Consequences of cathepsin C inactivation for membrane exposure of proteinase 3, the target antigen in autoimmune vasculitis.

Membrane-bound proteinase 3 (PR3m) is the main target antigen of anti-neutrophil cytoplasmic autoantibodies (ANCA) in granulomatosis with polyangiitis, a systemic small-vessel vasculitis. Binding of ANCA to PR3m triggers neutrophil activation with the secretion of enzymatically active PR3 and related neutrophil serine proteases, thereby contributing to vascular damage. PR3 and related proteases are activated from pro-forms by the lysosomal cysteine protease cathepsin C (CatC) during neutrophil maturation. We hypothesized that pharmacological inhibition of CatC provides an effective measure to reduce PR3m and therefore has implications as a novel therapeutic approach in granulomatosis with polyangiitis. We first studied neutrophilic PR3 from 24 patients with Papillon-Lefèvre syndrome (PLS), a genetic form of CatC deficiency. PLS neutrophil lysates showed a largely reduced but still detectable (0.5-4%) PR3 activity when compared with healthy control cells. Despite extremely low levels of cellular PR3, the amount of constitutive PR3m expressed on the surface of quiescent neutrophils and the typical bimodal membrane distribution pattern were similar to what was observed in healthy neutrophils. However, following cell activation, there was no significant increase in the total amount of PR3m on PLS neutrophils, whereas the total amount of PR3m on healthy neutrophils was significantly increased. We then explored the effect of pharmacological CatC inhibition on PR3 stability in normal neutrophils using a potent cell-permeable CatC inhibitor and a CD34+ hematopoietic stem cell model. Human CD34+ hematopoietic stem cells were treated with the inhibitor during neutrophil differentiation over 10 days. We observed strong reductions in PR3m, cellular PR3 protein, and proteolytic PR3 activity, whereas neutrophil differentiation was not compromised.

Papillon-Lefèvre syndrome with homozygous nonsense mutation of cathepsin C gene presenting with late-onset periodontitis.

Papillon-Lefèvre syndrome (PLS) is a rare autosomal recessive disorder of keratinization caused by homozygous mutations in the gene encoding lysosomal protease cathepsin C (CTSC). It is clinically characterized by transgredient palmoplantar keratoderma (PPK) and periodontitis. A 15-year-old boy presenting with PPK from the age of 6 months and late-onset periodontitis that began at the age of 12 years is described. Mutation analysis revealed a homozygous nonsense mutation (p.Y304X) in exon 7 of the CTSC gene. Late-onset periodontitis in a patient with Papillon-Lefèvre syndrome is a rare phenotypic variation.

The rash that becomes an erythroderma.

Erythroderma is a dermatologic emergency with potentially serious consequences. Several diseases with different etiologies characteristically appear as erythroderma. Depending on the age groups, congenital ichthyosiform disorders, infections, preexisting dermatoses, drug eruptions, and internal malignancies commonly present with, or progress to, erythroderma. The course, prognosis, and management strategies also vary depending on the cause of erythroderma; hence, an accurate diagnosis is essential in minimizing associated morbidity and mortality. The generalized erythema and scaling often obscure the classic clinical features of the underlying skin diseases, posing a diagnostic challenge to dermatologists. Awareness and elicitation of subtle signs and clinical manifestations are crucial. A step-wise approach ensures completeness of clinical evaluation and avoids missing any relevant clinical data. The initial clinical presentation, cutaneous examination findings, and systemic clues reveal important information regarding the diagnosis, course, and prognosis of erythroderma. The age at onset, symptomatology, duration of illness, initial lesions, initial site of onset, clinical course, family history, types of scales, changes in cutaneous integuments and systemic clues will assist in delineating the nature of underlying disease.

Diffuse nonscarring alopecia of scalp: an indicator of early infantile scurvy?

An infant with diffuse nonscarring alopecia of scalp and radiologic features of scurvy responded dramatically to oral vitamin C therapy. The characteristic cutaneous manifestations of scurvy are usually not seen in infancy. The manifestations of initial stage of scurvy that are not related to collagen synthesis, as in the present case, should alert to the possibility of this potentially fatal condition.

Comparative study of efficacy, rapidity of detection, and cost-effectiveness of potassium hydroxide, calcofluor white, and Chicago sky blue stains in the diagnosis of dermatophytoses.

BACKGROUND: The diagnosis of superficial mycosis such as dermatophytosis is often done clinically. However, in difficult cases, a rapid test with high sensitivity and specificity helps in the immediate confirmation and administration of treatment. METHODS: The efficacy, rapidity of detection, and cost-effectiveness of KOH preparation, calcofluor white (CW) stain, and Chicago sky blue (CSB) stain in the identification of fungal elements were assessed in patients with dermatophytoses attending the dermatology clinic of a tertiary care hospital. All three tests were performed on each sample collected from 73 patients according to standard procedure. The slides were examined after 5 and 30 minutes in × 10 and × 40 magnifications. The sensitivity and specificity of CW and CSB at 5 and 30 minutes were calculated using KOH preparation as the standard test. RESULTS: CSB stain showed highest positivity (94.5%) within 5 minutes when compared to KOH (75.3%) and CW (83.5%). After 30 minutes, positivity increased in KOH (84.9%) and CW stains (89%), but it remained the same in CSB stain. Both CW and CSB stains when compared to 10% KOH are equally sensitive (100%), but CW was more specific (72.7%), particularly at 30 minutes. When cost of performing tests on 100 specimens is considered, KOH, CW, and CSB stains cost Rs 5, 100, and 15, respectively. CONCLUSION: CSB stain is a better stain for rapid diagnosis of dermatophytoses because of ease of performance, rapidity of detection, better appreciation of morphology of fungal elements, and cost effectiveness.

Analysis of urinary cathepsin C for diagnosing Papillon-Lefèvre syndrome.

Papillon-Lefèvre syndrome (PLS) (OMIM: 245000) is a rare disease characterized by severe periodontitis and palmoplantar keratoderma. It is caused by mutations in both alleles of the cathepsin C (CatC) gene CTSC that completely abrogate the proteolytic activity of this cysteine proteinase. Most often, a genetic analysis to enable early and rapid diagnosis of PLS is unaffordable or unavailable. In this study, we tested the hypothesis that active CatC is constitutively excreted and can be easily traced in the urine of normal subjects. If this is true, determining its absence in the urine of patients would be an early, simple, reliable, low-cost and easy diagnostic technique. All 75 urine samples from healthy control subjects (aged 3 months to 80 years) contained proteolytically active CatC and its proform, as revealed by kinetic analysis and immunochemical detection. Of the urine samples of 31 patients with a PLS phenotype, 29 contained neither proteolytically active CatC nor the CatC antigen, so that the PLS diagnosis was confirmed. CatC was detected in the urine of the other two patients, and genetic analysis revealed no loss-of-function mutation in CTSC, indicating that they suffer from a PLS-like condition but not from PLS. Screening for the absence of urinary CatC activity soon after birth and early treatment before the onset of PLS manifestations will help to prevent aggressive periodontitis and loss of many teeth, and should considerably improve the quality of life of PLS patients.

Actinomycetoma: dramatic response to modified two-step regimen.

Mycetoma is a chronic granulomatous infection of the subcutaneous tissue caused by fungi or fungus-like bacteria. The infection eventually spreads to bone resulting in significant morbidity. Rarely, viscera may be involved through contiguous spread. It is common in tropical countries like India, though disease is worldwide in distribution. A 22-year-old male patient, a farmer by occupation, presented with multiple discharging sinuses over the left chest wall, shoulder, upper arm, and adjacent neck of eight months duration. A diagnosis of actinomycetoma was made based on clinical and histopathological features as culture was negative for both fungus and bacteria. The patient was treated with a modified two-step regimen. It consisted of an intensive phase with intravenous gentamicin 80 mg 12th hourly and cotrimoxazole 320/1600 mg twice daily orally for four weeks. This was followed by a maintenance phase with oral cotrimoxazole and doxycycline 100 mg twice daily. Patient showed excellent response with healing of all sinuses after two months of therapy. Involvement of covered parts of the body such as chest wall and shoulders is common in actinomycetoma compared to eumycetoma. Early institution of long-term combination therapy with antimicrobials results in excellent outcome.

Cutaneous disorders in 500 diabetic patients attending diabetic clinic.

BACKGROUND: The metabolic complications and pathologic changes that occur in diabetes mellitus (DM) influence the occurrence of various dermatoses. AIM: To study the impact of control of diabetes on the pattern of cutaneous disorders. MATERIALS AND METHODS: A cross-sectional descriptive study of patients attending diabetic clinic in a tertiary care hospital. A total of 500 consecutive patients were studied. Detailed history, clinical examination and relevant investigations were done to diagnose diabetic complications and cutaneous disorders. Dermatoses with or without known pathogenesis were correlated with age, gender, fasting plasma glucose (FPG), duration of diabetes, and complications of DM. Statistical analysis was carried out using Student "t" test and Chi-square test with 5% confidence interval (P value 0.05). RESULTS: Majority of patients had well-controlled (FPG<130 mg/ml, 60%) type 2 DM (98.8%). No statistically significant difference (P>0.05) between the patients with or without DM specific cutaneous disorders was noticed with reference to age and gender distribution, duration of DM and FPG. Signs of insulin resistance, acrochordon (26.2%), and acanthosis nigricans (5%) were common, followed by fungal (13.8%) and bacterial (6.8%) infections. Eruptive xanthoma (0.6%), diabetic foot (0.2%), diabetic bulla (0.4%), diabetic dermopathy (0.2%), generalized granuloma annulare (0.2%), and insulin reactions (6.2%) and lipodystrophy (14%) were also seen. CONCLUSION: Well-controlled diabetes decreases the prevalence of DM-specific cutaneous disorders associated with chronic hyperglycemia. It is necessary to have a dermatologist in the diabetic clinic for early detection of potentially grave or predisposing conditions.