It is possible that the hypogammaglobulinemia observed is related to a high degree of systemic inflammation in the more severely ill patients, independently of treatment given, and it is known that frequent exacerbations may be caused by chronic inflammation.26 However, in our study we found no difference in CRP or white blood cell counts at inclusion when comparing patients with hypogamma-COPD and those with normal IgG levels. The gene discussed is CRP; the disease is Decreased circulating immunoglobulin concentration.