Celiac Disease and Increased Risk of Pneumococcal Infection: A Systematic Review and Meta-Analysis

Pneumococcal vaccination in celiac disease

“…In the 14-65 age group there is in fact an excess of risk, in part likely due to a lack of pneumococcal vaccination, in the absence of vaccination schemes [10].…”

“…More specifically, an impairment of the immune function of the spleen results in: (a) a reduction in IgM-memory B cells and a defective opsonization activity, thus predisposing to infections caused by encapsulated bacteria (mainly Streptococcus pneumoniae, Neisseria meningitidis and Haemophylus influenzae); and (b) a decrease in marginal zone B cells which, in turn, predisposes to the emergence of autoreactive T-cell clones, as a consequence of contemporary T-regulatory cell depletion, with the subsequent development of autoimmunity. Moreover, it must be remembered that the spleen also has an important filtering function; impairment results in (a) the defective removal of pits from erythrocytes, with a consequent increase in circulating pitted red cells and Howell-Jolly bodies, and (b) reduced platelet sequestration, leading to thrombocytosis, which, in turn, predisposes to thromboembolism [10,11].…”

“…Finally, a recent meta-analysis [10] evaluated the risk of pneumococcal infection compared to the general population, showing a higher risk in CD patients than in the general population (Odds Ratio, OR, 1.66, 95% CI 1.43-1.92).…”

Defective spleen function in autoimmune gastrointestinal disorders

“…In CD, the prevalence of defective spleen function is particularly increased in patients with concomitant autoimmune disorders and in refractory CD (RCD) [6]. Patients with CD have a higher risk of overwhelming septicaemia sustained by encapsulated bacteria [7,8], and this susceptibility has been related to the depletion of IgM memory B cells which derive from the marginal zone of the spleen and are known to be crucial in opsonising encapsulated bacteria [9]. The impairment of spleen function may be reversible, as in the case of CD after gluten-free diet [2], or Crohn's disease after anti-TNF- therapy with infliximab [10], or eosinophilic gastrointestinal disorders after corticosteroid treatment [5], and it is not necessarily associated with reduced spleen size.…”

“…ulcerative jejunoileitis, enteropathy-associated T-cell lymphoma, is often linked to splenic atrophy [6]. Recent studies [7,8] showing the significantly higher risk for pneumococcal sepsis in large cohorts of CD patients highlighted the importance of prevent overwhelming post-splenectomy infections in hyposplenic patients through vaccine prophylaxis [3].…”