Quantitative Analysis of Fibroblastic Foci in Usual Interstitial Pneumonia: Results

The clinical characteristics and laboratory findings of the patients with CVD-UIP and IPF/UIP are summarized in Table 1. There were no significant differences in clinical characteristics between CVD-UIP and IPF/UIP, although the proportion of female patients with CVD-UIP tended to be higher than that with IPF/UIP, and pack-years of smoking in IPF/UIP tended to be higher than those in CVD-UIP. In laboratory findings, serum surfactant pro-tein-D levels of IPF/UIP were higher than that of CVD-UIP, although the difference was not significant. In pulmonary function tests or BAL analysis, no significant difference was found between CVD-UIP and IPF/UIP.
Quantitative Analysis of the Degrees of FF: the Quantitative %FF Score
Using a CCD camera and the analytic software, we readily calculated the %FF in the sections of surgical lung biopsy (Fig 1). Even in IPF/UIP, the FF areas occupied only < 4% of the target fields, but our method enabled us to accurately quantify the extent of FF. The calculated proportion of the FF areas, the quantitative %FF score, was 1.67 ± 0.90% (± SD) in IPF/UIP patients. Interestingly, patients with CVD-UIP had much lower %FF score (0.39 ± 0.24%, p < 0.0001, compared with patients with IPF/UIP) [Fig 2].
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Intraobserver and Interobserver Correlation in the Quantitative Scoring Method
Using the Pearson correlation coefficient, we examined the intraobserver and interobserver correlation of the quantitative %FF scores. When our quantitative scoring was repeated on different days by the same observer, a significantly high correlation was found between the first time scores and second time scores (r = 0.898, p < 0.0001; Fig 3, top, A). Additionally, when the scoring was done by different observers, a significantly high correlation was also found between them (r = 0.877, p < 0.0001; Fig 3, bottom, B).

Table 1—Clinical Characteristics, and Laboratory, Physiologic and BAL Fluid Cell Findings of the Study Populations

Variables CVD-UIP IPF/UIP p Value, x2 Test
Clinical characteristics
Male/female gender, No. 8/7 13/3 0.20
Age at biopsy, yr 58.6 ± 8.6 (42-70) 62.0 ± 7.7 (50-79) 0.43
Pack-yr of smoking 23.5 ± 23.4 (0-50) 47.7 ± 48.7 (0-177) 0.17
Symptom onset, mo 7.9 ± 13.1 (1-43) 7.6 ± 12.1 (3-48) 0.86
Laboratory findings
Serum lactate dehydrogenase, U/L 234 ± 64 (174-377) 264 ± 100 (180-526) 0.50
Serum KL-6, U/L 785 ± 865 (254-2,320) 782 ± 562 (303-1,400) 0.65
Serum surfactant protein D, U/L 123 ± 47 (89-207) 311 ± 185(100-447) 0.30
Physiologic
FVC, % predicted 82.1 ± 15.2 (66-111) 81.1 ± 25.2 (45-128) 0.98
FEVj, % predicted 83.4 ± 8.4 (73-100) 85.4 ± 8.7 (72-100) 0.58
Resting Pao2, mm Hg 89.6 ± 9.2 (76-103) 79.6 ± 11.2 (64-102) 0.08
BAL fluid cell analysis, %
Lymphocytes 7.0 ± 5.8 (0.5-20) 4.4 ± 2.0 (0-26) 0.18
Neutrophils 1.2 ± 1.7 (0-39) 0.9 ± 2.2 (0-8.1) 0.42
Eosinophils 4.4 ± 12.2 (0-7) 1.1 ± 2.0 (0-8.6) 0.15

Figure-2

Figure 2. Quantitative %FF scores in patients with CVD-UIP and in IPF/UIP. The quantitative %FF scores were significantly higher in IPF/UIP than in CVD-UIP (p < 0.0001).

Figure-3

Figure 3. Intraobserver and interobsever correlations of %FF score. Significantly high intraobserver and interobserver correlations were noted (top, A: r = 0.898, p < 0.0001; bottom, B: r = 0.877, p < 0.0001, respectively).

This entry was posted in Pulmonary Function and tagged collagen vascular disease, fibroblastic foci, idiopathic interstitial pneumonia, quantitative analysis, usual interstitial pneumonia.