Helicobacter pylori eradication shifts monocyte Fcγ receptor balance toward inhibitory FcγRIIB in immune thrombocytopenic purpura patients
Atsuko Asahi, … , Yasuo Ikeda, Masataka Kuwana
Atsuko Asahi, … , Yasuo Ikeda, Masataka Kuwana
Published July 24, 2008
Citation Information: J Clin Invest. 2008;118(8):2939-2949. https://doi.org/10.1172/JCI34496.
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Research Article

Helicobacter pylori eradication shifts monocyte Fcγ receptor balance toward inhibitory FcγRIIB in immune thrombocytopenic purpura patients

Abstract

Immune thrombocytopenia purpura (ITP) is a bleeding disorder in which platelet-specific autoantibodies cause a loss of platelets. In a subset of patients with ITP and infected with Helicobacter pylori, the number of platelets recovers after eradication of H. pylori. To examine the role of H. pylori infection in the pathogenesis of ITP, the response of 34 ITP patients to treatment with a standard H. pylori eradication regimen, irrespective of whether they were infected with H. pylori, was evaluated. Eradication of H. pylori was achieved in all H. pylori–positive patients, and a significant increase in platelets was observed in 61% of these patients. By contrast, none of the H. pylori–negative patients showed increased platelets. At baseline, monocytes from the H. pylori–positive patients exhibited an enhanced phagocytic capacity and low levels of the inhibitory Fcγ receptor IIB (FcγRIIB). One week after starting the H. pylori eradication regimen, this activated monocyte phenotype was suppressed and improvements in autoimmune and platelet kinetic parameters followed. Modulation of monocyte FcγR balance was also found in association with H. pylori infection in individuals who did not have ITP and in mice. Our findings strongly suggest that the recovery in platelet numbers observed in ITP patients after H. pylori eradication is mediated through a change in FcγR balance toward the inhibitory FcγRIIB.

Authors

Atsuko Asahi, Tetsuya Nishimoto, Yuka Okazaki, Hidekazu Suzuki, Tatsuhiro Masaoka, Yutaka Kawakami, Yasuo Ikeda, Masataka Kuwana

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Figure 1

Immunologic and platelet turnover parameters prior to treatment in ITP patients with or without H. pylori infection.

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Immunologic and platelet turnover parameters prior to treatment in ITP p...
The anti-GPIIb/IIIa Ab–producing B cells, platelet-associated (PA) anti-GPIIb/IIIa Abs, GPIIb/IIIa-specific T cell response, tetanus toxoid–specific (TT-specific) T cell response, proportion of reticulated platelets (%RP), circulating TPO level, expression levels of FcγRI and FcγRII (FcγRIIA plus FcγRIIB) on monocytes, proportion of FcγRIII-positive monocytes, expression level of CD86 on monocytes, and nonspecific phagocytosis of monocytes were compared among 23 ITP patients infected with H. pylori and 11 ITP patients who were not infected with H. pylori. Expression of FcγRII was examined using mAb clone FLI8.26, which reacts with both FcγRIIA and FcγRIIB. The differences between the 2 groups were analyzed using the Mann-Whitney U test.