Association between Klebsiella pneumoniae and ankylosing spondylitis: A systematic review and meta‐analysis

Abstract

Aim The aim of this study is to evaluate the association between Klebsiella pneumoniae infection and ankylosing spondylitis (AS). Method Five electronic databases, PubMed, Embase, Medline, Web of Science, and Scopes, were searched until September 29, 2021. Cohort and case‐control studies that assessed the association between K. pneumoniae infection and AS were included. Pooled odds ratio (OR) was selected to show the effect size. Subgroup analysis (active or inactive AS) and 2 forms of sensitivity analysis were conducted. All statistical analyses were conducted by using STATA 12.0. Results There were 25 case‐control studies finally included, including 8 studies concerning presence of K. pneumoniae in feces, and 17 studies concerning serum antibody (immunoglobulin [Ig]G, IgM, IgA) against K. pneumoniae. The results suggested that when compared with healthy people, presence of K. pneumoniae in feces was associated with AS (OR: 5.65; 95% CI: 1.68‐19.00). Similarly, when compared with healthy people, higher positive rates of IgA (OR: 6.28; 95% CI: 3.32‐11.91) and IgG (OR: 5.22; 95% CI: 1.36‐19.99) were observed. Subgroup analyses suggested that association between K. pneumoniae and AS appears stronger in active AS. Conclusion When compared with healthy people, a significantly higher positive rate of K. pneumoniae in feces, serum IgA and IgG were observed in patients with AS, suggesting that K. pneumoniae probably plays a crucial role in the occurrence of AS. The findings in this study need further prospective investigations for confirmation.

The bacterial link with rheumatoid arthritis

“…pneumoniaeinfecesofpatientswithAS. 13 However, K. pneumoniae has not been demonstrated to cause AS-like phenotype in animal models. IgA antibodies to K. pneumoniae derived from AS patients may be used as probes to identify serotypes of…”

“…The similar approaches by Chriswell et al 11 and other studies in RA can be adopted to investigate the bacterial association with ankylosing spondylitis (AS), another inflammatory arthritis with high suspicion of bacteria as a trigger. A meta‐analysis reports presence of IgA and IgG antibodies against Klebsiella pneumoniae in serum and presence of K. pneumoniae in feces of patients with AS 13 . However, K. pneumoniae has not been demonstrated to cause AS‐like phenotype in animal models.…”

Vesicular traffic-mediated cell-to-cell signaling at the immune synapse in Ankylosing Spondylitis

“…Self-reactive T cells with poor immunological synapse formation may be able to circumvent negative selection in the thymus, where self-antigen expression is exceedingly low, owing to the extremely low expression of selfantigens. Numerous self-and foreign-antigen peptides have been analyzed and sequenced in the past, but there is no evidence that any of these peptides are cross-reactive (19). In addition, Taurog et al observed that clinical symptoms manifested in HLA-B27/Hu2m transgenic rats lacking functional CD8+ T cells (20,21).…”

Joint together: The etiology and pathogenesis of ankylosing spondylitis

“…Early results suggested Klebsiella pneumoniae , a Gram-negative bacterium causing pneumonia and sepsis, as a potential candidate. It was first related to AS development due to its fecal carriage and increased serum antibody levels compared to those in HLA-B27-negative patients ( 15 ). Then members from Enterobacteriaceae including Yersinia , Salmonella , and Shigella are considered as potential candidates for causing typhoid fever and sequelae of arthritis.…”