ACT principle

ACT Early

Pay attention to all infections and spot recurrent and persisting infections as well as severe ones as soon as possible.^1,2
Ask your patients about potential signs of infections and act early.

Serum immunoglobulin G (IgG) levels are not an independent marker of SID, but lower than normal IgG levels (<4 g/L in adults) with severe or recurrent infections resistant to anti-infective therapy should be followed up.^2,3
Measuring serum IgG levels before starting an anti-cancer therapy, and even during, may help identify patients at risk of infections who may benefit from timely treatment.³
Do vaccinate whenever possible, e.g. pneumococcus or salmonella typhi, and make sure to monitor the response of the immune system.^1,3

Treat with IgGs when recurrent or severe infections are associated with low IgG levels or insufficient vaccination response. Do not wait until infections persist or get more serious.
Treatment with IgGs should also be considered in patients with haematological malignancies and low IgG levels (<4 g/L in adults) who have experienced a single serious infection, or recurrent or persistent infections, despite receiving anti-infective therapy.³
After a clinically relevant interval without severe and recurrent infections or immunological recovery discontinuation of IgGs should be considered.³

Sánchez-Ramón S, et al. Primary and Secondary Immunodeficiency Diseases in Oncohaematology: Warning Signs, Diagnosis, and Management. Front Immunol. 2019; 10: 586.
Guideline on core SmPC for human normal immunoglobulin for intravenous administration (IVIg); EMA/CHMP/BPWP/94038/2007.
Jolles S, et al. Treating secondary antibody deficiency in patients with haematological malignancy: European expert consensus. Eur J Haematol 2021 Jan 16. doi: 10.1111/ejh.13580.