To the Editor:

We thank Dr. Fernández-Fernández for his interesting letter in response to our article on the risk of infections in GCA. We agree that hypogammaglobulinemia is one of many potential mechanisms that could explain the increased risk of infections we observed in patients with GCA. Little is known about the frequency of hypogammaglobulinemia in GCA patients, and the nature of our data does not allow us to explore this. Future studies of GCA should include measurement of gammaglobulins in order to assess the prevalence of hypogammaglobulinemia in these patients and its possible association with infection.

Madeleine Durand MD, MSc, FRCPC*, Sara L. Thomas MBBS, MSc, PhD†, * Centre Hospitalier de l'Université de Montréal, Montreal, Quebec, Canada, † London School of Hygiene and Tropical Medicine, London, UK.