Table 3 Studies measuring serum biomarkers in patients with IPF
Investigator | Patients Controls | Biomarker / Summary | ROC curve analysis Cut-off values | Specificity – Sensitivity Diagnostic accuracy | Limitations |
|---|---|---|---|---|---|
Kobayashi et al. 50 | 45 67 | KL-6: a serum marker for interstitial pneumonia | Yes KL-6: 500–550 U/ml | KL-6: 95 - 95% | Non ILD-specific marker Potential influence by malignancies / Small number of patients |
Takahashi et al. 56 | 52 108 | Serum SP-A and SP-D as prognostic factors IPF and their relationship to disease extent | Yes SP-A: 45 ng/ml SP-D: 110 ng/ml | SP-A: 79 - 94% SP-D: 85 - 95% | Weak correlations with CT features / Inconclusive analysis of disease mortality / Reproducibility issues / Small number of patients |
Yokoyama et al. 57 | 14 | Circulating KL-6 predicts the outcome of rapidly progressive IPF | No | Not estimated | Small number of patients / Outcome prediction with pretreatment levels / Non ILD-specific marker |
Ishii et al. 61 | 49 9 | High serum concentrations of SP-A in UIP compared with NSIP | No | Not estimated | Small number of patients / Overlap of SP-A levels in UIP and NSIP / No ROC curve analysis / cut-off levels |
Satoh et al. 69 | 41 | Ca 19-9 serum levels as markers of disease activity in patients with fibrosing lung disease | No | Not estimated | Small number of IPF patients / No serial measurement / No ROC curve analysis / cut-off levels |
Takayama et al. 70 | 16 | Elevated Ca 19-9 serum levels are well Correlated with the disease activity | No | Not estimated | Small number of IPF patients / No serial measurement / No ROC curve analysis / cut-off levels |
Yokoyama et al. 71 | 35 70 | Superiority of KL-6 serum levels as a diagnostic marker of interstitial pneumonia | Yes KL-6: 449 U/ml Ca 19-9: 26 U/ml SLX: 41 U/ml | KL-6: 74 - 91 - 99% Ca 19-9: 43 - 77 - 94% SLX: 20 - 71 - 96% | Small number of IPF patients / Non ILD-specific markers / Not definitive cut-off values |
Satoh et al. 72 | 23 | Western blotting of serum SLX may serve as differentiator between lung adenocarcinoma and IPF | Yes SLX: 50 U/ml | SLX: 93 - 83% | Small number of patients / Low statistical power / Technical deficiencies |
Suga et al. 74 | 86 10 | Clinical significance of MCP-1 levels in BAL and serum in patients with ILDs | No | Not estimated | No definitive relation with disease severity / Influence by steroid treatment / Potential influence by other lung disorders |
Strieter et al. 75 | 32 | Effects of IFN-γ-1b on biomarker expression in patients with IPF | No | Not estimated | Pre- and post-treatment fluctuations / Not definitive results |