Analysis of EBV genome load and EBV sequences present in XLP patients. (A) The graph shows the results of quantitative PCR analysis to determine the EBV load in PBMC samples collected prospectively from patients XLP5 and XLP6 between 2003 and 2006. (B) Analysis of EBV sequences present in the same PBMC samples from patient XLP5 using EBNA2 and LMP1 HTAs. In the top panel, PBMC DNA was PCR-amplified using type 1 specific EBNA2 primers and the resulting PCR products analyzed by HTA using a 1.1 EBNA2 allele-specific probe. Also shown are the results from a panel of reference control isolates known to carry a 1.1, 1.2, 1.3A,1.3B or 1.3E EBNA2 allele. In the bottom panel, the same DNA samples were PCR-amplified using LMP1-specific primers and the resulting PCR products analyzed by HTA using a Med⁺ LMP1 allele-specific probe. Also shown are the results from a panel of reference control isolates known to carry a B95-8, Ag876/Ch1, Ch2, Med⁺ or Med⁻ LMP1 allele. The results show that each XLP5 PBMC sample contains detectable 1.3B EBNA2 and Med⁻ LMP1 alleles.