Cortisol metabolism, cortisol sensitivity and the pathogenesis of leprosy reactions

Host-Related Laboratory Parameters for Leprosy Reactions

Leprosy reactions are acute inflammatory episodes that complicate the course of a Mycobacterium leprae infection and are the major cause of leprosy-associated pathology. Two types of leprosy reactions with relatively distinct pathogenesis and clinical features can occur: type 1 reaction, also known as reversal reaction, and type 2 reaction, also known as erythema nodosum leprosum. These acute nerve-destructive immune exacerbations often cause irreversible disabilities and deformities, especially when diagnosis is delayed. However, there is no diagnostic test to detect or predict leprosy reactions before the onset of clinical symptoms. Identification of biomarkers for leprosy reactions, which impede the development of symptoms or correlate with early-onset, will allow precise diagnosis and timely interventions to greatly improve the patients' quality of life. Here, we review the progress of research aimed at identifying biomarkers for leprosy reactions, including its correlation with not only immunity but also genetics, transcripts, and metabolites, providing an understanding of the immune dysfunction and inflammation that underly the pathogenesis of leprosy reactions. Nevertheless, no biomarkers that can reliably predict the subsequent occurrence of leprosy reactions from non-reactional patients and distinguish type I reaction from type II have yet been found.

Endocrine dysfunction in patients of leprosy

BACKGROUND

Leprosy is a chronic granulomatous disease and affects many internal organs in addition to the skin and peripheral nerves. Endocrine dysfunction is often silent and is often missed in patients of leprosy leading to significant morbidity. We studied the presence of occult endocrine disorders in leprosy patients and compared the same with disease parameters.

MATERIALS AND METHODS

We evaluated 40 patients of leprosy (aged 18-70 years, any duration) in this cross-sectional, observational study. All subjects were assessed for pituitary, thyroid, adrenal, gonadal function, and dynamic testing was done when deemed necessary. The participants were divided into two groups: Group 1 (Leprosy, n = 40) and Group 2 (Controls, n = 20) and the data were analyzed with appropriate statistical tests.

RESULTS

The study participants (35 males, 5 females) had a mean age of 36.4 ± 11.3 years, and duration of the disease was 2.5 ± 5.5 years. Eleven out of 40 patients showed results consistent with an endocrine disorder, including subclinical hypothyroidism (n = 4), sick euthyroid syndrome (n = 3), growth hormone (GH) deficiency (n = 2), primary hypogonadism (n = 2) and secondary hypogonadism in one patient. One patient had partial hypopituitarism (GH deficiency and secondary hypogonadism) and none of the controls showed any hormonal dysfunction. Testosterone levels showed inverse correlation with the number of skin patches (P = 0.0006).

CONCLUSION

Occult endocrine dysfunction is seen in a quarter of patients with leprosy. Thyroid and gonadal axes abnormalities are common, and the severity is more in lepromatous forms of the disease. Further large studies are required to confirm the findings observed in our study.

Genetics of leprosy reactions: an overview

Type-1 (T1R) and Type-2 (T2R) leprosy reactions (LR), which affect up to 50% of leprosy patients, are aggressive inflammatory episodes of sudden onset and highly variable incidence across populations. LR are often diagnosed concurrently with leprosy, but more frequently occur several months after treatment onset. It is not uncommon for leprosy patients to develop recurring reactional episodes; however, they rarely undergo both types of LR. Today, LR are the main cause of permanent disabilities associated with leprosy and represent a major challenge in the clinical management of leprosy patients. Although progress has been made in understanding the immunopathology of LR, the factors that cause a leprosy patient to suffer from LR are largely unknown. Given the impact that ethnic background has on the risk of developing LR, host genetic factors have long been suspected of contributing to LR. Indeed, polymorphisms in seven genes [Toll-like receptors (TLR)1, TLR2, nucleotide-binding oligomerisation domain containing 2, vitamin D receptor, natural resistance-associated macrophage protein 1, C4B and interleukin-6] have been found to be associated with one or more LR outcomes. The identification of host genetic markers with predictive value for LR would have a major impact on nerve damage control in leprosy. In this review, we present the recent advances achieved through genetic studies of LR.

Cortisol and proinflammatory cytokine profiles in type 1 (reversal) reactions of leprosy

PURPOSE

Cortisol levels in the circulation and at the sites of peripheral inflammation regulate type 1 (Reversal) reactions in leprosy akin to delayed type hypersensitivity reactions (DTH). In this study we determine the extent to which the differential mRNA expression of genes encoding cortisone-cortisol shuttle enzymes (11 β hydroxysteriod dehydrogenase I & II (11 β HSD I & II)), circulatory levels of proinflammatory cytokines (IL-6, IL-7, IP-10, IL-17F, IL-23, TNF-α, IL-1β, PDGF BB and CRP) and cortisol are associated with development of type 1 reactions in leprosy.

METHODS

Urine, blood and incisional skin biopsy samples from site of lesions were collected from 49 newly diagnosed untreated leprosy cases in T1R and 51 cases not in reaction (NR). mRNA expression levels of genes encoding 11 β HSD I & II in skin biopsy samples were determined by realtime PCR. Cortisol levels from the lesional skin biopsies, serum and urine samples and serum proinflammatory cytokine levels were measured using ELISA.

RESULTS

The mean expression ratios of 11 β HSD I & II are significantly lower in leprosy cases with T1R when compared to the NR leprosy cases. Cortisol levels in lesional skin biopsies and in urine are significantly lower (p=0.001) in leprosy cases with T1R. Serum cytokine levels of IP-10, IL-17F, IL-IL-6 and TNF-α are significantly higher (p<0.05) in leprosy cases with T1R when compared the NR leprosy cases.

CONCLUSION

Our study indicated an association of urinary and lesional skin cortisol levels with the manifestation of T1R in leprosy. IP-10, IL-17F, IL-6 and TNF-α can be potential prognostic serological markers and gene expression markers for early detection of type 1 reactions in leprosy.

Endocrine dysfunction in leprosy

Leprosy is still an endemic disease, especially in Third World countries, and, because of migration, it still persists in Europe and the United States. The disease affects the peripheral nerves, skin, and multiple internal organs, making its clinical recognition difficult. In particular, the endocrine manifestations caused by leprosy have been underestimated, even by specialists. The endocrine changes present in leprosy include hypogonadism, sterility, and osteoporosis. In addition, the spectral immune nature of leprosy offers an attractive model to investigate the pathogenetic correlation between the patterns of inflammation in the poles of its spectrum and the hormonal disarrangements observed in this disease. It is important that those involved in leprosy management be aware of the potential endocrine changes and their treatment to address the disease in all of its aspects. In this article, we review the findings on endocrine dysfunction in leprosy, including a survey of the literature and of our own work.

Alteration of the cortisol–cortisone shuttle in leprosy type 1 reactions in leprosy patients in Hyderabad, India

Regulation of inflammation in leprosy may be influenced by local concentrations of active cortisol and inactive cortisone, whose concentrations are regulated by enzymes in the cortisol-cortisone shuttle. We investigated the cortisol-cortisone shuttle enzymes in the skin of leprosy patients with type 1 reactions (T1R), which are characterised by skin and nerve inflammation. Gene expression of the shuttle enzymes were quantified in skin biopsies from 15 leprosy patients with new T1R before and during prednisolone treatment and compared with levels in skin biopsies from 10 borderline leprosy patients without reactions. Gene expression of 11beta-hydroxysteroid dehydrogenase (11beta-HSD) type 2, which converts cortisol to cortisone, is down-regulated in skin from T1R lesions. However expression levels of 11beta-HSD type 1, which converts cortisone to cortisol, were similar in skin with and without reactions and did not change during anti-leprosy drug treatment. Prednisolone treatment of patients with reactions is associated with an upregulation of 11beta-HSD2 expression in skin. The down regulation of 11beta-HSD2 at the beginning of a reaction may be caused by pro-inflammatory cytokines in the leprosy reactional lesion and may be a local attempt to down-regulate inflammation. However in leprosy reactions this local response is insufficient and exogenous steroids are required to control inflammation.

A comparison between the effects of low (1 microg) and standard dose (250 microg) acth stimulation tests on adrenal cortex functions with leprosy patients

Leprosy is a chronic granulomatous disease that either remains localized or widespread depending on the immunological status of the affected patient. It can lead to clinical or subclinical adrenal failure by influencing adrenal steroidogenesis. In the present study, 26 patients (21 males and 5 females) who were diagnosed with lepromatous leprosy and 15 healthy individuals who were compatible with the patients in terms of age and sex were subjected to an adrenocorticotrophic hormone (ACTH) stimulation test. The leprosy and control groups were subjected to 1microg low dose (LDT) and 250 microg intravenous standard dose (SDT) ACTH stimulation tests after 12-hour nocturnal fasting with an interval of three days. Cortisol responses in 0, 30, and 60 minutes were examined. There was no difference between leprosy and control groups in terms of mean baseline cortisol values. Mean value of the peak cortisol response to both LDT and SDT was found to be significantly lower in the leprosy group than in the control group (p < 0.001 and p < 0.01, respectively). Peak cortisol response to LDT in the leprosy group was found below 20 microg/dL in 9 patients (34.6%). As for the peak cortisol response to SDT, it was lower than 20 microg/dL, in 5 patients (19.23%). It was found that LDT response was abnormally low in 4 patients (15.38%) who responded normally to SDT. It was observed that there could be a decrease in adrenocortical reserve capacity although baseline adrenocortical functions were normal in patients with leprosy. It was seen that LDT was more sensitive than SDT in identifying this decrease.

Mycobacterium leprae and leprosy: a compendium

Leprosy is a chronic infectious disease caused by Mycobacterium leprae, which was discovered by G.H.A. Hansen in 1873. M. leprae is an exceptional bacterium because of its long generation time and no growth in artificial media. Entire sequencing of the bacterial genome revealed numerous pseudogenes (inactive reading frames with functional counterparts in M. tuberculosis) which might be responsible for the very limited metabolic activity of M. leprae. The clinical demonstration of the disease is determined by the quality of host immune response. Th1-type immune response helps to kill the bacteria, but hosts are encroached upon when Th2-type response is predominant. The bacteria have affinity to the peripheral nerves and are likely to cause neuropathy. M. leprae/laminin-alpha2 complexes bind to alpha/beta dystroglycan complexes expressed on the Schwann cell surface. WHO recommends a chemotherapy protocol [multidrug therapy (MDT)] which effectively controls the disease and contributes to the global elimination program. Leprosy has been stigmatized throughout history, and recent topics regarding the disease in Japan are also discussed.