Does anybody know how pocket and loss of attachment correlate with gingival crevicular fluid tumour necrosis factor alpha in children?

In children it is not clear how pocket and loss of attachment correlate with periodontal disease and if they even can be measured in children around 10 years old. Gingival crevicular fluid tumour necrosis factor alpha is sometime used as a marker of periodontal inflammation in children. I am wondering if anybody knows how valid and reliable this is to measure periodontal inflammation or if anybody knows about a publication that looked into that question. Thanks!