Platelet Activation and Reactivity in a Large Cohort of Patients with Gaucher Disease.

OBJECTIVES: Patients with Gaucher disease (GD) are at increased risk of bleeding and have varying degrees of thrombocytopenia, making the analysis of platelet function difficult. This study aimed to provide a clinically relevant quantitative assessment of platelet function and determine its relationship with bleeding and GD-related data. METHODS: Unstimulated and stimulated platelet function was measured by whole blood flow cytometry of platelet surface-activated αIIbß3 integrin (detected with monoclonal antibody PAC1), P-selectin (CD62P), and lysosomal-associated membrane protein (LAMP3/CD63) in 149 GD patients. RESULTS: GD patients had a higher level of unstimulated CD63 expression than healthy subjects, which was mildly correlated with glucosylsphingosine (lyso-Gb1) levels (r = 0.17, p-value = 0.042). Splenectomized GD patients had a higher level of unstimulated αIIbß3 integrin and P-selectin expression. Reduced platelet reactivity (-2 standard deviation of reference range) was found in 79 (53%, 95% confidence interval [CI]: 44-61%) patients, of whom 10 (6.7%, 95% CI: 3.3-12%) had more severe platelet dysfunction. In a multivariate model, only lyso-Gb1 levels were associated with the more severe platelet dysfunction. Fifty-four (49%) of 128 adult patients who completed the bleeding tendency questionnaire reported positive bleeding history. In a multivariate logistic model, older age (odds ratio [OR]: 1.05, 95% CI: 1.01-1.1) and low P-selectin reactivity (OR: 2.03, 95% CI: 1.25-3.35) were associated with more than one bleeding manifestation. CONCLUSION: Flow cytometry enables the study of platelet function in thrombocytopenic GD patients. A platelet degranulation defect, but not αIIbß3 integrin activation defect, is associated with clinical bleeding. In vivo increased CD63 expression may be related to GD-related inflammation.

Low Interferon Relative-Response to Cytomegalovirus Is Associated with Low Likelihood of Intrauterine Transmission of the Virus.

BACKGROUND: Congenital Cytomegalovirus (CMV) is a very common intrauterine infection which can cause severe mental and hearing impairments. Notably, only 40% of primarily infected women transmit CMV to the fetus. CMV-specific T-cell response has a role in CMV disease but individual immune heterogeneity precludes reliable correlation between measurable T-cells response and intrauterine transmission. STUDY AIM: To establish a correlation between maternal T-cells response and fetal CMV transmission using an individual normalized immune response. METHODS: We analyzed IFN-γ secretion upon whole blood stimulation from primary CMV-infected pregnant women, with either CMV-peptides or PHA-mitogen. RESULTS: We established a new normalization method of individual IFN-γ response to CMV by defining the ratio between specific-CMV response and non-specific mitogen response (defined as IFN-γ relative response, RR), aiming to overcome high person-to-person immune variability. We found a unique subpopulation of women with low IFN-γ RR strongly correlated with absence of transmission. IFN-γ RR lower than 1.8% (threshold determined by ROC analysis) reduces the pre-test probability of transmission from 40% to 8%, revealing an unexpected link between low IFN-γ RR and non-transmission. CONCLUSION: In pregnant women with primary CMV infection, low IFN-γ RR is associated with low risk of transmission.