* pediatric patients (aged \< 18 years). * diagnosis of any kind of shock. * organ transplants in the past 3 months. * patients receiving immunosuppressive therapy. * diagnostic of hepatitis b virus (hbv) infection. * diagnostic of human immunodeficiency virus (hiv) infection or acquired immunodeficiency syndrome (aids). * current diagnosis of cancer. * history of malignancies in the past 5 years. * pregnant or lactating women. * have participated in other clinical trials in the past 3 months. * inability to comply with test requirements and peripheral blood stem cells collection. * inability to provide informed consent.

* pediatric patients (aged \< 18 years). * diagnosis of any kind of shock. * organ transplants in the past 3 months. * patients receiving immunosuppressive therapy. * diagnostic of hepatitis b virus (hbv) infection. * diagnostic of human immunodeficiency virus (hiv) infection or acquired immunodeficiency syndrome (aids). * current diagnosis of cancer. * history of malignancies in the past 5 years. * pregnant or lactating women. * have participated in other clinical trials in the past 3 months. * inability to comply with test requirements and peripheral blood stem cells collection. * inability to provide informed consent.

- pediatric patients (aged < 18 years). - diagnosis of any kind of shock. - organ transplants in the past 3 months. - patients receiving immunosuppressive therapy. - diagnostic of hepatitis b virus (hbv) infection. - diagnostic of human immunodeficiency virus (hiv) infection or acquired immunodeficiency syndrome (aids). - current diagnosis of cancer. - history of malignancies in the past 5 years. - pregnant or lactating women. - have participated in other clinical trials in the past 3 months. - inability to comply with test requirements and peripheral blood stem cells collection. - inability to provide informed consent.

- pediatric patients (aged < 18 years). - diagnosis of any kind of shock. - organ transplants in the past 3 months. - patients receiving immunosuppressive therapy. - diagnostic of hepatitis b virus (hbv) infection. - diagnostic of human immunodeficiency virus (hiv) infection or acquired immunodeficiency syndrome (aids). - current diagnosis of cancer. - history of malignancies in the past 5 years. - pregnant or lactating women. - have participated in other clinical trials in the past 3 months. - inability to comply with test requirements and peripheral blood stem cells collection. - inability to provide informed consent.