CELIAC DISEASE (CD) is an autoimmune disorder in which exposure to gluten triggers an inappropriate immune response against the cells in the mucosal lining of the gastrointestinal system, particularly the small intestines. CD and other autoimmune disorders are among the many conditions associated with the development of hyposplenism and an impaired immune response.1

This article discusses why some patients with CD are at increased risk for the development of certain infections and how the pneumococcal vaccine helps protect these vulnerable patients from some pulmonary infections.

What is hyposplenism?

Hyposplenism, also called hyposplenia, refers to reduced splenic function.2 The spleen is responsible for some essential immune functions and plays a central role in clearing pathogens from the bloodstream and controlling infection.3 The spleen produces antibodies and houses macrophages that identify and destroy dysfunctional red blood cells, bacteria, and parasites.4,5 It also synthesizes immunoglobulin M (IgM), an antibody that maintains the survival of IgM memory B cells and produces proteins responsible for coating cells and promoting phagocytosis.5 The liver can also remove many varieties of bacteria, but the spleen is more efficient when it comes to removing encapsulated bacteria such as Streptococcus pneumoniae, Haemophilus influenzae, and Neisseria meningitidis.6

Hyposplenism is associated with decreased phagocytosis of encapsulated bacteria, decreased antibody production, and alterations in the activation of the alternative complement pathway producing increased susceptibility to infection and impaired immune response to some infections, particularly those associated with encapsulated bacteria.6

Hyposplenism and CD

The incidence of hyposplenism in adult patients with CD ranges from 19% to 80%.7 A higher prevalence of hyposplenism is seen in patients with poorly controlled CD.6 This high incidence is particularly concerning because hyposplenism is associated with a fourfold increase in the risk of fulminant and fatal septicemia from encapsulated organisms in patients with CD.6

Clinical features

Hyposplenism is frequently asymptomatic or may include nonspecific signs and symptoms, such as anemia, fatigue, frequent infections, or excessive bleeding.8 No validated and feasible diagnostic studies are recommended for screening asymptomatic patients with CD for splenic function.6 However, if patients with CD present with thrombocytosis, they should have further follow-up to assess for hyposplenism.6

The controversy

Because hyposplenism may progress in severity, appropriate vaccination efforts should be initiated promptly after diagnosis while the best immune response to the vaccine is possible.3 However, without routine screening for the disorder among patients at risk, many patients with hyposplenism are undiagnosed and remain at high risk for infection.6 This has led to controversy about whether and when to vaccinate patients with CD against pneumococcal pneumonia. Because no screening method exists for hyposplenism and the risk is high, should we just give the pneumococcal vaccine, recommended for patients with hyposplenism, to all patients with CD?

The Advisory Committee on Immunization Practices (ACIP) and CDC recommend pneumococcal vaccination for all patients with a condition that increases risk for developing pneumonia or another invasive pneumococcal disease and for those at risk for a serious outcome if pneumonia develops.9 The Infectious Diseases Society of America recommends immunization against encapsulated organisms for all patients with conditions associated with hyposplenism.7 In 2014, the British Society of Gastroenterology updated its recommendations for patients with CD to include routine pneumococcal vaccination of all adults diagnosed with CD, regardless of splenic function.10 A recent review and metanalysis conducted by Simons and colleagues also concluded that CD is associated with an increased risk of pneumococcal infection and that providers should consider vaccination for all patients with CD.7 The most recent guidelines from the American College of Gastroenterology were published in 2013 and did not include this recommendation, but some providers now think it should be included.11

Until a better screening option is available, it may be a prudent course of action for providers to ensure that adults diagnosed with CD receive a dose of pneumococcal 13-valent conjugate vaccine (PCV13) followed by the 23-valent pneumococcal polysaccharide vaccine (PPSV23) at least 8 weeks later.12 Booster doses of PPSV23 should be administered following clinical guidelines. ACIP recommends a single booster dose 5 years after the first PPSV23 dose while others recommend a booster dose of PPSV23 be given every 5 years.3

Follow-up

Nurses who care for patients with CD can take steps to prevent a serious and possibly fatal infection. Ensuring patients with CD are up-to-date with all vaccinations is important. Also, counsel patients on appropriate steps to preventing infections, such as avoiding exposure to people with known infections, appropriate hand hygiene, and routine vaccination of household members. Teach patients how to self-monitor for signs and symptoms of infection and when to seek medical care.

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