Comparative evaluation of serological tests used for the diagnosis of rickettsial diseases prevalent in the temperate region of North India

PurposeThe clinical manifestations of rickettsial diseases mimic other endemic infections with similar presentations thus posing a serious challenge to clinicians for their diagnosis. For the diagnosis of rickettsial disease serological tests like Weil Felix, ELISA and IFA are used. There are limited studies that have evaluated different serological tests for the diagnosis of rickettsial diseases. Therefore, the present study was undertaken to evaluate the ELISA and Weil Felix test for the diagnosis of rickettsial diseases prevalent in this region.MethodsSamples from 281 patients clinically suspected of rickettsial diseases were tested for spotted fever group (SFG), typhus group (TG) and scrub typhus group (STG) by Weil Felix, ELISA and IFA was taken as the gold standard. Baseline titers and cut-off ODs were calculated by taking samples from healthy blood donors.ResultsThe sensitivity, specificity, positive and negative predictive value of Weil Felix test ranged from 30% to 44%, 83.46%–97.86%, 9%–77%, 92–96% respectively. The sensitivity and specificity, positive and negative predictive value of ELISA ranged from 80.77% to 96.15%, 96.33%–98.43%, 70.21%–88.64%, 92.89%–99.60% respectively. Maximum cross-reactions were observed between SFG and STG by the Weil Felix test and between STG and TG by ELISA.ConclusionsELISA was found to be sensitive and specific for the diagnosis of rickettsial diseases. It is easy to perform, does not require a technical expert for result interpretation and a large number of samples can be processed at a time.     

Routine Laboratory Testing Every 4 Versus Every 6 Weeks for Patients on Maintenance Hemodialysis: A Quality Improvement Project

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Fractional CO2 laser,platelet rich plasma and narrow band ultraviolet B in the treatment of Vitiligo (A randomized clinical trial)

Lasers in Medical Science - Vitiligo is a chronic acquired disease. Various therapeutic strategies are available but with variable degrees of success. Fractional CO2 laser is claimed to be...     

Characterizing Bariatric Surgery Utilization and Complication Rates in the Adolescent Population

Introduction

Bariatric surgery is an increasingly common treatment of morbid obesity in the United States and has demonstrated effective weight loss and improvement of comorbidities. We used the National Surgical Quality Improvement Program (NSQIP) data to characterize bariatric surgery utilization and complication rates in the adolescent population.

Cytotoxic Effects of Betel Quid and Areca Nut Aqueous Extracts on Mouse Fibroblast,Human Mouth-Ordinary-Epithelium 1 and Human Oral Squamous Cell Carcinoma Cell Lines

Background: Betel quid chewing is more common among the older generation in rural areas of Malaysia. Oral cancer in Asia has been associated with the habit of chewing betel quid and areca nut. Objective:  This study aims to investigate the cytotoxic effects of betel quid and areca nut extracts on the fibroblast (L929), mouth-ordinary-epithelium 1 (MOE1) and oral squamous cell carcinoma (HSC-2) cell lines. Methods: L929, MOE1 and HSC-2 cells were treated with 0.1, 0.2 and 0.4 g/ml of betel quid and areca nut extracts for 24, 48 and 72 h. MTT assay was performed to assess the cell viability. Results: Both extracts, regardless of concentration, significantly reduced the cell viability of L929 compared with the control (P<0.05). Cell viability of MOE1 was significantly enhanced by all betel quid concentrations compared with the control (P<0.05). By contrast, 0.4 g/ml of areca nut extract significantly reduced the cell viability of MOE1 at 48 and 72 h of incubation. Cell viability of HSC-2 was significantly lowered by all areca nut extracts, but 0.4 g/ml of betel quid significantly increased the cell viability of HSC-2 (P<0.05). Conclusion: Areca nut extract is cytotoxic to L929 and HSC-2, whereas the lower concentrations of areca nut extract significantly increased the cell viability of MOE1 compared to the higher concentration and control group. Although betel quid extract is cytotoxic to L929, the same effect is not observed in MOE1 and HSC-2 cell lines. Further investigations are needed to clarify the mechanism of action.     

Sex bias of females in survival from cancer and infections. Is X the answer?

Major differences in survival of men and women from infectious diseases and cancers have been highlighted by death rates from COVID-19 infections. In cancer, attention has been focussed on differences in gene expression from X chromosomes in men and women with a preponderance of genes involved in immune responses being expressed in women. Important findings have been that some of the genes are important epigenetic regulators that play fundamental roles in immune responses.Subject terms: Cancer epigenetics, Oncology

One of the striking features of the coronavirus disease 2019 (COVID-19) outbreak has been the higher death rates in men even though the infection rates seem similar between men and women.¹ Similar findings were reported from Wuhan where men had 2.4 times the death rate of women² and in New York where press releases stated twice the death rate of men compared with women.³ Although men had higher rates of comorbidities, these differences were not considered sufficient to explain the higher death rates and other explanations have been sort. Women are considered to have stronger immune responses against infective diseases and a higher rate of autoimmune diseases, so this has questioned whether the lower death rate may have an immune basis.A sex bias is not only seen in infections, but also in cancers where a strong sex bias in survival from cancer is well documented.^4,5 For example, women in Australia have approximately half the death rates from melanoma as males.⁶ A number of explanations have been proposed to account for these major differences in melanoma, such as higher sun exposure in males⁷ and higher mutation rates⁸ in melanoma from males. When stringent statistical analyses are carried out, however, female sex remains as the major contributor to longer survival.⁴Melanoma is not the only cancer to show improved survival in females and previous researchers have asked whether this may be due to differences in the sex chromosomes between male and females. In a mammoth study, Dunford and colleagues examined information in The Cancer Genome Atlas (TCGA) from 21 different tumour types from 4100 cancers.⁵ They found that 6 out of 783 X chromosome genes had loss-of-function mutations with tumour-suppressive function in males but not in females. There were no similar differences in 18,055 non-X autosomal genes. Importantly, four of the six genes were known epigenetic regulators, such as KDM6A (lysine-specific demethylase 6A), KDM5C (lysine-specific demethylase 5C), ATRX (Alpha thalassaemia/mental retardation syndrome X-linked) and DDX3X (DEAD-box helicase 3 X-linked).⁵These findings point to important differences in X chromosomes between the sexes. The Y chromosome codes mainly for genes that determine male sex, but X chromosomes are quite large and code for >800 genes many of which are involved in immune responses.⁹ To equalise the number of genes between the sexes, one of the X chromosomes in females undergoes inactivation (Xi) of its genes.¹⁰ The silencing process is, however, not perfect and between 10 and 20% of the genes on the X may be expressed in females depending on the tissue involved. It is probably of significance that failure to silence genes may be particularly high in activated lymphocytes.¹¹ As a result of this phenomenon, females have double expression of many genes involved in immune responses compared with males. Biologists have speculated that this is an evolutionary mechanism to protect the species by enhancing immune responses in females against harmful infections.Analysis of data in the TCGA on 458 melanoma patients revealed that KDM6A expression was strongly related to improved survival from melanoma in female patients. ATRX had prognostic significance in both sexes. Analysis of another series of 678 patients with earlier melanoma referred to as the Leeds Melanoma Cohort confirmed the association with KDM6A expression and also identified KDM5C and DDX3X as being related to improved survival.¹² Immune responses are known to be critical in survival from melanoma and the TCGA analysis allowed us to link high KDM6A to components of the immune system considered important in killing of melanoma. This was particularly so in the production of interferon γ in female patients which is a key cytokine needed by the immune system to kill cancer cells. Gene set analysis also showed downregulation of Myc and other oncogenic pathways that may have contributed to the improvement in survival.¹²These data add to a number of studies implicating KDM6A in immune responses against viral infections and in autoimmune diseases.¹³ At a molecular level, KDM6A is known to have an opposing role to EZH2 (enhancer of Zeste homologue 2) in the PRC2 complex in methylation of Lys 27 on H3 histone. This role may explain some of the effects of KDM6A on the immune system in that we previously reported that EZH2 was associated with the repression of several genes associated with antigen presentation and chemokines involved in T cell responses.¹⁴Although these studies are compelling in linking KDM6A to immune responses, it is still questionable whether it has a role in immune responses against COVID-19. If this was the case, we would expect that women being treated for severe COVID-19 infections in intensive care would have lower KDM6A expression than those with infections not requiring such care.¹⁵ We examined the RNA-seq data from blood samples of 102 COVID-19 patients. This included 38 women and 64 men, where 17 women and 34 men were admitted to intensive care unit. The analysis of KDM6A levels in the women showed that treatment in intensive care unit was associated with higher KDM6A expression ({"type":"entrez-geo","attrs":{"text":"GSE157103","term_id":"157103"}}GSE157103,¹⁵ data not shown). Although this was unexpected, it may indicate that KDM6A expression was linked to stronger responses causing higher inflammation in organs such as the lungs. No differences in KDM6A levels were detected in men irrespective of whether they were admitted to intensive care or not.Female patients with bi-allelic expression of KDM6A may induce the expression of interferon γ pathways which enhance anti-tumour immunity by recruiting immune modulatory cells (Fig. 1). These results point to the need for a better understanding of the role of X-linked genes in immune responses and whether EZH2-mediated suppression of immune modulatory genes have a role in infections as well as in cancer. In cancers and infections that have worst outcomes in males versus females, one approach might be to target (inhibit) the EZH2 epigenetic regulator that opposes KDM6A (Fig. 1). Another option may be to increase levels of KDM6A by administration of oestrogens. Oestrogen α receptors are expressed in practically all lymphocytes and were shown to physically interact with KDM6A to create a permissive chromatin state on endoplasmic reticulum (ER) targets such as C-X-C chemokine motif receptor 4.¹⁶ It was transactivated by ER to form a feed-forward loop. Administration of 17β-oestradiol has been suggested by others as treatment for COVID-19 infections.¹⁷Open in a separate windowFig. 1Proposed model of sex-biased role of the X-linked KDM6A gene in promoting immunity.Males harbour one X chromosome with no functional Y chromosome homologue. Hence, mutation in the X-linked epigenetic modifier KDM6A with tumour-suppressive or immunomodulatory role will probably lead to cancer or infection in males. Immune-related genes will be repressed by EZH2-mediated H3K27me3 deposition resulting in low KDM6A protein and immune evasion in male patients. In females, with two X chromosome, [one active (Xa) and one inactive (Xi)], a single mutation (m) in KDM6A is less likely to develop cancer or infections since another functional allele escapes X inactivation. Cells with high KDM6A level would be expected to demethylate H3K27me3 resulting in activation of the interferon γ pathway resulting in inactivation of natural killer (NK), dendritic or cytotoxic T cells to induce anti-tumour immunity and adaptive immunity against virus-infected cells.These studies have therefore raised many questions that require more detailed study to identify how the powerful survival benefits of the X-linked epigenetic regulators might be used to improve the therapeutic outcome in patients.