strong. The sum of the staining intensity was used for total immunoreactivity.

Immunoreactivity was scored on a scale of 0 to 4 as follows: 0 representing negative or

less than 2% of positively stained cells, 1 representing 2-10% of positive cells, 2 for 11-

25% positive cells, 3 for 26-50% positive cells, and 4 representing more than 50%

positively stained cells. Dividing the total number of stained cells by the total number of

cells present and multiplying this value by 100 provided the approximate percentage of

positively stained cells [92, 93, and 94].

 In general description terms, weak immunoreactivity refers to gingival tissue

samples that had an average score between 0 and 1, moderate immunoreactivity to

gingival tissue samples with a score of 2-3, and strong immunoreactivity to gingival

tissue samples that had an average score between 3 and 4. Sections were examined and

scored "blindly" under a light microscope by two previously calibrated investigators

independent of each other [92, 93, and 94]. Dr. Indraneel Bhattacharyya of the Oral

Pathology department and Dr. Matthew Rudolph of the Periodontics department were the

grading investigators.

 First positive slides were differentiated from the negative controls. Then three

appropriate sections of each slide with adequate structural integrity were selected by the

examiners and graded according to the previously described protocol. The sections were

examined blindly by the two investigators independently of each other. As a group the

slides were reviewed and each sample was assigned a grade.