Tacrolimus (FK 506)

Drug-drug interaction between ensitrelvir and tacrolimus in a patient undergoing treatment for COVID-19: a case report

BACKGROUND

Ensitrelvir is a novel SARS-CoV-2 3-chymotrypsin-like protease inhibitor, similar to nirmatrelvir/ritonavir. Several case reports have demonstrated the efficacy of 3-chymotrypsin-like protease inhibitors in treating prolonged coronavirus disease 2019 (COVID-19) in immunocompromised patients. Tacrolimus (TAC) is a widely used immunosuppressive agent whose blood level can increase significantly due to the inhibition of cytochrome P450 3A (CYP3A) and P-glycoprotein by nirmatrelvir/ritonavir. Since ensitrelvir also inhibits CYP3A and P-gp, similar elevations in TAC levels are expected. A prior case report observed an increase in TAC trough levels with concurrent administration of ensitrelvir. However, no studies have quantitatively described the changes in TAC blood levels and clearances before and after ensitrelvir administration when TAC administration was discontinued to mitigate the drug-drug interaction (DDI) risk; data on safe dosing protocols to avoid the DDI during co-administration of ensitrelvir and TAC remain lacking. Here, we report a case in which TAC levels were successfully managed in a patient with rheumatoid arthritis (RA) who received ensitrelvir for persistent COVID-19 by preemptive discontinuation of TAC and close monitoring of TAC blood levels following ensitrelvir administration.

CASE PRESENTATION

An 81-year-old Japanese woman who had been administered TAC (1.5 mg once daily) for RA received two courses of remdesivir for moderate COVID-19. However, her viral load remained high and her respiratory status deteriorated. Considering persistent COVID-19, we initiated combination therapy with remdesivir and ensitrelvir (day 0). TAC was discontinued, and the TAC blood levels decreased from 3.6 ng/mL to 1.1 ng/mL over five days. Subsequently, we re-administered TAC (0.2 mg), observing a level of 1.0 ng/mL by day 7. The TAC dose was adjusted to 1.0 mg daily, and TAC levels on day 12 and 14 were 6.5 and 3.7 ng/mL, respectively. TAC (1.5 mg daily) was resumed on day 15. The calculated t1/2 of TAC were 33.7, 71.9, and 114.6 h from day -1 to 0, day 0 to 2, and day 2 to 5, respectively. The t1/2 of TAC was extended to 3.4-fold its original duration under ensitrelvir treatment.

CONCLUSIONS

This DDI extended the half-life of TAC by approximately 3.4-fold, an effect that gradually diminished over 7 to 10 days. When patients receiving TAC treatment start ensitrelvir therapy, a dose reduction of TAC by approximately one-third to one-fourth is considered appropriate.

Immunosuppressive Agents-Effects on the Cardiovascular System and Selected Metabolic Aspects: A Review

The widespread use of immunosuppressive drugs makes it possible to reduce inflammation in autoimmune diseases, as well as prevent transplant rejection in organ recipients. Despite their key action in blocking the body's immune response, these drugs have many side effects. These actions primarily affect the cardiovascular system, and the incidence of complications in patients using immunosuppressive drugs is significant, being associated with a higher incidence of cardiovascular incidents such as myocardial infarction and stroke. This paper analyzes the mechanisms of action of commonly used immunosuppressive drugs and their impact on the cardiovascular system. The adverse effect of immunosuppressive drugs is associated with toxicity within the cardiovascular system, which may be a problem in the clinical management of patients after transplantation. Immunosuppressants act on the cardiovascular system in a variety of ways, including fibrosis and myocardial remodeling, endothelium disfunction, hypertension, atherosclerosis, dyslipidemia or hyperglycaemia, metabolic syndrome, and hyperuricemia. The use of multidrug protocols makes it possible to develop regimens that can reduce the incidence of cardiovascular events. A better understanding of their mechanism of action and the range of complications could enable physicians to select the appropriate therapy for a given patient, as well as to reduce complications and prolong life.

Analysis of clinical features of tacrolimus-induced optic neuropathy

WHAT IS KNOWN AND OBJECTIVE

Tacrolimus is associated with optic neuropathy. The clinical features of tacrolimus-induced optic neuropathy (TION) are unclear. The purpose of this article is to explore the clinical features of TION.

METHODS

TION-related case reports were collected and analysed by searching Chinese and English databases from 1989 to 31 December 2021.

RESULTS AND DISCUSSION

Twelve males and 7 females were included, with a median age of 54 years (range 23-66). TION onset time ranged from 2 months to 16 years after administration, and the main clinical features were blurred vision (4 cases), decreased visual acuity (7 cases), decreased visual acuity (5 cases), grey films (3 cases), visual field damage (3 cases) and headache (2 cases). Fifteen patients developed bilateral optic neuropathy. Ophthalmological examination showed visual acuity ranging from 20/25 to blindness, pupillary examination revealed relative afferent pupillary defect in 9 patients and marked decrease in colour vision in 15 eyes. The optic disc showed pallor (10 cases), oedema (8 cases), atrophy (4 cases) and haemorrhage (2 cases). After discontinuation or dose reduction of tacrolimus, symptoms improved in 10 patients, 1 patient recovered completely, and 4 patients did not recover.

WHAT IS NEW AND CONCLUSION

TION presents diverse clinical manifestations. TION should be promptly identified and treated to prevent severe and permanent vision loss.

Off-label use of tacrolimus in children with glomerular disease: Effectiveness, safety and pharmacokinetics

Glomerular diseases are leading causes of end-stage renal disease in children. Tacrolimus is frequently used off-label in the treatment of glomerular diseases. The effectiveness, safety and pharmacokinetic data of tacrolimus in the treatment of glomerular diseases in children are reviewed in this paper to provide evidence to support its rational use in clinical practice. The remission rates in previously published studies were different. In 19 clinical trials on children with nephrotic syndrome, the overall remission rate was 52.6-97.6%. In four clinical trials on children with lupus nephritis, the overall remission rate was 81.8-89.5%. In a pilot study with paediatric Henoch-Schönlein purpura nephritis patients, the overall remission rate was 100.0%. Infection, nephrotoxicity, gastrointestinal symptoms and hypertension are the most common adverse events. Body weight, age, CYP3A5 genotype, cystatin-C and daily dose of tacrolimus may have significant effects on the pharmacokinetics of tacrolimus in children with glomerular disease. More prospective controlled trials with long follow-up are needed to demonstrate definitely the effectiveness, safety and pharmacokinetics of tacrolimus in children with glomerular diseases.

Synthesis of poly(lactide-co-glycerol) as a biodegradable and biocompatible polymer with high loading capacity for dermal drug delivery

Due to the low cutaneous bioavailability of tacrolimus (TAC), penetration enhancers are used to improve its penetration into the skin. However, poor loading capacity, non-biodegradability, toxicity, and in some cases inefficient skin penetration are challenging issues that hamper their applications for the dermal TAC delivery. Here we present poly(lactide-co-glycerol) (PLG) as a water soluble, biodegradable, and biocompatible TAC-carrier with high loading capacity (14.5% w/w for TAC) and high drug delivery efficiencies into the skin. PLG was synthesized by cationic ring-opening copolymerization of a mixture of glycidol and lactide and showed 35 nm and 300 nm average sizes in aqueous solutions before and after loading of TAC, respectively. Delivery experiments on human skin, quantified by fluorescence microscopy and LC-MS/MS, showed a high ability for PLG to deposit Nile red and TAC into the stratum corneum and viable epidermis of skin in comparison with Protopic® (0.03% w/w, TAC ointment). The cutaneous distribution profile of delivered TAC proved that 80%, 16%, and 4% of the cutaneous drug level was deposited in the stratum corneum, viable epidermis, and upper dermis, respectively. TAC delivered by PLG was able to efficiently decrease the IL-2 and TSLP expressions in human skin models. Taking advantage of the excellent physicochemical and biological properties of PLG, it can be used for efficient dermal TAC delivery and potential treatment of inflammatory skin diseases.

Off-label use of tacrolimus in children with Henoch-Schönlein purpura nephritis: a pilot study

BACKGROUND

Tacrolimus is used off-label in the treatment of Henoch-Schönlein purpura nephritis (HSPN) in children, with limited evidence-based data. Based on clinical empirical experience and mechanism of action, tacrolimus might be promoted as treatment for childhood HSPN. The objectives of this pilot study were to assess its effectiveness and safety, and to explore the potential impact of CYP3A5 genotype.

METHODS

Children with HSPN receiving tacrolimus as empirical treatment were included in this prospective, observational study. Effectiveness was classified as complete remission, partial remission or non-response. General safety data analyses during and after study drug exposure included adverse events, reasons for discontinuation, deaths, laboratory data and vital signs. Trough concentration was determined using high-performance liquid chromatography with tandem mass spectrometry. Pharmacogenetic analysis was performed on the CYP3A5 gene.

RESULTS

A total of 20 patients with a mean age of 7.5 (SD 2.1) years participated in the whole process of the study. Twelve patients reached complete remission and eight patients reached partial remission at the end of 6-month treatment. No patients discontinued tacrolimus treatment due to adverse events, and no drug-related adverse events were shown to have a causal association with tacrolimus therapy. Dose-adjusted trough concentration was significantly higher in children with CYP3A5*1 allele as compared with patients with CYP3A5*3/*3 genotype (170.7±100.9 vs 79.8±47.4 (ng/mL)/(mg/kg)).

CONCLUSION

This pilot study showed that tacrolimus might be an effective and well-tolerated drug for the treatment of HSPN in children. CYP3A5 polymorphism had a significant impact on tacrolimus concentration.

HMGB1 blockade differentially impacts pulmonary inflammation and defense responses in poly(I:C)/LPS-exposed heart transplant mice

A large number of recipients are in a compromised immune defense condition because of the routine application of immunosuppressive regimens after heart transplantation. Our previous work demonstrated that blockade of high-mobility group box 1 (HMGB1) prolongs the graft survival. Whether and how HMGB1 blockade impacts respiratory responses against pathogen-like challenge in organ transplant recipients when it improves cardiac graft are not elucidated. At the present study, after abdominal heterotopic heart transplantation, the recipient mice were treated with HMGB1 mAb, and then challenged with poly(I:C) or LPS intratracheally on day 7 post transplantation. We found that the level of bronchoalveolar lavage (BAL) HMGB1 was elevated after heart transplantation, and aggravated responses to respiratory tract poly(I:C)/LPS challenge were observed. HMGB1 neutralizing mAb treatment in poly(I:C)-challenged recipient mice alleviated pulmonary histopathological changes, neutrophil infiltration and inflammatory cytokine release, but unaffected the level of IFN-β, the distribution of CD11b(+)CD27(+)/CD11b(+)CD27(-) NK cell subsets, and CD8(+) T cell responses. In LPS-exposed recipient mice, HMGB1 mAb treatment ameliorated pulmonary inflammatory damage and enhanced the phagocytosis of phagocytic cells. Thus, this study may establish a basis for the application of HMGB1 blockade to improve the outcomes of heart transplant recipients because HMGB1 inhibition ameliorates pulmonary inflammation, but maintains defense-associated responses.

Treatment of symptomatic oral lichen planus (OLP) with 0.1% tacrolimus powder in Oraguard-B - A pilot prospective study

OBJECTIVES

The purpose of this study was to investigate the efficacy and safety of 0.1% tacrolimus powder in Oraguard-B for the treatment of patients with symptomatic oral lichen planus (OLP).

METHODS

This was a nonrandomized, nonblinded study conducted in the outpatient department. The 20 patients with symptomatic OLP oral lichen planus who were asked to participate in the study were provided with 20-g containers of the study medication. Patients were asked to use the medication over the symptomatic areas three times a day until resolution of the lesion. Patients were recalled to assess the drug response every 15 days.

RESULTS

The duration of treatment ranged from 30 to 183 days, with a mean of 81.8 ± 44.4 days; all 20 patients reported a favourable response to the topical tacrolimus therapy. Eleven patients had complete resolution of their lesions. In 16 of 20 patients, there was marked resolution in symptoms as recorded by visual analogue scale. Out of 10 patients followed up for a period of 3 months, 5 had recurrence of their lesions but with less intensity, and the patients were symptomless. No serious side effects were associated with the study medication.

CONCLUSION

Topical tacrolimus 0.1% in Oraguard-B was effective and safe in treating patients with OLP. However, there is still a need to undertake more detailed and objective clinical studies to determine the exact benefit of tacrolimus compared with conventional therapies and examine the influence of different dose regimes and formulations and assess the incidence of recurrence.

Fusion processing of itraconazole solid dispersions by kinetisol dispersing: a comparative study to hot melt extrusion

KinetiSol Dispersing (KSD) is a novel high energy manufacturing process investigated here for the production of pharmaceutical solid dispersions. Solid dispersions of itraconazole (ITZ) and hypromellose were produced by KSD and compared to identical formulations produced by hot melt extrusion (HME). Materials were characterized for solid state properties by modulated differential scanning calorimetry and X-ray diffraction. Dissolution behavior was studied under supersaturated conditions. Oral bioavailability was determined using a Sprague-Dawley rat model. Results showed that KSD was able to produce amorphous solid dispersions in under 15 s while production by HME required over 300 s. Dispersions produced by KSD exhibited single phase solid state behavior indicated by a single glass transition temperature (T(g)) whereas compositions produced by HME exhibited two T(g)s. Increased dissolution rates for compositions manufactured by KSD were also observed compared to HME processed material. Near complete supersaturation was observed for solid dispersions produced by either manufacturing processes. Oral bioavailability from both processes showed enhanced AUC compared to crystalline ITZ. Based on the results presented from this study, KSD was shown to be a viable manufacturing process for the production of pharmaceutical solid dispersions, providing benefits over conventional techniques including: enhanced mixing for improved homogeneity and reduced processing times.

Effects and mechanisms of aloperine on 2, 4-dinitrofluorobenzene-induced allergic contact dermatitis in BALB/c mice

Allergic contact dermatitis is a prototypic T-cell-mediated cutaneous inflammatory response. Multiple cell types, inflammatory mediators and cytokines are involved in the regulation of immunologic and inflammatory processes in allergic contact dermatitis. Aloperine is an isolated alkaloid found in the plant of Sophora alopecuroides L. It has been clinically proved effective in China for a long time for skin inflammatory diseases such as allergic contact dermatitis. However, the mechanism of aloperine on allergic contact dermatitis is largely unknown. Therefore, the aim of this study was to investigate the effect of aloperine on 2, 4-dinitrofluorobenzene (DNFB)-induced allergic contact dermatitis in BALB/c mice and the possible underlying mechanisms. The results showed that topical application of DNFB on the ear provoked typical allergic contact dermatitis with ear swelling and ear erythema in BALB/c mice. Treatments with 1% aloperine suppressed DNFB-induced increase in ear thickness and ear erythema. Moreover, 1% aloperine treatment significantly decreased the up-regulated mRNA and protein levels of tumor necrosis factor-alpha (TNF-alpha), interleukin-1beta (IL-1beta) and interleukin-6 (IL-6) induced by DNFB in ear biopsy homogenates. Our findings suggest that aloperine greatly improves the DNFB-induced allergic contact dermatitis in mice. The therapeutic mechanism might be related to the reduction of TNF-alpha, IL-1beta and IL-6 production induced by DNFB.

The development of eosinophilic colitis after liver transplantation in children

Tacrolimus-based immunosuppression in pediatric liver transplant recipients is known to be associated with EGID. Our goal was to determine the incidence, risk factors, and characteristics of EGID in our pediatric liver transplantation program. This study was a retrospective analysis of 38 pediatric liver transplant recipients. Rectal mucosal biopsy was performed to evaluate for gastrointestinal PTLD and eosinophilic colitis. There were 14 patients (37%) who were diagnosed with eosinophilic colitis. The mean age at transplantation was 10.8 +/- 1.8 months. Those with eosinophilic colitis had a higher incidence of peripheral eosinophilia (p = 0.003) during the first two months following transplantation and had a higher EBV infection rate. Symptoms, such as diarrhea, hematochezia, and abdominal pain, became apparent after an average of three months; diagnoses were made at 6.9 +/- 2.0 months after transplantation. There were eight patients (57%) with elevated food-specific IgE levels. With food restriction treatment, the symptoms of patients improved. EGID should be considered when clinical symptoms are present, because symptoms of this disorder are similar to those of gastrointestinal PTLD. It should also be considered when peripheral eosinophila is detected or when EBV seroconversion develops during the first two months following transplantation.

Incidence and prevalence of diabetes mellitus in patients with cystic fibrosis undergoing lung transplantation before and after lung transplantation

Cystic fibrosis (CF) related diabetes mellitus (DM) occurs in 15% of adult pancreatic insufficient CF patients. Lung transplantation is a treatment option for end-stage CF. We hypothesized that the prevalence of DM increases after lung transplantation. The study population included adult patients undergoing lung transplantation from March 1988 to March 2002 for end-stage CF at the University of Toronto. Demographic data, exocrine pancreatic function, presence of DM before and after transplant, as well as timing of its development after transplant were collected. Eighty-six patients met the study criteria; 77 of 86 (89.5%) of patients were pancreatic insufficient and were further analyzed. Median follow-up post-transplant was 3.3 yr (interquartile range: 1.2-7.2). Their mean age was 29.7 +/- 8.1 yr and 46 of 77 (59.7%) were male. The prevalence of DM increased from 22 of 77 (28.6%) before transplant to 38 of 77 (49.4%) after transplant (p = 0.008). The median time of DM development after transplant was 80 d (range: 13-4352). Sixteen of 55 (29.1%) of pancreatic insufficient patients who were non-diabetic prior to transplant, developed DM after transplant. DM is common in CF patients undergoing lung transplantation and the prevalence increases after transplant.

Effect of FK506 on the interleukin 15-driven proliferation and apoptosis of anti-CD3-activated umbilical cord blood T cells

BACKGROUND

Increased susceptibility of umbilical cord blood (CB) T cells to FK506 immunosuppression may contribute to the lessened severity of graft-vs-host disease in CB transplantation.

OBJECTIVE

To investigate the FK506 sensitivity of interleukin 15 (IL-15)- and IL-2-driven proliferation and apoptosis of anti-CD3-stimulated CB T cells compared with adult peripheral blood (APB) T cells.

METHODS

Surface flow cytometric analysis (CD25 and CD95), carboxyfluorescein diacetae succinimidyl ester staining to track CD3+ T-cell division, and flow cytometric analysis of apoptotic cell death using Annexin V were performed to determine the effect of FK506 on CD3+ T-cell activation and apoptosis after anti-CD3 stimulation in the presence of IL-15 or IL-2.

RESULTS

IL-15 is superior to IL-2 in promoting CD25 expression and proliferation of anti-CD3-stimulated CB and APB T cells. Although IL-15-driven proliferation evaluated by carboxyfluorescein diacetae succinimidyl ester staining revealed comparable sensitivity to FK506 in anti-CD3-stimulated CB and APB T cells, IL-15-driven CD25 up-regulation in CB T cells was more sensitive to FK506 inhibition than APB T cells. FK506 down-regulated anti-CD3-induced apoptosis in CB and APB T cells (P < .01). However, the FK506 sensitivity of anti-CD3-induced T-cell apoptosis was lost in IL-15-supplemented CB cultures (P = .51) but not in corresponding APB cultures (P = .002). The IL-15-enhanced Fas expression on CB T cells (CD95) was decreased by FK506, similar to that observed with adults.

CONCLUSIONS

We observed differential FK506 sensitivity of IL-15-driven CD25 up-regulation and apoptotic response comparing CB and APB T cells. This finding suggests the potential therapeutic benefit of FK506 in ameliorating graft-vs-host disease by decreasing IL-15-driven donor T-cell proliferation without inhibiting associated activation-induced apoptosis during CB transplantation.

Severe Angioedema Caused by Banana Allergy UnderTacrolimus Immunosuppression

Occurrences of allergic reactions induced by various foods have been reported in pediatric liver graft recipients receiving tacrolimus immunosuppression. We describe herein a female infant, who was admitted to our hospital with life-threatening angioedema because of banana hypersensitivity, 8 months after orthotopic liver transplantation. Food allergies should be screened in all tacrolimus-immunosuppressed pediatric liver recipients who show suggestive clinical symptoms. Banana must be added to allergen batteries during etiologic investigations. Cyclosporine represents an option for drug conversion to prevent organ rejection.

Topical nanocrystalline silver cream suppresses inflammatory cytokines and induces apoptosis of inflammatory cells in a murine model of allergic contact dermatitis

BACKGROUND

Nanocrystalline silver has both antimicrobial and anti-inflammatory properties. However, the exact mechanisms underlying these activities are not known.

OBJECTIVES

The objectives of this study were to assess the anti-inflammatory effects of nanocrystalline silver using a murine model of allergic contact dermatitis, compare the effects with those of tacrolimus and a high potency steroid, and to relate the effects to modulation of pro-inflammatory cytokines and apoptosis of inflammatory cells.

METHODS

Dermatitis was induced on the ears of BALB/c mice using dinitrofluorobenzene. Topical treatment, including vehicles, 1% nanocrystalline silver cream, tacrolimus ointment and a high potency steroid, was applied once a day for 4 days. Ear swelling was measured and the erythema was evaluated daily. After 4 days of treatment the mice were killed and samples from the ears were collected for histological and immunohistochemical examination, terminal deoxynucleotidyl transferase (TdT)-mediated dUTP-biotin nick end labelling (TUNEL) staining and extraction of total RNA for reverse transcriptase polymerase chain reaction (RT-PCR).

RESULTS

Significant reductions of ear swelling, erythema and histopathological inflammation in mice ears were observed after 4 days of treatment with 1% nanocrystalline silver cream, tacrolimus ointment or a high potency steroid with no significant difference among them. Both RT-PCR and immunohistochemical staining of sections from ear biopsies demonstrated that nanocrystalline silver, tacrolimus and steroid significantly suppressed the expression of tumour necrosis factor (TNF)-alpha and interleukin (IL)-12. TUNEL staining demonstrated a significant increase in the numbers of apoptotic cells in material from the group treated with nanocrystalline silver when compared with that from groups treated with vehicle, tacrolimus or steroid.

CONCLUSIONS

This study demonstrates that nanocrystalline silver inhibits allergic contact dermatitis in mice, similar to steroid and tacrolimus. Nanocrystalline silver suppresses the expression of TNF-alpha and IL-12 and induces apoptosis of inflammatory cells; mechanisms by which nanocrystalline silver may exert its anti-inflammatory effects.

Anti-inflammatory effect of topical nanocrystalline silver cream on allergic contact dermatitis in a guinea pig model

The anti-inflammatory activity of topical nanocrystalline silver cream was assessed and compared with the effects of topical steroids and currently available immunosuppressants using a guinea pig model of allergic contact dermatitis. Dermatitis was induced with dinitrochlorobenzene and treated with different concentrations of nanocrystalline silver, medium and high potency steroids, tacrolimus and pimecrolimus, or appropriate vehicles once daily for 5 days. Erythema was evaluated daily (on a score of 0 to 4, from absent to very severe) and histopathology of the skin biopsies was evaluated after 5 days of treatment. Prior to treatment, the average scores of erythema in all the groups were in the range of 3(+) to 4(+). In the no treatment and vehicles groups these scores remained at about this level for the subsequent 5 days of the study. Nanocrystalline silver reduced erythema within 1 day of treatment in a concentration-dependent manner with significant reduction at silver concentrations of 0.5% and 1% (P < 0.05) and this reduction progressed throughout the study period. Steroids and immunosuppressants produced similar decreases in erythema, with no significant differences compared to 0.5% and 1% nanocrystalline silver. In skin biopsies scored for degree of inflammatory response, effects of treatments mirrored erythema results. This study suggests that nanocrystalline silver cream may have therapeutic potential for topical treatment of inflammatory skin diseases.

Mechanisms and management of gingival overgrowth in paediatric transplant recipients: a review

Increasing numbers of children are receiving solid organ transplants namely kidney, liver, heart and lung. Patient survival rates following such transplants are essentially good with much of the success attributable to the development of Cyclosporine A (CyA), an immunosuppressive drug, that minimizes organ rejection. However the gingival overgrowth (GO) associated with the use of CyA is not only disfiguring but in paediatric recipients, may interfere with normal oral development and function.

OBJECTIVE

The aim of this review is to summarize current knowledge concerning the aetiology, pathogenesis and management of gingival overgrowth.

METHODS

Literature pertaining to gingival overgrowth is reviewed with particular reference to the paediatric population. Emphasis is placed on summarizing the evidence pertaining to the effectiveness of intervention.

CONCLUSION

CyA undoubtedly causes gingival overgrowth, the effects and levels of which appears to be more severe in younger patients. There is conflicting evidence as to the effectiveness of oral hygiene regimes, antibiotics and surgery in reducing overgrowth. The introduction of an alternative immunosuppressive agent (Tacrolimus) offers potential as it does not appear to cause overgrowth, although research to date is limited by the small sample size of many of the studies. This is an area in which multicentre studies would be of great value.

Different mechanisms are utilized by HIV-1 Nef and staphylococcal enterotoxin A to control and regulate interleukin-10 production

Interleukin-10 (IL-10) plays an important immunopathogenic role in immunologic diseases, especially in HIV infection and atopic dermatitis. The control and regulatory mechanisms of IL-10 production have not been described in these diseases. Recently, we demonstrated that HIV-1 Nef induces IL-10 production in monocytes and that staphylococcal enterotoxin A (SEA) induces IL-10 production in T-lymphocytes. Here we show that Nef-induced IL-10 production and mRNA expression are strongly blocked by rapamycin, but are not blocked by cyclosporin (CsA) or FK506. Conversely, we show that CsA and FK506 completely inhibit SEA-induced IL-10 protein production and mRNA expression. The results of this study demonstrate that IL-10 production by Nef and SEA is controlled and regulated by different mechanisms.

Evolving new therapies of autoimmune hepatitis

Refinements in the understanding of the mechanisms of immunocyte activation and the emergence of new immunosuppressive agents with highly selective actions has created opportunities for improving the treatment of autoimmune hepatitis. Drugs, such as budesonide and deflazacort, may inhibit immunocyte activation and limit corticosteroid-related side effects. Agents, such as cyclosporine and tacrolimus, can impair calcineurin activity and restrict the generation of transcription factors necessary for T cell responses. Intravenous immunoglobulin can bind anti-idiotype antibodies and reduce interleukin-2 secretion, and monoclonal antibodies directed against critical components of the T cell activation cascade can dampen the immune reaction. Drugs, such as mycophenolate mofetil, cyclophosphamide, methotrexate, and KF20444, can inhibit T cell proliferation, and other interventions promise to deplete activated T cells, impair effector mechanisms, and induce self-tolerance.

Axonal regeneration after cold preservation of nerve allografts and immunosuppression with tacrolimus in mice

OBJECT

The purpose of this study was to combine the immunosuppressive and neuroregenerative effects of tacrolimus (FK506) with cold preservation of peripheral nerve allografts to maximize axonal regeneration across short peripheral nerve gaps.

METHODS

Ninety-six male C3H mice were randomized to six groups, which were composed of animals with isografts (Group 1, positive control), allografts (Group 2, negative control), allografts treated with subtherapeutic doses of FK506 without and with cold preservation (Groups 3 and 4), and allografts treated with therapeutic doses of FK506 without and with cold preservation (Groups 5 and 6). Results were determined using walking-track data and histomorphometric measurements. Three weeks postoperatively, animals treated with therapeutic doses of FK506 after receiving cold-preserved allografts demonstrated accelerated functional recovery relative to all other groups. In addition, histomorphometric parameters in these animals (1,257 +/- 847 total axons, 6.7 +/- 3.3% nerve tissue, 11.8 +/- 6.5% neural debris, 8,844 +/- 4,325 fibers/mm2 nerve density, and 2.53 +/- 0.25 microm fiber width) were the same as or better than in all other groups. The parameters of percent nerve tissue (p < 0.016), nerve density (p < 0.038), and percent neural debris (p < 0.01) were statistically significantly better than those in all other groups, including Group 1 (isograft, positive control).

CONCLUSIONS

The combination of FK506 treatment with cold preservation of nerve allografts resulted in functional and histomorphometric recovery superior to that with either modality alone.

Advances in myasthenia gravis

Recent advances in the diagnosis and treatment of acquired myasthenia gravis (MG) are reviewed. Increased awareness about the need for more uniform methods of reporting treatment trials for MG has prompted systematic review of the literature and inspired an effort to develop better classifications and disease-specific outcome measures. New antibodies have been discovered in patients with seronegative MG, possibly defining an immunologically distinct form of the disease. A new immunosuppressant, mycophenolate mofetil, may be an additional and safe option in the treatment of MG. Other work supports the possibility of developing a vaccine against MG suitable for trial in humans.

The immunosuppressant drug FK506 is a potent trophic agent for human fetal neurons

FK506 is a potent immunosuppressive drug used to prevent rejection post-organ transplantation. It is activated upon binding to members of the immunophilin chaperone proteins (e.g. FK506-binding protein, FKBP 12). Studies of the distribution of FKBP12 reveal that it is enriched in neurons throughout the central and peripheral nervous system. In vitro, FK506 augments neurite outgrowth; in animal models, it enhances axonal re-growth and functional recovery following lesioning. The effects on human neurons and glial cells have not yet been studied. Using immunofluorescent laser scanning confocal microscopy we demonstrate that in human fetal brain cultures FK506 significantly increases cell numbers, including neurons, and the expression of the neuronal marker MAP-2. This suggests that the drug has a potent effect in stimulating neuronal survival, proliferation and dendrite extension. Interestingly, in combination with brain-derived neurotrophic factor, FK506 induces a prominent decrease in glial fibrillary acidic protein expression, which indicates an inhibitory effect on astrogliosis in vitro. Our data support a potential role for FK506 and its analogues in the treatment of neurodegenerative disorders.

The many faces of systemic mastocytosis

OBJECTIVE

This short review article will augment the reader's knowledge of mast cell physiology and will offer an overview of current information on the pathophysiology, heterogeneity, and treatment of human mastocystosis.

DATA SOURCES AND STUDY SELECTION

Articles published since 1980, textbooks, information from computerized databases, references identified from bibliographies of relevant articles, and books published in the last 10 years.

RESULTS AND CONCLUSIONS

Mastocytosis is a complex disease with a multitude of clinical presentations, often misdiagnosed, which can embrace characteristics of other diseases and generate a chameleon-like picture. Mast cells possess many important physiologic functions in the human body, but as a consequence of poorly understood events, they can also start a cascade of pathologic reactions. Although a great deal is known about mechanisms involved in physiologic and pathologic processes of mast cells, many areas are waiting to be explored in this millennium.

Tacrolimus in dermatologic disorders

OBJECTIVE

To review the data surrounding the use of tacrolimus for skin disorders.

DATA SOURCES

Articles were obtained through a MEDLINE search of English-language literature (1990-May 2000); references of the retrieved publications were further reviewed for relevant literature.

STUDY SELECTION

Orginal studies in humans regarding the use of tacrolimus for skin disorders were included.

DATA EXTRACTION

The major outcomes extracted from the literature involved patient response to therapy and adverse effects.

DATA SYNTHESIS

Tacrolimus offers an additional therapeutic approach to the treatment of immunologically based skin disorders. led trials and case reports indicates topical tacrolimus is a safe and effective alternative treatment in patients with atopic dermatitis. Case reports document efficacy in recalcitrant pyoderma gangrenosum, mucosal lichen planus, and ichthyosis linearis trolled trials and case reports indicate oral tacrolimus is effective in recalcitrant plaque psoriasis. Case reports document efficacy in recalcitrant pyoderma gangrenosum and leukocytclastic vascultis. The clinical utility of oral tacrolimus in skin disorders is limited due to potentially severe adverse effects such as infections, hypertension, hyperglcemia hyperkalemia, nephrotoxicity neurotoxicity, and increased risk of neoplasia.

CONCLUSIONS

Most of the available data indicate short-term (3 wk to 3 mo) topical tacrolimus is a safe and effective treatment alternative for inflammatory skin disorders. Further study is needed to evaluate long-term safety and efficacy and to determine the best dosage regimen. Although oral tacrolimus has demonstrated efficacy in inflammatory skin disorders, the potenial for serious adverse effects limits its utility to third-line therapy for patients who are resistant to, or intolerant of, conventional therapies.

Effect of FK-506 on inflammation and behavioral outcome following intracerebral hemorrhage in rat

Beginning 15 min after induction of intracerebral hemorrhage (ICH) by intrastriatal administration of collagenase, rats were treated intramuscularly with FK-506 (3 mg/kg) or with vehicle. Treatment was repeated daily for 7 days. MR imaging 1, 7, and 28 days post-ICH showed that treatment did not affect hematoma size or its subsequent resolution. Two days post-ICH, neutrophil infiltration around the hematoma was decreased in the FK-506-treated rats, as was the number of TUNEL-positive cells at the edge of the hematoma and in the peripheral region. The decreased inflammatory response was accompanied by functional improvement in the treated rats. The neurological deficit induced by the ICH (beam walking ability, postural reflex, spontaneous circling) was significantly decreased from 3 to 21 days post-ICH by treatment with FK-506. Skilled use of the forelimb ipsilateral to the ICH was improved and sensory neglect of the same limb was decreased 8-9 weeks post-ICH in rats treated with FK-506. However, neuronal loss assessed 9 weeks post-ICH was not different in the treated and untreated rats.

Acquired Pelger-Huët anomaly in association with concomitant tacrolimus and fluconazole therapy following allogeneic bone marrow transplantation

A 38-year-old Japanese woman with severe aplastic anemia received an allogeneic bone marrow transplant from her serologically HLA-identical father. Cyclosporine and methotrexate were administered to prevent graft-versus-host disease (GVHD). However, grade III acute GVHD developed on day 44, which was successfully treated with methylprednisolone and tacrolimus. Fluconazole therapy was started for oral candidiasis on day 112, but she complained of headache soon after. In addition to glycosuria and increased serum creatinine levels, Pelger-Huët anomaly of granulocytes was found in her blood, which disappeared after discontinuation of tacrolimus. Transient occurrence of Pelger-Huët cells may be associated with tacrolimus toxicity due to drug interaction with fluconazole.