Lower CH50 as a predictor for intractable or recurrent lupus enteritis: A retrospective observational study.

OBJECTIVES: Lupus enteritis (LE) is a rare but well-known gastrointestinal manifestation of systemic lupus erythematosus (SLE). This study was conducted to identify prognostic factors associated with poor responses in patients with LE. METHODS: We consecutively registered patients diagnosed with LE between January 2009 and October 2019, and retrospectively compared their clinical characteristics based on whether they had good or poor responses to treatment. RESULTS: A total of 13 patients (17 episodes) were included. The median age was 41 years, and 12 patients were female. A comparison of clinical characteristics between groups revealed similar computed tomography (CT) findings. However, serum CH50 levels were significantly lower in the poor response group (median [interquartile ranges (IQR)]; 29.2 [25.3-46.9] U/mL vs 19.3 [7.8-24.0] U/mL, p = .0095). More patients in the poor response group had higher titers of anti-cardiolipin ß2-glycoprotein I antibody (anti-CL ß2GPI Ab) and were started on glucocorticoids (GCs) at moderate doses. In multivariable analysis, serum CH50 level was independently associated with poor response to induction therapy. CONCLUSION: Lower levels of CH50 at the time of initial treatment predicted inadequate treatment response in patients with LE.

Cut-off values of immunological tests to identify patients at high risk of severe lupus nephritis.

Cut-off values for anti-dsDNA, anti-nucleosome and anti-C1q antibodies tests and for complementmediated hemolytic activity (CH50) were explored to identify patients with high risk of developing severe lupus nephritis (LN). Forty-one patients with confirmed systemic lupus erythematosus (SLE) were identified; their levels for the three antibodies and complement had been measured on a same serum sample. These patients were classified based on the presence of renal involvem ent; sixteen had active proliferative LN. With the cut-off values accepted in the laboratory for SLE diagnosis (anti-dsDNA > 100 UI/ml, anti-nucleosome > 50 U/ml or CH50 < 190 UCH50%) no significant differences were found between patients with and without LN. Anti-C1q > 40 U/ml showed a statistically significant association with LN and had 80% of specificity. Cut-off values for LN identified by Receiver Operating Characteristic curves (ROC) were higher for anti-dsDNA (> 455 IU/ml) and antinucleosome (>107 U/ml), lower for CH50 (< 150 UCH50%) and, for anti-C1q (> 41 U/ml) coincided with the cut-off values accepted for SLE. Anti-C1q > 134 U/ml had a 92% of specificity, 56% of sensibility and was associated with a fifteen-fold increased risk of LN. The simultaneous presence of anti-nucleosome > 107 U/ml and anti-C1q > 134 U/ml was associated with a 27-fold higher probability for LN. According to these results, the cut-off values used to detect SLE activity could be inadequate to identify patients at high risk of severe LN.

Cut-off values of immunological tests to identify patients at high risk of severe lupus nephritis

Cut-off values for anti-dsDNA, anti-nucleosome and anti-C1q antibodies tests and for complement-mediated hemolytic activity (CH50) were explored to identify patients with high risk of developing severe lupus nephritis (LN). Forty-one patients with confirmed systemic lupus erythematosus (SLE) were identified; their levels for the three antibodies and complement had been measured on a same serum sample. These patients were classified based on the presence of renal involvem ent; sixteen had active proliferative LN. With the cut-off values accepted in the laboratory for SLE diagnosis (anti-dsDNA > 100 UI/ml, anti-nucleosome > 50 U/ ml or CH50 < 190 UCH50%) no significant differences were found between patients with and without LN. Anti-C1q > 40 U/ml showed a statistically significant association with LN and had 80% of specificity. Cut-off values for LN identified by Receiver Operating Characteristic curves (ROC) were higher for anti-dsDNA (> 455 IU/ml) and anti-nucleosome (>107 U/ml), lower for CH50 (< 150 UCH50%) and, for anti-C1q (> 41 U/ml) coincided with the cut-off values accepted for SLE. Anti-C1q > 134 U/ml had a 92% of specificity, 56% of sensibility and was associated with a fifteen-fold increased risk of LN. The simultaneous presence of anti-nucleosome > 107 U/ml and anti-C1q > 134 U/ml was associated with a 27-fold higher probability for LN. According to these results, the cut-off values used to detect SLE activity could be inadequate to identify patients at high risk of severe LN.

Se exploraron valores de corte para los ensayos de anti-ADNdc, anti-nucleosoma, anti-C1q y complemento hemolítico total (CH50) capaces de identificar los casos con mayor riesgo de nefritis lúpica (NL) grave. Se seleccionaron 41 pacientes ≥ 16 años con lupus eritematoso sistémico (LES) confirmado que tenían titulados los niveles de los tres anticuerpos y CH50, en una misma muestra de suero. Fueron clasificados según presencia de compromiso renal; 16 presentaron formas proliferativas de NL activa. Con los valores de corte aceptados por el laboratorio para el diagnóstico de LES (anti-ADNdc > 100 UI/ml, anti-nucleosoma > 50 U/ml o un CH50 < 190 UCH50%) no se encontraron diferencias significativas entre casos con y sin NL. Un anti-C1q > 40 U/ml tuvo una especificidad del 80% y mostró una asociación estadísticamente significativa con NL. Al aplicar curvas Receiver Operating Characteristic (ROC) para NL, se identificaron valores de corte más altos para anti-ADNdc (> 455 IU/ml) y anti-nucleosoma (> 107 U/ml), más bajo para CH50 (< 150 UCH50%) y para el anti-C1q (> 41 U/ml) coincidió con el aceptado para diagnóstico de LES. Un anti-C1q > 134 U/ml presentó una sensibilidad del 56%, una especificidad del 92% y se asoció con quince veces más riesgo de NL. La presencia simultánea de anti-C1q > 134 U/ml y anti-nucleosoma > 107 U/ml se asoció 27 veces más riesgo de NL. De acuerdo a estos resultados los valores de corte empleados para actividad en pacientes con LES podrían resultar inadecuados para identificar pacientes con mayor riesgo de NL grave.

Comparison of neutralising antibody assays for detection of antibody to influenza A/H3N2 viruses: an international collaborative study.

A study was performed to investigate the reproducibility of haemagglutinin-inhibition (HI) and virus neutralising (VN) assays for detection of anti-influenza antibody. Participants in 11 laboratories from eight countries measured antibody to egg-grown A/Japan/434/2003, cell-grown A/Japan/434/2003 and A/Panama/2007/99 (H3N2) viruses in 18 human and two post-infection ferret sera. There was significant intra-laboratory assay variability for VN compared to HI. For replicate assays within laboratories, 14/410 (3%) and 130/631 (21%) titres differed by >2-fold (p<0.0001), and 0/410 (0%) and 35/631 (6%) titres differed by >5-fold (p<0.0001) by HI and VN, respectively. Although both assays showed inter-laboratory variation, VN assays were significantly more variable than HI. Median geometric coefficients of variation (GCV) for VN assays with each virus were 256%, 323% and 359% compared to 138%, 155% and 261% with HI. A serum standard improved inter-laboratory agreement and reduced median GCVs. This study raises concern about comparability of serology results from H5N1 vaccine trials and it is proposed that an International Standard for influenza H5N1 antibody is developed.

Determination of optimal in vitro conditions for caprine alternative complement pathway assay.

Optimal in vitro testing conditions for caprine alternative complement pathway assay were determined. Effects of the following variables were tested: heterologous erythrocytes; pH, ionic strength and Mg2+ ion concentration of the complement diluent; incubation time and temperature. Rabbit erythrocytes were the optimal target cells. The optimal buffer conditions were: pH 8.0, ionic strength 0.06 mmol NaCl and 5mmol Mg2+ ion. Optimal incubation time and temperature were 75 min and 30 degrees C, respectively.