The purpose of this study was to evaluate the safety and efficacy of umbilical cord blood mononuclear cell in the treatment of refractory immune effector cell-related hemocytopenia by observing the efficacy related factors and adverse reactions.

Inclusion Criteria:

1. Age ≥18 years old (including boundary values), gender is not limited
2. ECOG score 0-2 points
3. Expected survival ≥6 months
4. Patients who have received immune effector cell therapy (marketed CAR-T cell therapy or dual antibody therapy) (no target), have grade 3-4 hemocytopenia after treatment, and do not recover to grade 2 within 3 weeks after conventional treatment. Defined as follows:

1) The neutrophils again decreased to grade ≥3 within 1 week after G-CSF discontinuation, or 2) Unable to detach from red blood cell or platelet transfusion (infusion time less than one week requires re-infusion) (5) Understand the research protocol and sign the informed consent voluntarily

Exclusion Criteria:

1. Patients who intend to undergo autologous hematopoietic stem cell transfusion or have undergone autologous hematopoietic stem cell transfusion
2. Significant lack of compliance to complete the study plan (such as suffering from uncontrolled mental illness, etc.)
3. Allergy or known allergy to any drug active ingredients, excipients, and blood products or preparations included in this study
4. Pregnancy, breastfeeding, planning pregnancy, or unwillingness to use effective contraception as required by research
5. There are other conditions that researchers believe are not suitable for inclusion