Prevalence of depression in Latin America and the Caribbean: protocol for a systematic review and meta-analysis.

OBJECTIVE: The objective of this review is to evaluate the best available evidence to determine the prevalence of depression in the general population of Latin America and the Caribbean countries. INTRODUCTION: Depression is a common mental disorder that affects quality of life and has been ranked as the largest contributor to non-fatal health loss. Knowledge of this disorder serves as a relevant instrument for policy makers and for the reassignment of public health resources. Although the prevalence of depression is well documented in high-income countries, little is known about the prevalence in Latin America and the Caribbean. INCLUSION CRITERIA: This review will include studies that report the prevalence of depression in the general adult (14 years and older) population of countries in Latin America and the Caribbean. Non-representative subsets of the population will be excluded. METHODS: The search strategy will be designed to obtain both published and unpublished studies. Information sources include PubMed, PsycINFO, Cochrane CENTRAL, and SciELO. Sources of unpublished studies include literature from government departments, international agencies, and academic institution repositories or websites. Eligible studies will be critically appraised for methodological quality. Prevalence estimates will be statistically pooled in a meta-analysis after heterogeneity interpretation; data not appropriate for pooling will be reported in a narrative review. Finally, risk of publication bias will be studied via funnel plot analysis and the Egger test. SYSTEMATIC REVIEW REGISTRATION NUMBER: PROSPERO (CRD42019143054).

The Prevalence of Rheumatoid Arthritis in Chile: A Nationwide Study Performed as Part of the National Health Survey.

OBJECTIVE: Genetic and environmental backgrounds influence the development of rheumatoid arthritis (RA). In Latin America, epidemiologic data are scarce. We aimed to determine the prevalence of RA in Chile in a population-based study. METHODS: The National Health Survey was a cross-sectional household survey with a stratified multistage probability sample of 6233 participants performed between August 2016 and March 2017. A screening instrument for RA was applied to a random sample of 3847 subjects > 30 years old. Positive screening was defined by at least 1 of the following: 2 swollen joints for at least 4 consecutive weeks (past/present), and/or a diagnosis of arthritis in the past. Individuals with positive screening had rheumatoid factor, anticitrullinated protein antibodies, and C-reactive protein measured, as well as clinical examination performed by a rheumatologist. Self-report of doctor-diagnosed RA was also performed. RESULTS: The screening questionnaire was applied to 2998 subjects. A positive screening was found for 783 (22.1%). Among subjects with positive screening, 493 (66%) had a clinical evaluation performed by a rheumatologist. Using the American College of Rheumatology/European League Against Rheumatism 2010 classification criteria, prevalence was 0.6% (95% CI 0.3-1.2). Prevalence was higher in women, and 3.3% of subjects self-reported having RA. CONCLUSION: According to this national population-based study, RA prevalence in Chile is 0.6% (0.3-1.2), a value similar to what has been found in developed countries and slightly lower than some Latin American countries. Self-reporting leads to overestimating RA.

Heme-Oxygenase-1 Is Decreased in Circulating Monocytes and Is Associated With Impaired Phagocytosis and ROS Production in Lupus Nephritis.

Lupus nephritis (LN) is one of the most serious manifestations of systemic lupus erythematosus (SLE). Based on studies showing the potential role of heme oxygenase-1 (HO-1), an enzyme that catalyzes the degradation of heme and has anti-inflammatory properties in SLE development, we decided to explore HO-1 in LN. Accordingly, we evaluated HO-1 levels and function in circulating and infiltrating monocytes and neutrophils of LN patients. HO-1 levels were assessed in peripheral monocytes of LN patients and controls by flow cytometry and immunofluorescence microscopy. Phagocytosis and the production of reactive oxygen species (ROS) were evaluated to determine the effect of HO-1 in monocyte function. In addition, renal biopsies with proliferative LN were used to identify HO-1 in infiltrating cells and renal tissue by immunofluorescence and immunohistochemistry. Biopsies of healthy controls (HC) and patients who underwent nephrectomy were included as controls. Circulating pro-inflammatory monocytes and activated neutrophils were increased in LN patients. HO-1 levels were decreased in all subsets of monocytes and in activated neutrophils. LN monocytes showed increased phagocytosis and higher production of ROS than those of HC. When HO-1 was induced, phagocytosis and ROS levels became similar to those of HC. HO-1 was mostly expressed in renal tubular epithelial cells (RTEC). Renal tissue of LN patients showed lower levels of HO-1 than HC, whereas infiltrating immune cells of LN showed lower levels of HO-1 than biopsies of patients who had renal surgery. HO-1 is decreased in circulating monocytes and activated neutrophils of LN patients. HO-1 levels modulate the phagocytosis of LN monocytes and ROS production. HO-1 expression in RTEC might be an attempt of self-protection from inflammation.

Adoptive transfer of autoimmune splenic dendritic cells to lupus-prone mice triggers a B lymphocyte humoral response.

Systemic lupus erythematosus (SLE) is an autoimmune disease characterized by increased autoantibody production that leads to multiple tissue injuries. Dendritic cells (DCs) are important orchestrators of immune responses and key components in fine-tuning the balance between tolerance and immunity. However, their role in autoimmune disorders such as SLE remains uncertain. We analyzed the contribution of DCs in triggering SLE by adoptively transferring splenic DCs from aged autoimmune [NZB×NZW]F1 (BWF1) mice to young healthy BWF1 mice. We observed that the transfer of DCs from autoimmune mice to pre-autoimmune mice induced high autoantibody titers in the serum of recipient mice. Moreover, autoimmune DCs from aged BWF1 mice were crucial for the expansion and differentiation of plasmablasts and CD5+ B cells or B1-like cells in the peripheral blood, and spleen of recipient BWF1 mice, a phenomenon that is observed in autoimmune BWF1 mice. On the other hand, DCs from aged BWF1 mice participated in the expansion and differentiation of DCs and IFN-γ-producing T cells. These results reveal that DCs from autoimmune BWF1 mice exhibit functional and phenotypic characteristics that allow them to trigger B cell hyperactivation, as well as DC and T cell expansion and differentiation, thereby promoting an exacerbated humoral response in lupus-prone mice.

Vitamin A Impairs the Reprogramming of Tregs into IL-17-Producing Cells during Intestinal Inflammation.

Maintaining the identity of Foxp3(+) regulatory T cells (Tregs) is critical for controlling immune responses in the gut, where an imbalance between Tregs and T effector cells has been linked to inflammatory bowel disease. Accumulating evidence suggests that Tregs can convert into Th17 cells and acquire an inflammatory phenotype. In this study, we used an adoptive transfer model of Ag-specific T cells to study the contribution of different factors to the reprogramming of in vitro-generated Treg cells (iTreg) into IL-17-producing cells in a mouse model of gut inflammation in vivo. Our results show that intestinal inflammation induces the reprogramming of iTreg cells into IL-17-producing cells and that vitamin A restrains reprogramming in the gut. We also demonstrate that the presence of IL-2 during the in vitro generation of iTreg cells confers resistance to Th17 conversion but that IL-2 and retinoic acid (RA) cooperate to maintain Foxp3 expression following stimulation under Th17-polarizing conditions. Additionally, although IL-2 and RA differentially regulate the expression of different Treg cell suppressive markers, Treg cells generated under different polarizing conditions present similar suppressive capacity.

Dendritic and stromal cells from the spleen of lupic mice present phenotypic and functional abnormalities.

Systemic lupus erythematosus (SLE) is an autoimmune disease characterized by the increase in the percentage of autoreactive B and T lymphocytes. Since dendritic cells (DCs) are essential for B cell and T cell function, we hypothesized that changes in DC biology may play a critical role in the pathogenesis of the disease. We analyzed the phenotype and distribution of two main DC subsets, conventional (cDC) and plasmacytoid (pDC), in lupus prone (NZW × NZB)F1 (BWF1) mice and age-matched NZW × BALB/c control mice. Our results show that both subsets of lupic DCs displayed an abnormal phenotype, characterized by an over-expression of the co-stimulatory molecules CD80, CD86, PD-L1 and PD-L2 compared with control mice. Accordingly, spleen CD4(+) T cells from lupic mice exhibit an activated phenotype characterized by a higher expression of PD-1, CD25, CD69 and increased secretion of IFN-γ and IL-10. Interestingly, lupic mice also present an increase in the percentage of cDC in peripheral blood and an increase in the percentage of pDCs in spleen and mesenteric lymph nodes (MLNs) compared with control and pre-lupic mice. Homing experiments demonstrate that lupic and pre-lupic DCs migrate preferentially to the spleen compared to DCs from control mice. This preferential recruitment and retention of DCs in the spleen is related to an altered expression of different chemokine and chemokine receptors on both, DCs and stromal cells from lupic mice. Our results suggest that this altered phenotype and migratory behavior shown by DCs from lupic mice may account for the abnormal T cell and B cell responses in lupus.