Table 9. Immunosuppression risk groups of the Commission for Hospital Hygiene and Infection Prevention (KRINKO) at the Robert Koch Institute [349].

Risk group 1 (moderate immunosuppression/deficiency)

– Granulocytopenia < 0.5 × 109 /L; (< 500/µL) probably up to 10 days (analogous to leukopenia < 1 × 109 /L; < 1,000/µL), – Autologous stem cell transplantation up to 3 months after day 0 (day of stem cell return) – Lack of CD4-positive T helper cells < 200/µL (Caveat: age-appropriate normal values in children) – Autologous stem cell transplantation up to 3 months after intensive therapy phase Patients who have more than one characteristic of the immunosuppression/deficiency listed under risk group 1 are assigned to risk group 2.

Risk group 2 (severe immunosuppression/deficiency)

– Granulocytopenia < 0.5 × 109 /L (< 500/μL) for more than 10 days (analogous to leukopenia < 1× 109 /L; < 1,000/μL) – Severe aplastic anemia or macrophage activation syndrome during intensive immunosuppressive therapy – Allogeneic bone marrow or stem cell transplantation up to 6 months after completion of the intensive therapy phase (important: extent of GVHD and ongoing iatrogenic immunosuppression) – Acute inpatient treatment phase for autologous stem cell transplantation or after solid organ transplantation (until discharge)

Risk group 3 (very severe immunosuppression/deficiency)

– Allogeneic BMT/PBSCT in intensive therapy phase (until engraftment = regeneration of granulopoiesis) – Severe GVHD grade III or IV under intensive immunosuppression The decision to assign patients after allogeneic stem cell transplantation to group 3 is ultimately made by the treating hematologist-oncologist after reviewing all findings.

GVHD = graft-versus-host-disease = graft-versus-host-reaction; BMT = mone marrow transplantation; PBSCT = peripheral blood stem cell transplantation.