Human immune system aging results in impaired responses to pathogens or vaccines. In the innate immune system, which mediates the earliest pro-inflammatory responses to immunologic challenge, processes ranging from Toll-like Receptor function to Neutrophil Extracellular Trap formation are generally diminished in older adults. Dysregulated, enhanced basal inflammation with age reflecting activation by endogenous damage-associated ligands contributes to impaired innate immune responses. In the adaptive immune system, T and B cell subsets and function alter with age. The control of cytomegalovirus infection, particularly in the T lineage, plays a dominant role in the differentiation and diversity of the T cell compartment.

The seasonal influenza vaccine is an important public health tool but is only effective in a subset of individuals. The identification of molecular signatures provides a mechanism to understand the drivers of vaccine-induced immunity. Most previously reported molecular signatures of human influenza vaccination were derived from a single age group or season, ignoring the effects of immunosenescence or vaccine composition. Thus, it remains unclear how immune signatures of vaccine response change with age across multiple seasons. In this study we profile the transcriptional landscape of young and older adults over five consecutive vaccination seasons to identify shared signatures of vaccine response as well as marked seasonal differences. Along with substantial variability in vaccine-induced signatures across seasons, we uncovered a common transcriptional signature 28 days postvaccination in both young and older adults. However, gene expression patterns associated with vaccine-induced Ab responses were distinct in young and older adults; for example, increased expression of killer cell lectin-like receptor B1 (KLRB1; CD161) 28 days postvaccination positively and negatively predicted vaccine-induced Ab responses in young and older adults, respectively. These findings contribute new insights for developing more effective influenza vaccines, particularly in older adults.

Cutaneous leishmaniasis is a parasitic infection that causes significant maternal morbidity, and even fetal mortality, during pregnancy, yet there are limited therapeutic options. Here, we report a case of leishmaniasis in a pregnant immigrant with exuberant mucocutaneous lesions with favorable response to liposomal amphotericin B.

Prototheca wickerhamii is an alga that rarely causes human disease but has been reported increasingly among immunocompromised individuals. We report a fatal case of P. wickerhamii in a renal transplant recipient who presented with a cutaneous lesion that led to disseminated disease despite treatment with voriconazole. We reviewed previous cases of protothecosis involving solid organ transplant recipients in the literature and discussed the value of newer microbiology platforms, i.e., matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF), to achieve early diagnosis and impact outcomes.

Cryptococcus neoformans is a ubiquitous encapsulated environmental yeast that can cause severe central nervous system disease, primarily in immune compromised hosts. In patients with AIDS, the spectrum of cryptococcal central nervous system disease includes meningitis, cystic lesions, and mass-like cryptococcomas. We report a fatal case of meningitis and cerebritis caused by C. neoformans in an AIDS patient refractory to multiple courses of liposomal amphotericin B despite immune recovery with antiretroviral therapy. This case highlights ongoing diagnostic and therapeutic challenges in the face of treatment failure for cryptococcal meningitis and reinforces the need for improved treatment approaches.