The objective of our study was to evaluate the association between peptidylarginine deiminase 4 (PAD4) concentration and its polymorphisms with mortality in patients with septic shock. We prospectively evaluated 175 patients aged over 18 years with septic shock upon intensive care unit (ICU) admission. However, 48 patients were excluded. Thus, 127 patients were enrolled in the study. At the time of the patients’ enrollment, demographic information was recorded. Blood samples were taken within the first 24 hours of the patient's admission to determine serum PAD4 concentrations and its polymorphism PADI4_89 [rs11203366], PADI4_94 [rs2240340] and PADI4_104 [rs1748033]. The mean age was 63.3 ± 15.2 years, 56.7% were male, PAD4 concentration was 4.62 (2.48‐6.20) ng/mL and the ICU mortality rate was 67.7%. The patients who died in the ICU had higher APACHE II and Sequential Organ Failure Assessment (SOFA) scores. In addition, PAD4 concentration was higher in patients who died during ICU stay. However, there were no differences regarding PADI4 polymorphisms and ICU mortality. In the logistic regression models, PAD4 concentrations were associated with ICU mortality when adjusted for APACHE II score and lactate (OR: 1.477; CI 95%: 1.186‐1.839; P < .001), and when adjusted for age, gender and APACHE II score (OR: 1.392; CI 95%: 1.145‐1.692; P < .001). In conclusion, PAD4 concentration, but not PADI4_89, PADI4_94 and PADI4_104 polymorphisms, is associated with ICU mortality in septic shock patients.

y unitermos key words resumoOs antígenos nucleares extraíveis (ENAs) são encontrados no soro da maioria dos pacientes com doença reumática sistêmica. Os principais ENAs estudados são SS-A/Ro, SS-B/La, RNP, Sm, Scl-70 e Jo-1. Objetivou-se neste trabalho: a) padronizar a técnica de contra-imunoeletroforese (CIE) para a detecção de ENAs; b) padronizar o substrato antigênico (ENAs) para a CIE a partir de baço de cão; c) comparar os resultados da CIE com as técnicas de imunofluorescência indireta (IFI) e Elisa para esses antígenos. Para tal foram estudados 40 soros de pacientes com doença reumática sistêmica confirmada por exames clínico e laboratorial (sorológico e biópsia). Como controle negativo foram utilizados dez soros de doadores de sangue normais, e, como controles positivos, seis soros-padrão anti-Ro, anti-La, anti-RNP, anti-Sm, anti-Scl-70, anti-Jo-1, para caracterizar os antígenos presentes no extrato de baço. Neste último foram detectados vários ENAs, exceto RNP e Scl-70. A técnica de CIE apresentou boas sensibilidade (70%) e especificidade (100%) em relação às outras técnicas (IFI e Elisa). A titulação dos soros pela CIE revelou positividade até diluições de 1:16 em 32,5% dos casos. Concluímos que a CIE e os antígenos extraídos de baço de cão podem ser utilizados na rotina laboratorial para triagem destes ENAs, com a vantagem, em relação à IFI, de poderem ser titulados. Auto-anticorpos Testes sorológicos Antígenos nucleares extraíveis Contra-imunoeletroforese abstract Extractable nuclear antigens (ENAs) are detected in the sera of the majority of patients with rheumatic systemic disease. The main ENAs studied are SS-A/Ro, SS-B/La, RNP, Sm, Scl-70 and Jo-1. The aim of this work was: a) to standardize the counterimmunoelectrophoresis technique (CIE) to detect ENAs; b) to standardize the extration of ENAs from dog spleen as a substract for CIE test; c) to compare the results obtained by CIE with those of indirect immunofluorescence (IFI) and Elisa for these antigens. Forty sera from individuals with rheumatic systemic disease confirmed by clinical and serological tests and by skin and/or kidney biopsies were tested. Ten normal sera from blood donors were used as negative control, and as positive control to check for ENAs in the spleen extract, six positive sera for anti