Pranab Kumar Das

Serum levels of interferon-γ, tumour necrosis factor-α, soluble interleukin-6R and soluble cell activation markers for monitoring response to treatment of leprosy reactions

Identifying pathogen and host‐related laboratory parameters are essential for the early diagnosis of leprosy reactions. The present study aimed to clarify the validity of measuring the profiles of serum cytokines [interleukin (IL)‐4, IL‐6, IL‐10, interferon (IFN)‐γ and tumour necrosis factor (TNF)‐α], the soluble IL‐6 receptor (sIL‐6R), soluble T cell (sCD27) and macrophage (neopterin) activation markers and Mycobacterium leprae‐specific anti‐PGL‐I IgM antibodies in relation to the leprosy spectrum and reactions. Serum samples from 131 Indonesian leprosy patients (82 non‐reactional leprosy patients and 49 reactional) and 112 healthy controls (HC) from the same endemic region were investigated. Forty‐four (89·8%) of the reactional patients had erythema nodosum leprosum (ENL) while only five (10·2%) had reversal reaction (RR). Follow‐up serum samples after corticosteroid treatment were also obtained from 17 of the patients with ENL and one with RR. A wide variability in cytokine levels was observed in the patient groups. However, IFN‐γ and sIL‐6R were elevated significantly in ENL compared to non‐ENL patients. Levels of IFN‐γ, TNF‐α and sIL‐6R declined significantly upon corticosteroid treatment of ENL. Thus, although the present study suggests limited applicability of serial measurement of IFN‐γ, TNF‐α and sIL‐6R in monitoring treatment efficacy of ENL, reactions it recommends a search for a wider panel of more disease‐specific markers in future studies.

Utility of measuring serum levels of anti-PGL-I antibody, neopterin and C-reactive protein in monitoring leprosy patients during multi-drug treatment and reactions

Objective  To verify the validity of measuring the levels of Mycobacterium leprae‐specific anti‐phenolic glycolipid (PGL)‐I antibody, neopterin, a product of activated macrophages, and C‐reactive protein (CRP), an acute phase protein, in serial serum samples from patients for monitoring the leprosy spectrum and reactions during the course of multi‐drug treatment (MDT).

An automated method for the quantification of immunostained human Langerhans cells.

Allergic contact dermatitis is a frequent and increasing health problem. For ethical reasons, the current animal tests used to screen for contact sensitizers should be replaced by in vitro alternatives. Contact sensitizers have been shown to accelerate Langerhans cell (LC) migration from human organotypic skin explant cultures (hOSECs) more rapidly than non-sensitizers and it has been proposed that the hOSEC model could be used to screen for sensitizers. However, chemically induced decreases in epidermal LC numbers need to be accurately quantified if the alterations in epidermal LC numbers are to form the basis of an alternative system for screening contact sensitizers in vitro. As manual counting of LCs is labour intensive and subject to intra- and inter-personal variation we developed an image analysis routine, using the Leica QWin image analysis software, to quantify LCs in situ using immunohistochemically stained skin sections. LCs can be identified using antibodies against the membrane molecule CD1a or the Lag antibody, which recognises cytoplasmic Birbeck granules. Quantification of epidermal LC number using the image analysis software had a much lower inter-person variation than when the same specimens were counted manually, using both the anti-Lag and CD1a antibodies. The software-aided quantification of epidermal LCs provides an accurate method for measuring chemically-induced changes in LC numbers.

Increased chitotriosidase activity in serum of leprosy patients: Association with bacillary leprosy

Human phagocyte-specific chitotriosidase is associated with several diseases involving macrophage activation. Since macrophage activation plays an important role in the control of Mycobacterium leprae infection, we studied the association of chitotriosidase with leprosy both in serum and in situ in lesional skin biopsies from patients. Serum samples from 78 Indonesian leprosy patients (39 non-reactional and 39 reactional leprosy patients) and 36 healthy controls (HC) from the same endemic region were investigated. The patients were classified as multibacillary (MB, n=69) or paucibacillary (PB, n=9) based on the bacterial index in slit-skin smears. Thirty-six of the reactional patients had erythema nodosum leprosum (ENL), while only 3 had reversal reaction (RR). Follow-up serum samples after corticosteroid treatment were also obtained from 17 patients with ENL and one with RR. Multibacillary (MB) patients showed increased chitotriosidase activity in serum as compared to paucibacillary (PB) patients and healthy controls. Although no significant difference was observed between reactional and the corresponding non-reactional groups, ENL showed significantly higher chitotriosidase activity as compared to HC. Furthermore, corticosteroid treatment resulted in significant decline of enzyme activity in ENL sera. Chitotriosidase activity correlated with levels of neopterin, another macrophage activation marker, but not with IL-6, IFN-gamma, TNF-alpha and IL-10. Immunohistochemical staining of 6 MB (LL=5, BL=1) lesional skin sections from stored material showed positive staining for chitotriosidase within lipid-laden macrophages suggesting that macrophages are the source of the enzyme detected in serum. Thus, serum chitotriosidase activity is potentially useful in distinguishing MB from PB leprosy and in monitoring response to therapy in ENL.

Defining the Antigen Determinant for T-Cell-Mediated Contact Dermatitis Using p-Phenylenediamine: A Gateway to Chemical Immunology

By binding to host proteins to form haptens, low-molecular-weight compounds such as p-phenylenediamine (PPD) can become contact sensitizers. In this issue, Jenkinson et al. demonstrate that it is possible to use chemically characterized hapten-protein complexes to analyze T-cell responses in cells from allergic individuals. This approach may help in the development of in vitro tests for diagnosing contact dermatitis.

Melanocytes: interface of cell biology and pathobiology with a focus on nitric oxide and cGMP signaling

Human epidermal melanocytes represent a crucial protective barrier against UV irradiation and oxidative stress by generating the radical scavenging pigment melanin. Melanin is also known to act as a photosensitizer that generates active oxygen species upon UV irradiation, which may initiate hypopigmentary disorders (e.g., vitiligo) as well as UV-induced oncogene cell transformation. Finally, melanocytes in vivo are permanently targeted by environmental mechanical stimuli.