We read the Rong’s paper [Citation1] with great interest. In this article, a total of 53 acquired pure red cell aplasia (PRCA) patients, including 30 idiopathic PRCA and 23 secondary PRCA patients, were retrospectively analyzed. Their data was determined that thymoma and viral infections were the most common causes for secondary PRCA. However, in this article, the results of IgG level or CD19+B cells number in the peripheral blood were not examined, although the CD5+CD19+ activated B cells were investigated in 46 PRCA patients.
Importantly, hypogammaglobulinemia and the almost complete absence of peripheral CD19+ B cells, along with thymoma, are the prominent features in Good’s syndrome (GS) patients. Since the original description by Dr Robert Good’s over 60 years ago, most publications of GS are single case reports or small case series [Citation2]. It is a rare secondary immunodeficiency (SID) disease, which could develop severe and recurrent infections [Citation2,Citation3]. However, the SID diagnosis is often neglected due to its rarity [Citation2]. The early diagnosis and adequate therapy with immunoglobulin (Ig) replacement are mandatory to reduce recurrent infection and mortality associated with this syndrome [Citation2]. Moreover, thymoma commonly triggers paraneoplastic autoimmune complications, which affects the bone marrow precursors [Citation2]. The pathogenesis of this complication involves either the production of anti-erythropoeitin (EPO) antibodies in PRCA or destruction of bone marrow precursors by CD8T-lymphocytes in PRCA and GS [Citation2].
In 78 UK patients with GS cohort, 8 patients had been developed PRCA [Citation2]. Another systematic review study also revealed that there were 8 GS patients who suffered PRCA among 47 GS patients in 27 Chinese researches [Citation4]. Moreover, 31 PRCA patients were also documented in 152 GS patients worldwide [Citation3]. Therefore, we highlight that monitor of Ig levels and peripheral B cell number, combined with the thymoma past history, are critical for the diagnosis of GS in secondary PRCA patients. This could increase the awareness of this rare GS disease.
In this Rong’s article [Citation1], only PRCA patients with virus infections were given intravenous Ig (IVIG) (10 g per week), while it is not conformed to the criteria of low IgG levels in the peripheral blood. The dose of IVIG (10 g per week) was also fixed, not depend on the individual body weight (BW). While, whether these patients had hypogammaglobulinemia is still unclear. In an international online survey which contains 230 physicians responsible for the diagnosis of SID and the prescription of Ig replacement therapy (IgRT) for patients with hematological malignancies [Citation5], the average initial monthly starting dose of IgG was 0.35 g/kg BW and higher doses of 0.4–0.5 g/kg BW were prescribed by 70% of immunologists. Thus, the management for these PRCA patients with hypogammaglobulinemia deserved to be discussed. Furthermore, for the PRCA treatment in this article [Citation1], after hemoglobin recovered to the normal, cyclosporine A (CsA) (1–2 mg/kg × d) was given as maintenance therapy and lasted for at least one year [Citation1]. In contrast, if the GS diagnosis was confirmed as the secondary PRCA diagnosis, the CsA should be used with caution, and the appropriate IgRT should be administrated to these patients, maintain adequate IgG values to boost the immunity.
Therefore, astute clinical acumen and increased awareness of this rare disease will enhance the early diagnosis of this syndrome and reduce mortality [Citation3].
Acknowledgments
The authors really appreciate the encouragement of the members in the Department of Clinical Laboratory, Zhejiang Provincial People’s Hospital.
Disclosure statement
No potential conflict of interest was reported by the author(s).
References
- Fu R, Zhang T, Liu B, et al. The clinical characteristics and therapy response of patients with acquired pure red cell aplasia. Hematology. 2018;23(9):639–645.
- Zaman M, Huissoon A, Buckland M, et al. Clinical and laboratory features of seventy-eight UK patients with Good's syndrome (thymoma and hypogammaglobulinaemia). Clin Exp Immunol. 2019;195(1):132–138.
- Kelesidis T, Yang O. Good's syndrome remains a mystery after 55 years: a systematic review of the scientific evidence. Clin Immunol. 2010;135(3):347–363.
- Dong JP, Gao W, Teng GG, et al. Characteristics of Good's syndrome in China: a systematic review. Chin Med J (Engl). 2017;130(13):1604–1609.
- Na IK, Buckland M, Agostini C, et al. Current clinical practice and challenges in the management of secondary immunodeficiency in hematological malignancies. Eur J Haematol. 2019;102(6):447–456.