Inclusion Criteria:

Stage A

• Age ≥ 18 years old.
• Patients who require or are expected to require a transfusion of RBC component(s), including red cell exchange transfusion.
• Signed and dated informed consent.
• Female patients of child-bearing potential must:
  • Have negative serum or urine pregnancy tests prior to study treatment to rule out pregnancy; and
  • Use at least one method of birth control that results in a low failure rate (i.e., less than 1% per year) when used consistently and correctly such as implants, injectables, combined oral contraceptives, some intrauterine devices (IUDs), sexual abstinence or vasectomized partner for the duration of study participation and an additional 28 days.

Stage B

• Age ≥ 11 years old.
• Patients expected to require or requiring a transfusion of RBC component(s), including red cell exchange transfusion.
• Signed and dated informed consent and assent (if applicable).
• Female patients of child-bearing potential must:
  • Have negative serum or urine pregnancy tests prior to study treatment to rule out pregnancy; and
  • Use at least one method of birth control that results in a low failure rate (i.e. less than 1% per year) when used consistently and correctly such as implants, injectables, combined oral contraceptives, some intrauterine devices (IUDs), sexual abstinence or vasectomized partner for the duration of study participation and an additional 28 days.

Exclusion Criteria:

Stage A

• Confirmed positive baseline serum/plasma antibody specific to IBS RBC (S-303 treated RBC) as determined by INTERCEPT antibody screening panel prior to receiving the first study transfusion.
• Pregnant or breast feeding.
• Presence of a RBC warm autoantibody.
• Positive DAT as defined below:
  • A polyspecific-DAT reaction strength > 2+; or
  • A polyspecific-DAT (any strength) in conjunction with pan-reactivity with a commercial IAT antibody screening panel that precludes the identification of underlying alloantibodies or indicates the presence of autoantibody.
• Have had an RBC transfusion within 14 days prior to S-303 antibody screen for eligibility.
• Have received investigational products, including investigational blood products, pharmacologic agents or imaging materials, within the prior 28 days. Prior receipt of conventional blood products tested with an investigational ZIKV NAT test are not considered grounds for exclusion despite the investigational nature of the NAT test.
• Patients presenting with or expected to have massive hemorrhage (≥ 10 RBC units within 24 hours) or expected to require massive transfusion protocols. Planned red cell exchange does not apply.
• Patients who require neonatal transfusions and intrauterine transfusions.
• Pre-existing antibody to RBC antigens that may make the provision of compatible study RBC components difficult.
• History of transfusion reactions requiring washed RBCs, volume reduced RBC, or RBCs with additive solution removed.
• Patients with documented IgA deficiency or a history of severe allergic reactions to blood products.

Stage B

• Confirmed positive baseline serum/plasma antibody specific to IBS RBC as determined by antibody screening panel to S-303 treated RBC prior to receiving their first study transfusion.
• Pregnant or breast feeding.
• Patients who require neonatal transfusions and intrauterine transfusions.
• Patients with documented IgA deficiency or a history of severe allergic reactions to blood products.
• Pre-existing antibody to RBC antigens that may make the provision of compatible study RBC components difficult.
• History of transfusion reactions requiring washed RBCs, volume reduced RBC, or RBCs with additive solution removed.