Practical issues for clinicians using high-dose intravenous immunoglobulin.

Sir,

We read with interest Dr Dhar's perspective on use of high-dose intravenous immunoglobulin (hd-IVIG) in dermatological conditions[1] and wish to comment on some of the important issues raised by the author. In our opinion, hd-IVIG has a rather limited role in the treatment of hypersensitive dermatoses.

The author has further suggested saving of IVIG samples prior to every infusion. This is neither necessary nor recommended as per international guidelines.[23] It has been recommended and is considered a good clinical practice to save serum samples for one-off infusions and annually for those on long-term therapy so as to enable “look-back” studies in case of viral outbreaks.[23] Records of batch numbers of immunoglobulin products should be maintained so that product recall can be facilitated, if required in the future. Although manufacturers of all IVIG preparations routinely employ viral inactivation techniques (solvent/detergent process that destroys lipid-coated viruses) as well as polymerase chain reaction screening tests to detect known viruses (HIV-1, HIV-2, hepatitis B surface antigen, and hepatitis C viruses), any new positive serology (post-IVIG infusion) should be properly investigated and notified to the relevant authorities.

Of the several IVIG preparations currently available in India, only one product ImmunoRel (5% preparation) from Reliance Life Sciences, has the manufacturing plant based in India, while the rest of the products are sourced from abroad.[4] So far, to the best of our knowledge, there has been no case of HIV transmission via immunoglobulin therapy, and therefore, monitoring of hepatitis B and C [yearly monitoring with hepatitis B surface antigen (HbsAg) and hepatitis C PCR for patients with antibody deficiency on long-term IVIG] is considered to be sufficient.

Even though hd-IVIG works in many dermatological conditions, clinicians must consider use of adjunctive therapy than just hd-IVIG, as concurrent immunosuppression (such as using anti-CD20 monoclonal antibody, Rituximab) has a synergistic effect with hd-IVIG[5] and can lead to long-term tolerance which is the proposed “vaccinal effect” of Rituximab.[5] Data from uncontrolled studies and case reports should be interpreted with caution, as often only favorable outcomes end up being published. Several confounding factors like differences in IVIG preparations, dosing schedules, use of concurrent immunosuppression and disease severity may affect the outcome of a given disease in an individual patient, and not just hd-IVIG on its own.