Basophil activation test: Implementation and standardization between systems and between instruments.

The basophil activation test (BAT) is a good ex vivo alternative for measuring hypersensitivity to an allergen in sensitized patients but still lacks standardization. In this present study, we have implemented one of the systems and proposed inter-systems, inter-instrument standardization. Our method for basophil activation and labeling on whole blood: EDTA in one step using BasoflowEx® and FlowCast® . Setup on Navios and fluorescence targets converted to set up FACSCanto™ instrument. Our results: 1) A CD203c/CD63 (BasoflowEx) method was adapted for EDTA samples and simplified. 2) Final washing and concentration and use of time parameter help acquiring as many basophils as possible, spare acquisition time and noise. 3) The modified method was validated according to ISO15189 with a precision at 5.1% RCV, linearity between 1 and 1/8 of anti-IgE stimulation. Results were very close with CCR3/CD63 system (FlowCast). 4) Standardization, between systems and even between instruments. Mean Fluorescence Intensity targets are proposed using standard beads (Cytocal® ) middle peak: FITC = 19.4; PE = 28.8 on Navios® corresponding to FITC = 4,966; PE = 7,373 for FACSCanto. Data analyzed on common software (Kaluza® ) were very closely correlated. 5) Co-labeling of B cells (CD20+) gives the possibility to monitor a significant drop of basophils under stimulation that could explain some underestimation in case of strong hypersensitivity. In conclusion, BAT would strongly benefit from easy implementation [EDTA, one step stimulation/labeling, wash, full sample analysis over time parameter, B cell relative basophil count] and standardization of instrument settings on MFI targets whatever system or instrument is used. © 2017 International Society for Advancement of Cytometry.

Major influence of CD4 count at the initiation of cART on viral and immunological reservoir constitution in HIV-1 infected patients.

BACKGROUND: A persistent immune activation is observed in gut during HIV-1 infection, which is not completely reversed by a combined antiretroviral therapy (cART). The impact of the time of cART initiation may highly influence the size of the viral reservoir and the ratio of CD4(+)/CD8(+) T cells in the gut. In this study, we analyzed the characteristics of HIV rectal reservoir of long-term treated patients, regarding their blood CD4(+) T cells count at the time of cART initiation. RESULTS: Twenty-four consenting men were enrolled: 9 exhibiting a CD4(+) T cells count >350/mm(3) ("high-level CD4 group") and 15 < 350/mm(3) ("low-level CD4 group") in blood, at the start of cART. An immunophenotypical analysis of T and B cells subpopulations was performed in blood and rectal biopsies. HIV cell-associated DNA loads and qualitative intra-cellular RNA were determined in both compartments. The ratio of CD4(+)/CD8(+) T cells was significantly decreased in the blood but not in the rectum of the "low-level CD4 group" of patients. The alteration in ß7(+) CD4(+) T cells homing was higher in this group and was correlated to a low ratio of CD4(+)/CD8(+) T cells in blood. An initiation of cART in men exhibiting a low-level CD4 count was also associated with an alteration of B cells maturation. HIV blood and gut DNA reservoirs were significantly lower in the "high-level CD4 group" of men. A high HIV DNA level was associated to a detectable intracellular HIV RNA in rectum. CONCLUSIONS: An early initiation of cART could significantly preserve gut immunity and limit the viral reservoir constitution.

Brief Report: A High Rate of ß7+ Gut-Homing Lymphocytes in HIV-Infected Immunological Nonresponders is Associated With Poor CD4 T-Cell Recovery During Suppressive HAART.

OBJECTIVE: Correlation between GALT homing markers on lymphocytes and the low blood CD4 T-cell reconstitution in immunological nonresponders (INRs) has been studied. DESIGN: Thirty-one INRs, 19 immunological responders (IRs), and 12 noninfected controls were enrolled in this study. INRs were defined by an undetectable plasma viral load RNA less than 40 copies per milliliter and CD4 T-cell count <500 cells per cubic milliliter in at least 3 years. METHODS: A complete peripheral and mucosal lymphocyte immunophenotyping was performed on these patients with a focus on the CCR9, CCR6, and α4ß7 gut-homing markers. RESULTS: A highly significant upregulation of α4ß7 on INRs peripheral lymphocytes compared with that of IRs has been observed. This upregulation impacts different lymphocyte subsets namely CD4, CD8, and B lymphocytes. The frequency of ß7 Th17 and Treg cells are increased compared with IRs and healthy controls. The frequency of ß7 CD8 T cells in the blood is negatively correlated with integrated proviral DNA in rectal lymphoid cells in contrast to ß7 CD4 T cells associated with HIV integration. CONCLUSIONS: Alteration of lymphocyte homing abilities would have deleterious effects on GALT reconstitution and could participate to HIV reservoir constitution. These results emphasize the great interest to consider α4ß7-targeted therapy in INR patients to block homing of lymphocytes and/or to directly impair gp120-α4ß7 interactions.