Influence of TT virus infection on the thrombocytopenia of patients with chronic liver disease

TT virus (TTV) can replicate not only in the liver but also in hematopoieti c cells. To investigate the possible influence of TTV infection on the hema tological parameters of patients with chronic liver disease, serum samples from 581 patients with chronic. viral or non-viral liver disease were teste d for TTV DNA by polymerase chain reaction (PCR). PCR was performed by two distinct methods using N22 primer pairs (N22 PCR), which detect primarily t he four major TTV genotypes (1-4). and using genotype 1-specific primers (G enotype I-PCR). Thirteen hematological parameters measured in routine labor atory tests were compared among the patients who were positive or negative for TTV infection. The platelet count was significantly lower in the N22 PC R-positive group than in the N22 PCR-negative group among the 189 patients with chronic hepatitis C (CH-C) and among the 40 patients with chronic hepa titis without serological markers of ongoing hepatitis B virus or hepatitis C virus infection (CH-NBNC) (P < 0.0001, P < 0.005, respectively). Similar ly, among the patients with CH-C or CH-NBNC, the platelet count was signifi cantly lower in the TTV genotype 1-positive group than in the TTV genotype 1-negative group (P < 0.001, P < 0.05, respectively). The reduced platelet count of the TTV DNA-positive group was observed in every fibrotic stage of chronic hepatitis (F0-F3). These results suggest that infection of TTV of certain genotypes including genotype 1 may worsen the thrombocytopenia of p atients with CH-C or CH-NBNC, irrespective of the degree of hepatic fibrosi s. (C) 2001 Elsevier Science B.V. All rights reserved.