Development and application of a multiplex PCR method for the simultaneous detection and differentiation of feline panleukopenia virus, feline bocavirus, and feline astrovirus.

A multiplex polymerase chain reaction (mPCR) assay was developed to detect and distinguish feline panleukopenia virus (FPV), feline bocavirus (FBoV) and feline astrovirus (FeAstV). Three pairs of primers were designed based on conserved regions in the genomic sequences of the three viruses and were used to specifically amplify targeted fragments of 237 bp from the VP2 gene of FPV, 465 bp from the NP1 gene of FBoV and 645 bp from the RdRp gene of FeAstV. The results showed that this mPCR assay was effective, because it could detect at least 2.25-4.04 × 104 copies of genomic DNA of the three viruses per µl, was highly specific, and had a good broad-spectrum ability to detect different genotypes of the targeted viruses. A total of 197 faecal samples that had been screened previously for FeAstV and FBoV were collected from domestic cats in northeast China and were tested for the three viruses using the newly developed mPCR assay. The total positive rate for these three viruses was 59.89% (118/197). From these samples, DNA from FPV, FBoV and FeAstV was detected in 73, 51 and 46 faecal samples, respectively. The mPCR testing results agreed with the routine PCR results with a coincidence rate of 100%. The results of this study show that this mPCR assay can simultaneously detect and differentiate FPV, FBoV and FeAstV and can be used as an easy, specific and efficient detection tool for clinical diagnosis and epidemiological investigation of these three viruses.

Significance of changes in local immunity in patients with hepatocellular carcinoma after percutaneous microwave coagulation therapy.

OBJECTIVE: To assess the local immune response in patients with hepatocellular carcinoma after percutaneous microwave coagulation therapy (PMCT). METHODS: Seventy-eight patients with hepatocellular carcinoma underwent PMCT. Both cancerous and adjacent liver tissue were taken before, and 3, 17 and 30 days after PMCT using ultrasound-guided liver biopsy. Specimens were stained by immunohistochemical techniques for detecting CD3, CD45RO, CD56, CD68, and CD20 positive cells. RESULTS: A few CD3, CD45RO, CD56, CD68 and CD20 positive cells were observed in the cancer stroma and surrounding sinusoids in liver tissue pre-PMCT. The number of immunocytes, except for CD20 positive cells, was significantly increased both within the cancer and the adjacent liver tissue, with a larger increase in tumor tissue at day 3 post-PMCT compared with pre-PMCT. These immunocytes were enlarged in size. The number of CD3, CD45RO and CD56 positive cells peaked at day 17 and CD68 positive cells peaked at days 3 post-PMCT. At day 30 post-PMCT, this increase still existed. These infiltrating immunocytes distributed in the parenchyma of the tumor, and within the lumen of small blood vessels after PMCT. In addition, more infiltrated immune cells were seen in cancer cell spaces. CONCLUSIONS: A change in immunocyte infiltration takes place in number, configuration and location after patients with HCC are treated with percutaneous microwave coagulation, suggesting that local immune function is enhanced post-PMCT.