Association of Vitamin D with Suicide Behaviors: A Systematic Review and Meta-Analysis.

Objective: Research findings on the relationship between vitamin D and suicide are not consistent; therefore, the objective of the present paper is to assess the relationship between vitamin D and suicide behaviors using a systematic review and meta-analysis. Method : A search strategy was developed using keywords including "Vitamin D", "Vitamin D deficiency", "suicide" "attempted suicide", "completed suicide", "Suicide, Attempted", "Suicidal Ideation." We searched databases including Scopus, Medline, Web of Science, and Google Scholar by July 7, 2022. We examined the titles, abstracts, and full texts of the articles to select eligible ones. To pool the results of the selected studies, we used the random-effect method and mean difference as the effect size. The quality of the articles was evaluated by the Newcastle-Ottawa Scale (NOS). Moreover, heterogeneity and bias of reporting were evaluated by the I2 statistic and Egger's and Begg's tests, respectively. Results: Out of 149 studies retrieved in the databases, 11 studies were included in the final phase. Among these, the pooled findings of seven studies included in the meta-analysis phase showed that low levels of vitamin D are related to increased probability for suicide behaviors (P < 0.05). Moreover, subgroup analysis showed a significant relationship between vitamin D and suicide ideation and suicide attempt (P < 0.05). In addition, the I2 statistic indicated moderate heterogeneity (58%) and Egger's and Begg's tests did not show any evidence of publication bias (P > 0.05). Conclusion: This study provides evidence in favor of the relationship between vitamin D and suicide behaviors. It suggests that insufficient levels of vitamin D play a role in suicidal behaviors. However, it should be noted that further and stronger evidence is needed to establish this role. Finally, incorporating vitamin D-rich foods into the diet or taking vitamin D supplements is recommended to reduce the risk of suicide.

Analysis of dengue specific memory B cells, neutralizing antibodies and binding antibodies in healthy adults from India.

BACKGROUND: The Indian population is facing highest dengue burden worldwide supporting an urgent need for vaccines. For vaccine introduction, evaluation and interpretation it is important to gain a critical understanding of immune memory induced by natural exposure. However, immune memory to dengue remains poorly characterized in this region. METHODS: We enumerated levels of dengue specific memory B cells (MBC), neutralizing (NT) and binding antibodies in healthy adults (n=70) from New Delhi. RESULTS: NT-antibodies, binding antibodies and MBC were detectable in 86%, 86.56% and 81.63% of the subjects respectively. Among the neutralizing positive subjects, 58%, 27%, 5% and 10% neutralized all four, any three, any two and any one dengue serotypes respectively. The presence of the neutralizing antibodies was associated with the presence of the MBC and binding antibodies. However, a massive interindividual variation was observed in the levels of the neutralizing antibodies (range, <1:50-1:30,264), binding antibodies (range, 1:3,000-1:134,000,) as well as the MBC (range=0.006%-5.05%). CONCLUSION: These results indicate that a vast majority of the adults are immune to multiple dengue serotypes and show massive interindividual variation in neutralizing/binding antibodies and MBCs - emphasizing the importance of monitoring multiple parameters of immune memory in order to properly plan, evaluate and interpret dengue vaccines.

Osmolytes in vaccine production, flocculation and storage: a critical review.

Small molecule osmolytes, responsible for protecting stresses have long been known to rescue proteins and enzymes from loss of function. In addition to protecting macromolecules integrity, many osmolytes also act as potential antioxidant and also help to prevent protein aggregation, amyloid formation or misfolding, and therefore are considered promising molecules for neurodegenerative and many other genetic diseases. Osmolytes are also known to be involved in the regulation of several key immunological processes. In the present review we discuss in detail the effect of these compounds on important aspects of vaccines i.e., increasing the efficiency, production and purification steps. The present review therefore will help researchers to make a better strategy in vaccine production to formulation by incorporating specific and appropriate osmolytes in the processes.

Analysis of localized immune responses reveals presence of Th17 and Treg cells in cutaneous leishmaniasis due to Leishmania tropica.

PURPOSE: The interaction between the Leishmania parasite and the host cell involves complex, multifaceted processes. The disease severity in cutaneous leishmaniasis (CL) is largely dependent on the causative species. Most of the information on immune responses in human CL is available with respect to L. major infection and is lacking for L. tropica species. In this study, we employed cytokine/chemokine/receptor membrane cDNA array to capture comprehensive picture of immuno-determinants in localized human tissue during L. tropica infection. Expression of selected molecules was evaluated by real time PCR in dermal lesion tissues at pre- and post treatment stages. Plasma IL-17 level was estimated by sandwich ELISA. RESULTS: The cDNA array analysis identified several immuno-determinants in tissue lesions of Indian CL including cytokines (IFN-γ, TNF-α, IL-1ß, IL-10, IL-13), chemokines (IL-8, CCL2, CCL3, CCL4) and apoptotic molecules (Fas, TRAIL, IRF-1). Elevated mRNA levels of Th17 (IL-17, IL-23 and RORγt) and Treg (CD25, CTLA-4 and Foxp3) markers were observed in lesion tissues of CL patients compared to the control group, which subsided post treatment. Plasma IL-17 levels were found to be significantly higher in CL samples compared to controls. CONCLUSIONS: In addition to defining comprehensive immunological responses inside lesion tissues of CL patients, our study demonstrated the presence of Th17 and Treg cells in CL caused by L. tropica.

Evidence for involvement of Th17 type responses in post kala azar dermal leishmaniasis (PKDL).

BACKGROUND: Post kala-azar dermal leishmaniasis (PKDL), a dermal sequel of visceral leishmaniasis, caused by Leishmania donovani, constitutes an important reservoir for the parasite. Parallel functioning of counter acting immune responses (Th1/Th2) reflects a complex immunological scenario, suggesting the involvement of additional regulatory molecules in the disease pathogenesis. METHODOLOGY/PRINCIPAL FINDINGS: In the present study, human cytokine/chemokine/receptor specific cDNA array technique was employed to identify modulations in gene expression of host immuno-determinants during PKDL, followed by evaluation of Th17 type responses by analyzing mRNA and protein expression of Th17 markers (IL-23, IL-17, RORγt) and performing functional assays using Leishmania antigen (TSLA) or recombinant (rec)IL-17. Array analysis identified key immuno-regulatory molecules including cytokines (TNF-α, IFN-γ, IL-10, IL-17), chemokines (MCP-1, MIP-1α), apoptotic molecules (FasL, TRAIL, IRF-1) and receptors (CD40, Fas). Up regulation in lesional expression of Th17 markers was observed during PKDL compared to control (IL-17 and IL-23, P = 0.0008; RORγt, P = 0.02). In follow-up samples, chemotherapy significantly down regulated expression of all markers. In addition, lesional expression of IL-17 was confirmed at protein level by Immuno-histochemistry. Further, systemic presence of Th17 responses (IL-17 and IL-23) was observed in plasma samples from PKDL patients. In functional assays, TSLA stimulated the secretion of IL-17 and IL-23 from PBMCs of PKDL patients, while recIL-17 enhanced the production of TNF-α as well as nitric oxide (NO) in PKDL compared to control (TNF-α, P = 0.0002; NO, P = 0.0013). Further, a positive correlation was evident between lesional mRNA expression of IL-17 and TNF-α during PKDL. CONCLUSION/SIGNIFICANCE: The results highlight key immune modulators in PKDL and provide evidence for the involvement of Th17 type responses in the disease pathogenesis.

IL-10 neutralization promotes parasite clearance in splenic aspirate cells from patients with visceral leishmaniasis.

The mechanisms underlying the failure to contain the growth of Leishmania parasites in human visceral leishmaniasis (VL) are not understood. L donovani amastigotes were quantified in cultured splenic aspirate cells to assess the function of IL-10 in lesional tissue ex vivo. In 67 patients with active VL, IL-10 neutralization promoted parasite killing in 73% and complete clearance in 30%, while 18% had more parasites and 9% did not change. The splenic cells secreted increased levels of both tumor necrosis factor α (TNFα) and interferon γ (IFNγ) under IL-10-neutralizing conditions. These findings provide direct support for targeting IL-10 as an approach to therapy in human VL.

Foxp3 and IL-10 expression correlates with parasite burden in lesional tissues of post kala azar dermal leishmaniasis (PKDL) patients.

BACKGROUND: Post kala-azar dermal leishmaniasis (PKDL), a sequel to visceral leishamaniasis (VL) in 5-15% cases, constitutes a parasite reservoir important in disease transmission. The precise immunological cause of PKDL outcome remains obscure. However, overlapping counter regulatory responses with elevated IFN-γ and IL-10 are reported. METHODOLOGY/PRINCIPAL FINDINGS: Present study deals with ex-vivo mRNA and protein analysis of natural regulatory T cells (nTreg) markers (Foxp3, CD25 and CTLA-4) and IL-10 levels in lesion tissues of PKDL patients at pre and post treatment stages. In addition, correlation of nTreg markers and IL-10 with parasite load in tissue lesions was investigated. mRNA levels of nTreg markers and IL-10 were found significantly elevated in pre-treatment PKDL cases compared to controls (Foxp3, P = 0.0009; CD25 & CTLA-4, P<0.0001; IL-10, P<0.0001), and were restored after treatment. Analysis of nTreg cell markers and IL-10 in different clinical manifestations of disease revealed elevated levels in nodular lesions compared to macules/papules. Further, Foxp3, CD25 and IL-10 mRNA levels directly correlated with parasite load in lesions tissues. CONCLUSION/SIGNIFICANCE: Data demonstrated accumulation of nTreg cells in infected tissue and a correlation of both IL-10 and nTreg levels with parasite burden suggesting their role in disease severity in PKDL.

IL-27 and IL-21 are associated with T cell IL-10 responses in human visceral leishmaniasis.

IL-10 is believed to underlie many of the immunologic defects in human visceral leishmaniasis (VL). We have identified CD4(+)CD25(-)Foxp3(-) T cells as the major source of IL-10 in the VL spleen. IL-27, a member of the IL-6/IL-12 cytokine family, has been shown to promote development of IL-10-producing T cells, in part by upregulating their production of autocrine IL-21. We investigated whether IL-27 and IL-21 are associated with human VL. IL-27 was elevated in VL plasma, and at pretreatment, spleen cells showed significantly elevated mRNA levels of both IL-27 subunits, IL-27p28 and EBI-3, as well as IL-21, compared with posttreatment biopsies. CD14(+) spleen cells were the main source of IL-27 mRNA, whereas CD3(+) T cells were the main source of IL-21. IL-27 mRNA could be strongly upregulated in normal donor macrophages with IFN-γ and IL-1ß, conditions consistent with those in the VL spleen. Last, a whole-blood assay revealed that most VL patients could produce Ag-specific IFN-γ and IL-10 and that the IL-10 could be augmented with recombinant human IL-21. Thus, proinflammatory cytokines acting on macrophages in the VL spleen have the potential to upregulate IL-27, which in turn can induce IL-21 to expand IL-10-producing T cells as a mechanism of feedback control.

Immune response following miltefosine therapy in a patient with post-kala-azar dermal leishmaniasis.

We report a case of post-kala-azar dermal leishmaniasis in which real-time PCR was exploited to measure changes in cytokine transcripts in lesion tissue before and after oral miltefosine treatment. Unlike antimonial therapy elevated levels of IFNgamma transcripts were noted, whereas TNFalpha, IL-10 and transforming growth factor-beta declined similar to that observed after therapy with antimonials. A significant increase in IFNgamma and CD40 levels seen after miltefosine therapy could enhance parasite clearance. The patient remained normal after 18 months of follow-up.

Cutaneous leishmaniasis in Nepal: Leishmania major as a cause.

Nepal is endemic for visceral leishmaniasis; however, recently a solitary report of cutaneous leishmaniasis (CL) was recorded. The present report describes a CL case in a Nepalese woman, initially referred as a case of basal cell carcinoma. Histopathological examination, culture and PCR analysis of lesions revealed it to be a case of CL. Molecular methods, including kDNA PCR, ITS-1 PCR-RFLP and sequence analysis, revealed the species as Leishmania major. The patient was cured with sodium stibogluconate. This report suggests that the extent to which L. major causes CL in the Indian subcontinent needs to be monitored.

Cutaneous leishmaniasis caused by Leishmania tropica in Bikaner, India: parasite identification and characterization using molecular and immunologic tools.

Identification of new foci of cutaneous leishmaniasis (CL), along with reports of Leishmania donovani causing the disease, is an issue of concern. Clinico-epidemiologic analysis of 98 cases in the endemic regions of Rajasthan state, India, suggested the preponderance of infection in men (62.24%) compared with women (37.75%). Species characterization by internal transcribed spacer 1 (ITS1) polymerase chain reaction (PCR)-restriction fragment length polymorphism (RFLP), kDNA-PCR, and immunofluorescence assay established L. tropica as the causative organism. When applied directly to 32 clinical samples, kDNA PCR had a sensitivity of 96.6%, whereas ITS1 PCR had a sensitivity of 82.75%, thus facilitating diagnosis and species identification. Either parasite culture or direct microscopy alone detected 48.2% and 65.5% of the positive samples, respectively, whereas culture and microscopy together improved overall sensitivity to 89.3% (25/28). Except for the kDNA PCR, all other assays were 100% specific. This study provides the first comprehensive molecular and immunologic studies of CL in India.

Circulating nitric oxide and C-reactive protein levels in Indian kala azar patients: correlation with clinical outcome.

Interferon gamma (IFN-gamma) and nitric oxide (NO) are the major players of the host defense against Leishmania. In the present study circulating levels of IFN-gamma, NO, interleukin (IL)-6 and C-reactive protein (CRP) were compared in kala azar (KA), post-kala azar dermal leishmaniasis (PKDL) and healthy controls. A significantly elevated level of these parameters was evident in KA compared to PKDL or control. Further, significantly elevated levels of IFN-gamma, NO and CRP were observed in sodium antimony gluconate (SAG) unresponsive cases compared to responsive cases. In PKDL cases, NO was significantly elevated while other parameters were comparable to control. At post-treatment stage, KA patients showed a significant decrement in all the parameters, however, IL-6 and CRP remained above control level. Hence, data implies that the parasites survive in spite of the presence of effector molecules, and the excessive release of IFN-gamma and NO could be associated with the progression of the disease.

Interferon (IFN)-gamma , tumor necrosis factor-alpha , interleukin-6, and IFN-gamma receptor 1 are the major immunological determinants associated with post-kala azar dermal leishmaniasis.

Semiquantitative reverse-transcription polymerase chain reaction was used to analyze intralesional cytokine gene expression in 28 patients with post-kala azar dermal leishmaniasis (PKDL) and 14 patients with kala azar (KA). The data revealed mixed T helper cell type 1 (Th1) and T helper cell type 2 (Th2) responses, as reflected by elevated expression of interferon (IFN)-gamma , tumor necrosis factor (TNF)-alpha , transforming growth factor (TGF)-beta , interleukin (IL)-10, IL-6, and IL-4 mRNA, with minimal expression of IFN-gamma receptor 1 (IFN-gamma R1) mRNA in PKDL lesions, compared with that in normal skin tissue. In comparison with those in KA lesions, mRNA levels for IFN-gamma , TNF-alpha , and IL-6 were found to be significantly elevated in PKDL lesions, implying that these cytokines play an important role in PKDL pathogenesis. In the presence of elevated levels of IFN-gamma and TNF-alpha , interference with type 1 effector activity in PKDL may be due to minimal expression of the IFN-gamma R1 gene or the simultaneous presence of elevated levels of IL-10, IL-6, and TGF-beta , which have counteracting effects. After treatment, the restoration of IFN-gamma R1 at both mRNA and protein levels, coupled with down-regulation of counteracting cytokines, may facilitate the action of signals associated with IFN-gamma , yielding parasite clearance. Therefore, unfavorable clinical evolution in PKDL may not be due to the absence of an intralesional Th1 response but rather may be due to the presence of counteracting cytokines along with the down-modulation of IFN-gamma R1.

Elevated levels of interferon-gamma, interleukin-10, and interleukin-6 during active disease in Indian kala azar.

We have evaluated levels of 6 cytokines in sera of 35 patients of kala azar (KA), 29 post kala azar dermal leishmaniasis (PKDL), and 18 healthy controls using cytometric bead array technology. Results indicated significantly high levels of interferon gamma (IFN-gamma), interleukin (IL)-10, and IL-6 during active KA, while tumor necrosis factor alpha (TNF-alpha), IL-2, and IL-4 were minimal. Serum level of cytokines in PKDL was comparable to the controls while TNF-alpha was significantly elevated compared to KA or control. At post-treatment stage, KA patients showed a significant decrement in the levels of IFN-gamma, IL-10, and IL-6; however, IL-6 remained significantly elevated above control levels. Further, comparison of cytokine levels in children and adults revealed elevated level of IL-10 in pediatric cases. SAG unresponsive cases showed significantly elevated levels of IFN-gamma in comparison with the responsive cases. The results depict that type1 response is not depressed during active KA and suggest the possibility that unresponsiveness to type1 stimuli may prevail.

A novel semiquantitative fluorescence-based multiplex polymerase chain reaction assay for rapid simultaneous detection of bacterial and parasitic pathogens from blood.

A multiplex polymerase chain reaction assay was developed for the rapid simultaneous detection of category A select bacterial agents (Bacillus anthracis and Yersinia pestis) and parasitic pathogens (Leishmania species) in blood using the Cepheid Smart Cycler platform. B. anthracis (Sterne) and Yersinia. pseudotuberculosis were used in the assay for optimization for B. anthracis and Y. pestis, respectively. The specificity of the target amplicons [protective antigen gene of B. anthracis and rRNA genes of other pathogens or human (internal control)] was evaluated by staining the amplicons with SYBR Green I and determining their individual melting temperatures (T(m)). As a novel approach for pathogen semiquantitation, the Tm peak height of the amplicon was correlated with a known standard curve of pathogen-spiked samples. This assay was able to detect DNA in blood spiked with less than 50 target cells/ml for all of the pathogens. The sensitivity of this assay in blood was 100% for the detection of Leishmania donovani from leishmaniasis patients and B. anthracis (Sterne) from symptomatic mice. The time necessary for performing this assay including sample preparation was less than 1.5 hours, making this a potentially useful method for rapidly diagnosing and monitoring the efficacy of drugs or vaccines in infected individuals.