The dm of the study was to evduate the incidence of parvovirus B19 infection in agroup of children suffering from the chronic pure red cell aplasiamd, to establish its role in the disease etiology. The laboratory results, their correlation with the clinicd picture, the course of the disease aid treatment response in dl cases of parvovirus B19 infection were aidysed. Methods: Over the period of 1996-1999,29 children from dl centers of Paedistric Haematology in the Czech Republic being treated for the chronic form of pure red cell aplasiawere exanined. Sérologie testing of IgG aid IgM aitibodies agdnst parvovirus 19, cytologicd bone marrow exanination aid parvovirus B19 DNA aidysis by PCR methods were performed. Results: The DNA of the pa*vovirus B19 was found in 7/29 (24%) of the children with chronic pure red cell aplasia In two infaits, intraiterine pa-vovird infection led to a severe form of chronic pure red cell aplaeia accompanied by hydrops fetdis in one. The DNA of pa*vovirus B19 wa> dso found in aiother 5 DBA patients. In two, substaitid aggraváion of aiaemiaduring pavov ird infection wa> observed and in three other children the presence of parvovirus B19 DNA in the bone marow wa? detected without any change in the clinicd course of the disease. The sensitivity of IgG and IgM aitibody testing using ELISA was low (57% and 14% respectively). Only two children (29%) had the typicd giait proerythroblasts in their bone marrow. Conclusions: Parvovirus B19 infection should be excluded in dl cases of fetd hydrops aid chronic erythro-blastopeniadiagnosed in the neonád period or early infaicy. Pavoviius B19 infection cai mimic DBA in this age group. Vird DNA testing by the PCR method is necessary in the čase of ai unexpláned worsening of aiaemia in DBA patients and in dl patients indicated for SCT. Severe and occasiondly life threatening complicdions may be caised by areactivation or anew infection with pa-vovirus B19 during severe immunosupression rfter SCT. The presence of IgM aid IgG aitibodies against parvovirus B19 aid of typicd giait proerythroblasts in the bone marrow exanindion a*e highly specific for the diagnosis, but their negativity is insufficient for the exdusion of apa*vovirus B19 infection in infaits aid ininiunocompromised individuds, in whom vird DNA testing by PCR method is the only reliáMe method a. álaMe. The results cai help in estdilishing the correct diagnosis and choice of aipropriáe thera^y.

        Key words: pavov irus B19, pure red cell n> lasiaj Diamond-Blackfai aiaemia giait proerythroblasts, hydrops fetdis, chronic aiaemia