Progressive neuropathy in patients with lepromatous leprosy after multidrug therapy

BACKGROUND The lepromatous pole is a stigmatising prototype for patients with leprosy. Generally, these patients have little or no symptoms of peripheral nerve involvement at the time of their diagnosis. However, signs of advanced peripheral neuropathy would be visible during the initial neurological evaluation and could worsen during and after multidrug therapy (MDT). Disabilities caused by peripheral nerve injuries greatly affect these patients' lives, and the pathophysiological mechanisms underlying nerve damage remain unclear. OBJECTIVES To evaluate the outcome of peripheral neuropathy in patients with lepromatous leprosy (LL) and persistent neuropathic symptoms years after completing MDT. METHODS We evaluated the medical records of 14 patients with LL who underwent nerve biopsies due to worsening neuropathy at least four years after MDT. FINDINGS Neuropathic pain developed in 64.3% of the patients, and a neurological examination showed that most patients had alterations in the medium- and large-caliber fibers at the beginning of treatment. Neurological symptoms and signs deteriorated despite complete MDT and prednisone or thalidomide use for years. Nerve conduction studies showed that sensory nerves were the most affected. MAIN CONCLUSIONS Patients with LL can develop progressive peripheral neuropathy, which continues to develop even when they are on long-term anti-inflammatory and immunosuppressive therapy.

Fibrosis: a distinguishing feature in the pathology of neural leprosy

BACKGROUND Fibrosis in the peripheral nerve is the end stage of leprous neuropathy and the cause of the resulting permanent neural function impairments. Preventive measures to avoid this irreversible pathological state are a relief strategy for leprosy sufferers. OBJECTIVES The present study describes the frequency of fibrosis along with its characterisation and pathogenic development. METHODS Six-hundred-and-thirteen nerve samples were sorted from 278 neural leprosy (NL) and 335 non-leprosy neuropathy patients (ON). The total number of samples was histologically examined by routine staining methods (haematoxylin-eosin, Wade staining and Gomori's trichrome) and fibrosis was evaluated via semi-quantitative estimation. FINDINGS Fibrosis was most frequent in the NL group (33% against 0.4% in ON) while fibrosis in association with endoneurial microfasciculation was found in 38 (41.3%) of the NL samples in the examination of semithin sections. Pericytic activation in the perivascular environment was confirmed to be the source of the fibroblasts and perineurial cells delimiting microfascicles. End-stage fibrosis in leprosy displays an arrangement of microfascicles devoid of neural components (i.e., Schwann cells and axons) lined by an intermediate phenotype of fibroblastic-perineurial cells filled with bundles of collagen fibres. MAIN CONCLUSIONS The present study underscores that fibrosis is frequently the severe end stage of neural leprosy NL pathogeny after analysing the notably distinct development of fibrosis within the neural environment.

Erythema multiforme in leprosy

The clinical course of leprosy is often interrupted by reactions, which are acute inflammatory episodes that can be classified as type I or type II. Type II reactions can present as cutaneous lesions that resemble erythema multiforme (EM). EM is classically associated with drug allergies or pre-existing viral infections. However, the differential diagnostic criteria of the diverse causative agents remain controversial. The aim of this study was to determine both the clinical relevance and the morphological and immunohistochemical characteristics of the EM-like lesions during the course of type II leprosy reactions. Twenty-seven skin biopsies were taken from typical EM-like lesions of multibacillary patients and reviewed; their histological features were correlated to their clinical aspects. Then, a computer-assisted morphometric analysis was performed to measure the extent of angiogenesis during these acute episodes. The histopathological and immunohistochemical analysis of the EM lesions revealed that they shared the same features that have been previously described for ENL, including immunopositivity in the identical cell-mediated immune markers. Our results point to leprosy as the cause of the EM-like lesions in our patients. Therefore, leprosy should be considered in the differential diagnosis of EM.

Cutaneous lesions sensory impairment recovery and nerve regeneration in leprosy patients

It is important to understand the mechanisms that enable peripheral neurons to regenerate after nerve injury in order to identify methods of improving this regeneration. Therefore, we studied nerve regeneration and sensory impairment recovery in the cutaneous lesions of leprosy patients (LPs) before and after treatment with multidrug therapy (MDT). The skin lesion sensory test results were compared to the histopathological and immunohistochemical protein gene product (PGP) 9.5 and the p75 nerve growth factor receptors (NGFr) findings. The cutaneous neural occupation ratio (CNOR) was evaluated for both neural markers. Thermal and pain sensations were the most frequently affected functions at the first visit and the most frequently recovered functions after MDT. The presence of a high cutaneous nerve damage index did not prevent the recovery of any type of sensory function. The CNOR was calculated for each biopsy, according to the presence of PGP and NGFr-immunostained fibres and it was not significantly different before or after the MDT. We observed a variable influence of MDT in the recovery from sensory impairment in the cutaneous lesions of LPs. Nociception and cold thermosensation were the most recovered sensations. The recovery of sensation in the skin lesions appeared to be associated with subsiding inflammation rather than with the regenerative activity of nerve fibres.

Histopathological examination of nerve samples from pure neural leprosy patients: obtaining maximum information to improve diagnostic efficiency

Nerve biopsy examination is an important auxiliary procedure for diagnosing pure neural leprosy (PNL). When acid-fast bacilli (AFB) are not detected in the nerve sample, the value of other nonspecific histological alterations should be considered along with pertinent clinical, electroneuromyographical and laboratory data (the detection of Mycobacterium leprae DNA with polymerase chain reaction and the detection of serum anti-phenolic glycolipid 1 antibodies) to support a possible or probable PNL diagnosis. Three hundred forty nerve samples [144 from PNL patients and 196 from patients with non-leprosy peripheral neuropathies (NLN)] were examined. Both AFB-negative and AFB-positive PNL samples had more frequent histopathological alterations (epithelioid granulomas, mononuclear infiltrates, fibrosis, perineurial and subperineurial oedema and decreased numbers of myelinated fibres) than the NLN group. Multivariate analysis revealed that independently, mononuclear infiltrate and perineurial fibrosis were more common in the PNL group and were able to correctly classify AFB-negative PNL samples. These results indicate that even in the absence of AFB, these histopathological nerve alterations may justify a PNL diagnosis when observed in conjunction with pertinent clinical, epidemiological and laboratory data.

Mast cell subsets and neuropeptides in leprosy reactions

The immunohistochemical identification of neuropeptides (calcitonin gene-related peptide, vasoactive intestinal polypeptide, substance P, alpha-melanocyte stimulating hormone and gamma-melanocyte stimulating hormone) quantification of mast cells and their subsets (tryptase/chymase-immunoreactive mast cells = TCMC and tryptase-immunoreactive mast cells = TMC) were determined in biopsies of six patients with leprosy reactions (three patients with type I reaction and three with type II). Biopsies were compared with those taken from the same body site in the remission stage of the same patient. We found a relative increase of TMC in the inflammatory infiltrate of the reactional biopsies compared to the post-reactional biopsy. Also, the total number of mast cells and the TMC/TCMC ratio in the inflammatory infiltrate was significantly higher than in the intervening dermis of the biopsies of both periods. No significant difference was found regarding neuroptide expression in the reactional and post-reactional biopsies. The relative increase of TMC in the reactional infiltrates could implicate this mast cell subset in the reported increase of the immune response in leprosy reactions

The expression of NGFr and PGP 9.5 in leprosy reactional cutaneous lesions: an assessment of the nerve fiber status using immunostaining

The effects of reactional episodes on the cutaneous nerve fibers of leprosy patients was assessed in six patients (three with reversal reactions and three with erythema nodosum leprosum). Cryosections of cutaneous biopsy of reactional lesions taken during the episode and of another sample during the remission period were immunostained with anti-NGFr and anti-PGP 9.5 (indirect immunofluorescence). We found no significant statistical difference in the number of NGFr- and PGP 9.5-positive fibers between the reactional and post-reactional groups. A significant difference was detected between the number of NGFr and PGP 9.5-stained fibers inside of the reactional group of biopsy cryosections but this difference was ascribed to the distinct aspects of the nerve fibers displayed whether stained with anti-NGFr or with anti-PGP 9.5; NGFr-positive branches looked larger and so interpreted as containing more fibers. In addition, a substantial number NGFr-positive fibers were PGP 9.5-negative. No differences in the number of stained fibers among the distinct cutaneous regions examined (epidermis + upper dermis, mid and deep dermis) was detected. In conclusion, the number of PGP- and NGFr-positive fibers were not significantly different in the reactional and post-reactional biopsies in the present study. NGFr-staining of the nerve fibers is different from their PGP-imunoreactivity and the evaluation of the nerve fiber status on an innervated target organ should be carried out choosing markers for both components of nerve fibers (Schwann cells and axons)

The diagnosis of leprosy among patients with symptoms of peripheral neuropathy without cutaneous lesions: a follow-up study

Forty-four patients with neuritic leprosy were individually followed for periods ranging from 4 months to almost 4 years for the purpose of ascertaining the presence and/ or absence of leprosy. The neural symptoms presented were sensory impairment (41), parasthesia (28), nerve enlargement (22), nerve tenderness (20), paresia (20), amyotrophy (8). Leprosy was diagnosed in ten out of the total number of patients studied. Leprosy was confirmed by the appearance of reactional neuritis (4), reversal reaction (2), biopsy of the hypoesthesic area (3) and the appearance of non-reactional cutaneous lesion. We reported an experience in the diagnosis of neuritic leprosy and its most frequent clinical presentation with which clinicians have to be acquainted. We can also state that the clinical follow-up was an effective strategy for the diagnosis of the disease when diagnostic facilities are not available or have not confirmed the diagnosis

Ultrastructural study of the dermal nerves in the cutaneous macular lesions of patients with early leprosy

Thirteen biopsies of macular lesions of early leprosy patients were studied ultrastructurally with transmission electron microscopy (TEM). All of the biopsies displayed at least one dermal nerve partially or completely encircled by mononuclear cells in the conventional histopathological study with light microscopy. The patients'diagnosis varied from indeterminate leprosy to borderline tuberculoide (BT). In the ultrastructural study, twenty-seven dermal nerve branches were found in the thirteen biopsies. Twenty dermal nerve branches in eleven biopsies were found to display no inflammatory involvement. Seven nerves in seven biopsies were morphologically associated with mononuclear leukocytic cells. Four biopsies exhibited nerves with and without inflammatory involvement concomitantly. Three nerves showed morphological evidence of endoneurial fibrosis, not morphologically associated with the inflammatory process at least in the sections examined. No detectable axional and Schwann cell ultra strutural changes even in the twenty-seven nerves were found. The sensorial loss exhibited by the patients before the institution of treatment was completely reversed in eight patients after the end of multidrug therapy regimen. These findings suggest that sensory loss in the early stages of leprosy may be caused by reversible pathological mechanisms, rather than anatomical damage. It is also possible, concerning the mechanisms of nerve damage in leprosy, to speculate on the existence of a pathological process which may precede the inflammation.

DOPA-stained melanocytes in the macular lesions of early leprosy

The mechanism of association of hypopigmentation and sensorial loss in a leprosy macular lesions has not been clarified yet. The biopsy of a macular lesion on the medial face of the right forearm of a fourteen-year old male leprosy patient was submitted to DOPA-staining for melanocytes, which is specific for the melanocytic tyrosinase enzyme and it is a proper method for identifying and couting these cells in the skin. A contralateral specimen of the same patient went through the same procedure as a control experiment. The specimen from the macular lesion showed a higher number of DOPA-stained melanocytes than the control fragment. Dermal melanocytes were present in high amounts in the abnormal specimen. Increased expression of tyrosinase by melanocytes in the macular lesions may reflect a positive feed-back stimulus represented by the lack of substance tyrosine, which may in turn be utilized by the myocobacterial agent. Ultrastructural study of the normal and pathological specimens showed no significant differences in the morphological appearance of melanocytes and their melanosomes. These results suggests that the utilization of phenolic compound by the Mycobacterium leprae may be involved in the mechanism of hypopigmentation. A higher number of cases will be necessary to confirm this hypothesis.

Estudo imunohistoquímico e ultra-estrutural da inervação de de lesões cutâneas de hanseníase em fase inicial / Immunohistochemistry and ultrastructural analysis of the innervation of the skin lesions of leprosy in early stage

A neuropatia hanseniana (NH) é a principal condição responsável pela incapacidade e deformidade apresentadas pelo paciente portador da hanseníase...O conhecimento aprofundado sobre a biologia da NH além de ser justificado pelo seu fascinante interesse biológico, faz-se necessário para os programas de controle que almejam não só a diminuição da prevalência e da incidência da hanseníase, mas também a redução da morbidade das lesões neurais incapacitantes causadas pela doença.