An apheresis machine configured to extract, purify, and collect at least 55% of the IgG present in whole blood, the machine comprising: (a) a separation container having an inlet and an outlet, and comprising a solid support covalently bonded to a ligand that specifically binds to the IgG; (b) a centrifuge bowl having an inlet to receive anticoagulated whole blood, and having an outlet coupled to the inlet of the separation container, the centrifuge bowl being configured to separate a plasma product from the whole blood and direct the plasma product to the inlet of the separation container; and (c) a collection container coupled to the outlet of the separation container, the collection container adapted for collecting purified IgG product, wherein the apheresis machine is configured to execute a method comprising: (i) contacting the plasma product with the solid support covalently bonded to the ligand that specifically binds to IgG in the separation container under conditions sufficient for non-covalent binding of immunoglobulin to the ligand; (ii) contacting the solid support in the separation container with an elution solution under condition whereby the non-covalently bound IgG is released from the ligand and into the elution solution to obtain elution solution comprising the IgG; (iii) collecting purified IgG in the collection container as an eluate comprising the eluted IgG; (iv) adding a neutralizing buffer to the eluate comprising the eluted IgG to result in a final solution comprising the collected purified IgG having a pH of between about 7.0 and about 8.0; and (v) wherein the method occurs without removing the separation container from the apheresis machine, which constitutes a closed system. (a) a separation container having an inlet and an outlet, and comprising a solid support covalently bonded to a ligand that specifically binds to the IgG; (b) a centrifuge bowl having an inlet to receive anticoagulated whole blood, and having an outlet coupled to the inlet of the separation container, the centrifuge bowl being configured to separate a plasma product from the whole blood and direct the plasma product to the inlet of the separation container; and (c) a collection container coupled to the outlet of the separation container, the collection container adapted for collecting purified IgG product, (i) contacting the plasma product with the solid support covalently bonded to the ligand that specifically binds to IgG in the separation container under conditions sufficient for non-covalent binding of immunoglobulin to the ligand; (ii) contacting the solid support in the separation container with an elution solution under condition whereby the non-covalently bound IgG is released from the ligand and into the elution solution to obtain elution solution comprising the IgG; (iii) collecting purified IgG in the collection container as an eluate comprising the eluted IgG; (iv) adding a neutralizing buffer to the eluate comprising the eluted IgG to result in a final solution comprising the collected purified IgG having a pH of between about 7.0 and about 8.0; and (v) wherein the method occurs without removing the separation container from the apheresis machine, which constitutes a closed system.