Seasonal influence of tuberculosis diagnosis in Rwanda.

BACKGROUND: Tuberculosis (TB) remains a major global health concern. Previous research reveals that TB may have a seasonal peak during the spring and summer seasons in temperate climates; however, few studies have been conducted in tropical climates. This study evaluates the influence of seasonality on laboratory-confirmed TB diagnosis in Rwanda, a tropical country with two rainy and two dry seasons. METHODS: A retrospective chart review was performed at the University Teaching Hospital-Kigali (CHUK). From January 2016 to December 2017, 2717 CHUK patients with TB laboratory data were included. Data abstracted included patient demographics, season, HIV status, and TB laboratory results (microscopy, GeneXpert, culture). Univariate and multivariable logistic regression (adjusted for age, gender, and HIV status) analyses were performed to assess the association between season and laboratory-confirmed TB diagnoses. RESULTS: Patients presenting during rainy season periods had a lower odds of laboratory-confirmed TB diagnosis compared to the dry season (aOR=0.78, 95% CI 0.63-0.97, p=0.026) when controlling for age group, gender, and HIV status. Males, adults, and people living with HIV were more likely to have laboratory-confirmed TB diagnosis. On average, more people were tested for TB during the rainy season per month compared to the dry season (120.3 vs. 103.3), although this difference was not statistically significant. CONCLUSION: In Rwanda, laboratory-confirmed TB case detection shows a seasonal variation with patients having higher odds of TB diagnosis occurring in the dry season. Further research is required to further elucidate this relationship and to delineate the mechanism of season influence on TB diagnosis.

Unwitting adult marijuana poisoning: a case series.

STUDY PURPOSE: With increasing state legalization, marijuana use has become commonplace throughout much of the United States. Existing literature on unintentional exposure focuses primarily on children.We report on a cluster of adults with unwitting marijuana exposure. METHODS: A cluster of cases were referred to the Medical Toxicology Service after ingesting marijuana-contaminated food at a family event. We conducted a retrospective analysis of twelve subject charts and a qualitative analysis with six of these subjects who willingly consented to be interviewed about their experiences. The study was approved by the Institutional Review Board. RESULTS: Three of the subjects (25%) required prolonged observation due to persistent symptoms. Eleven (92%) were urine immunoassay positive for tetrahydrocannabinol (THC). Two subjects (17%) tested positive for ethanol in their blood. Common symptoms experienced by the subjects included confusion (50%), difficulty speaking (67%), nausea (25%), tremors (17%), and feelings of unreality (33%). All interviewed subjects reported sleepiness and three (50%) reported a negative impact on work. Subjects also reported multiple emotions, including anger, confusion, disbelief, and helplessness. None of the cases resulted in admission for critical care or death. CONCLUSIONS: Our series illuminates effects of unwitting and/or unintentional marijuana exposure in adults. Unintentional marijuana poisonings have increased, but legal and regulatory barriers have limited the study of marijuana outside highly controlled conditions. While the marijuana exposure in this study did not result in admission for critical care or death, it did result in psychological distress and adversely affected work in some cases.

Recurrent group A Streptococcus tonsillitis is an immunosusceptibility disease involving antibody deficiency and aberrant TFH cells.

"Strep throat" is highly prevalent among children, yet it is unknown why only some children develop recurrent tonsillitis (RT), a common indication for tonsillectomy. To gain insights into this classic childhood disease, we performed phenotypic, genotypic, and functional studies on pediatric group A Streptococcus (GAS) RT and non-RT tonsils from two independent cohorts. GAS RT tonsils had smaller germinal centers, with an underrepresentation of GAS-specific CD4+ germinal center T follicular helper (GC-TFH) cells. RT children exhibited reduced antibody responses to an important GAS virulence factor, streptococcal pyrogenic exotoxin A (SpeA). Risk and protective human leukocyte antigen (HLA) class II alleles for RT were identified. Lastly, SpeA induced granzyme B production in GC-TFH cells from RT tonsils with the capacity to kill B cells and the potential to hobble the germinal center response. These observations suggest that RT is a multifactorial disease and that contributors to RT susceptibility include HLA class II differences, aberrant SpeA-activated GC-TFH cells, and lower SpeA antibody titers.

An Inexpensive Conceptual Training Model for Transvenous Pacemaker Placement.

INTRODUCTION: Emergent transvenous (TV) pacemaker placement can be life-saving, but it has associated complications. Emergency medicine (EM) educators must be able to teach this infrequent procedure to trainees. METHODS: We constructed a conceptually-focused, inexpensive training model made from polyvinyl chloride pipes and connectors, vinyl tubing, and a submersible pump. Cost of the model was $51. We tested the model with a group of 15 EM residents. We then asked participants to complete a survey reporting confidence with the procedure before and after the session. Confidence was compared using a Wilcoxon matched-pairs test. RESULTS: Confidence improved after the session, with a median confidence before the session of 2 (minimally confident; interquartile range [IQR] 1-3) and a median confidence after the session of 4 (very confident; IQR 3-4, p=0.001). All residents agreed that the model helped them to understand the process of placing a TV pacemaker. CONCLUSION: Our TV pacemaker placement model was inexpensive and allowed for practice of a complex emergency procedure with direct visualization. It improved trainee confidence.

Composite lymphoma with diffuse large B-cell lymphoma and classical Hodgkin lymphoma components: A case report and review of the literature.

Composite lymphoma (CL) is an infrequently diagnosed entity in which two or more distinct types of lymphomas occur synchronously in the same organ or anatomical site. Most commonly, CLs are composed of two non-Hodgkin B-cell lymphomas. We present a case of a composite lymphoma with diffuse large B-cell lymphoma, not otherwise specified (DLBCL-NOS) and classical Hodgkin lymphoma (CHL) components involving the terminal ileum, colon and pericolic lymph nodes. Immunohistochemical evaluation for determination of cell of origin of the DLBCL-NOS component indicated a germinal center B-cell subtype. Immunoglobulin heavy chain fragment length analysis revealed identical dominant monoclonal peaks on the DH1-6-JH reaction, and also a dominant monoclonal peak observed only in the framework II reaction done on the CHL component, indicating a partial clonal relationship between the two components. Additionally, a review of the available literature reveals a total of 20 previously reported cases of CL with DLBCL-NOS and CHL components, and most of the tested cases showed clonal relationship between the two components. The overall findings indicate that in most cases, the two components of CL with DLBCL-NOS and CHL components are clonally related, and suggest a shared origin from a common B-cell precursor.

Cytokine-Independent Detection of Antigen-Specific Germinal Center T Follicular Helper Cells in Immunized Nonhuman Primates Using a Live Cell Activation-Induced Marker Technique.

A range of current candidate AIDS vaccine regimens are focused on generating protective HIV-neutralizing Ab responses. Many of these efforts rely on the rhesus macaque animal model. Understanding how protective Ab responses develop and how to increase their efficacy are both major knowledge gaps. Germinal centers (GCs) are the engines of Ab affinity maturation. GC T follicular helper (Tfh) CD4 T cells are required for GCs. Studying vaccine-specific GC Tfh cells after protein immunizations has been challenging, as Ag-specific GC Tfh cells are difficult to identify by conventional intracellular cytokine staining. Cytokine production by GC Tfh cells may be intrinsically limited in comparison with other Th effector cells, as the biological role of a GC Tfh cell is to provide help to individual B cells within the GC, rather than secreting large amounts of cytokines bathing a tissue. To test this idea, we developed a cytokine-independent method to identify Ag-specific GC Tfh cells. RNA sequencing was performed using TCR-stimulated GC Tfh cells to identify candidate markers. Validation experiments determined CD25 (IL-2Rα) and OX40 to be highly upregulated activation-induced markers (AIM) on the surface of GC Tfh cells after stimulation. In comparison with intracellular cytokine staining, the AIM assay identified >10-fold more Ag-specific GC Tfh cells in HIV Env protein-immunized macaques (BG505 SOSIP). CD4 T cells in blood were also studied. In summary, AIM demonstrates that Ag-specific GC Tfh cells are intrinsically stingy producers of cytokines, which is likely an essential part of their biological function.

CXCL13 is a plasma biomarker of germinal center activity.

Significantly higher levels of plasma CXCL13 [chemokine (C-X-C motif) ligand 13] were associated with the generation of broadly neutralizing antibodies (bnAbs) against HIV in a large longitudinal cohort of HIV-infected individuals. Germinal centers (GCs) perform the remarkable task of optimizing B-cell Ab responses. GCs are required for almost all B-cell receptor affinity maturation and will be a critical parameter to monitor if HIV bnAbs are to be induced by vaccination. However, lymphoid tissue is rarely available from immunized humans, making the monitoring of GC activity by direct assessment of GC B cells and germinal center CD4(+) T follicular helper (GC Tfh) cells problematic. The CXCL13-CXCR5 [chemokine (C-X-C motif) receptor 5] chemokine axis plays a central role in organizing both B-cell follicles and GCs. Because GC Tfh cells can produce CXCL13, we explored the potential use of CXCL13 as a blood biomarker to indicate GC activity. In a series of studies, we found that plasma CXCL13 levels correlated with GC activity in draining lymph nodes of immunized mice, immunized macaques, and HIV-infected humans. Furthermore, plasma CXCL13 levels in immunized humans correlated with the magnitude of Ab responses and the frequency of ICOS(+) (inducible T-cell costimulator) Tfh-like cells in blood. Together, these findings support the potential use of CXCL13 as a plasma biomarker of GC activity in human vaccine trials and other clinical settings.

Multicentric Castleman Disease with Monoclonal Incomplete IgH Restriction: A Rare Coexistence.

Castleman disease is a rare lymphoproliferative disorder that may have a unicentric or multicentric clinical presentation. Herein we present the case of a 49-year-old female with a 3-year history of progressively worsening lymphadenopathy associated with fevers, chills and night sweats. Laboratory studies showed anemia and mildly elevated sedimentation rate. A computed tomogram scan of the chest, abdomen and pelvis showed multiple enlarged bilateral axillary, supraclavicular, subpectoral, submental, retroperitoneal, and para-aortic lymph nodes. A right axillary lymph node biopsy was performed and found to display histopathologic features compatible with the plasma cell type of Castleman disease. The patient was found to be human immunodeficiency virus (HIV)-positive, with a viral load of 104,000/mL and a CD4 cell count of 84 cells/mm(3). Molecular studies on the lymph node specimen revealed an incomplete monoclonal DH-JH rearrangement in the IgH gene. The patient was initially treated with antiretroviral therapy with a combination of elvitegravir, cobicistat, emtricitabine and tenofovir that improved her fatigue and malaise. As treatment for Castleman disease, she was administered a combination of rituximab and etoposide, which led to a reduction in lymphadenopathy. To the best of the authors' knowledge, this is the first reported case of multicentric Castleman disease with monoclonal incomplete IgH gene rearrangement in an HIV-positive patient.