Given the importance of monocytes in pathogenesis of infectious and other inflammatory disorders, delineating functional and phenotypic characterization of monocyte subsets has emerged as a critical requirement. Although human monocytes have been subdivided into three different populations based on surface expression of CD14 and CD16, published reports suffer from contradictions with respect to subset phenotypes and function. This has been attributed to discrepancies in reliable gating strategies for flow cytometric characterization and purification protocols contributing to significant changes in receptor expression. By using a combination of multicolour flow cytometry and a high-dimensional automated clustering algorithm to confirm robustness of gating strategy and analysis of ex-vivo activation of whole blood with LPS we demonstrate the following: a. ‘Classical’ monocytes are phagocytic with no inflammatory attributes, b. ‘Non-classical’ subtype display ‘inflammatory’ characteristics on activation and display properties for antigen presentation and c. ‘Intermediate’ subtype that constitutes a very small percentage in circulation (under physiological conditions) appear to be transitional monocytes that display both phagocytic and inflammatory function. Analysis of blood from patients with Sepsis, a pathogen driven acute inflammatory disease and Systemic Lupus Erythmatosus (SLE), a chronic inflammatory disorder validated the broad conclusions drawn in the study.

BackgroundErythrocyte-associated antigenic polymorphisms or their absence have perhaps evolved in the human population to protect against malarial infection. Studies in various populations consistently demonstrate that blood group 'O' confers resistance against severe falciparum infection. In India, Odisha state has one of the highest incidences of Plasmodium falciparum infection and contributes to the highest number of deaths by falciparum malaria. This study aims to evaluate the relationship between ABO blood group and severe malaria in an adult population at the tertiary care centre in Odisha.MethodsA total of 353 P. falciparum infected subjects and 174 healthy controls were screened for ABO blood group. Falciparum-infected individuals were categorized as severe malaria and uncomplicated malaria. Severe malaria was further clinically phenotyped into cerebral malaria, non-cerebral severe malaria and multi-organ dysfunction. A meta-analysis was performed to assess the role of ABO blood group in severe malaria.ResultsFrequency of blood group 'B' was significantly higher in patients with severe malaria compared to the uncomplicated cases (P < 0.0001; OR = 4.09) and healthy controls (P < 0.0001; OR = 2.79). Irrespective of the level of clinical severity, blood group 'B' was significantly associated with cerebral malaria (P < 0.0001; OR = 5.95), multi-organ dysfunction (P < 0.0001; OR = 4.81) and non-cerebral severe malaria patients (P = 0.001; OR = 3.02) compared to the uncomplicated category. Prevalence of 'O' group in uncomplicated malaria (P < 0.0001; OR = 2.81) and healthy controls (P = 0.0003; OR = 2.16) was significantly high compared to severe malaria. Meta-analysis of previous studies, including the current one, highlighted the protective nature of blood group 'O' to severe malaria (P = 0.01). On the other hand, carriers of blood group 'A' (P = 0.04) and 'AB' (P = 0.04) were susceptible to malaria severity.ConclusionsResults of the current study indicate that blood group 'O' is associated with reduced and 'B' blood group with increased risk of development of severe malaria in Odisha, India. Meta-analysis also supports the protective nature of blood group 'O' from severe falciparum infection.

IntroductionLow levels of vitamin D have been associated with several autoimmune disorders including multiple sclerosis, rheumatoid arthritis, type 1 diabetes and systemic lupus erythematosus (SLE). The major source of vitamin D is sunlight but exposure of SLE patients to UV rays has been shown to exacerbate disease pathology. Studies in various populations have shown an association between low vitamin D levels and higher SLE disease activity.MethodsWe enrolled 129 patients who fulfilled American College of Rheumatology criteria in the study. There were 79 treatment-naïve cases and 50 patients who were under treatment for underlying SLE. There were 100 healthy subjects from similar geographical areas included as controls. Plasma 25-OH vitamin D3 and interferon (IFN)-α levels were quantified by enzyme-linked immunosorbent assay (ELISA). The gene expression level of IFN-α was determined by quantitative real-time reverse transcriptase polymerase chain reaction (RT-PCR).ResultsPlasma 25-OH vitamin D3 significantly correlated in an inverse manner with systemic lupus erythematosus disease activity index (SLEDAI) scores (P <0.0001, r = -0.42), anti-dsDNA (P <0.0001, r = -0.39), plasma IFN-α (P <0.0001, r = -0.43) and levels of IFN-α gene expression (P = 0.0009, r = -0.45). Further, plasma levels of IFN-α positively correlated with gene expression of IFN-α (P <0.0001, r = 0.84). Treatment-naïve SLE patients displayed significantly higher plasma levels of IFN-α compared to patients under treatment (P <0.001) and controls (P <0.001).ConclusionsThese results suggest an important role of vitamin D in regulating disease activity in SLE patients and the need to supplement vitamin D in their treatment.

Dengue is the most rapidly spreading viral disease transmitted by the bite of infected Aedes mosquitos. The pathogenesis of dengue is still unclear; although host immune responses and virus serotypes have been proposed to contribute to disease severity. In this study, we examined the circulating dengue virus (DENV) and measured plasma levels of inflammatory mediators. Ninety-eight patients during a dengue outbreak in eastern India in 2016 were included in the study. The presence of DENV was demonstrated by detecting NS1 antigen; IgM capture ELISA and serotypes were discriminated by type-specific RT-PCR and/or sequencing. Plasma samples were assayed for 41-plex cytokine/chemokines using multiplex Luminex assay. Eighty-five (87%) samples were positive by NS1/IgM capture ELISA/RT-PCR. All four serotypes of DENV were detected in this outbreak, with DENV-2 as the predominant type, seen in 55% of cases. Mixed infections were seen in 39% of subjects. Among the host inflammatory biomarkers, GM-CSF, IFN-γ, IL-10, IL-15, IL-8, MCP-1, IL-6, MIP-1β, and TNF-α levels were significantly increased in dengue with and without warning signs, in severe dengue patients in comparison to healthy controls. Four cytokines IFN-γ, GM-CSF, IL-10, and MIP-1β correlated significantly with disease severity and could serve as potential predictor for disease severity. Information on the host biomarkers and the dengue serotype may help guide in optimizing effective intervention strategies.

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BackgroundIn Plasmodium falciparum infection, complement receptor-1 (CR1) on erythrocyte’s surface and ABO blood group play important roles in formation of rosettes which are presumed to be contributory in the pathogenesis of severe malaria. Although several studies have attempted to determine the association of CR1 polymorphisms with severe malaria, observations remain inconsistent. Therefore, a case control study and meta-analysis was performed to address this issue.MethodsCommon CR1 polymorphisms (intron 27 and exon 22) and blood group were typed in 353 cases of severe malaria (SM) [97 cerebral malaria (CM), 129 multi-organ dysfunction (MOD), 127 non-cerebral severe malaria (NCSM)], 141 un-complicated malaria and 100 healthy controls from an endemic region of Odisha, India. Relevant publications for meta-analysis were searched from the database.ResultsThe homozygous polymorphisms of CR1 intron 27 and exon 22 (TT and GG) and alleles (T and G) that are associated with low expression of CR1 on red blood cells, conferred significant protection against CM, MOD and malaria deaths. Combined analysis showed significant association of blood group B/intron 27-AA/exon 22-AA with susceptibility to SM (CM and MOD). Meta-analysis revealed that the CR1 exon 22 low expression polymorphism is significantly associated with protection against severe malaria.ConclusionsThe results of the present study demonstrate that common CR1 variants significantly protect against severe malaria in an endemic area.

FokI and TaqI variants are significantly associated with SLE in an eastern Indian cohort. The cause-effect relationship can be assessed from the combined analyses of VDR polymorphism, plasma vitamin D levels and clinical manifestations.

IntroductionA role for mannose binding lectin (MBL) in autoimmune diseases has been demonstrated earlier and elevated level of MBL has been shown in systemic lupus erythematosus (SLE) patients. In the current study, we investigated MBL as a potential biomarker for disease activity in SLE.MethodsIn a case control study SLE patients (93 females) and 67 age, sex, ethnicity matched healthy controls were enrolled. Plasma MBL levels were quantified by enzyme linked immunosorbent assay (ELISA). Clinical, serological and other markers of disease activity (C3, C4 and anti-dsDNA) were measured by standard laboratory procedures.ResultsPlasma MBL levels were significantly high in SLE patients compared to healthy controls (P < 0.0001). MBL levels were variable in different clinical categories of SLE. Lower levels were associated with musculoskeletal and cutaneous manifestations (P = 0.002), while higher and intermediate MBL levels were significantly associated with nephritis in combination with other systemic manifestations (P = 0.01 and P = 0.04 respectively). Plasma MBL correlated with systemic lupus erythematosus disease activity index (SLEDAI) (P = 0.0003, r = 0.36), anti-dsDNA (P < 0.0001, r = 0.54), proteinuria (P < 0.0001, r = 0.42) and negatively correlated with C3 (P = 0.007, r = -0.27) and C4 (P = 0.01, r = -0.29).ConclusionsPlasma MBL is a promising marker in the assessment of SLE disease activity.