Etoposide as an Effective Drug for Adult Macrophage Activation Syndrome: A Retrospective Study

Background


Background
Hemophagocytic syndrome(HPS) is a hyperin ammatory condition with high mortality, characterized by the cytokine storm originate from excessive activated macrophages and T cells [1], also known as Hemophagocytic lymphohistiocytosis(HLH). HLH is de ned into two forms as primary and secondary, secondary hemophagocytic lymphohistiocytosis(sHLH) can be triggered by infection, malignancy and autoimmune diseases(AID) [2], autoimmune disease associated hemophagocytic syndrome(AID-HLH), in other words, macrophage activation syndrome is a rare, but lethal complication of AID. Approximately the mortality of sHLH is 41% [3], although prognosis of MAS is better than other subtypes, for AID patients, accompanying HLH reduced the survival rate dramatically [4]. Currently, speci c treatment guidelines for adult MAS have not been formulated, glucocorticoid pulse therapy is the major treatment for MAS patients according to experience derived from children. November 2019 were collected in this study. All patients met HLH-2004 diagnostic criteria [21]. The survival time was calculated from the time patients were diagnosed as HLH until death or February 2020. Assessment of therapy E cacy was evaluated every 2 weeks after initiating therapy, Complete response(CR) was de ned as the normalization of all quanti able symptoms and laboratory markers of HLH, including levels of soluble CD25, ferritin, triglyceride, hemoglobin levels, neutrophil and platelet counts, and alanine aminotransferase(ALT). Partial response(PR) was de ned as improvement in two or more of the following quanti able symptoms and laboratory markers by 2 weeks: 1.5-fold decrease in soluble CD25 response; ferritin and triglyceride decreases of at least 25%; an increase of at least 100% to >0.5x10 9 /L in patients with an initial neutrophil count of <0.5x10 9 /L; an increase of at least 100% to >2.0x10 9 /L in patients with an initial neutrophil count of 0.5-2.0x10 9 /L; and a decrease of at least 50% in patients with initial ALT levels >400u/l. In addition, the body temperature must have reverted to normal ranges for either CR or PR to be diagnosed. No response(NR):Failure to achieve PR was de ned as no response [23,24].
The overall response rate was de ned as the ratio of patients with CR and PR to all patients.

Research design
Patients were divided into two groups according to initial therapy. Group 1: VP-16 was excluded in initial regimen, Group 2: VP-16 was included in initial regimen. The gender, age, clinical characteristics, laboratory indicators, underlying disease, regimens and prognosis of two groups were analyzed retrospectively.
Statistical analysis SPSS 24.0 statistical software was adopted, all normally distributed data were represented by means ± standard deviations, all data that were not distributed normally were represented by median and range. T test is used for normally distributed data and rank sum test is used for non-normal distribution data. P < 0.05 was considered to denote a signi cant difference. Some patients lack of sCD25 and NK cell activity results, missing data was deleted.

General information
A total of 74 patients with autoimmune disease related hemophagocytic syndrome were involved in this study, female patients representing 78.4% of the total number (58/74), male representing 21.6% (16/74). The male to female ratio was 1:3.6. The median age of the patients was 31 years (16~72 years). Among these cases, underlying diseases included AOSD, SLE, undifferentiated connective tissue disease(UCTD), rheumatoid arthritis(RA) and other variety of autoimmune diseases (Fig 1).

Treatment
Patients were de ned into two groups based on the initial regimens. Group 1(n=53): the initial treatment plan didn't contain VP-16, the speci c treatment includes corticosteroids, corticosteroids plus cyclosporine A, corticosteroids plus methotrexate and corticosteroids plus hydroxychloroquine. Group 2(n=21): the initial treatment included VP-16, the speci c treatment options includes HLH-94, HLH-2004 and DEP regimen. Group 2 patients had lower ALT and T-BIL than group 1 patients, other baseline data showed no signi cant difference (Table 1). A total of 65 patients reached at least PR eventually, according to whether VP-16 was used or not, we divided this part of patients into two groups, group A: VP-16 was not included during the whole treatment, and group B: VP-16 was administrated in the treatment. We compared laboratory indicators of two groups at the remission stage of HLH, the data suggested patients in group B had lower sCD25 and higher NK cell activity than group A, while blood cell counts had no signi cant differences between two groups( Table 2). The survival time was calculated from the time patients were diagnosed HLH until death or January 2020. A total of 9 deaths occurred in 74 patients with a mortality of 12.16%. The mortality rate of group 1 was 13.2%(7/53), and that of group 2 was 9.5%(2/21). Of patients who achieved PR, 1 patient died(1/48,2.1%), nonresponsive patients were all died within 6 weeks after diagnosis with a median survival of 29 days, the HLH states in uenced the prognosis signi cantly (Fig 3, P<0.01).

Discussion
HLH is a rare, but lethal complication of adult autoimmune diseases patients, most common in AOSD, accounting for 58.1% in our study, consistent with literature reports [5]. HLH may occur at each stage of autoimmune diseases, even becomes the initial manifestation, but the speci c mechanism is still not clear, polymorphism of UNC13D is possibly a predisposing factor [6,7].
The treatment strategy of HLH contains two parts, short term and long term. The short-term strategy focuses on the control of cytokine storm to suppress the excessive in ammatory status, and the longterm strategy targets on the underlying diseases [8]. Although the prognosis of adult acquired HLH was mainly determined by the underlying diseases, fail to stabilize the in ammatory condition may lead to a rapid death [9,10].
In order to achieve short-term goal, diagnosis should be established promptly and effective regimens should be taken. Fever and abnormal hemogram are common in patients with autoimmune disease [11,12], makes it di cult to distinguish HLH at the early stage [13]. Studies proves that NK cell activity and sCD25 are sensitive indicators for early diagnosis of HLH, a ferritin level above 10,000ug/L appears to be speci c and sensitive for HLH diagnosis [14]. In addition to assessing the activity, examination of NK cell activity, sCD25 and serum ferritin are valuable for patients with rapid condition deterioration. Meanwhile, the signi cance of sCD25 in autoimmune diseases has gradually attracted attention [15,16], whether routine monitoring of sCD25 is needed or not in patients with autoimmune diseases still needs further study.
At present, glucocorticoid pulse therapy is the major treatment for MAS patients [17,18], but most researches were based on children, although adult HLH presented similar clinical features as in children, adult HLH still has different characteristics with pediatric HLH, so far there is no uni ed therapy for adult MAS. Song et al [19] found that in EBV-HLH patients, the use of VP-16 in initial treatment has no signi cant relationship with the prognosis for patients under the 18 years old, but for adult patients, the prognosis was improved, our data demonstrated that VP-16 contained initial therapy reveals same results in adult MAS patients. In our study, the mortality of MAS patients was 12.16%, and the prognosis of patients with different HLH remission status was signi cantly different, only 24.5% patients were responsive to glucocorticoid pulse therapy, adopting VP-16 in the initial regimen reached a signi cantly higher ORR and CRR. Even for patients nonresponsive to glucocorticoid pulse therapy, VP-16 contained therapies lead to a high response rate as 91.9%.
A signi cant portion of patients was transferred to our center as a result of poor treatment outcome or di culties in diagnosis, consequently, referral bias existed in this study, which may in uence the overall response rate of glucocorticoid pulse therapy. We believe it re ected effectiveness of the etoposide.
VP-16 is one of cell cycle speci c drugs which acts on topoisomerase II. By blocking the reconnection of DNA strand by forming drug enzyme DNA complex, anti-tumor effect was achieved. VP-16 can selectively bypass the over activated T cells to inhibit the activation of monocyte macrophages, thereby controlling HLH by reducing the generation of cytokine storm without compromising quiescent phase and memory T cells [20]. In accordance with whether VP-16 was used or not, we analyzed patients' laboratory indicators, and came to a same conclusion with Henter et al [21], Arca et al [22], e cacy of VP-16 on HLH is far outstrip than the risk of hemogram deterioration.

Conclusion
Determined by the underlying disease, MAS patients had a better prognosis than other type of HLH patients, but occurrence of HLH signi cantly reduced the survival rate of patients with autoimmune diseases [4], and we demonstrated that remission of HLH, especially CR, is the key to improve the prognosis of MAS patients. Currently, there is no uni ed treatment guideline for adult MAS patients, our study has con rmed that admitting VP-16 in the initial regimens signi cantly increase the CR and OR rate of adult MAS patients, and did not cause severe adverse reactions such as bone marrow suppression. VP-16 is safe and effective for MAS patients.

Declarations
Ethics approval and consent to participate The study was approved by the Ethics Committee at Beijing Friendship Hospital

Consent for publication
Not applicable.

Availability of data and materials
The datasets used and/or analysed during the current study are available from the corresponding author on reasonable request.

Competing interests
The authors declare that they have no competing interests. Author's contributions Yini Wang and Zhao Wang designed the study manuscript and Lingbo He wrote the initial draft. All authors were involved in data acquisition and analysis. All authors read and approved the nal manuscript.

Figure 2
Clinical characteristics of 74 patients.