Purpose: This document seeks to establish guidance for the evaluation and management of women with recurrent urinary tract infections (rUTI) to prevent inappropriate use of antibiotics, decrease the risk of antibiotic resistance, reduce adverse effects of antibiotic use, provide guidance on antibiotic and nonantibiotic strategies for prevention, and improve clinical outcomes and quality of life by reducing recurrence of urinary tract infection (UTI) events. Materials and Methods: The systematic review utilized to inform this guideline was conducted by a methodology team at the Pacific Northwest Evidence-based Practice Center. A research librarian conducted searches in Ovid MEDLINE (1946 to January Week 1 2018), Cochrane Central Register of Controlled Trials (through December 2017) and Embase (through January 16, 2018). An update literature search was conducted on September 20, 2018. Results: When sufficient evidence existed, the body of evidence was assigned a strength rating of A (high), B (moderate), or C (low). Such evidence-based statements are provided as Strong, Moderate, or Conditional Recommendations. In instances of insufficient evidence, additional guidance is provided as Clinical Principles and Expert Opinions. Conclusions: Our ability to diagnose, treat, and manage rUTI long-term has evolved due to additional insights into the pathophysiology of rUTI, a new appreciation for the adverse effects of repetitive antimicrobial therapy, rising rates of bacterial antimicrobial resistance (AMR), and better reporting of the natural history and clinical outcomes of acute cystitis and rUTI. As new data continue to emerge in this space, this document will undergo review to ensure continued accuracy.

In this review, we discuss recent data from our laboratory that address two aspects of major histocompatibility complex (MHC) class I-restricted antigen processing. First, we consider the nature of the peptide-loading complex, which is the assembly of proteins in the endoplasmic reticulum (ER) into which newly synthesized MHC class I-beta(2) microglobulin (beta(2)m) heterodimers are incorporated, and the mechanisms involved in MHC class I assembly and peptide loading that are facilitated by the peptide-loading complex. Second, we discuss mechanisms of cross-presentation, the phenomenon whereby extracellular and luminal protein antigens can be processed by antigen-presenting cells, particularly dendritic cells, and presented by MHC class I molecules to CD8(+) T cells. The focus of the discussion is mainly on the human MHC class I system.

Conventionally, MHC class I-restricted antigen (Ag) processing requires the action of the multimolecular peptide-loading complex within the endoplasmic reticulum (ER). Here we show that early phagosomes from human dendritic cells (DCs) contain the peptideloading complex, incorporating MHC class I, ␤2 microglobulin, transporter associated with Ag processing (TAP), calreticulin, tapasin, and ERp57. Antigenic peptides could be translocated into purified phagosomes by TAP and loaded onto cognate class I molecules, inducing their specific dissociation from the loading complex. Endoglycosidase H-sensitive class I molecules were detected at the DC cell surface, suggesting that these molecules traffic there directly from phagosomes. Macropinocytosis also allowed internalized soluble Ags access to an ER-like compartment containing the class I loading complex. Blockade of TAP by endocytosis of a soluble derivative of human cytomegalovirus protein US6 confirmed that, although retrotranslocation into the cytosol is critical for processing, efficient association of class I molecules with peptides derived from exogenous Ags occurs within a compartment directly accessible to internalized proteins. Together, this evidence suggests that early phagosomes and pinosomes facilitate cross presentation of exogenous Ags by DCs.