Persistent immune thrombocytopaenic purpura associated with SARS‐CoV‐2 infection

We describe evolution of persistent immune thrombocytopaenic purpura (ITP) from acute ITP in a young woman with clinically other-wise inapparent severe acute respiratory syndrome - coronavirus 2 (SARS-CoV-2) infection (COVID-19); her development of ITP was mat-ter for an earlier report.[1] ITP is an acquired disease in which thrombocytopaenia results from autoantibodies against platelet antigens. Approximately10%ofpatientswithacuteITPdeveloppersistent(last-ing 3–12 months) or chronic ( > 12 months) ITP.[2] Infections with viruses like Epstein-Barr virus and cytomegalovirus can trigger acute ITP.[3] Many instances of acute ITP associated with COVID-19 are described Instances of persistent or chronic ITP associated with COVID-19

We describe evolution of persistent immune thrombocytopaenic purpura (ITP) from acute ITP in a young woman with clinically otherwise inapparent severe acute respiratory syndrome -coronavirus 2 (SARS-CoV-2) infection (COVID-19); her development of ITP was matter for an earlier report. [1] ITP is an acquired disease in which thrombocytopaenia results from autoantibodies against platelet antigens.
A previously well 30-year-old woman sought dental care for new-onset gingival bleeding in August 2020. A markedly decreased platelet count (3 × 10 9 /L) was found. She was referred to our hospital.
Real-time polymerase chain reaction (RT-PCR) testing for SARS-CoV-2, using saliva, accordingly was performed 2 days in a row, in both without detecting evidence of infection.
Acute ITP was diagnosed, and intravenous immunoglobulin therapy (IVIG), 400 mg/kg, was initiated. Corticosteroids were not used because of possible pneumonia. On the fourth day of IVIG, her platelet count had increased to 38 × 10 9 /L. Nasopharyngeal RT-PCR testing detected SARS-CoV-2 sequences. Haemorrhagic disease responded to IVIG. The patient was discharged home on hospital day 10 [1].
She attended clinic monthly in follow-up. In October 2020, her platelet count had recovered (190 × 10 9 /L); however, it gradually fell again (97 × 10 9 , 68 × 10 9 , 30 × 10 9 /L: January, February, March 2021, respectively). Anti-SARS-CoV-2 immunoassays of serum detected anti-SARS-CoV-2 IgG-but not IgM-class antibody. Autoantibodies and evidence of infection again were absent (Table 1), and bone-marrow examination findings were like those before (increase in megakaryocyte numbers at 51 × 10 6 /L without dysplasia [ Figure 1C]). Persistent ITP following acute ITP associated with COVID-19 was diagnosed. As her platelet count is steady at >30 × 10 9 /L ( Figure 1D  Mild thrombocytopaenia has been observed in approximately 5%-10% of patients with COVID-19 infection [7]. Implicated factors and mechanisms include cytokine storm, direct infection of haematopoietic and bone-marrow stromal cells, antibody-mediated platelet destruction, reduced effect of thrombopoietin, increased circulating-platelet consumption via lung injury or multiple-organ failure, and immune complexes [8,9]. Recent guidelines recommend steroids as first-line therapy for ITP associated with COVID-19. IVIG is recommended when an immediate rise in platelet count is required [10]. Administration of thrombopoietin-receptor agonists may be associated with increased risk of thrombosis and hepatobiliary biomarker abnormalities; that these agents be avoided in COVID-19 is recommended at present [5,10]. As noted above, we refrained from administering corticosteroids for fear of potentiating infection via immunosuppression.
Platelet counts promptly rose with IVIG treatment.
Failure to develop anti-SARS-CoV-2 antibodies associated with immunochemotherapy (e.g., rituximab, corticosteroids) is described [11,12] during follow-up [5]. As their follow-up period was only 50-60 days, whether persistent or chronic ITP developed is unknown. The authors point out, however, that COVID-19 may trigger a tolerance breakdown that could lead to persistent or chronic ITP.
We believe that our patient is the first instance described of persistent ITP (>7 months follow-up) evolved from acute ITP associated with COVID-19. Thrombocytopaenia is a common comorbidity in COVID-19, likely with several aetiologies, among them ITP. As acute ITP triggered by events other than COVID-19 may progress to persistent or chronic ITP even after initial recovery in platelet count, we anticipate that more patients like ours will be encountered. Continuous and longterm monitoring of acute ITP associated with COVID-19 thus must be considered essential.

ACKNOWLEDGEMENTS
Written informed consent was obtained from the patient for publication of the case report and accompanying images.

CONFLICT OF INTEREST
The authors declare that there was no conflict of interest in carrying out this study.