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Christopher T Ritchlin

Publications and source records attributed to Christopher T Ritchlin.

25 records · Page 2Linked to original sources
PubMed2004

Pneumococcal vaccine response in psoriatic arthritis patients during treatment with etanercept.

OBJECTIVE: Therapeutics used to treat inflammatory diseases, including psoriatic arthritis (PsA), may potentially interfere with normal immune system function. Immune system function can be assessed by evaluating response to vaccination. We assessed the ability of patients with PsA treated with etanercept to produce antibodies in response to pneumococcal antigen challenge. METHODS: Patients with PsA (n = 205) were stratified by methotrexate (MTX) use and randomly assigned to receive either placebo or etanercept 25 mg twice weekly by subcutaneous injection. After 4 weeks of treatment with study drug, a 23-valent pneumococcal vaccination was administered. Antibody levels to 5 antigens (9V, 14, 18C, 19F, and 23F) were measured by ELISA before and 4 weeks after vaccination in 184 patients. The proportion (%) of patients with 2- and 4-fold increases in antibody titers was analyzed. RESULTS: Patients treated with etanercept or placebo had similar responses to the vaccine. A 2-fold increase in titer to at least 2 antigens was achieved by 67% of patients, and a 4-fold increase to at least 2 antigens was achieved by 47% of patients. Approximately 20% of patients in each group failed to show a 2-fold response to any antigens. Logistic regression analysis showed MTX use and age were predictors of a poor response. CONCLUSIONS: Patients with PsA treated with etanercept were able to produce antibodies in response to pneumococcal vaccination. Patients receiving MTX had lower mean antibody levels in response to the vaccine. There was no increased risk of poor response with etanercept treatment given alone or with MTX.

Adolescent↗
PubMed2003

Mechanisms of TNF-alpha- and RANKL-mediated osteoclastogenesis and bone resorption in psoriatic arthritis.

Psoriatic arthritis (PsA) is an inflammatory joint disease characterized by extensive bone resorption. The mechanisms underlying this matrix loss have not been elucidated. We report here that blood samples from PsA patients, particularly those with bone erosions visible on plain radiographs, exhibit a marked increase in osteoclast precursors (OCPs) compared with those from healthy controls. Moreover, PsA PBMCs readily formed osteoclasts in vitro without exogenous receptor activator of NF-kappaB ligand (RANKL) or MCSF. Both osteoprotegerin (OPG) and anti-TNF antibodies inhibited osteoclast formation. Additionally, cultured PsA PBMCs spontaneously secreted higher levels of TNF-alpha than did healthy controls. In vivo, OCP frequency declined substantially in PsA patients following treatment with anti-TNF agents. Immunohistochemical analysis of subchondral bone and synovium revealed RANK-positive perivascular mononuclear cells and osteoclasts in PsA specimens. RANKL expression was dramatically upregulated in the synovial lining layer, while OPG immunostaining was restricted to the endothelium. These results suggest a model for understanding the pathogenesis of aggressive bone erosions in PsA. OCPs arise from TNF-alpha-activated PBMCs that migrate to the inflamed synovium and subchondral bone, where they are exposed to unopposed RANKL and TNF-alpha. This leads to osteoclastogenesis at the erosion front and in subchondral bone, resulting in a bidirectional assault on psoriatic bone.

Arthritis, Psoriatic↗
PubMed2003

Etanercept in psoriatic arthritis.

Psoriatic arthritis (PsA), an inflammatory arthritis associated with psoriasis, can lead to disability from progressive joint destruction and bony fusion. To date, conventional disease modifying antirheumatic drugs (DMARDS) have not convincingly lessened joint pain and inflammation in PsA and there is very little data on the limitation of radiographic progression with these agents. The biological agent etanercept (Enbrel, Amgen, Inc, Thousand Oaks, California, USA) is a soluble TNF receptor fusion protein with proven efficacy in the treatment of rheumatoid arthritis (RA). In a Phase II and Phase III trial, conducted in moderate-to-severe PsA, etanercept significantly reduced joint pain and swelling and lowered the erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) level. A significant decline in structural damage was observed as early as 6 months after starting the drug. Etanercept also improved quality of life measures (Health Assesment Questionnaire [HAQ] and global assessment scores). Up to a third of patients experienced transient injection-site reactions. Rare cases of opportunistic infection, demyelinating disorders and aplastic anaemia have been reported, but a causal link has not been established. In summary, etanercept is a safe and effective agent for the treatment of PsA and represents a major advance in the therapy of this potentially crippling disease.

Animals↗
PubMed2002

Pseudoxanthoma elasticum masquerading as Sjögren's syndrome.

Pseudoxanthoma elasticum is an inherited disorder of abnormal calcification of elastic fibers in the skin, retina, and cardiovascular system. Herein, we report a patient who had dry eyes and mouth, keratoconjunctivitis sicca, and a low titer ANA at presentation. A lip biopsy was performed to confirm a clinical suspicion of Sjögren's syndrome; however, the histologic findings were diagnostic of pseudoxanthoma elasticum. Antibodies to Ro and La were negative. Subsequently, she was found to have skin and eye findings consistent with pseudoxanthoma elasticum. Although a causal relationship between keratoconjunctivitis sicca and pseudoxanthoma elasticum is not proven, salivary gland involvement with pseudoxanthoma elasticum may explain this patient's symptoms. Physicians should consider the diagnosis of pseudoxanthoma elasticum in patients who present with sicca symptoms without obvious cause, especially if cutaneous or ophthalmologic abnormalities, or both, are present. Careful monitoring for associated problems is needed as soon as pseudoxanthoma elasticum is diagnosed.

Journal Article↗
PubMedDate not supplied

Microarray analyses of peripheral blood cells identifies unique gene expression signature in psoriatic arthritis.

Psoriatic arthritis (PsA) is a chronic and erosive form of arthritis of unknown cause. We aimed to characterize the PsA phenotype using gene expression profiling and comparing it with healthy control subjects and patients rheumatoid arthritis (RA). Peripheral blood cells (PBCs) of 19 patients with active PsA and 19 age- and sex-matched control subjects were used in the analyses of PsA, with blood samples collected in PaxGene tubes. A significant alteration in the pattern of expression of 313 genes was noted in the PBCs of PsA patients on Affymetrix U133A arrays: 257 genes were expressed at reduced levels in PsA, and 56 genes were expressed at increased levels, compared with controls. Downregulated genes tended to cluster to certain chromosomal regions, including those containing the psoriasis susceptibility loci PSORS1 and PSORS2. Among the genes with the most significantly reduced expression were those involved in downregulation or suppression of innate and acquired immune responses, such as SIGIRR, STAT3, SHP1, IKBKB, IL-11RA, and TCF7, suggesting inappropriate control that favors proin-flammatory responses. Several members of the MAPK signaling pathway and tumor suppressor genes showed reduced expression. Three proinflammatory genes--S100A8, S100A12, and thioredoxin--showed increased expression. Logistic regression and recursive partitioning analysis determined that one gene, nucleoporin 62 kDa, could correctly classify all controls and 94.7% of the PsA patients. Using a dataset of 48 RA samples for comparison, the combination of two genes, MAP3K3 followed by CACNA1S, was enough to correctly classify all RA and PsA patients. Thus, PBC gene expression profiling identified a gene expression signature that differentiated PsA from RA, and PsA from controls. Several novel genes were differentially expressed in PsA and may prove to be diagnostic biomarkers or serve as new targets for the development of therapies.

Adult↗