Figure 3

Representative images of A (H1N1) RNA detection in lung samples obtained from eight patients with influenza-like illness and pneumonia using in situ RT-PCR. Tissue was processed and in situ RT-PCR was done with NA specific primers as described in the Methods section and in Figure 1. Arrows indicate intense cytoplasmic signal in P01-P04 (a) and P05-P08 (b) positive samples in comparison with samples obtained from two A (H1N1)-negative patients [Neg ILI (−) 1 and 2]. Obtained signal suggested that amplification was positive in pneumocytes (black empty arrows) or macrophage-like cells (solid arrows; patients P01 and P02) and tracheal epithelium (patient P03). Recovered cDNA was subsequently amplified and PCR products were validated using sequencing reactions. (a) P01-P04: Tissue samples from patients 1 to 4. Neg ILI (−) 1: Negative Influenza-like illness patient 1. (b) P05-P08: Tissue samples from patients 5 to 8. Neg ILI (−) 2: Negative Influenza-like illness patient 2. Neg (No RT): Negative controls without reverse transcription reaction. Magnification: 40X and 100X.