[Assessment of the PCR-Southern blot technique for the analysis of viremia in patients with acute hepatitis A]. / Valoración de la técnica de PCR-Southern blot para el análisis de la viremia en pacientes con hepatitis aguda A.

Assessment of viremia in hepatitis A virus (HAV) infection is not frequently performed with conventional methods because the techniques used are laborious, have low sensitivity are usually performed in feces. The aims of this study were to develop a polymerase chain reaction (PCR) and Southern blot technique to detect HAV-RNA in the serum of patients with acute HAV infection and to determine the relationship between HAV-RNA and anti-HAV IgM and alanine aminotransferase (ALT) levels. The presence of HAV-RNA was studied in 26 serum samples from 21 patients with acute hepatitis A. We also studied 11 samples from patients with acute hepatitis B and 15 samples from patients with non-A, non-E hepatitis. HAV-RNA was detected in 10 (38%) of the 26 serum samples from patients with acute hepatitis A. Simple PCR was positive in 5 samples and PRC-Southern blot was positive in 10. All the serum samples obtained during the first week of onset were HAV-RNA positive and 50% of those obtained during the second week were positive. None of the serum samples obtained after the second week of onset were HAV-RNA positive. None of the serum samples from the 11 patients with acute hepatitis B or from the 15 patients with non-A, non-E acute hepatitis were positive for HAV-RNA. No significant relationship was detected between HAV-RNA detection and an IgM anti-HAV or ALT positive result. In conclusion, the presence of HAV-RNA in acute hepatitis A is frequent but the PCR Southern blot technique is required for detection, which is transitory during the first weeks after onset.

Assessment of inactivation of hepatitis A vaccine by compound PCR.

Assuring the complete inactivation of hepatitis A virus (HAV) vaccine commonly requires prolonged tissue culture amplification, followed by detection of virus antigen in cell lysates. A reliable, but faster, alternative procedure is highly desirable since it will permit the prescreening of experimental batches of killed HAV, prior to tissue-culture amplification. We established experimental conditions for simultaneous, polymerase chain reaction (PCR)-based amplification of viral and cellular mRNA sequences from infected cell RNA (compound PCR). Under these conditions, the presence of virus-specific amplified sequences, as detected by Southern blot, allows the identification of incompletely inactivated vaccine batches with a threshold practically identical to that of the more time-consuming subculture and ELISA. Compound PCR is, by its nature flexible enough for adaption to different requirements and it should prove useful for rapid prescreening of vaccine batches and pilot studies for improvement of inactivation protocols.