiles of patients presenting a risk or potential risk for occupational exposure of healthcare workers. DESIGN: Observational survey involving HIV-infected patients. Blood samples collected from source-patients and potential source-patients underwent HIV-1 genotypic antiretroviral resistance testing and determination of CD4 counts and viral load. Affected healthcare workers were monitored for 6 months after exposure. SETTING: The survey was conducted in a tertiary-care hospital located in Sao Paulo, Brazil. Sao Paulo is considered the epicenter of the HIV-acquired immunodeficiency (AIDS) virus epidemic in Brazil. PARTICIPANTS: Source-patients, potential source-patients, and affected healthcare workers. RESULTS: A total of 371 occupational exposures to biological materials were reported, 46 (12.3%) of which were from HIV-seropositive source-patients. Samples from 18 source-patients and 26 patients considered "potential sources for accidents" were analyzed. Of these 44 samples, 18 (41%) presented resistance-related mutations in reverse transcriptase, protease, or both. Of these 18 samples, 16 (89%) had resistance to drugs included in the prophylactic schedule recommended by the Brazilian Ministry of Health. CONCLUSIONS: Use of the Centers for Disease Control and Prevention-Brazilian post-exposure prophylaxis regimen will result in the administration of antiretroviral agents to which the source HIV-1 isolate will often be resistant. Therefore, it would be advisable to carefully investigate the history of use of antiretroviral agents by source-patients and adjust the prophylactic therapy based on those data and, subsequently, the results of resistance testing.

The pattern recognition receptors expressed on neutrophils and the associated cytokine profile from different aged patients with Candida-related denture stomatitis.

This study evaluated the expression of pattern recognition receptors (PRRs) and activation factors associated with salivary and blood neutrophils from different aged patients diagnosed with Candida-related denture stomatitis (DS). Expression of neutrophil PRRs was determined by flow cytometry and immunofluorescence, and the levels of selected cytokines that influence immune activation were determined by ELISA. The salivary (but not the serum derived) neutrophils of individuals with DS were found to have an increased expression of CD69 regardless of the age of the patient compared to patients without DS. However, these salivary neutrophils had a lower expression of CD66b and CD64. Expression of TLR2 was lower on the salivary- and serum-derived neutrophils from elderly individuals compared to the neutrophils of younger subjects, regardless of whether the individual had DS. Salivary interleukin (IL)-4 was elevated in both of the elderly subject groups (with or without DS). Only elderly DS patients were observed to have increased serum IL-4 levels and reduced salivary IL-12 levels. Younger DS patients showed an increase in salivary IL-10 levels, and both the saliva and the serum levels of IFN-γ were increased in all of the younger subjects. Our data demonstrated that changes in both the oral immune cells and the protein components could be associated with DS. Furthermore, changes in the blood-derived factors were more associated with age than DS status.