RESUMO
Antigen-specific B cells bifurcate into antibody-secreting cells (ASCs) and memory B cells (MBCs) after infection or vaccination. ASCs (plasmablasts) have been extensively studied in humans, but less is known about B cells that become activated but do not differentiate into plasmablasts. Here we have defined the phenotype and transcriptional program of a subset of antigen-specific B cells, which we have called 'activated B cells' (ABCs), that were distinct from ASCs and were committed to the MBC lineage. We detected ABCs in humans after infection with Ebola virus or influenza virus and also after vaccination. By simultaneously analyzing antigen-specific ASCs and ABCs in human blood after vaccination against influenza virus, we investigated the clonal overlap and extent of somatic hypermutation (SHM) in the ASC (effector) and ABC (memory) lineages. Longitudinal tracking of vaccination-induced hemagglutinin (HA)-specific clones revealed no overall increase in SHM over time, which suggested that repeated annual immunization might have limitations in enhancing the quality of influenza-virus-specific antibody.
Assuntos
Subpopulações de Linfócitos B/imunologia , Linfócitos B/imunologia , Ebolavirus/fisiologia , Doença pelo Vírus Ebola/imunologia , Vírus da Influenza A/fisiologia , Vacinas contra Influenza/imunologia , Influenza Humana/imunologia , Fator de Transcrição PAX5/metabolismo , Plasmócitos/imunologia , Adulto , Anticorpos Antivirais/sangue , Diferenciação Celular , Células Clonais , Glicoproteínas de Hemaglutininação de Vírus da Influenza/imunologia , Humanos , Memória Imunológica , Ativação Linfocitária , Hipermutação Somática de Imunoglobulina/genética , Vacinação , Adulto JovemRESUMO
Left ventricular assist device infections (LVADIs) are common but challenging to treat, often requiring prolonged courses of intravenous antibiotics. Dalbavancin could have a role in treating patients with chronic LVADIs given its less frequent dosing requirements. Here, we illustrate a case in which dalbavancin was used as suppressive therapy for an LVADI for greater than 7 months.
RESUMO
Between October 1998 and April 1999, 51 persons belonging to two separate groups developed acute pulmonary histoplasmosis after visiting a cave in Costa Rica. The first group consisted of 61 children and 14 adults from San Jose, Costa Rica; 44 (72%) were diagnosed with acute histoplasmosis. The second group comprised 14 tourists from the United States and Canada; 9 (64%) were diagnosed with histoplasmosis. After a median incubation time of 14 days, the most common symptoms were headache, fever, cough, and myalgias. Risk factors for developing histoplasmosis included crawling (odds ratio [OR] = 17.5, 95% confidence interval [CI] = 2.3-802) and visiting one specific room (OR = 3.4, 95% CI = 1.0-12.3) in the cave. Washing hands (OR = 0.1, 95% CI = 0.01-0.6) after exiting the cave was associated with a decreased risk of developing histoplasmosis. Histoplasma capsulatum was isolated from bat guano collected from inside the cave. Persons who explore caves, whether for recreation or science, should be aware of the risk bat-inhabited caves pose for developing histoplasmosis, especially if they are immunocompromised in any way.