Phenotypic and functional features of innate and adaptive immunity as putative biomarkers for clinical status and leprosy reactions

Increased CD8dim and Decreased CD8bright T Cells as Immunological Signature for Multibacilary Leprosy Patients

Leprosy, a chronic infectious disease caused by Mycobacterium leprae, manifests in a spectrum of clinical forms and severity. This study investigated the percentage of CD8+ T cells and their subpopulations (CD8bright and CD8dim T cells) in leprosy patients stratified by clinical forms, bacterial load, and age. No significant differences were observed in the overall percentage of CD8+ T cells among healthy controls and leprosy patients. However, an increased percentage of CD8dim T cells and a decreased percentage of CD8bright T cells were associated with severe multibacillary and lepromatous forms of leprosy, independent of bacillary load. Further, these cellular profiles correlated more strongly with disease severity than with age, in spite of elderly multibacillary patients exhibiting significant reductions in CD8bright T cells and increases in CD8dim T cells compared to young or middle-aged paucibacillary patients, but not compared to young and middle-aged multibacillary patients. These findings suggest that CD8bright and CD8dim T cell profiles are critical indicators of disease progression and severity in leprosy, highlighting their potential as biomarkers for clinical evaluation.

Immune mediators as plasma biomarkers for identifying household contacts and classifying clinical forms and leprosy reactions

The present study aimed to evaluate the performance of plasma immune mediators in classifying leprosy patients [L(PB) and L(MB), paucibacillary and multibacillary leprosy, respectively], leprosy reaction patients (T1LR and T2LR, type 1 and type 2 leprosy reaction, respectively), household contacts (HHC), and non-infected (NI) controls. Quantitative measurements of these immune mediators were carried out using high-throughput multiplex microbead array. The results demonstrated that most of the plasma immune mediators were increased in all clinical groups compared with NI controls. Higher frequencies but lower maximum magnitudes of increase (fold change according to NI) were observed for T1LR (63%, 6.1×) and T2LR (63%, 9.7×) compared with HHC (48%, 68.5×), L(PB) (56%, 8.5×), and L(MB) (48%, 37.9×). The bi-dimensional scattering profiles (magnitude order vs. significance) identified a higher number of immune mediators in T2LR (12/27) compared with HHC (8/27), L(PB) (7/27), L(MB) (5/27), and T1LR (5/27). CXCL8 was selected as the parameter with the highest accuracy and significance [area under the receiver operating characteristic curve (AUC) = 0.98, p = 0.0002] in classifying NI vs. HHC. CCL3 (C-C motif chemokine ligand 3) was the single analyte with moderate accuracy and significance (AUC = 0.74, p = 0.0422) in classifying L(PB) vs. L(MB). IL-9 was selected as an attribute with moderate accuracy and significance (AUC = 0.77, p = 0.0041) in classifying T1LR vs. T2LR. Decision tree algorithms confirmed the high accuracy (96%) of CXCL8 in classifying NI vs. HHC. The use of CCL3 followed by IFN-γ classified L(MB) vs. L(PB) with high accuracy (93%). Moreover, the analysis of IL-9 followed by IL-6 and CXCL10 classified T1RL vs. T2RL with high accuracy (96%). In general, combined stepwise algorithms showed enhanced classification accuracy compared with single-attribute analysis. Together, our findings supported the potential use of plasma immune mediators as complementary laboratory biomarkers for the identification of HHC and the classification of distinct clinical forms of leprosy and leprosy reactions.

Different profiles of chemokines, cytokines and cell growth factors in plasma samples from patients with leprosy, leprosy reactions and households contacts

BACKGROUND

Leprosy is a highly neglected disease that is considered a serious public health problem in many countries. This illness is characterised by a variety of clinical and histopathological manifestations that are related to the patient immune response.

OBJECTIVES

This work aimed evaluate the profile of circulating immune mediators in the plasma from patients classified clinically as paucibacillary (PB), multibacillary (MB), households contacts (HHC), type1 leprosy reaction (T1R), type2 leprosy reaction (T2R) and control individuals without medical history of leprosy (CTL).

METHODS

To assessment of the plasma immune mediators was used multiplex microbeads immunoassay "Luminex".

FINDINGS

The results showed that patients (PB) had a regulatory-biased profile, while MB revealed a pro-inflammatory trend of highly expressed biomarkers. HHC display conspicuously increased levels in the plasma of the chemokines (CCL2, CCL3, CCL4, CCL5 and CXCL8), pro-inflammatory cytokines (IFN-γ,TNF and IL-1β), modulating cytokines (IL-9 and IL-1Ra) and growth factors (PDGF, G-CSF and IL-2). Interestingly, HHC displayed superior production of IFN-γ as compared to other leprosy groups, indicating a putative protective role for this cytokine during chronic Mycobacterium leprae exposure.

MAIN CONCLUSION

Further investigations are currently underway to elucidate the potential of these mediators as biomarkers applicable to the diagnosis/prognosis of leprosy and also T1R and T2R leprosy reactions.

Leprosy Classification, Clinical Features, Epidemiology, and Host Immunological Responses: Failure of Eradication in 2023

Leprosy is of big concern in the medical fraternity. Leprosy is also known as Hansen's disease. It is a curable communicable disease that remains prevalent in most countries all over the globe. It is a chronic granulomatous infection commonly caused by Mycobacterium leprae and Mycobacterium lepromatosis, which mainly show an effect on the skin and peripheral nerves. To control the disease and minimize the impact of the disease, much effort has been put into it for decades. Nearly 0.2 million fresh cases were documented in 2017 worldwide in spite of being declared "eradicated" by the WHO in the year 2000. However, impressive achievements have been made in several countries, including India; still, we are lagging behind the ultimate goal of the final disappearance of leprosy. Extensive migration is a crucial element that may transmit leprosy to unaffected areas. Additionally, there are several areas in the USA where person-to-person leprosy transmission has been reported without a prior history of exposure. Recently, WHO instigated a new Global Leprosy Strategy 2021-2030, termed "Towards Zero Leprosy." In this article, we review the clinical features, leprosy epidemiology, transmission, classification, host immunological response, and diagnostic challenges.

Presence of Senescent and Memory CD8+ Leukocytes as Immunocenescence Markers in Skin Lesions of Elderly Leprosy Patients

Leprosy is an infectious disease that remains endemic in approximately 100 developing countries, where about 200,000 new cases are diagnosed each year. Moreover, multibacillary leprosy, the most contagious form of the disease, has been detected at continuously higher rates among Brazilian elderly people. Due to the so-called immunosenescence, characterized by several alterations in the quality of the immune response during aging, this group is more susceptible to infectious diseases. In view of such data, the purpose of our work was to investigate if age-related alterations in the immune response could influence the pathogenesis of leprosy. As such, we studied 87 individuals, 62 newly diagnosed and untreated leprosy patients distributed according to the age range and to the clinical forms of the disease and 25 healthy volunteers, who were studied as controls. The frequency of senescent and memory CD8⁺ leukocytes was assessed by immunofluorescence of biopsies from cutaneous lesions, while the serum levels of IgG anti-CMV antibodies were analyzed by chemiluminescence and the gene expression of T cell receptors' inhibitors by RT-qPCR. We noted an accumulation of memory CD8⁺ T lymphocytes, as well as reduced CD8⁺CD28⁺ cell expression in skin lesions from elderly patients, when compared to younger people. Alterations in LAG3 and PDCD1 gene expression in cutaneous lesions of young MB patients were also observed, when compared to elderly patients. Such data suggest that the age-related alterations of T lymphocyte subsets can facilitate the onset of leprosy in elderly patients, not to mention other chronic inflammatory diseases.

Expression of annexin-A1 in blood and tissue leukocytes of leprosy patients

INTRODUCTION

In leprosy, immune system mediators that regulate the infectious process act in a complex manner and can lead to several clinical outcomes. To understand the behavior of these mediators we quantified the expression of annexin-A1 (ANXA1) in the peripheral blood and plasma as well as tissue leukocytes in all clinical forms of leprosy and compared with healthy controls.

METHODS

Seventy healthy controls and 70 patients with leprosy, tuberculoid (TT) (n = 13), borderline tuberculoid (BT) (n = 15), borderline borderline (BB) (n = 13), borderline lepromatous (BL) (n = 15), and lepromatous leprosy (LL) (n = 14), were selected. Phenotyping of the lymphocyte cells and the intracellular expression of ANXA1 in leukocytes was performed by immunofluorescence. Plasma protein levels were determined by enzyme-linked immunosorbent assay.

RESULTS

Histiocytes and CD4⁺ and CD8⁺ T cells in the skin of BL and LL patients had higher ANXA1 expression. ANXA1 expression was also high in circulating polymorphonuclear, monocytes, and CD4⁺ and CD8⁺ T cells in the blood of LL patients compared to those of TT, BT, BB, and BL patients, and these levels were similar to those in healthy controls. Plasma ANXA1 levels indicate an increase in paracrine release in patients with LL.

CONCLUSIONS

The data indicate that ANXA1 expression is enhanced in the leukocytes and plasma of patients with LL, and may contribute to the inhibition of leukocyte action, leading to inadequate functioning of the immune system and thus contributing to the spread of M. leprae infection.

Diagnostic value of neutrophil-to-lymphocyte ratio in patients with leprosy reactions

INTRODUCTION

Leprosy reactions, classified as type 1 and type 2 reactions, are acute clinical conditions of exacerbation of localized or systemic inflammatory response inpatients with leprosy. No laboratory biomarker is available to predict the emergence of these reactions. Neutrophil-to-lymphocyte ratio (NLR) is an accurate biomarker for diagnosis and prognosis of various inflammatory and neoplastic diseases.

OBJECTIVE

This study aimed to investigate the accuracy of the NLR in the diagnosis of leprosy reactions.

MATERIALS AND METHODS

NLR was calculated for all patients and a receiver operating characteristic curve (ROC) were generated to identify the NLR cut-off point.

RESULTS

A total of 123 patients with leprosy were included, 98 with leprosy reactions of which 56 (45.5%) had type 1 and 42 (34.1%) with type 2. Mean NLR was higher among patients with reactions than among those without. It was also statistically higher among patients with type 2 reactions than in those with type 1 reactions. Receiver operating characteristic curves were generated to identify the NLR cut-off point. The area under the ROC curve was 0.794 for diagnosis of any leprosy reaction and 0.796 for the diagnosis of type 2 reaction. The NLR cut-off points for diagnosis of any leprosy reaction and for type 2 reaction were 2.75 (sensitivity 61.0%, specificity 92.0%, accuracy 77.0%) and 2.95 (sensitivity 81.0%, specificity 74.0%, accuracy 78.0%), respectively.

CONCLUSION

These results suggest that NLR could be a potential biomarker for diagnosis of leprosy reaction and useful for discriminating patients with type 2 reactions from those with type 1 leprosy reactions.