Effects of Janus kinase inhibitor tofacitinib on circulating serum amyloid A and interleukin-6 during treatment for rheumatoid arthritis

The Janus kinase inhibitor tofacitinib is currently being investigated as a disease-modifying agent in rheumatoid arthritis (RA). We investigated the in-vivo effects of tofacitinib treatment for 4 weeks on elevated circulating acute-phase serum amyloid (SAA) levels in 14 Japanese patients with RA. SAA levels fell from 110·5 ± 118·5 μg/ml (mean ± standard deviation) at treatment initiation to 15·3 ± 13·3 μg/ml after 4 weeks treatment with tofacitinib. The reduction in SAA levels was greater in patients receiving tofacitinib plus methotrexate compared with those receiving tofacitinib monotherapy. Tofacitinib was also associated with reduced serum interleukin (IL)-6, but had no effect on serum levels of soluble IL-6 receptor. Patients were divided into groups with adequate (normalization) and inadequate SAA responses (without normalization). Serum IL-6 levels were reduced more in the group with adequate SAA response compared with those with inadequate SAA response. These results suggest that tofacitinib down-regulates the proinflammatory cytokine, IL-6, accompanied by reduced serum SAA levels in patients with active RA. The ability to regulate elevated serum IL-6 and SAA levels may explain the anti-inflammatory activity of tofacitinib.

Genetic association analysis of the IGFBP7, ADAMTS3, and IL8 genes as the potential osteoarthritis susceptibility that maps to chromosome 4q

OBJECTIVES

To determine by genetic association analysis whether the 4q functional candidate genes IGFBP7, ADAMTS3, and IL8 might encode for susceptibility to osteoarthritis (OA).

METHODS

Expression of IGFBP7, ADAMTS3, and IL8 in adult OA articular cartilage chondrocytes was demonstrated by reverse transcription-polymerase chain reaction. The genes were screened for common polymorphic DNA variants by direct sequencing of exons, intron-exon boundaries, and the 5' and 3' untranslated regions. The variants were genotyped in the female probands from the 146 families which each contained two or more sisters who had undergone total hip replacement (THR) and in 375 female controls matched for age. Variants showing evidence for association were subsequently genotyped in 244 female-THR patients with OA. Allele frequencies between the probands (or patients) and the controls were compared by chi(2) analysis.

RESULTS

Fourteen common variants were identified in the three genes. An ADAMTS3 single nucleotide polymorphism was associated in the probands (p = 0.015) and an ADAMTS3 insertion/deletion approached significance (p = 0.059). However, neither variant was associated in the additional 244 patients with hip OA, with p values of 0.12 and 0.19, respectively.

CONCLUSIONS

The analysis implies that the chromosome 4q female hip OA susceptibility is not coded for by polymorphism within the functional candidates IGFBP7, ADAMTS3, or IL8.

Cloning and functional analysis of human p51, which structurally and functionally resembles p53

The p53 tumor suppressor gene, which is induced by DNA damage and/or stress stimuli, causes cells to undergo G1-arrest or apoptotic death; thus it plays an essential role in human carcinogenesis. We have searched for p53-related genes by using degenerate PCR, and have identified two cDNA fragments similar to but distinct from p53: one previously reported, p73, and the other new. We cloned two major splicing variants of the latter gene and named these p51A and p51B (a human homologue of rat Ket). The p51A gene encodes a 448-amino-acid protein with a molecular weight of 50.9 kDa; and p51B, a 641-amino-acid protein with a molecular weight of 71.9 kDa. In contrast with the ubiquitous expression of p53, expression of p51 mRNA was found in a limited number of tissues, including skeletal muscle, placenta, mammary gland, prostate, trachea, thymus, salivary gland, uterus, heart and lung. In p53-deficient cells, p51A induced growth-suppression and apoptosis, and upregulated p21waf-1 through p53 regulatory elements. Mutations in p51 were found in some human epidermal tumors.