Clinical associations of the risk alleles of HLA-Cw6 and CCHCR1*WWCC in psoriasis

The PSORS1 locus is the consistently replicated genetic risk factor for psoriasis. Clinical associations with the main marker allele of PSORS1, HLA-Cw6, have been addressed in a number of studies, but clinical associations have not been used as a way to distinguish the effects of the neighbouring candidate genes in PSORS1. Our results show that HLA-Cw6 and CCHCR1 risk allele associations with clinical features of psoriasis are predictably highly similar in a Finnish nationwide cohort of 379 psoriasis patients. The clinical profiling of a small group of patients (n=34) who were HLA-Cw6- but CCHCR1*WWCC positive suggested that no great differences existed between them and HCR-Cw6- patients. HCR+ genotype (as well as Cw6+ genotype) correlated for the first time positively with female sex and, in contrast with previous studies, negatively with disease severity. Presence of psoriatic arthritis was more pronounced in HCR- psoriasis (as well as in Cw6- psoriasis). Clinical profiling may be a useful approach to distinguishing genetic effects of candidate genes even within a locus in sufficiently large cohorts.

Efficacy of once-daily treatment regimens with calcipotriol/betamethasone dipropionate ointment and calcipotriol ointment in psoriasis vulgaris

BACKGROUND

A two-compound ointment containing calcipotriol 50 micro g g-1 and betamethasone dipropionate 0.5 mg g-1 has recently been shown to be an effective treatment for psoriasis.

OBJECTIVES

This study was designed to investigate efficacy and safety of different treatment regimens with the two-compound product (Daivobet/Dovobet; LEO Pharma, Ballerup, Denmark) and calcipotriol 50 micro g g-1 ointment (Daivonex/Dovonex; LEO Pharma).

METHODS

In total, 972 patients with psoriasis vulgaris were randomized to one of three treatment regimens: group 1, the two-compound product once daily for 8 weeks followed by calcipotriol ointment once daily for 4 weeks; group 2, the two-compound product once daily for 4 weeks followed by 8 weeks of treatment with calcipotriol ointment once daily on weekdays and the two-compound product once daily at weekends; and group 3, calcipotriol ointment twice daily for 12 weeks. The efficacy was evaluated by Psoriasis Area and Severity Index (PASI) and investigators' global assessments of disease severity. The primary response criteria were percentage reduction in PASI and proportion of patients with absent/very mild disease according to the investigators' global assessments after 8 weeks of treatment.

RESULTS

The mean reduction in PASI from baseline to the end of 8 weeks of treatment was 73.3% for group 1, 68.2% for group 2 and 64.1% for group 3. The proportion of patients with absent/very mild disease at the end of 8 weeks of treatment was 55.3% for group 1, 47.7% for group 2 and 40.7% for group 3. For both primary response criteria, group 1 was statistically superior to group 3 (P < 0.001), whereas group 2 did not differ significantly from group 3. The difference between group 1 and group 2 was statistically significant with regard to PASI but not regarding the proportion of patients with absent/very mild disease. Patients receiving initial therapy with the two-compound product achieved the fastest treatment response, and the maximum treatment effect for these patients was seen after 5 weeks. This effect was maintained with continued treatment with the two-compound product for up to 8 weeks. After 12 weeks of treatment, no significant differences were seen between the three groups with regard to reduction in PASI, whereas the proportion of patients with absent/very mild disease in group 2 was superior to that in group 3. Patients receiving therapy with the two-compound product experienced fewer lesional/perilesional adverse drug reactions than the calcipotriol-treated patients (P < 0.001): 10.9% in group 1, 11.5% in group 2 and 22.3% in group 3.

CONCLUSIONS

Two different short-term treatment regimens employing a recently developed two-compound product (calcipotriol/betamethasone dipropionate) provided rapid and marked clinical efficacy and were shown to be safe therapies for psoriasis vulgaris.

Psoriasis Susceptibility Locus on 18p Revealed by Genome Scan in Finnish Families Not Associated with PSORS1

The major susceptibility locus for psoriasis, PSORS1, resides on chromosome 6p and includes the candidate genes HLA-C, HCR, and CDSN. Based on a nationwide collection of psoriasis patients and genotyping for the PSORS1 susceptibility haplotype, we selected for a genome scan nine families who do not show association with PSORS1 to more easily detect minor loci for psoriasis susceptibility. In the genome scan, five loci gave initial evidence of linkage and were studied with a denser marker map. After fine mapping, only one locus on 18p11.23 showed suggestive evidence of linkage (nonparametric multipoint linkage analysis score, 3.58; p = 0.0038). The bootstrapping analysis showed that one large family contributed the majority of the linkage (p = 0.0039), but was supported by other families. Haplotype sharing between the linked families and haplotype association analysis gave additional support for the locus. Further, the 18p locus has shown nominal evidence of linkage with psoriasis in the British population. Taken together, these findings confirm the presence of a minor susceptibility locus for psoriasis on 18p11.

Matrix metalloproteinase-19 is expressed by keratinocytes in psoriasis

Keratinocyte hyperproliferation, inflammatory infiltrates, neoangiogenesis and alterations in cytokine levels are hallmarks of psoriatic skin. Matrix metalloproteinases (MMPs) have been associated with the remodeling of the extracellular matrix during inflammation, neovascularization, and malignant transformation. We have previously shown that particularly MMP-12 is abundantly expressed by macrophages and MMP-9 in macrophages and neutrophils of psoriatic lesions. In this work the expression of two novel metalloproteinases, MMP-19 and MMP-28, was investigated in psoriatic lesional and non-lesional skin. MMP-19 protein was detected by immunohistochemistry in 28/29 samples in keratinocytes in the same regions as Ki67 (marker of proliferating keratinocytes) and p63 (marker of keratinocyte stem cells). Immunosignaling was also seen in endothelial cells and fibroblasts. Furthermore, MMP-19 mRNA was upregulated in psoriatic keratinocytes and skin as assessed by quantitative real-time polymerase chain reaction. In lichen planus and lichenoid chronic dermatitis, MMP-19 staining was found in keratinocytes in areas where the basement membrane was abnormal. MMP-28 was not detected in psoriatic or non-lesional skin. Our results suggest that keratinocytes as well as the previously reported cell types (smooth muscle, endothelial and macrophages) can express MMP-19 in psoriasis and lichen planus. Upregulation of MMP-19 in keratinocytes may be influenced by changes in the architecture of the basement membrane zone.