Matrix-dependent HHV-8 DNA detection in paired buffy coat and plasma from patients with hematological diseases in the Brazilian Amazon.

BACKGROUND: HHV-8 is a lymphotropic oncogenic virus associated with Kaposi sarcoma and lymphoproliferative disorders. In the Western Brazilian Amazon, limited molecular data may underestimate its circulation, particularly when detection relies on one biological matrix. OBJECTIVES: To estimate HHV-8 molecular prevalence and compare viral DNA detection in paired buffy coat and plasma samples from patients with hematological diseases, METHODS: Paired buffy coat and plasma samples from 350 patients receiving care at a reference hematology center in the Western Brazilian Amazon were tested using qualitative nested PCR targeting HHV-8 ORF26. Demographic and diagnosis-related information was collected. Detection frequencies, prevalence ratios, and paired-matrix agreement metrics were estimated. RESULTS: HHV-8 DNA was detected in at least one matrix in 19/350 patients (5.43%; 95% CI: 3.50-8.32). Results were discordant in 18/19 positive participants: nine were positive only in buffy coat, nine only in plasma, and one in both matrices. Each matrix alone identified 10 participants, whereas paired testing identified 19. No statistically significant associations were identified with sex, age group, or hematological disease group. Agreement between matrices was low, with Cohen's kappa of 0.074 and positive agreement of 10.00%, indicating that buffy coat and plasma provided complementary rather than interchangeable qualitative PCR results. CONCLUSIONS: Buffy coat and plasma yielded largely non-overlapping qualitative HHV-8 PCR detections. Paired testing increased detections from 10 with either matrix alone to 19 when both were considered. These findings support matrix-informed surveillance in hematological populations from endemic or underrepresented settings.