Generation of canine induced pluripotent stem cells under feeder-free conditions using Sendai virus vector encoding six canine reprogramming factors

Although it is in its early stages, canine induced pluripotent stem cells (ciPSCs) hold great potential for innovative translational research in regenerative medicine, developmental biology, drug screening, and disease modeling. However, almost all ciPSCs were generated from fibroblasts, and available canine cell sources for reprogramming are still limited. Furthermore, no report is available to generate ciPSCs under feeder-free conditions because of their low reprogramming efficiency. Here, we reanalyzed canine pluripotency-associated genes and designed canine LIN28A, NANOG, OCT3/4, SOX2, KLF4, and C-MYC encoding Sendai virus vector, called 159cf. and 162cf. We demonstrated that not only canine fibroblasts but also canine urine-derived cells, which can be isolated using a noninvasive and straightforward method, were successfully reprogrammed with or without feeder cells. ciPSCs existed in undifferentiated states, differentiating into the three germ layers in vitro and in vivo. We successfully generated ciPSCs under feeder-free conditions, which can promote studies in veterinary and consequently human regenerative medicines.

Gli1+-PDL Cells Contribute to Alveolar Bone Homeostasis and Regeneration

The periodontal ligament (PDL) contains mesenchymal stem cells (MSCs) that can differentiate into osteoblasts, cementoblasts, and fibroblasts. Nevertheless, the distribution and characteristics of these cells remain uncertain. Gli1, an essential hedgehog signaling transcription factor, functions in undifferentiated cells during embryogenesis. Therefore, in the present study, the differentiation ability of Gli1⁺ cells was examined using Gli1-CreERT2/ROSA26-loxP-stop-loxP-tdTomato (iGli1/Tomato) mice. In 4-wk-old iGli1/Tomato mice, Gli1/Tomato⁺ cells were only slightly detected in the PDL, around endomucin-expressing blood vessels. These cells had proliferated over time, localizing in the PDL as well as on the bone and cementum surfaces at day 28. However, in 8-wk-old iGli1/Tomato mice, Gli1/Tomato⁺ cells were quiescent, as most cells were not immunoreactive for Ki-67. These cells in 8-wk-old mice exhibited high colony-forming unit fibroblast activity and were capable of osteogenic, chondrogenic, and adipogenic differentiation in vitro. In addition, after transplantation of teeth of iGli1/Tomato mice into the hypodermis of wild-type mice, Tomato fluorescence indicating the progeny of Gli1⁺ cells was detected in the osteoblasts and osteocytes of the regenerated bone. These results demonstrate that Gli1⁺ cells in the PDL were MSCs and could contribute to the alveolar bone regeneration.

O-015 Results of urological consultation in the setting of IVF clinic

Study question

In the management of male infertility, we investigated whether urological consultation could improve the live birth rate, and who should visit urologists in the setting of IVF clinic.

Summary answer

Urologic consultation resulted in improvement of semen quality and live birth rate with more IVF use in those with adverse semen parameters.

What is known already

Male factor infertility exists in about a half of infertility couples. This accounts for about 8% in male reproductive age. Therefore, ideally every male partner of infertility couples attempting conception should have a urological evaluation. However, it is not very easy to access urologists who specialized in reproductive medicine in Japan because we have very few of such urologists. One the other hand, a certain number of couples are wasting their time during IVF failure without urological evaluation.

Study design, size, duration

This is a single-institution retrospective study. We enrolled male partners of infertility couples who visited Kameda IVF clinic Makuhari, Chiba, Japan, between May 2016 and December 2020 and followed at least one year. Live birth rate and the frequency of IVF use were investigated according to semen quality and urological consultation status. Chi-square tests and T tests were used to compare the results between groups.

Participants/materials, setting, methods

Among 2225 couples who visited Kameda IVF clinic Makuhari, 803 male partners (Group A, 36.0%) were evaluated by urologists who were specialized in male reproductive medicine. Remaining 1422 patients did not (Group B, 64.0%). Lifestyle evaluation, physical examination, semen analyses, scrotal ultrasonography, blood test including sexual hormones and zinc concentration were performed in Group A. Semen analyses and lifestyle evaluation were performed in Group B. Urological treatments were done according to factors of male infertility.

Main results and the role of chance

Semen quality was worse in Group A as compared to Group B (sperm motility, 28.5±16.9% vs. 46.0±17.0%; total sperm count, 105±108 million/mL vs. 176±155; total motile sperm count, 34±49 vs.87±98; mean±S.D.; p = 0.0001, 0.0001, 0.0001, A vs. B, respectively). After urologic consultation and managements, sperm motility was improved to 34±18% (p = 0.001). Live birth rate in groups A and B were similar (56.0% vs. 57.2%), however couples who obtained a child in Group A used IVF more often than those in Group B (70% vs. 49.9%, p < 0.001). Among those with adverse semen quality (total motile sperm count less than 15.6 million/mL, n = 472), 350 visited urologists (Group 1, 74.2%) and remaining 122 did not (Group 2, 25.8%). Live birth rate in Group 1 was significantly better than in Group 2 (65.3% vs. 54.1%, p = 0.0359). Use of IVF was significantly more frequent in Group 1 than Group 2 (79.3% vs. 63.6%, p = 0.0359) among who obtained a child. In those with better semen quality (motile sperm count >50 million, n = 900), 119 visited urologist (31.1%, Group 3) and 781 did not (Group 4). Live birth rate and the use of IVF were not different between Groups 3 and 4 (51.1% vs.60.9%; 50.4% vs. 62.9%).

Limitations, reasons for caution

This study is a single-institution, retrospective study in the setting of IVF clinic. There may be a selection bias since men first visit gynecologists. These could affect the study results.

Wider implications of the findings

In the setting of IVF clinic, urologic consultation resulted in improved semen quality and better live birth rate with the use of IVF, especially in those who have adverse semen parameters. The results of this study encourage patients to see urologists and physicians to introduce urologist to patients.

Trial registration number

not applicable

Successful trachelectomy and re-vaginoplasty for cervico-vaginal stenosis following unsuccessful uterovaginal anastomosis and vaginoplasty in congenital cervical and vaginal aplasia: description of technique and a case report

We describe a successful surgical technique of abdominal trachelectomy and re-vaginoplasty for cervico-vaginal stenosis following unsuccessful uterovaginal anastomosis and vaginoplasty in a patient with congenital cervical and vaginal aplasia. After the surgical procedure, cervico-vaginal stenosis was resolved and periodic menstruation without dysmenorrhoea resumed. While long-term follow-up is essential to ensure successful pregnancy and delivery, we conclude that this novel surgical procedure is a promising alternative for improvement of the quality of life and normal sexual function, and for preservation of fertility in patients with cervical and vaginal aplasia.

Changes in penile length after radical prostatectomy: effect of neoadjuvant androgen deprivation therapy

Although reports have shown evidence for penile length (PL) shortening after radical prostatectomy (RP), the association between neoadjuvant androgen deprivation therapy (NADT) and PL after RP has yet to be determined. This study evaluates chronological changes in PL after NADT and RP. Stretched PLs (SPLs) of 143 patients, 41 of whom had undergone NADT, were measured before, 10 days after, and 1, 3, 6, 9, 12, 18, and 24 months after RP. Chronological erectile function and testosterone levels were then evaluated. SPL was shortest 10 days after RP in both the NADT (-) and NADT (+) groups and gradually recovered in length thereafter. SPL in the NADT (-) group was significantly longer than that in the NADT (+) group before RP. However, no significant differences in SPLs were found between both groups 6 months after RP. Although all subjects in the NADT (+) group had testosterone levels of <50 ng/dL before RP, such levels increased after RP. Before RP, the NADT (-) group was found to have significantly better erectile function than the NADT (+) group. However, differences in erectile function between the NADT (-) and NADT (+) groups after RP were not significant. This report is the first to show that among patients with prostate cancer, those who underwent NADT had greater PL recovery after RP than those who did not. Data regarding PL recovery after NADT and RP obtained in this study could be useful for patients with prostate cancer who plan to undergo such procedures.

Cerebrospinal fluid orexin-A levels in systemic lupus erythematosus patients presenting with excessive daytime sleepiness

Objective Involvement of the hypothalamus is rare in patients with systemic lupus erythematosus (SLE). In this study, we measured cerebrospinal fluid (CSF) orexin-A levels in SLE patients with hypothalamic lesions to investigate whether the orexin system plays a role in SLE patients with hypothalamic lesions who present with excessive daytime sleepiness (EDS). Methods Orexin-A levels were measured in CSF from four patients with SLE who presented with hypothalamic lesions detected by MRI. Three patients underwent repeated CSF testing. All patients met the updated American College of Rheumatology revised criteria for SLE. Results Tests for serum anti-aquaporin-4 antibodies, CSF myelin basic protein and CSF oligoclonal bands were negative in all patients. All patients presented with EDS. Low to intermediate CSF orexin-A levels (92-180 pg/ml) were observed in three patients in the acute stage, two of whom (patients 1 and 2) underwent repeated testing and showed increased CSF orexin-A levels, reduced abnormal hypothalamic lesion intensities detected by MRI and EDS dissipation at follow-up. In contrast, CSF orexin-A levels were normal in one patient (patient 4) while in the acute stage and at follow-up, despite improvements in EDS and MRI findings. Patient 4 showed markedly increased CSF interleukin-6 levels (1130 pg/ml) and a slightly involved hypothalamus than the other patients. Conclusions Our findings suggest that the orexinergic system has a role in EDS in SLE patients with hypothalamic lesions. Furthermore, cytokine-mediated tissue damage might cause EDS without orexinergic involvement.

Sensitive and long-term monitoring of intracellular microRNAs using a non-integrating cytoplasmic RNA vector

MicroRNAs (miRNAs) are small noncoding RNAs that modulate gene expression at the post-transcriptional level. Different types of cells express unique sets of miRNAs that can be exploited as potential molecular markers to identify specific cell types. Among the variety of miRNA detection methods, a fluorescence-based imaging system that utilises a fluorescent-reporter gene regulated by a target miRNA offers a major advantage for long-term tracking of the miRNA in living cells. In this study, we developed a novel fluorescence-based miRNA-monitoring system using a non-integrating cytoplasmic RNA vector based on a replication-defective and persistent Sendai virus (SeVdp). Because SeVdp vectors robustly and stably express transgenes, this system enabled sensitive monitoring of miRNAs by fluorescence microscopy. By applying this system for cellular reprogramming, we found that miR-124, but not miR-9, was significantly upregulated during direct neuronal conversion. Additionally, we were able to isolate integration-free human induced pluripotent stem cells by long-term tracking of let-7 expression. Notably, this system was easily expandable to allow detection of multiple miRNAs separately and simultaneously. Our findings provide insight into a powerful tool for evaluating miRNA expression during the cellular reprogramming process and for isolating reprogrammed cells potentially useful for medical applications.

Selective intracellular vaporisation of antibody-conjugated phase-change nano-droplets in vitro

While chemotherapy is a major mode of cancer therapeutics, its efficacy is limited by systemic toxicities and drug resistance. Recent advances in nanomedicine provide the opportunity to reduce systemic toxicities. However, drug resistance remains a major challenge in cancer treatment research. Here we developed a nanomedicine composed of a phase-change nano-droplet (PCND) and an anti-cancer antibody (9E5), proposing the concept of ultrasound cancer therapy with intracellular vaporisation. PCND is a liquid perfluorocarbon nanoparticle with a liquid–gas phase that is transformable upon exposure to ultrasound. 9E5 is a monoclonal antibody targeting epiregulin (EREG). We found that 9E5-conjugated PCNDs are selectively internalised into targeted cancer cells and kill the cells dynamically by ultrasound-induced intracellular vaporisation. In vitro experiments show that 9E5-conjugated PCND targets 97.8% of high-EREG-expressing cancer cells and kills 57% of those targeted upon exposure to ultrasound. Furthermore, direct observation of the intracellular vaporisation process revealed the significant morphological alterations of cells and the release of intracellular contents.

Characterization of PTEN mutations in brain cancer reveals that pten mono-ubiquitination promotes protein stability and nuclear localization

PTEN is a PIP3 phosphatase that antagonizes oncogenic PI3-kinase signalling. Due to its critical role in suppressing the potent signalling pathway, it is one of the most mutated tumour suppressors, especially in brain tumours. It is generally thought that PTEN deficiencies predominantly result from either loss of expression or enzymatic activity. By analysing PTEN in malignant glioblastoma primary cells derived from 16 of our patients, we report mutations that block localization of PTEN at the plasma membrane and nucleus without affecting lipid phosphatase activity. Cellular and biochemical analyses as well as structural modelling revealed that two mutations disrupt intramolecular interaction of PTEN and open its conformation, enhancing polyubiquitination of PTEN and decreasing protein stability. Moreover, promoting mono-ubiquitination increases protein stability and nuclear localization of mutant PTEN. Thus, our findings provide a molecular mechanism for cancer-associated PTEN defects and may lead to a brain cancer treatment that targets PTEN mono-ubiquitination.

High efficiency penetration of antibody-immobilized nanoneedle thorough plasma membrane for in situ detection of cytoskeletal proteins in living cells

Background

The field of structural dynamics of cytoskeletons in living cells is gathering wide interest, since better understanding of cytoskeleton intracellular organization will provide us with not only insights into basic cell biology but may also enable development of new strategies in regenerative medicine and cancer therapy, fields in which cytoskeleton-dependent dynamics play a pivotal role. The nanoneedle technology is a powerful tool allowing for intracellular investigations, as it can be directly inserted into live cells by penetrating through the plasma membrane causing minimal damage to cells, under the precise manipulation using atomic force microscope. Modifications of the nanoneedles using antibodies have allowed for accurate mechanical detection of various cytoskeletal components, including actin, microtubules and intermediate filaments. However, successful penetration of the nanoneedle through the plasma membrane has been shown to vary greatly between different cell types and conditions. In an effort to overcome this problem and improve the success rate of nanoneedle insertion into the live cells, we have focused here on the fluidity of the membrane lipid bilayer, which may hinder nanoneedle penetration into the cytosolic environment.

Results

We aimed to reduce apparent fluidity of the membrane by either increasing the approach velocity or reducing experimental temperatures. Although changes in approach velocity did not have much effect, lowering the temperature was found to greatly improve the detection of unbinding forces, suggesting that alteration in the plasma membrane fluidity led to increase in nanoneedle penetration.

Conclusions

Operation at a lower temperature of 4 °C greatly improved the success rate of nanoneedle insertion to live cells at an optimized approach velocity, while it did not affect the binding of antibodies immobilized on the nanoneedle to vimentins for mechanical detection. As these experimental parameters can be applied to various cell types, these results may improve the versatility of the nanoneedle technology to other cell lines and platforms.

Electronic supplementary material

The online version of this article (doi:10.1186/s12951-016-0226-5) contains supplementary material, which is available to authorized users.

A PLK4 mutation causing azoospermia in a man with Sertoli cell-only syndrome

About 15% of couples wishing to have children are infertile; approximately half these cases involve a male factor. Polo-like kinase 4 (PLK-4) is a member of the polo protein family and a key regulator of centriole duplication. Male mice with a point mutation in the Plk4 gene show azoospermia associated with germ cell loss. Mutational analysis of 81 patients with azoospermia and Sertoli cell-only syndrome (SCOS) identified one man with a heterozygous 13-bp deletion in the Ser/Thr kinase domain of PLK4. Division of centrioles occurred in wild-type PLK4-transfected cells, but was hampered in PLK-4-mutant transfectants, which also showed abnormal nuclei. Thus, this PLK4 mutation might be a cause of human SCOS and nonobstructive azoospermia.

Antidepressant and anxiolytic profiles of newly synthesized arginine vasopressin V1B receptor antagonists: TASP0233278 and TASP0390325

BACKGROUND AND PURPOSE

Vasopressin V1B receptor antagonists may be effective for the treatment of depression and anxiety and the objective of this study was to characterize the pharmacological profiles of two newly synthesized arginine vasopressin receptor 1B (V1B receptor) antagonists, TASP0233278 and TASP0390325.

EXPERIMENTAL APPROACH

We investigated the in vitro profiles of TASP0233278 and TASP0390325. In addition, the effect of TASP0390325 on the increase in plasma adrenocorticotropic hormone (ACTH) levels induced by corticotropin-releasing factor (CRF)/desmopressin (dDAVP) was investigated. We also investigated the antidepressant and anxiolytic profiles of TASP0233278 and TASP0390325 in animal models.

KEY RESULTS

Both TASP0233278 and TASP0390325 showed a high affinity and potent antagonist activity for V1B receptors. Oral administration of TASP0390325 antagonized the increase in plasma ACTH levels induced by CRF/dDAVP in rats, indicating that TASP0390325 blocks the anterior pituitary V1B receptor in vivo. Oral administration of TASP0233278 or TASP0390325 also exerted antidepressant effects in two models of depression (a forced swimming test and an olfactory bulbectomy model). Moreover, TASP0233278 improved depressive-like behaviour induced by repeated treatment with corticosterone, a model that has been shown to be resistant to treatment with currently prescribed antidepressants. In addition to depression models, TASP0233278 or TASP0390325 exerted anxiolytic effects in several anxiety models (social interaction, elevated plus-maze, stress-induced hyperthermia, separation-induced ultrasonic vocalization and sodium lactate-induced panic-like responses in panic-prone rats).

CONCLUSION

TASP0233278 and TASP0390325 are potent and orally active V1B receptor antagonists with antidepressant and anxiolytic activities in rodents.

Effect of dentist's clinical experience on treatment satisfaction of a complete denture

The relationship between the prosthodontic experience of dentists and satisfaction of complete denture wearers remains unknown. To investigate whether a prosthodontist's clinical experience affects treatment satisfaction of a complete denture wearer. From April 2004 to July 2006, we conducted a randomised controlled trial at two centres, including 74 edentulous patients; of these, 32 and 30 were randomly allocated to the ED or ID group, respectively. All the patients rated their satisfaction with dentures, including general satisfaction and satisfaction of chewing ability, speaking, cleaning, stability, retention, comfort and aesthetics. These satisfaction ratings were measured by a 100-mm visual analog scale (VAS). Perceived chewing ability to foods, divided into five grades, was measured using a questionnaire. The mastication index (MI) was calculated for each grade. General satisfaction and satisfaction of speaking, stability and retention were significantly higher in the ED than in the ID group (P = 0·049, 0·003, 0·019 and 0·041, respectively). No significant difference existed between the MI of the ED (71·3 ± 18·4) and ID group (64·1 ± 16·53). However, the perceived chewing ability of grade 5 food, whose texture was the hardest among all the grades, was significantly higher in the ED group than in the ID group. Within its limitations, this study showed that a clinician's prosthodontic experience affects a complete denture wearer's satisfaction ratings.

Left-right asymmetric expression of dpp in the mantle of gastropods correlates with asymmetric shell coiling

Background

Various shapes of gastropod shells have evolved ever since the Cambrian. Although theoretical analyses of morphogenesis exist, the molecular basis of shell development remains unclear. We compared expression patterns of the decapentaplegic (dpp) gene in the shell gland and mantle tissues at various developmental stages between coiled-shell and non-coiled-shell gastropods.

Results

We analyzed the expression patterns of dpp for the two limpets Patella vulgata and Nipponacmea fuscoviridis, and for the dextral wild-type and sinistral mutant lineage of the pond snail Lymnaea stagnalis. The limpets had symmetric expression patterns of dpp throughout ontogeny, whereas in the pond snail, the results indicated asymmetric and mirror image patterns between the dextral and sinistral lineages.

Conclusion

We hypothesize that Dpp induces mantle expansion, and the presence of a left/right asymmetric gradient of the Dpp protein causes the formation of a coiled shell. Our results provide a molecular explanation for shell, coiling including new insights into expression patterns in post-embryonic development, which should aid in understanding how various shell shapes are formed and have evolved in the gastropods.

Possible involvement of CD14+ CD16+ monocyte lineage cells in the epidermal damage of Stevens-Johnson syndrome and toxic epidermal necrolysis

BACKGROUND

Stevens-Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN) are characterized by keratinocyte apoptosis and necrosis, resulting in epidermal detachment. Although monocytes abundantly infiltrate the epidermis in SJS/TEN skin lesions, the properties and functions of these cells have not been fully examined.

OBJECTIVES

To determine the properties of monocytes infiltrating into the epidermis in SJS/TEN.

METHODS

Immunostaining of skin sections was performed to examine the membrane markers of monocytes infiltrating into skin lesions.

RESULTS

Immunostaining of cryosections from 11 SJS/TEN skin lesions revealed numerous CD14+ monocytes located along the dermoepidermal junction and throughout the epidermis. The cells coexpressed CD16, CD11c and HLA-DR. CD14+ CD16+ cells were identified in very early lesions without epidermal damage, suggesting that their infiltration is a cause, rather than a result, of epidermal damage. Moreover, these cells expressed CD80, CD86 and CD137 ligand, indicative of their ability to facilitate the proliferation and cytotoxicity of CD8+ T cells. CD16+ cells infiltrating the epidermis and detected at the dermoepidermal junction were immunostained and counted in paraffin-embedded skin sections obtained from 47 patients with drug rash manifested as TEN, SJS, maculopapular-type rash or erythema multiform-type rash. The number of CD16+ monocytes infiltrating the epidermis increased significantly, depending on the grade of epidermal damage.

CONCLUSIONS

These findings suggest that the appearance of CD14+ CD16+ cells of monocyte lineage plays an important role in the epidermal damage associated with SJS/TEN, most probably by enhancing the cytotoxicity of CD8+ T cells.

Differences in odor identification among clinical subtypes of Parkinson's disease

OBJECTIVE

Olfactory dysfunction is a non-motor symptom in idiopathic Parkinson's disease (PD). We investigated whether this dysfunction differs among clinical subtypes of PD.

METHODS

Participants comprised of 90 patients with idiopathic PD and without dementia. Olfactory function was evaluated using the odor stick identification test for Japanese, which evaluated the detection of 12 odorants familiar to Japanese participants. Patients were divided into tremor-dominant type (TDT), akinetic-rigid type (ART), and mixed type (MXT) PD subgroups using part III of the Unified Parkinson's Disease Rating Scale.

RESULTS

Fifty-five patients were classified as ART, 21 as MXT, and 14 as TDT. There were no differences in age, sex, or duration of illness among the subtypes. Subjective symptoms of impaired sense of smell were significantly higher (P<0.05) in the ART than in the TDT. Mean odor identification score was 4.3 in the ART, 5.2 in MXT, and 6.6 in TDT. It was significantly lower in the ART than in the TDT (P<0.01).

CONCLUSION

Olfactory dysfunction differed among the clinical subtypes of PD. This suggests that olfactory function might relate to prognosis of patients with PD.

Neonatal intrahepatic cholestasis caused by citrin deficiency (NICCD) as a cause of liver disease in infants in the UK

Citrin deficiency is a disorder with two phenotypes: neonatal intrahepatic cholestasis caused by citrin deficiency (NICCD), and adult-onset type II citrullinaemia (CTLN2). NICCD presents in the first few weeks of life with prolonged cholestasis and metabolic abnormalities including aminoacidaemia (notably citrulline, tyrosine, threonine, arginine and methionine) and galactosuria. Symptoms resolve within the first year of life, thus making a diagnosis difficult after this time. Although patients subsequently remain generally healthy, some may develop more severe symptoms of CTLN2, characterized by neurological changes, one or more decades later. To date more than 400 cases have been reported, almost all from East Asia (mainly Japan). Here we describe the first two cases of NICCD in infants from the UK, one of caucasian origin and one of Pakistani origin. Both showed typical clinical and biochemical changes with a diagnosis confirmed by the presence of previously unreported mutations in the SLC25A13 gene. The presence of citrin deficiency in other ethnic groups means that NICCD needs to be considered in the diagnosis of any neonate with an unexplained cholestasis. We discuss both the difficulties in diagnosing these patients in populations where very few DNA mutations have been identified and the problems faced in the management of these patients. These findings also raise the possibility of adults with CTLN2 in whom a diagnosis has yet to be made.

Repeated episodes of fixed eruption 3 months after discontinuing pegylated interferon-alpha-2b plus ribavirin combination therapy in a patient with chronic hepatitis C virus infection

We report a 73-year-old man who developed repeated episodes of erythematous, bullous plaques beginning 3 months after discontinuation of combination treatment with pegylated interferon (IFN)-alpha-2b and ribavirin for hepatitis C virus infection. The first episode resolved within a week without treatment, but the lesions recurred about once a month and were associated with high fever. Physical examination found darkly reddish, pigeon-egg-sized erythematous plaques with occasional flaccid blisters, predominantly on the trunk and proximal limbs, lip and penis. Histological examination showed well-demarcated foci of full-thickness epidermal necrosis and exocytosis of lymphoid cells. Pegylated IFN-alpha2b and ribavirin produced no response in lymphocyte stimulation tests. Systemic prednisolone led to rapid healing of skin lesions at the time of the fifth episode, leaving pigmented macules, but lesions recurred at the same sites within weeks of discontinuation of this treatment. It is uncertain whether this case represented a prolonged drug rash provoked by pegylated IFN-alpha2b or a fixed eruption in response to another antigen.