Objective: Anti‐p155 autoantibody, which was recently described in adult patients with dermatomyositis (DM), seems to be associated with cancer in this population. We performed a systematic review and meta‐analysis to ascertain the accuracy of anti‐p155 testing for the diagnosis of cancer‐associated myositis.Methods: We searched relevant databases, with no restrictions on study design or language, for original studies that included adult patients with probable/definite DM or amyopathic DM who were evaluated for neoplasm and anti‐p155 status. Pooled sensitivity and specificity were calculated using a bivariate model. We computed the diagnostic odds ratio (OR), likelihood ratios (LRs) for positive and negative test results, positive and negative predictive values, and the summary receiver operating characteristic (SROC) curve. Statistical heterogeneity between studies was assessed using the I² statistic, and 95% confidence intervals (95% CIs) were computed for the parameters studied.Results: Six studies including a total of 312 adult patients with DM were selected. The pooled sensitivity of anti‐p155 for diagnosing cancer‐associated DM was 78% (95% CI 45–94%), and specificity was 89% (95% CI 82–93%). The diagnostic OR was 27.26 (95% CI 6.59–112.82), and LRs for positive and negative test results were 6.79 (95% CI 4.11–11.23) and 0.25 (95% CI 0.08–0.76), respectively. Heterogeneity was substantial except with regard to the LR for a positive test result. The area under the SROC curve was 0.91 (95% CI 0.88–0.93). Taking the pooled prevalence of 17% as pretest probability, anti‐p155 had a positive predictive value of 58% and a negative predictive value of 95%.Conclusion: Our findings indicate that anti‐p155 autoantibody determination is useful for diagnosing cancer‐associated myositis and guiding disease management.

The objective of this study was to assess the prevalence, clinical, histological and immunological characteristics, and the long-term outcome of polymyositis-(PM) and dermatomyositis-(DM) associated lung disease, and to define subgroups of lung-associated inflammatory myopathies. This retrospective study included 81 consecutive patients diagnosed with PM/DM. Pulmonary involvement was systematically investigated in relation to clinical symptoms by chest radiography, high resolution computed tomography and pulmonary function testing. Anti-synthetase autoantibodies (ASA) were analysed by ELISAandconfirmedbyproteinandRNA immunoprecipitation methods. Statistical analyses were done with the Student t-test and Fisher exact test. Cumulative survival probabilities were estimated by the Kaplan-Meier method and Cox regression analysis. Fifty patients (61%) presented pulmonary involvement. Thirty-two (39%) had interstitial lung disease and five of them had devastating acute interstitial pneumonia with pneumomediastinum and an unfavorable prognosis. Histology showed diffuse alveolar damage in this subgroup and ASA were negative. Eighteen patients (22%) presented restrictive myopathic lung disease; in three of them respiratory muscles could not maintain ventilation. ASA were positive in 17 of the 50 patients (34%) and were significantly associated with interstitial lung disease (OR: 4.5 [95% CI: 1.3-15.3]), arthritis (OR: 6.0 [95% CI: 1.3-29.2]) and ‘mechanic hands’ (OR: 8.5 [95% CI: 1.7-41.4]); the presence of these autoantibodies did not imply worse survival prognosis. We concluded that clinical and immunological characteristics allowed the grouping of patients into different types of PM/DM lung-associated disease. Presence of ASA did not affect survival. ASA-negative patients with acute interstitial pneumonitis and pneumomediastinum had an unfavorable prognosis.

Objective: To determine the prevalence of myositis‐specific autoantibodies (MSAs) and myositis‐associated autoantibodies (MAAs) and their clinical and immunogenetic correlations in Mediterranean patients with idiopathic inflammatory myopathies.Methods: Sera from 88 patients were studied for MSAs and MAAs by RNA and protein immunoprecipitation. HLA typing was performed by sequence‐specific primer– and sequence‐specific oligonucleotide–polymerase chain reaction and serology. Statistical analyses were performed with Student's t‐test and Fisher's exact test. Cumulative survival probabilities were estimated by the Kaplan‐Meier method and Cox regression analysis.Results: Twenty‐eight patients (30%) had MSAs, most commonly antisynthetase antibodies (23.9%). Six patients (7.5%) had anti–Mi‐2 antibodies. No anti–signal recognition particles were found. Arthritis, mechanic's hands, interstitial lung disease, and sicca syndrome were more prevalent in patients with antisynthetase antibodies. Dysphagia and the need for more treatment courses were more frequent in patients who were anti–Mi‐2 positive. Forty‐three patients (48%) had MAAs, 20 (22%) with anti–Ro 60 and 18 (20.4%) with anti–Ro 52. Ten patients (11.4%) were positive for anti–PM‐Scl, 6 (6.8%) for anti‐RNP, and 1 for anti‐Ku antibodies. Patients with PM‐Scl, RNP, or Ro antibodies were more often classified as having overlap syndrome. Immunogenetic studies found a significant association between HLA–DR3 and the presence of antisynthetase antibodies (P = 0.049), anti–PM‐Scl antibodies (P = 0.017), and interstitial lung disease (P = 0.03). No statistically significant differences in mortality, survival, or clinical course were observed between patients positive for MSAs or MAAs and the remaining patients.Conclusion: These results are consistent with those from other published series, although some differences warrant consideration. Autoantibody studies may be useful for defining more homogeneous groups of patients with idiopathic inflammatory myopathies.

A new autoantibody against a 155-kDa protein has been described in patients with myositis. We conducted a study to determine the occurrence and types of cancer occurring in a cohort of patients with polymyositis (PM) or dermatomyositis (DM) and analyzed the value of this autoantibody as a serologic marker of cancer-associated myositis (CAM). Serum samples from all patients were examined by protein immunoprecipitation assays with HeLa cells to determine the presence of a 155-kDa protein band. HLA-DRB1 and DQA1 typing was performed by polymerase chain reaction-reverse sequence specific oligonucleotide. Statistical analyses were carried out with the Mann Whitney U and Fisher exact tests. Associations were determined using odds ratios (ORs) with 95% confidence intervals (CI). Eighty-five patients with myositis (20 PM and 65 DM) were included. CAM was detected in 16 patients (19%), 14 with DM. The shawl sign rash was significantly more frequent in patients with CAM than in those without (p < 0.01). Adenocarcinoma was the most frequent type of cancer (87.5%). Anti-p155 autoantibody was found in 1 of the 20 (5%) patients with PM and in 15 of the 65 (23%) patients with DM. A relationship between anti-p155 and CAM was found in DM patients (OR, 23; 95% CI, 5.23-101.2). The HLA-DQA1*0102 allele was not found in any of the anti-p155-positive patients. The prevalence of CAM in our cohort was 19%. Autoantibody against p155 was highly related to CAM and could be a reliable marker of cancer in patients with DM. Abbreviations CAM = cancer-associated myositis, CI = confidence interval, DM = dermatomyositis, OR = odds ratio, PM = polymyositis.