Przegląd Epidemiologiczny - Państwowy Zakład Higieny

94 Jolanta Goździk, Hanna Czajka i inniNr 1INTRODUCTIONHematopoietic stem cell transplantation (HSCT)is an established mode of therapy for a number of malignantand nonmalignant conditions (1). Substantialprogress has been made in the field of HSCT duringthe past 40 years. Despite these advances, infectiouscomplications constitute the major cause of morbidity,re-hospitalization and mortality after successful HSCT.There are several risk factors for infection that stillexist in transplanted patients (2, 3). Impairment of humoraland cell-mediated immunity is seen in almost allHSCT recipients. The degree of immunodeficiency isdetermined by many factors. Reconstitution of immunesystem after HSCT occurs over a period of months toyears (2, 4). Immune response to antigens is low and therisk of infectious complications is high during immunereconstitution. The restoration of humoral immunityfor vaccine-preventable diseases in the autologoussetting and the transfer of donor immunity for vaccinepreventable diseases in the allogeneic setting are bothlimited. Moreover, the recipients usually lose immunememory of exposure to infectious agents and vaccinesaccumulated throughout their lives and antibody titersto vaccine preventable disease decline after HSCT.Several studies have demonstrated low levels of immunityagainst, measles, mumps, rubella, poliovirus,tetanus, Streptococcus pneumoniae, hepatitis A virusand others (5). Additionally, especially in children,serious disease finally treated with HSCT discontinuebasic vaccination program. Therefore after HSCT theyhave none or below protective level of immunity forvaccine-preventable diseases.The objectives of our study were to evaluate therate of immunization before transplantation and thepersistence of vaccine-specific antibodies after HSCTbefore start of revaccination protocol.PATIENTS AND METHODSThirty-eight children (16 girls and 22 boys) treatedby high-dose chemotherapy with autologous (19) andallogeneic (19; 14 from sibling and 5 from unrelateddonors) HSCT were recruited to the study in years 2007-2010. Clinical details of patients are presented in table I.The indication to high-dose chemotherapy followed byautologous transplantation were: Ewing sarcoma (7),neuroblastoma (7), medulloblastoma (2), non-Hodgkinlymphoma (2) and yolk sack tumor (1). The patientswere eligible for allogeneic transplantation becauseof poor prognosis in course of different malignant andnon-malignant diseases: acute lymphoblastic leukemia(10), severe aplastic anemia (3), chronic granulomatousdisease (2), severe combined immunodeficiency (1),juvenile mielomonoblastic leukemia (1), high-IgMsyndrome (1) and Fanconi anemia (1).Tab. I. Clinical characteristicTab. I. Charakterystyka klinicznaHSCTall allogeneic autologousnumber of patients 38 19 19Gendermale 22 12 10female 16 7 9age at diagnosis of primary disease (year)mean 7.0 5.7 8.4median 6.3 4.2 9.8min 0.2 0.2 1.7max 17.5 16.8 17.5age at HSCT (year)mean 8.6 7.8 9.4median 8.5 7.2 10.4min 0.5 0.5 2.4max 18.7 17.3 18.7age at revaccination (year)mean 10.5 9.1 11.8median 9.8 7.9 13.6min 1.2 1.2 3.6max 22.3 18.3 22.3Patients were commenced revaccination if theymet inclusion criteria like as: at least 9 months afterHSCT, good clinical condition, stable engraftment(ANC>1000/μl, platelet count >50000/μl), no symptomsof active infection, no symptoms of active GvHD, notreatment with immunosupresant. Informed consent wasobtained from the patients or their parents. Vaccinationprotocol used was based on the European Blood andMarrow Transplantation group (EBMT), the Centersfor Disease Control and Prevention (CDC) internationalguidelines for vaccination of HSCT recipients as wellas personal experience (6, 7, 8, 9).Specific vaccination history was obtained fromparents and/or the individual vaccination book. The surveyquestions captured information, included the type,number, and schedule of specified vaccines executedbefore transplantation. Information collected was separatedby autologous (A) and allogeneic (B) source ofHSCT. Blood samples (5-10 ml) for serological testingwere collected on the day that revaccination was started.Usually, blood samples were obtained at the same timethat specimens were collected for routine blood tests.Blood was centrifuged, and serum was separated andfrozen in aliquots at -20 0 C on the same day, until thesamples were tested in batches.