Elevated anti-cyclic citrullinated peptide antibody titer is associated with increased risk for interstitial lung disease.

This paper is to examine the relationship between anti-cyclic citrullinated peptide (anti-CCP) antibody titers and the development of interstitial lung disease (ILD) in patients with and without rheumatoid arthritis (RA). A retrospective investigation was conducted on all adult patients tested for anti-CCP between January 1, 2007, and December 31, 2012, in a university healthcare system. Patients with specified exposures or conditions known to cause ILD were excluded. The prevalence of ILD was compared between those with and without a positive CCP. The study population was then divided into four titer groups based on anti-CCP titers: negative, low titer, moderate titer, high titer. Fisher's exact tests compared the prevalence of ILD among the anti-CCP titer groups. Multivariate logistic regression examined the association between anti-CCP and ILD while controlling for confounders. These analyses were repeated in two subgroups: a "confirmed RA" subgroup and an "unconfirmed RA" subgroup. Two thousand and thirty patients met inclusion criteria and 453 of those had confirmed RA. Progressively higher anti-CCP titer groups developed an increasingly higher prevalence of ILD (p < 0.01). When adjusting for age, tobacco, and a diagnosis of RA, higher anti-CCP titer groups continued to correlate with an increased prevalence of ILD (OR 1.47, 95% CI 1.10-1.96, p < 0.001). This study is the first to show that progressively higher anti-CCP titers correlate with increasing prevalence of ILD, even when adjusting for confounders.

Decreased CD3-CD16+CD56+ natural killer cell counts in children with orbital myositis: a clue to disease activity.

The study aimed to document the utility of the absolute number of natural killer cells as a biomarker in paediatric orbital myositis (OM). Extracted data from four children with OM included demographics, laboratory values, imaging and treatment response. Stored sera (-80°C) were tested for IgG4 levels in three cases and antibody to Coxsackie B in two cases. Their first symptom was at 14.4±1.2 years (mean±SD). At diagnosis three had creatine phosphokinase (CPK) of 97.3±44.2, aldolase of 8.5±2.8 (n=2), alanine aminotransferase (ALT) of 13±2.8 (n=2) and aspartate aminotransferase (AST) of 21.3±2.9. IG4 level was 87.7±66 (normal=8-89 mg/dL); two sera (patients 1and4) were positive (>1:8 dilution) for anti-Coxsackievirus antigen B5. The CD3-CD16+CD56+ natural killer absolute count was 96.7±28.7 (lower limit of normal=138), increasing to 163±57.2 with disease resolution in three patients. The fourth patient was followed elsewhere. CT showed involvement of bilateral superior oblique, lateral rectus or the left medial rectus muscles. Treatment included intravenous methylprednisolone, methotrexate (n=2) and other immunosuppressants. Paediatric OM disease activity was associated with initially low absolute CD3-CD16+CD56+ natural killer cell counts, which normalised with improvement. We speculate (1) infection, such as Coxsackie B virus, may be associated with paediatric OM; and (2) the absolute count of circulating CD3-CD16+CD56+ natural killer lymphocytes may serve as a biomarker to guide medical therapy.