Central hypothyroidism associated with retinoid X receptor-selective ligands

BACKGROUND

The occurrence of symptomatic central hypothyroidism (characterized by low serum thyrotropin and thyroxine concentrations) in a patient with cutaneous T-cell lymphoma during therapy with the retinoid X receptor-selective ligand bexarotene led us to hypothesize that such ligands could reversibly suppress thyrotropin production by a thyroid hormone-independent mechanism and thus cause central hypothyroidism.

METHODS

We evaluated thyroid function in 27 patients with cutaneous T-cell lymphoma who were enrolled in trials of high-dose oral bexarotene at one institution. In addition, we evaluated the in vitro effect of triiodothyronine, 9-cis-retinoic acid, and the retinoid X receptor-selective ligand LGD346 on the activity of the thyrotropin beta-subunit gene promoter.

RESULTS

The mean serum thyrotropin concentration declined from 2.2 mU per liter at base line to 0.05 mU per liter during treatment with bexarotene (P<0.001), and the mean serum free thyroxine concentration declined from 1.0 ng per deciliter (12.9 pmol per liter) at base line to 0.45 ng per deciliter (5.8 pmol per liter) (P<0.001) during treatment. The degree of suppression of thyrotropin secretion tended to be greater in patients treated with higher doses of bexarotene (>300 mg per square meter of body-surface area per day) and in those with a history of treatment with interferon alfa. Nineteen patients had symptoms or signs of hypothyroidism, particularly fatigue and cold intolerance. The symptoms improved after the initiation of thyroxine therapy, and all patients became euthyroid after treatment with bexarotene was stopped. In vitro, LGD346 suppressed the activity of the thyrotropin beta-subunit gene promoter in thyrotrophs by as much as 50 percent, an effect similar to that of triiodothyronine and 9-cis-retinoic acid.

CONCLUSIONS

Hypothyroidism may develop in patients with cutaneous T-cell lymphoma who are treated with high-dose bexarotene, most likely because the retinoid X receptor-selective ligand suppresses thyrotropin secretion.

Distinct serum cytokines in AIDS-related skin diseases

To determine whether common skin diseases associated with human immunodeficiency virus (HIV) were distinguishable based on the pattern of serum cytokine expression, we studied patients with psoriasis, pruritus, and Kaposi's sarcoma (KS) for levels of tumor necrosis factor (TNF)-alpha, interferon-gamma (IFN-y), interleukin (IL)-10, and IL-4. Thirty-two HIV-positive (HIV+) patients including 8 with KS, 11 with psoriasis, and 13 with pruritus along with 16 HIV-negative subjects with psoriasis were studied. IFN-gamma levels were highest in sera of HIV+ patients with psoriasis (p = 0.040). By contrast, TNF-alpha and IL-10 levels were highest in sera of HIV+ patients with pruritus (p = 0.012). Detectable levels of all cytokines in these patients were remarkably higher than for healthy adults. These results suggest that common skin diseases associated with HIV infection and AIDS can be distinguished by the production of unique cytokines.

Interleukin-10 levels are often elevated in serum of adults with Hodgkin's disease and are associated with inferior failure-free survival

BACKGROUND

Interleukin-10 (IL-10) is a pleiotropic cytokine that protects B- or T-lymphocytes and hemopoietic progenitors from apoptosis induced by doxorubicin, glucocorticoids, or deprivation of growth factors. IL-10 is also immunosupressive, and tumor cells secreting IL-10 can grow in syngeneic or allogeneic hosts, and can inhibit the generation of tumor-specific cytotoxic T cells. Hodgkin-Reed-Sternberg cells are derived from follicular center B cells and they may be latently infected by EBV. When this occurs they often express IL-10. Based on these considerations we investigated the relationship between pretreatment serum IL-10 levels and failure-free survival (FFS) in Hodgkin's disease (HD).

PATIENTS AND METHODS

Untreated patients, older than 16 years, with biopsy-proven HD, were included if treated with ABVD or equivalent regimens, and if pretreatment serum was available. IL-10 levels were determined with a capture enzyme-linked immunoassay specific for cellular IL-10.

RESULTS

Among healthy adult volunteers serum IL-10 levels ranged from 4.8-9.8 pg/ml (mean 7.1, standard deviation 1.5 pg/ml). Therefore levels > or = 10 pg/ml were considered elevated. We identified 101 patients with available serum. Their median age was 32 years, and 60% had B-symptoms. Ann Arbor stage was I in 4, II in 21, III in 35, and IV in 41 patients. Histology was nodular sclerosis in 74, mixed cellularity in 12, lymphocyte predominance in six, lymphocyte depletion in one, and unclassified in eight patients. Pretreatment serum IL-10 levels were elevated in 51 patients, and were higher in those with serum albumin < 3.5 g/dl, B symptoms, serum beta 2-microglobulin > or = 2.5 mg/l, anemia, and AAS III or IV. After a median follow-up of 32 months for survivors, 20 patients have progressed, and the three-year FFS of those with high vs. normal serum IL-10 was 60% +/- 9 vs. 91 +/- 9% (50% vs. 50% of the population; P = 0.004 by log-rank). Among patients with Ann Arbor stage III or IV the three-year FFS for those with high vs. normal serum IL-10 (58 vs. 42% of the population) was 57 +/- 9% vs. 92 +/- 6% (P = 0.008 by log-rank). Multivariate analysis using Cox's proportional hazards model confirmed that IL-10 was an independent variable associated with inferior FFS in this population.

CONCLUSIONS

Elevation of serum IL-10 levels is frequent and is associated with inferior FFS in adults with ABVD-treated HD. This observation should be verified in other patient populations. In addition, the source and the role of IL-10 in the biology of HD should be further investigated.

Alterations in HIV expression in AIDS patients with psoriasis or pruritus treated with phototherapy

BACKGROUND

Ultraviolet light (UVL) upregulates HIV transcription in vitro and in transgenic mice. AIDS-associated psoriasis and pruritus respond to phototherapy.

OBJECTIVE

Our goal was to determine the effect of phototherapy on viral load and immunologic parameters in HIV-positive patients.

METHODS

T cell subsets, p24, plasma cytokines, serum or plasma HIV-RNA, dosage, and antivirals were assessed in HIV-positive patients and negative controls receiving 6 weeks of phototherapy with UVB and in untreated controls.

RESULTS

Phototherapy improved skin conditions without significantly affecting T cell numbers. Plasma p24 increased 2-fold (P = .055) and HIV-RNA levels 4-fold (P = .022) 6 weeks from baseline in patients who entered the trial before March 1995. Later patients who were mostly receiving combination antiviral therapy showed a 4-fold reduction in serum HIV-RNA (P = .012) at 2 weeks. The effect of UVB on viral load at 6 weeks was dependent on the baseline level (P = .006). IL-10 increased and was inversely related to HIV-RNA levels (P = .0267).

CONCLUSION

Phototherapy is associated with HIV load alterations, depending on patients' initial HIV-RNA, antiviral therapy, skin type, and UVL dosage.

Dysregulated synthesis of intracellular type 1 and type 2 cytokines by T cells of patients with cutaneous T-cell lymphoma

Mycosis fungoides (MF) and Sezary syndrome (SS) are the two main clinical entities of cutaneous T-cell lymphoma (CTCL). As the disease progresses from MF to SS, a switch from a type 1 (interleukin [IL]-2 and gamma interferon [IFN-gamma]) to a type 2 (IL-4) cytokine production profile occurs. Although roles for type 1 and type 2 cytokines in the pathogenesis of CTCL have been proposed, the cellular origins of these cytokines are unclear. Using flow cytometry to identify individual T-cell subsets, we studied cytokine synthesis by the T cells of 13 patients with SS and 12 with MF and 9 hematologically healthy donors. Upon activation with phorbol 12-myristate 13-acetate (PMA), the numbers of T cells synthesizing IL-2 were similar for all study groups. Whereas the predominant T-cell producing IL-2 in healthy donors and in those with MF was CD7(+), in patients with SS, it was CD7(-). Although the number of IL-4(+) CD4(+) T cells was low for all study groups, there was a significantly higher number of IL-4(+) CD8(+) T cells in patients with MF than in those with SS or healthy donors. There was a decline in the number of IFN-gamma-producing T cells in CTCL donors compared to that in healthy donors. More importantly, there was a significant decrease in the number of IFN-gamma-producing T cells with disease progression from MF to SS. The inability of these T cells to synthesize IFN-gamma may have prognostic value in CTCL, since it may be responsible for the progression of the disease from MF to SS.

Identification and characterization of a retinoid-induced class II tumor suppressor/growth regulatory gene

Retinoids, synthetic and natural analogs of retinoic acid, exhibit potent growth inhibitory and cell differentiation activities that account for their beneficial effects in treating hyperproliferative diseases such as psoriasis, actinic keratosis, and certain neoplasias. Tazarotene is a synthetic retinoid that is used in the clinic for the treatment of psoriasis. To better understand the mechanism of retinoid action in the treatment of hyperproliferative diseases, we used a long-range differential display-PCR to isolate retinoid-responsive genes from primary human keratinocytes. We have identified a cDNA, tazarotene-induced gene 3 (TIG3; Retinoic Acid Receptor Responder 3) showing significant homology to the class II tumor suppressor gene, H-rev 107. Tazarotene treatment increases TIG3 expression in primary human keratinocytes and in vivo in psoriatic lesions. Increased TIG3 expression is correlated with decreased proliferation. TIG3 is expressed in a number of tissues, and expression is reduced in cancer cell lines and some primary tumors. In breast cancer cell lines, retinoid-dependent TIG3 induction is observed in lines that are growth suppressed by retinoids but not in nonresponsive lines. Transient over-expression of TIG3 in T47D or Chinese hamster ovary cells inhibits colony expansion. Finally, studies in 293 cells expressing TIG3 linked to an inducible promoter demonstrated decreased proliferation with increased TIG3 levels. These studies suggest that TIG3 may be a growth regulator that mediates some of the growth suppressive effects of retinoids.

Unusual presentation of mycosis fungoides as pigmented purpura with malignant thymoma

Thymoma is known to be associated with many lymphoreticular and nonlymphoreticular tumors. A woman who presented with patch stage mycosis fungoides with skin lesions resembling a pigmented purpura was found to have an anterior mediastinal mass on routine staging evaluation. A core needle biopsy of the mass revealed a lymphocyte predominant malignant thymoma. Review of the literature reveals many diseases with dermatologic manifestations associated with thymoma; however, malignant thymoma coexisting with mycosis fungoides has not previously been reported.

Nerve growth factor in normal and psoriatic skin equivalent models

Our objective was to determine the pattern and time course of nerve growth factor expression in an established skin equivalent model that we have used in the past to study wound healing and psoriasis phenotypes. Skin equivalents were constructed in triplicate using normal neonatal foreskin keratinocytes plated on collagen gels containing fibroblast lines. These lines were derived from five specimens of psoriatic lesions, three specimens of normal skin from patients with psoriasis, and three specimens of eyelid skin from normal donors. Immunohistochemistry and a monoclonal nerve growth factor-b antibody were used to determine the pattern of protein staining over 2 weeks. We looked at the wound healing phenotype using the skin equivalent model for 7-14 days. When keratinocytes invaginate into the dermis of skin equivalents (beginning at around 7 days of growth), dark staining of nerve growth factor was seen under the basal membrane zone, suggesting that nerve growth factor serves in the development of the basal membrane zone and the epidermis, and may influence the migration of nerves through the basal membrane zone into the regenerated skin.

The pathogenesis of psoriasis and the mechanism of action of tazarotene

The 3 major features of psoriasis--abnormal differentiation of keratinocytes, hyperproliferation of keratinocytes, and infiltration of inflammatory components into the skin--can be quantified by measuring levels of certain biochemical markers. Psoriasis is associated with upregulation or downregulation of several of these markers. Tazarotene helps to normalize the levels of the markers, thereby bringing about clinical improvement.

Antinuclear antibody seropositivity in patients with cutaneous T-cell lymphoma

BACKGROUND

We attempted to determine the frequency and clinical relevance of antinuclear antibody (ANA) testing and positive ANA test results in patients with cutaneous T-cell lymphoma (CTCL).

METHODS

A retrospective chart and computer record review was conducted to determine the frequency of ANA testing in CTCL patients and the rate of seropositivity. Patients with a positive ANA were further examined to define possible explanations of the positive test.

RESULTS

Of 381 patients with CTCL, 66 (17%) had ANA tests; 8 of these (12.1%) were found to have an ANA titer greater than or equal to 1:40. Of patients with a positive ANA test, one was found to have chronic cutaneous lupus erythematosus histologically and clinically mimicking CTCL. Others were found to have a comorbid connective tissue disorder, some had apparent drug-induced antinuclear antibodies, and some had no identifiable reason for a positive ANA test.

CONCLUSION

ANA seropositivity does not appear to be increased in CTCL patients, and the ANA test remains a useful screening tool for differentiating between CTCL and connective tissue disorders.

Transformation of mycosis fungoides/Sezary syndrome: clinical characteristics and prognosis

The occurrence of large cell transformation has been well documented in a subgroup of patients with mycosis fungoides/Sezary syndrome (MF/SS). However, because of the rarity of MF/SS, little is known about the influence of clinicopathologic features in predicting large cell transformation and about outcome in the transformed cases. We evaluated all patients with MF/SS who were registered in our clinic during the study period and for whom pathologic slides for review were available or could be obtained. Disease was classified as transformed if biopsy showed large cells (>/=4 times the size of a small lymphocyte) in more than 25% of the infiltrate or if they formed microscopic nodules. Twenty-six patients with transformation were identified from a total of 115 evaluable cases with a diagnosis of MF/SS. The actuarial cumulative probability of transformation reached 39% in 12 years. The median time from diagnosis of MF/SS to transformation was 12 months (range, 0 to 128 months). Thirty-one percent of all patients with stage IIB-IV disease at presentation eventually transformed versus 14% of those with stage I-IIA (P = . 03), with transformation being especially common in patients with tumors (T3), 46% of whom transformed. Combining elevated beta2 microglobulin and lactic dehydrogenase (neither elevated v one or both elevated) was also predictive for transformation (P = .009). The median survival from initial diagnosis of MF/SS for the transformed patients was 37 months versus 163 months for the untransformed group (P = .0029). The median survival from transformation was 19.4 months (range, 2+ to 138 months). The following characteristics were associated with an inferior survival in transformed patients: (1) early transformation (<2 years from the diagnosis v >/=2 years; P = .011) and (2) advanced stage (IIB-IV v I-IIA; 2-year survival, 23% v 86%; P = .0035). We conclude that MF/SS patients with stages IIB-IV disease and, in particular, those with tumors have a high incidence of large-cell transformation. Patients with transformation have a relatively poor survival, especially if transformation occurs early (within 2 years) in the course of disease or if they are staged as IIB or higher.

DAB389IL2 diphtheria fusion toxin produces clinical responses in tumor stage cutaneous T cell lymphoma

Four patients with late stage cutaneous T cell lymphoma (IB-IVA) who had failed at least two previous therapies were treated with DAB389IL2 at 9 or 18 microg/kg as 15-min intravenous infusions daily for 5 days every 3 weeks for eight cycles. Mild vascular leak syndrome (VLS) with transient edema, hypoalbuminemia, weight gain, and myalgias was observed in two of the patients lasting 7-10 days and only occurring on the first cycle. One stage IB patient had a pathologic complete remission (CR) lasting 11+ months from treatment initiation, one stage IIB patient had a complete clinical remission (CCR) lasting >6 months with complete clearing of a large tumor lasting >18 months, and one stage IIB and the one stage IVA patient had partial remissions (80-99% reduction in tumor masses) lasting 5 months. While IL2 receptor (IL2R) was expressed on 20-50% of tumor cells prior to therapy, recurrent tumor was IL2R negative in three of the patients. DAB389IL2 at tolerable doses decreased tumor burden in each of these four standard treatment refractory CTCL patients and may offer an important alternative to standard palliative chemotherapy regimens.

Tumor necrosis factor-alpha and interferon-gamma, but not HTLV-I tax, are likely factors in the epidermotropism of cutaneous T-cell lymphoma via induction of interferon-inducible protein-10

We have previously shown that Interferon-Inducible Protein-10 (IP-10), a cytokine chemotactic for CD4-positive lymphocytes, is overexpressed by lesional epidermal keratinocytes and probably accounts for the epidermotropism of cutaneous T-cell lymphoma (CTCL). The tax gene of human T-lymphotropic virus-I (HTLV-I) immortalizes CD4-positive lymphocytes, induces IFN-gamma, and has been detected in patients with classical CTCL who are seronegative for HTLV-I. TNF-alpha is synergistic with IFN-gamma for the induction of IP-10. We therefore decided to define the presence of tax, IFN-gamma, TNF-alpha, and IP-10 in lesions of 19 adults with classical CTCL who were seronegative for HTLV-I. Lesional mRNAs for actin, TNF-alpha, IFN-gamma, and tax were detected by reverse-transcriptase polymerase chain reaction (RT-PCR) amplification. In addition IP-10, TNF-alpha, and IFN-gamma were detected and localized with immunocytochemistry of frozen sections. In agreement with previous observations IP-10 was overexpressed in lesional keratinocytes of all 19 patients. By RT-PCR, mRNA for IFN-gamma was detected in lesions of 8, and for TNF-alpha in lesions of 13 patients. By immunocytochemistry, TNF-alpha was expressed by lesional keratinocytes in 10 of 13 tested patients, whereas IFN-gamma was focally expressed by lesional lymphocytes and faintly by lesional keratinocytes in 9 of 13 tested patients. tax mRNA was not detected in lesions of any patient, but was easily detectable in cutaneous lesions or peripheral blood of control patients who were seropositive for HTLV-I. We conclude that TNF-alpha and IFN-gamma may cause epidermotropism by inducing IP-10. However, the tax gene of HTLV-I does not appear to be involved in the pathogenesis of classical CTCL.

Alopecia areata and cytomegalovirus infection in twins: genes versus environment?

BACKGROUND

Alopecia areata (AA) is hypothesized to be an organ-specific autoimmune disease mediated by T cells directed to the hair follicle. Genetic susceptibility may be conferred by HLA, and an environmental trigger, such as a viral infection, is suspected. The incidence of AA in the population is estimated to be 1.7%, with an average of one in four patients having a positive family history.

OBJECTIVE

Our purpose was to examine the concordance rate of AA among identical versus fraternal twins and the correlation between stress, cytomegalovirus (CMV) infection, and disease.

METHODS

Families with AA were solicited from dermatologists in the United States and through a Website on the Internet. HLA class 2 typing and identification of CMV early and late genes were performed by polymerase chain reaction (PCR) on genomic peripheral blood DNA. Serum antibodies for CMV were determined by enzyme-linked immunosorbent assay.

RESULTS

From 114 families, we identified 11 sets of monozygotic twins and 3 sets of dizygotic twins. The concordance rate was 55% for monozygotic twins and 0% for fraternal twins. Most identical twins were male. The severity of the AA phenotype varied and appeared most severe in the first affected twin. Five of 24 twins were CMV seropositive but CMV DNA was not detected in blood lymphocytes of any of the subjects when studied after the onset of AA. The presence of AA in twins was not correlated with evidence of CMV.

CONCLUSION

A 55% concordance rate in identical twins and AA occurring in families support a genetic component as well as possible environmental triggers that remain unknown.

Mycosis fungoides with focal segmental glomerular sclerosis and nephrotic syndrome

Cutaneous T-cell lymphoma includes mycosis fungoides and the leukemic variant, Sézary syndrome. We report the first two cases of focal segmental glomerulosclerosis in patients with cutaneous T-cell lymphoma, with nephrotic range proteinuria and review the literature on renal disease coexisting with cutaneous T-cell lymphoma. We hypothesize that glomerular injury in cutaneous T-cell lymphoma may be related to interleukin-2.

Artificial skin equivalent differentiation depends on fibroblast donor site: use of eyelid fibroblasts

Our objective was to construct and explore human skin equivalents from several normal and pathologic donor skin sites to determine if the fibroblast origin influences epidermal differentiation. Also, we wanted to find out if fibroblasts from some donor sites produced epidermis of superior quality for plastic surgery repairs. Skin equivalents were constructed from 15 normal skin specimens, 9 normal eyelid specimens, 15 lesional skin specimens taken from patients with psoriasis, and 4 specimens from keloid scars. Results show that the tissue origin of the donor fibroblasts determines epidermal differentiation and the time period for regeneration. Eyelid fibroblasts were very dependable in establishing well-differentiated skin equivalents in all nine specimens. Our findings contribute to the accumulated knowledge of wound healing and should also be of value in skin grafting, especially when large areas are denuded as in burns, severe trauma, or cancer ablation.

Pharmacologic profile of tazarotene

The majority of patients with psoriasis exhibit a mild to moderate form of the disease. While topically applied agents represent the ideal therapeutic approach for these patients, our treatment options have been hampered by their inconsistent or limited efficacy, expense, and cosmetic properties. Furthermore, some of the topically applied preparations have the potential for systemic absorption and associated adverse events. Tazarotene is the first synthetically developed retinoid indicated for the topical treatment of patients with psoriasis. Pharmacologically, tazarotene affects the three primary abnormalities associated with psoriasis: it normalizes epidermal differentiation, it exhibits a potent antiproliferative effect, and it decreases epidermal inflammation. Following topical application, tazarotene is rapidly metabolized in the skin to tazarotenic acid, its primary and active metabolite. While tazarotenic acid achieves measurable levels in the systemic circulation, no drug-related hematologic, ophthalmologic, or metabolic adverse events have been observed. Only a minimal amount of tazarotene is absorbed into the circulation. While animal studies have found tazarotene to be nonmutagenic and nonteratogenic, women of child-bearing potential should be counseled regarding the potential risks of retinoid use during pregnancy. In summary, animal and clinical patient trials have found tazarotene to be effective, safe, and well-tolerated. The availability of such an agent in a topical formulation is a welcome treatment alternative for the management of patients with psoriasis.

Follicular mucinosis associated with scarring alopecia, oligoclonal T-cell receptor V beta expansion, and Staphylococcus aureus: when does follicular mucinosis become mycosis fungoides?

A diagnosis of alopecia mucinosa, occurring as a single scalp lesion, was made in a 40-year-old white woman who had a history of trauma. Follicular mucinosis, Staphylococcus aureus, and oligoclonal expansion of the T-cell receptor V beta chain genes 6 and 7 were present in the skin. Epidermotropic T-cell skin diseases with oligoclonal T-cell proliferations may be the result of HLA- and cytokine-determined reaction patterns to persistent antigens.

Ehlers-Danlos syndrome type VIIA and VIIB result from splice-junction mutations or genomic deletions that involve exon 6 in the COL1A1 and COL1A2 genes of type I collagen

Ehlers-Danlos syndrome (EDS) type VII results from defects in the conversion of type I procollagen to collagen as a consequence of mutations in the substrate that alter the protease cleavage site (EDS type VIIA and VIIB) or in the protease itself (EDS type VIIC). We identified seven additional families in which EDS type VII is either dominantly inherited (one family with EDS type VIIB) or due to new dominant mutations (one family with EDS type VIIA and five families with EDS type VIIB). In six families, the mutations alter the consensus splice junctions, and, in the seventh family, the exon is deleted entirely. The COL1A1 mutation produced the most severe phenotypic effects, whereas those in the COL1A2 gene, regardless of the location or effect, produced congenital hip dislocation and other joint instability that was sometimes very marked. Fractures are seen in some people with EDS type VII, consistent with alterations in mineral deposition on collagen fibrils in bony tissues. These new findings expand the array of mutations known to cause EDS type VII and provide insight into genotype/phenotype relationships in these genes.

HIV-related psoriasis and Reiter's syndrome

Infection with the human immunodeficiency virus (HIV) is associated with the development of psoriasis and related disorders, including psoriatic arthritis, dactylitis and enthesitis, and Reiter's syndrome. The etiologic mechanisms remain unclear but most likely represent a combination of genetic and environmental factors. Therapy for these diseases in the setting of HIV infection is often difficult not only because of their characteristically increased severity, but also because the use of conventionally effective immunosuppressive agents may be counterproductive in this patient population.

Molecular mechanisms of tazarotene action in psoriasis

Psoriasis is a chronic immune-mediated disease that is characterized by the hyperproliferation and abnormal differentiation of keratinocytes and by inflammation. The epidermal changes associated with psoriasis may be due to the infiltration of inflammatory T lymphocytes and the release of cytokines in response to antigenic stimulation. Tazarotene is a retinoic acid receptor-specific retinoid with demonstrated efficacy in the topical treatment of psoriasis. Tazarotene down-regulates markers of keratinocyte differentiation, keratinocyte proliferation, and inflammation. The drug also up-regulates three novel genes TIG-1 (tazarotene-induced gene-1), TIG-2, and TIG-3, which may mediate an antiproliferative effect. The effect of tazarotene on these markers is probably a direct effect on gene expression rather than an indirect effect associated with disease improvement.

Tazarotene gel, a new retinoid, for topical therapy of psoriasis: vehicle-controlled study of safety, efficacy, and duration of therapeutic effect

BACKGROUND

Topical therapy providing initial improvement and maintenance of effect after treatment of the large majority of patients with limited, mild to moderate psoriasis is not presently available. Previous topical retinoids have generally been either ineffective or too irritating for therapy of psoriasis.

OBJECTIVE

Our purpose was to evaluate a new topical retinoid, tazarotene, in the treatment of stable plaque psoriasis during treatment and posttreatment periods.

METHODS

In a double-blind manner, 324 patients were randomly selected to receive tazarotene 0.1% or 0.05% gel, or vehicle control, once daily for 12 weeks and were then followed up for 12 weeks after treatment.

RESULTS

Of the total, 318 patients could be evaluated. Tazarotene gels were superior (p < 0.05) to vehicle, often as early as treatment week 1, in all efficacy measures: plaque elevation, scaling, and erythema; treatment response; percentage treatment success (patients with > or = 50% improvement); and time to initial success. Efficacy was equivalent on target lesion sites (trunk or limbs and knees or elbows) and overall. A sustained therapeutic effect was observed for 12 weeks after treatment. Tazarotene gel was cosmetically acceptable. There was low systemic absorption, limiting toxicity to local irritation.

CONCLUSION

Once-daily tazarotene was effective and safe as a topical monotherapy for plaque psoriasis, providing rapid reduction of signs and symptoms.

Tazarotene-induced gene 2 (TIG2), a novel retinoid-responsive gene in skin

Retinoids exert their biologic effects through two families of nuclear receptors, retinoic acid receptors (RARs) and retinoid X receptors (RXRs), which belong to the superfamily of steroid/thyroid hormone nuclear receptors. By using a subtraction hybridization approach, we have identified a cDNA sequence TIG2 (Tazarotene-induced gene 2), whose expression is up-regulated by the treatment of skin raft cultures by an RAR beta/gamma-selective anti-psoriatic synthetic retinoid tazarotene [AGN 190168/ethyl 6-[2-(4,4-dimethylthiochroman-6-yl)-ethynyl] nicotinate]. The retinoid-mediated up-regulation in the expression of TIG2 was confirmed by Northern blot analysis. Upon sequencing, TIG2 was found to be a cDNA whose complete sequence was not in the GenBank and EMBL data bases. The TIG2 cDNA is 830 bp long and encodes a putative protein product of 164 amino acids. TIG2 is neither expressed nor induced by tazarotene in primary keratinocyte and fibroblast cultures. Thus, TIG2 is expressed and induced by tazarotene only when keratinocytes and fibroblasts form a tissue-like 3-dimensional structure. We further demonstrate that RAR-specific retinoids increase TIG2 mRNA levels. In contrast, neither RXR-specific retinoids nor 1,25-dihydroxyvitamin D3 increased TIG2 levels. Finally, we demonstrate that TIG2 is expressed at high levels in nonlesional psoriatic skin but at lower levels in the psoriatic lesion and that its expression is up-regulated in psoriatic lesions after topical application of tazarotene.