High dose dexamethasone as an alternative rescue therapy for active bleeding in children with chronic ITP: clinical and immunological effects

Revolution of Disturbed Bregs and Bmems Lymphocytes Homeostasis in Children With Chronic ITP After High-dose Dexamethasone Rescue Therapy

SUMMARY

Dexamethasone is approved as second-line therapy in pediatric chronic immune thrombocytopenic purpura (ITP). Several B-cell abnormalities have been described in ITP pathogenesis.This study assessed the effects of high-dose dexamethasone (HD-DXM) on the percentages and absolute counts of CD19+CD24hiCD38hi regulatory (Bregs) and CD19+CD27+ memory B lymphocytes (Bmems) in children with chronic ITP during active bleeding.The study was a prospective case-control, included 20 children with chronic ITP and uncontrolled bleeding. Children received a single daily dose of HD-DXM for 4 days. Blood samples were withdrawn from patients just before HD-DXM therapy and on day 5 to evaluate the platelet counts and flow cytometric analysis of Bregs and Bmem. The patients' platelet counts significantly increased after 5 days of the initiation of therapy (P=0.0001). Bmems percentage and absolute counts were significantly higher in patients before treatment (P=0.0007), and decreased after HD-DXM therapy (P=0.97) compared with the controls. Bregs percentage and absolute counts were significantly lower before treatment (P=0.0003) and increased after HD-DXM (P=0.003). There is a negative correlation between platelet counts and Bregs percentage and absolute count Bmems percentage before and after HD-DXM, whereas a positive correlation between platelets and Bregs before and after dexamethasone has been reported.

CONCLUSIONS

HD-DXM reestablishes the normal Bregs/Bmems balance. This finding discloses possible involvement of Bregs and Bmems in the pathogenesis of pediatric ITP and provides a novel vision for immune modulation and treatment perspectives.

An update on the pathophysiology of immune thrombocytopenia

: Immune thrombocytopenia (ITP) is an autoimmune bleeding disorder mediated by antiplatelet autoantibodies and antigen-specific T cells that either destroy platelets peripherally in the spleen or impair platelet production in the bone marrow. There have been a plethora of publications relating to the pathophysiology of ITP and since January of 2019, at least 50 papers have been published on ITP pathophysiology.

PURPOSE OF REVIEW

To summarize the literature relating to the pathophysiology of ITP including the working mechanisms of therapies, T-cell and B-cell physiology, protein/RNA/DNA biochemistry, and animal models in an attempt to unify the perceived abnormal immune processes.

RECENT FINDINGS

The most recent pathophysiologic irregularities associated with ITP relate to abnormal T-cell responses, particularly, defective T regulatory cell activity and how therapeutics can restore these responses. The robust literature on T cells in ITP points to the notion that ITP is a disease initiated by faulty self-tolerance mechanisms very much like that of other organ-specific autoimmune diseases. There is also a large literature on new and existing animal models of ITP and these will be discussed. It appears that understanding how to specifically modulate T cells in patients with ITP will undoubtedly lead to effective antigen-specific therapeutics.

CONCLUSIONS

ITP is predominately a T cell disorder which leads to a breakdown in self tolerance mechanisms and allows for the generation of anti-platelet autoantibodies and T cells. Novel therapeutics that target T cells may be the most effective way to perhaps cure this disorder.

An escalating treatment strategy for children with severe chronic immune thrombocytopenia: Preliminary report from a single center

OBJECTIVE

To analyze the effects of escalating treatment strategy in children with severe chronic immune thrombocytopenia (SCITP).

METHODS

This was a single-center, retrospective cohort study. Data from children with SCITP who received escalating treatment strategy in our center were collected between June 2017 and August 2019. The escalating strategy included three steps: Step I (six courses of high-dose dexamethasone [HDD]), Step II (HDD combined with low-dose rituximab), and Step III (eltrombopag).

RESULTS

A total of 30 cases (18 males and 12 females) were included, with duration of immune thrombocytopenia (ITP) of 20.5 (12.0-96.0) months. After treatment, the remission rate was 36.7% (11/30) and the sustained response (SR) rate was 68.2% (15/22). The distribution (remission rates) from Step I to III was as follows: nine of 30 (33.3%, 3/9); four of 30 (50%, 2/4); 17/30 (29.4%, 5/17), respectively. In eltrombopag (Step III) cases, 47.5% (8/17) maintained a platelet count of ≥50 × 10⁹ /L, 37.5% (3/8) had dose tapering, and 25% (2/8) have successfully discontinued the medication. The number of patients at 12, 24, and 36 months were 30, seven, and two, with a total response and remission rates of 80% (36.7%), 57.1% (28.6%), and 50% (50%), respectively. The total relapse rate was 26.7% (8/30), and three cases from Step II and five cases from Step III.

CONCLUSION

The escalating strategy for children SCITP showed an effective improvement rate with 36.7% remission and 68.2% SR, and 30% could benefit and retain SR from HDD treatment. Combined treatment with eltrombopag can reduce the relapse rate of low-dose rituximab.

Risk Factors and Psychological Analysis of Chronic Immune Thrombocytopenia in Children

OBJECTIVE

To study the risk factors and psychological changes in children with chronic immune thrombocytopenia (CITP).

METHODS

This was a retrospective analysis of 234 children with ITP diagnosed and treated in the Affiliated Hospital of Southwest Medical University from January 2016 to December 2018. The clinical characteristics and related laboratory factors of all patients were collected, and their impact on the chronicity of ITP was analyzed. The Eysenck Personality Questionnaire-Children's Version (7-15 years old) is a psychological assessment of children with chronic ITP (CITP).

RESULTS

Univariate analysis found that the course of the initial diagnosis (χ2 =6.879, P<0.05), the age of onset (χ2 =13.846, P<0.05) and the absolute value of the initial diagnosis of peripheral blood lymphocytes (χ2 =6.436, P<0.05) had statistical differences in the chronicity of ITP in children; a multivariate analysis of the course of the first diagnosis, the age of onset and absolute lymphocyte count (ALC) revealed that ALC is an independent factor in children's chronic ITP (P<0.05). Compared with normal children, children with CITP had statistical significance in extraversion (t=-3.476, P<0.05); compared with newly diagnosed children, they had statistical significance in extraversion (E) and lying (L) (P<0.05); and there was no statistical difference compared with persistent children (P>0.05).

CONCLUSION

The age of onset, the absolute value of lymphocytes at the initial diagnosis, and the course of the initial diagnosis are important for predicting the chronicity of ITP in children. ALC is an independent predictor; children with chronic ITP have psychological problems.