High-Resolution Sonography as an Additional Diagnostic and Prognostic Tool to Monitor Disease Activity in Leprosy: A Two-Year Prospective Study.

PURPOSE: Early diagnosis and treatment of leprosy and leprosy reactions are essential to prevent stigmatizing deformities and disability. Although the incidence of leprosy has decreased enormously, grade 2 disability due to nerve injury has remained the same. New tools are needed to better diagnose and monitor leprosy reactions and associated neuritis and this study assessed whether high-resolution sonography (HRUS) can be used as such a tool. MATERIALS AND METHODS: During a prospective follow-up period of 2 years at regular intervals, we performed clinical examination to assess sensory and motor function and HRUS of the four main peripheral nerves in 57 patients, of whom 36 were with reactions and 21 were without reactions. Normative data of the cross-sectional area (CSA) of these nerves were obtained from 55 healthy subjects (HS). Color Doppler (CD) was used to study blood flow in the nerves. RESULTS: At the baseline visit and during follow-up, all four nerves were significantly thicker in patients with leprosy reactions in comparison to HS (p < 0.0001) and to a lesser extent also in comparison to patients without reactions ranging from a p-value of < 0.05 to < 0.0001 in the different nerves tested. During follow-up, the nerve size did not change significantly in patients without reactions, while it decreased significantly in patients with reactions. At baseline, endoneural blood flow was present only in patients with reactions. This occurred in 20 of the 36 (55 %) patients (49 nerves) and decreased to only 1 patient (2.7 %) at the end of the follow-up period. CONCLUSION: This prospective study demonstrates the ability of HRUS to monitor disease activity and the effect of treatment in patients with leprosy reactions by determining changes in nerve size and vascularity, which are indicators of peripheral nerve involvement and damage.

Imaging techniques in leprosy clinics.

Leprosy is the most common treatable peripheral nerve disorder worldwide, with periods of acute neuritis leading to functional impairment of limbs and stigmatizing deformities. The nerve involvement in leprosy reactions, if recognized early and promptly treated with steroids and nerve release surgery, can be reversible. Currently, the nerve assessment in leprosy relies mainly on clinical assessment and nerve conduction studies. High-resolution ultrasonography (HRUS) of peripheral nerves is finding wider application in the differential diagnosis of peripheral neuropathy. HRUS provides a noninvasive tool that gives information on location and degree of nerve enlargement, nerve morphologic alterations, echo texture, fascicular pattern, and vascularity of the nerve, which mirrors the histologic changes. HRUS is amenable to studying structural changes in nerve sites that cannot be biopsied for histopathologic examination and is more cost effective than magnetic resonance imaging. So far other there are only five studies available on the sonographic findings in leprosy. These findings are reviewed and the technique of HRUS is described in this paper, with a recommendation of a standard protocol and proforma.

Imaging techniques in leprosy clinics

Leprosy is the most common treatable peripheral nerve disorder worldwide, with periods of acute neuritis leading to functional impairment of limbs and stigmatizing deformities. The nerve involvement in leprosy reactions, if recognized early and promptly treated with steroids and nerve release surgery, can be reversible. Currently, the nerve assessment in leprosy relies mainly on clinical assessment and nerve conduction studies. High-resolution ultrasonography (HRUS) of peripheral nerves is finding wider application in the differential diagnosis of peripheral neuropathy. HRUS provides a noninvasive tool that gives information on location and degree of nerve enlargement, nerve morphologic alterations, echo texture, fascicular pattern, and vascularity of the nerve, which mirrors the histologic changes. HRUS is amenable to studying structural changes in nerve sites that cannot be biopsied for histopathologic examination and is more cost effective than magnetic resonance imaging. So far other there are only five studies available on the sonographic findings in leprosy. These findings are reviewed and the technique of HRUS is described in this paper, with a recommendation of a standard protocol and proforma.

Association of Taq I, Fok I and Apa I polymorphisms in Vitamin D Receptor (VDR) gene with leprosy.

BACKGROUND: Vitamin D Receptor (VDR) is a transacting transcription factor which mediates immunomodulatory function and plays a key role in innate and adaptive immune responses through its ligand and polymorphisms in VDR gene may affect its regulatory function. OBJECTIVE: To investigate the association of three VDR gene polymorphisms (TaqI rs731236, FokI rs2228570 and ApaI rs7975232) with leprosy. METHODS: The study group includes 404 participants of which 222 were leprosy patients (paucibacillary=87, multibacillary=135) and 182 healthy controls. Genotyping was done using PCR-RFLP technique. Statistical analysis was performed using SNP Stats and PLINK software. RESULTS: The VDR FokI (rs2228570) ff genotype, ApaI (rs7975232) AA, Aa genotype and haplotype T-f-a, T-F-A were positively associated with leprosy when compared to healthy controls. CONCLUSION: The two variants at Fok and Apa positions in VDR gene are significantly associated with leprosy. Genotypes at FokI (ff), ApaI (aa) and haplotype (T-F-a, T-f-a) may contribute to the risk of developing leprosy by altering VDR phenotype/levels subsequently modulation of immune response.

Serological responses to prednisolone treatment in leprosy reactions: study of TNF-α, antibodies to phenolic glycolipid-1, lipoarabinomanan, ceramide and S100-B.

BACKGROUND: Corticosteroids have been extensively used in the treatment of immunological reactions and neuritis in leprosy. The present study evaluates the serological response to steroid treatment in leprosy reactions and neuritis. METHODS: Seven serological markers [TNF-α, antibodies to Phenolic glycolipid-1 (PGL-1 IgM and IgG), Lipoarabinomannan (LAM IgG1 and IgG3), C2-Ceramide and S100 B] were analyzed longitudinally in 72 leprosy patients before, during and after the reaction. At the onset of reaction these patients received a standard course of prednisolone. The levels of the above markers were measured by Enzyme linked immunosorbent assay (ELISA) and compared with the individuals own value in the month prior to the reaction and presented as percentage increase. RESULTS: One month before the reaction individuals showed a varying increase in the level of different markers such as TNF-α (53%) and antibodies to Ceramide (53%), followed by to PGL-1 (51%), S100B (50%) and LAM (26%). The increase was significantly associated with clinical finding of nerve pain, tenderness and new nerve function impairment. After one month prednisolone therapy, there was a fall in the levels [TNF-α (60%), C2-Ceramide (54%), S100B (67%), PGL-1(47%) and LAM (52%)] with each marker responding differently to steroid. CONCLUSION: Reactions in leprosy are inflammatory processes wherein a rise in set of serological markers can be detected a month before the clinical onset of reaction, some of which remain elevated during their action and steroid treatment induces a variable fall in the levels, and this forms the basis for a variable individual response to steroid therapy.

Genetic association of G896A polymorphism of TLR4 gene in leprosy through family-based and case-control study designs.

BACKGROUND: Polymorphisms in TLR4 may change the function of the protein and alter the efficiency of immune response of host to infection. The high relevance of host gene polymorphisms with outcome of Mycobacterium leprae infection led us to study the genetic association of TLR4 G896A polymorphism in order to identify its risk among contacts of affected leprosy patients. METHODS: For case-control study design a total of 628 individuals were recruited; 17 multicase leprosy families which included 32 case-parent trios were considered for family-based study. Genotyping was done using PCR-RFLP method. RESULTS: In case-control study AA genotype was positively associated while GA genotype was negatively associated with leprosy. In family based transmission disequilibrium test (TDT) analysis allele G was found to be over transmitted to the affected individuals. CONCLUSION: Case-control study suggests that homozygous AA genotype may confer susceptibility and heterozygous GA genotype may confer resistance to leprosy, while allele A was observed to increase risk and that of allele G may confer resistance to leprosy. No strong transmission disequilibrium was detected in family-based TDT analysis, possibly due to lower number of trios. In contrast to case-control data allele G was over transmitted to the affected ones in TDT analysis. To conclude, the frequencies of genotypes in household contacts were almost the same as in leprosy patients, suggesting that contacts with AA genotype may be at higher risk of leprosy and may therefore require prophylactic inputs.

Influence of Intron II microsatellite polymorphism in human toll-like receptor 2 gene in leprosy.

Leprosy is a chronic granulomatous infection caused by the obligate intracellular organism Mycobacterium leprae. TLR2 plays a key role when activated by M. leprae lipoproteins initiating protective responses which induce bacterial killing and therefore control of disease spread. Microsatellite polymorphisms in intron2 of TLR2 gene have been reported to be associated with development of clinical features of several infectious diseases. The study aims to evaluate the influence of GT microsatellite on the expression of TLR2 which could make humans prone to M. leprae infections. A total of 279 individuals were enrolled in the study, 88 were leprosy patients, 95 were house hold contacts (HHC) and 96 were healthy controls (HC). Genotyping was done using PCR-Sequencing method. TLR2 mRNA expression was analyzed by RT-PCR. IL-10 and IFN-γ levels were measured using ELISA in MLSA stimulated cell culture supernatants. Statistical analysis was performed using Chi-Square (χ(2)) test and t-tests. Allele/genotype of TLR2 microsatellite which includes longer GT repeats was associated with low TLR2 mRNA expression and high IL-10 production while that including shorter GT repeats was associated with high TLR2 mRNA expression and low IL-10 production. High IL10 producing allele of TLR2 microsatellite might predispose house hold contacts to leprosy.

Newer management options in leprosy.

Newer management options are needed for leprosy control even at present, as it is predicted that new cases of leprosy will continue to appear for many more years in future. This article detail newer methods of clinical grading of peripheral nerve involvement (thickening, tenderness and nerve pain which are subjective in nature) and the advances made in the use of Ultrasonography and Colour Doppler as an objective imaging tool for nerves in leprosy. It also briefly discusses the newer drugs and alternative regimens as therapeutic management options which hold promise for leprosy in future.

Genetic evidence of TAP1 gene variant as a susceptibility factor in Indian leprosy patients.

The heterodimeric transporter associated with antigen processing (TAP) gene loci is known to play a vital role in immune surveillance. We investigated a possible association of gene polymorphisms both in TAP1 and TAP2 in a cohort of clinically classified leprosy patients (n=222) and in ethnically matched controls (n=223). The TAP1 and TAP2 genes were genotyped for four single nucleotide polymorphisms TAP1 (rs1057141 Iso333Val and rs1135216 Asp637Gly) and TAP2 (rs2228396 Ala565Thr and rs241447 Ala665Thr) by direct sequencing and ARMS-PCR. The minor allele of TAP1 637G contributes to an increased risk to leprosy compared to controls (OR: 1.68, 95% CI 1.2-2.36, P=0.0057). An increased risk for the variant minor allele of the TAP1 637G to multibacillary (BL+LL) or paucibacillary (BT+TT) infections was also observed [multibacillary vs. controls (OR: 1.56, 95% CI 1.07-2.28, P=0.054); paucibacillary vs. controls (OR: 1.92, 95% CI 1.21-3.01, P=0.013)]. In the dominant model, the genotypes of the TAP1 rs1135216AG+GG additionally contributed to an increased risk. Overall our findings demonstrate that the TAP1 gene variant (rs1135216 Asp637Gly) influences the susceptibility to clinically classified leprosy patients in Indian population.

Morphological changes of the epineurium in leprosy: a new finding detected by high-resolution sonography.

INTRODUCTION: From histopathological studies of peripheral nerves in leprosy, it is known that the epineurium can be thickened. We measured the epineurial thickness of the ulnar nerve by high resolution sonography (HRUS). METHODS: The epineurium of the ulnar nerve was measured above the elbow on transverse scan in 25 healthy controls and 26 leprosy patients. RESULTS: The mean epineurial thickness was 0.77 mm (95% confidence interval [CI] 0.66-0.88) in symptomatic ulnar nerves (n = 20), 0.58 mm (CI 0.51-0.65) in asymptomatic nerves (n = 30), and 0.49 mm (CI 0.44-0.54) in healthy controls (n = 25) (P = 0.0001). This thickening was related to the cross-sectional area of the ulnar nerve, but not with increased blood flow. CONCLUSIONS: The epineurium of the ulnar nerve can be measured with the use of HRUS, and it is often strikingly thickened in leprosy patients, especially in those with ulnar involvement.

Ulnar neuropathy in hansen disease: clinical, high-resolution ultrasound and electrophysiologic correlations.

OBJECTIVE: To assess the relationship between the cross-sectional area (CSA) of the ulnar nerve by ultrasound (US) with clinical and electrophysiologic findings in Hansen ulnar neuropathy. METHODS: Twenty-one patients (42 arms) with Hansen disease (mean age 30.0 ± 12.97, range 13-61 years, borderline tuberculoid 29%, borderline lepromatous, 19% lepromatous leprosy 42%, and pure neuritic type 10%) were examined clinically for ulnar sensory and motor weakness. The ulnar nerve was ultrasonographically examined from the wrist to the axilla, and CSA was measured at the level of maximum enlargement. Ulnar sensory nerve conduction was recorded orthodromically with ring electrodes placed at the fifth digit and amplitude of sensory nerve action potential (SNAP) recorded 3 cm proximal to the distal wrist crease. Motor conduction velocity (MCV) was recorded at the wrist-below the elbow, below the elbow-above the elbow, and above the elbow-axilla segments. RESULTS: Out of the 42 arms with Hansen disease, 76% had clinically motor weakness, and 43% had sensory loss in the upper limbs innervated by the ulnar nerve. As compared with healthy subjects, the patients with Hansen ulnar neuropathy had a statistically significant reduction in SNAP (P ≤ 0.0001) and MCV (P ≤ 0.0001). It was observed that the maximum enlargement of the ulnar nerve in all the patients was a few centimeters above the elbow segment. The mean CSA of ulnar nerve above the medial epicondyle was 18 ± 15 mm as compared with controls 4.83 ± 1.12 mm (P < 0.0001). In addition to nerve thickening, US depicted abnormality in morphology. In 55%, the nerve was hypoechoic, and in 7.1%, the nerve pattern was oligofascicular. Color Doppler (CD) flow signals were observed in all the nerves with loss of fascicular pattern and in 40% of the nerves that were hypoechoic. A statistically significant correlation was found between CSA of ulnar nerve above the medial epicondyle vs. MCV at BE-AE and compound muscle action potentials (CMAP) above the elbow in the patients with clinical motor weakness (r = -0.55, P < 0.001) and (r = -0.57, P < 0.001), respectively. There was no statistical significant correlation between CSA and SNAP in the patients with (r = -0.52, P = 0.23) and without (r = -0.07, P = 0.83) sensory loss. CONCLUSIONS: In leprosy patients, a positive correlation exits between the presence of motor weaknesses of the ulnar nerve innervated muscles, sonographically thickening of the ulnar nerve, and motor conduction slowing of the ulnar nerve at the BE-AE segment. In addition, US provided information on nerve morphologic alterations regarding the echo texture and location of nerve enlargement.

Antibodies to myelin P0 and ceramide perpetuate neuropathy in long standing treated leprosy patients.

Anti neural antibodies are known to play a role in the immunopathogenesis of nerve damage in leprosy and HIV/AIDS. Myelin Protein zero (P0) and ceramide are two nerve components which maintain the integrity of the peripheral nerve. The present study was undertaken to identify antibodies to myelin P0 and ceramide in the sera of treated leprosy patients, HIV positive individuals and healthy subjects using enzyme linked immunosorbant assay (ELISA). The results revealed that treated leprosy patients continue to have significantly elevated myelin P0 and ceramide antibody levels as compared to healthy subjects (P < 0.05). The elevated antibody response to myelin P0 and ceramide in leprosy patients indicate a low grade autoimmune activity that perpetuates nerve damage in treated leprosy. There was no significant difference in the myelin P0 and ceramide antibody levels between HIV positive and healthy subjects (P > 0.05) suggesting that these antibodies do not play a role in early HIV infection.

VNTR typing of Mycobacterium leprae in South Indian leprosy patients.

OBJECTIVES: To study the suitability, stability and diversity of short tandem repeat (STR) genomic markers to elicit strain variation in the Mycobacterium leprae isolates within leprosy patients from Andhra Pradesh and Tamil Nadu states in South India. MATERIALS AND METHODS: Slit skin smear (SSS) samples were collected from lesions and various body sites of newly diagnosed leprosy patients. The SSSs from each patient were pooled, except in the case of five patients. Total DNA was extracted from SSS samples. M. leprae STRs were amplified from the DNA either by multiplex PCR (MP) or single PCR methods. The number of repeats for each STR locus (the STR allele) was obtained either by fragment length analysis (FLA) or by DNA sequencing of the PCR amplicons. RESULTS AND CONCLUSION: Multiplex PCR minimised the use of DNA and reagents, and together with FLA, was time and cost effective for STR strain typing. After examination of the isolates of South Indian origin at 13 STR loci, it was determined that the alleles for (AC)8b, (GGT)5, 6-3a (rpoT), 21-3, 27-5, and 23-3 were conserved in two study populations. In a family from Andhra Pradesh, the M. leprae STR patterns in two patients were identical in 16 of 18 loci which indicate a common source of infection. Fourteen of 15 STR loci showed no intra-patient variation in the five patients tested in Tamil Nadu. Altogether, these studies indicate the suitability of STR strain typing for assessing short-range transmission chains.

High-resolution sonography: a new technique to detect nerve damage in leprosy.

BACKGROUND: Leprosy is the most common treatable peripheral nerve disorder worldwide with periods of acute neuritis leading to functional impairment of limbs, ulcer formation and stigmatizing deformities. Since the hallmarks of leprosy are nerve enlargement and inflammation, we used high-resolution sonography (US) and color Doppler (CD) imaging to demonstrate nerve enlargement and inflammation. METHODOLOGY/PRINCIPAL FINDINGS: [corrected] We performed bilateral US of the ulnar (UN), median (MN), lateral popliteal (LP) and posterior tibial (PT) nerves in 20 leprosy patients and compared this with the clinical findings in these patients and with the sonographic findings in 30 healthy Indian controls. The nerves were significantly thicker in the leprosy patients as compared to healthy controls (p<0.0001 for each nerve). The two patients without nerve enlargements did not have a type 1 or type 2 reaction or signs of neuritis. The kappa for clinical palpation and nerve enlargement by sonography was 0.30 for all examined nerves (0.32 for UN, 0.41 for PN and 0.13 for LP). Increased neural vascularity by CD imaging was present in 39 of 152 examined nerves (26%). Increased vascularity was observed in multiple nerves in 6 of 12 patients with type 1 reaction and in 3 of 4 patients with type 2 reaction. Significant correlation was observed between clinical parameters of grade of thickening, sensory loss and muscle weakness and US abnormalities of nerve echotexture, endoneural flow and cross-sectional area (p<0.001). CONCLUSIONS/SIGNIFICANCE: We conclude that clinical examination of enlarged nerves in leprosy patients is subjective and inaccurate, whereas sonography provides an objective measure of nerve damage by showing increased vascularity, distorted echotexture and enlargement. This damage is sonographically more extensive and includes more nerves than clinically expected.

Use of short tandem repeat sequences to study Mycobacterium leprae in leprosy patients in Malawi and India.

BACKGROUND: Inadequate understanding of the transmission of Mycobacterium leprae makes it difficult to predict the impact of leprosy control interventions. Genotypic tests that allow tracking of individual bacterial strains would strengthen epidemiological studies and contribute to our understanding of the disease. METHODOLOGY/PRINCIPAL FINDINGS: Genotyping assays based on variation in the copy number of short tandem repeat sequences were applied to biopsies collected in population-based epidemiological studies of leprosy in northern Malawi, and from members of multi-case households in Hyderabad, India. In the Malawi series, considerable genotypic variability was observed between patients, and also within patients, when isolates were collected at different times or from different tissues. Less within-patient variability was observed when isolates were collected from similar tissues at the same time. Less genotypic variability was noted amongst the closely related Indian patients than in the Malawi series. CONCLUSIONS/SIGNIFICANCE: Lineages of M. leprae undergo changes in their pattern of short tandem repeat sequences over time. Genetic divergence is particularly likely between bacilli inhabiting different (e.g., skin and nerve) tissues. Such variability makes short tandem repeat sequences unsuitable as a general tool for population-based strain typing of M. leprae, or for distinguishing relapse from reinfection. Careful use of these markers may provide insights into the development of disease within individuals and for tracking of short transmission chains.

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.

Clinical course of erythema nodosum leprosum: an 11-year cohort study in Hyderabad, India.

Erythema nodosum leprosum (ENL) or type 2 lepra reactions complicate lepromatous leprosy and borderline lepromatous leprosy. We report an 11-year retrospective case record analysis of 481 outpatients with borderline lepromatous and lepromatous leprosy at the Dhoolpet Leprosy Research Center in Hyderabad, India.. The overall prevalence of ENL was 24%, 49.4% among cases of lepromatous leprosy (LL) and 9% among cases of borderline lepromatous (BL) leprosy. Logistic regression analysis identified LL (odds ratio [OR] = 8.4, 95% confidence interval [CI] = 4.6-15.4, P < 0.001) and BL with a bacterial index > or = 4+ (OR = 5.2, 95% CI = 2.1-12.9, P = 0.001) as major risk factors. The average patient with ENL was male, 34.7 years of age, and had multiple episodes of ENL (mean = 3.1) over an 18.5-month period. Three types of ENL were identified: single acute ENL, multiple acute ENL (repeated discrete episodes), and chronic ENL (continuous episodes). Acute single ENL is rare, accounting for only 8% of cases. Chronic ENL accounted for 62.5% of the cohort. Chronic ENL was of longer duration and more severe. An age > or = 35 years was a risk factor for developing chronic ENL. Patients with chronic ENL were more compliant with multi-drug therapy, especially during the first six doses of multi-drug therapy. Distinguishing these different types of ENL would be useful for patient management and developing improved treatment of these debilitating reactions. Improved strategies for treatment and management of these reactions need to be developed.

Effects of prednisolone treatment on cytokine expression in patients with leprosy type 1 reactions.

Leprosy type 1 reactions (T1R) are due to increased cell-mediated immunity and result in localized tissue damage. The anti-inflammatory drug prednisolone is used for treatment, but there is little good in vivo data on the molecular actions of prednisolone. We investigated the effect of prednisolone treatment on tumor necrosis factor alpha (TNF-alpha), interleukin-1beta (IL-1beta), IL-10, and transforming growth factor beta1 (TGF-beta1) mRNA and protein expression in blood and skin biopsies from 30 patients with T1R in India. After 1 month of prednisolone treatment the sizes of the skin granulomas were reduced, as were the grades of cells positive for TNF-alpha and IL-10 in skin lesions. Increased production of TGF-beta1 was seen in skin lesions after 6 months of prednisolone treatment. Expression of mRNA for TNF-alpha, IL-1beta, and TGF-beta1 was reduced, whereas no change in IL-10 mRNA expression was detected during treatment. The circulating cytokine profiles were similar in patients with and without T1R, and prednisolone treatment had no detectable effects on cytokine expression in the blood. The data emphasize the compartmentalization of pathology in T1R and the importance of the immune response in the skin. Clinical improvement and cytokine expression were compared. Surprisingly, patients with improved skin and nerve function and patients with nonimproved skin and nerve function had similar cytokine profiles, suggesting that clinical improvement is not directly mediated by the cytokines studied here. This in vivo well-controlled study of the immunosuppressive effects of prednisolone showed that the drug does not switch off cytokine responses effectively.

Microsatellite mapping of Mycobacterium leprae populations in infected humans.

To investigate genetic diversity in a bacterial population, we measured the copy numbers of simple sequence repeats, or microsatellites, in Mycobacterium leprae from patients living in and around Hyderabad, India. Three microsatellite loci containing trinucleotide or dinucleotide repeats were amplified from infected tissues, and the copy numbers were established by sequence analysis. Extensive diversity was observed in a cross-sectional survey of 33 patients, but closely related profiles were found for members of a multicase family likely to share a common transmission source. Sampling of multiple tissues from single individuals demonstrated identical microsatellite profiles in the skin, nasal cavity, and bloodstream but revealed differences at one or more loci for M. leprae present in nerves. Microsatellite mapping of M. leprae represents a useful tool for tracking short transmission chains. Comparison of skin and nerve lesions suggests that the evolution of disease within an individual involves the expansion of multiple distinct subpopulations of M. leprae.