Expression of TNF-α in the three organs were shown in the nuclei of the tissue cells and detected by IHC technique. Depending on the scoring system used for the TNF-α, two parameters were dependent; the intensity of the staining of the nuclei and the percentage of the cells giving positive expression. The intensity of the nuclei of the stained cells was negative if there is no expression. Expression was found positive in all the studied organs, but different in score and intensity, in lung over expression (score 3+) in 7, 14 and 21 days post infection with moderate staining at 7 day and intense staining at 14, 21 day respectively, in liver expression was (score 2+, score 2+, and 3+) with moderate staining at 7 and 14 day post infection while there is intense staining at 21 post infection. The expression in the spleen was (score1+) with light staining at the period between 7 to 14 day then increase at 21 day reach to score 2+ with moderate staining. TNF-α expression in all studied sample compared with the positive control. Results show significant difference (P value >0.01) in the expression between the studied organs. Correlation between the TNF-α expression and number and size of lesion in the infected tissues were studied statistically and the study revealed that there was a significant relationship between the immunoreactive cell and its intensity with number and size of lesion in the same tissue (P value >0.01).