Secondary Hemophagocytic Lymphohistiocytosis and Autoimmune Cytopenias: Case Description and Review of the Literature

Allogeneic stem cell transplant in primary hemophagocytic lymphohistiocytosis - a single-center experience

Hemophagocytic Lymphohistiocytosis (HLH) is a rare disorder of immune dysregulation characterized by fever, cytopenias, and splenomegaly. Its primary form poses a therapeutic challenge due to its high fatality when left untreated. We retrospectively analyzed 28 patients who underwent related-donor allogeneic stem cell transplant for primary HLH from 2010 to 2021. Among them were 10 cases of familial HLH, 8 cases of Griscelli syndrome type 2, and 1 case each with PRF1 and STX11 mutations. All the patients underwent transplants with reduced-intensity or myeloablative conditioning and 26 of them achieved neutrophil engraftment at a median of day + 14. The donors were either fully matched (68%) or haploidentical (32%). With a median follow-up of 1 year, overall survival was 68% (n = 19) and disease-free survival was 64.4% (n = 18). OS was better in patients transplanted with a sibling donor (compared to parent donor), who achieved complete donor chimerism, and those transplanted early in the course of the disease (diagnosis to transplant duration less than 6 months).

The History of Macrophage Activation Syndrome in Autoimmune Diseases

In 1979, it became recognized in the literature that what we call hemophagocytic lymphohistiocytosis (HLH) was a nonmalignant disease of histiocytes. Subsequently a familial form and a secondary form of HLH were differentiated. When HLH is secondary to an autoimmune disease, rheumatologists refer to this entity as macrophage activation syndrome (MAS) to differentiate it from HLH itself. Although the first cases of MAS likely appeared in the literature in the 1970s, it was not until 1985 that the term activated macrophages was used to describe patients with systemic juvenile idiopathic arthritis (sJIA) complicated by MAS and the term macrophage activation syndrome first appeared in the title of a paper in 1993.MAS is one of the many types of secondary HLH and should not be confused with primary HLH. Experience has taught that MAS secondary to different autoimmune diseases is not equal. In the 30 years since initial description in patients with sJIA, the clinical spectrum, diseases associated with MAS, therapy, and understanding the pathogenesis have all made significant gains. The diagnostic/classification criteria for MAS secondary to sJIA, SLE, RA, and KD differ based on the different laboratory abnormalities associated with each (Ahn et al., J Rheumatol 44:996-1003, 2017; Han et al., Ann Rheum Dis 75:e44, 2016; Ravelli et al., Ann Rheum Dis 75:481-489, 2016; Borgia et al., Arthritis Rheumatol 70:616-624, 2018). These examples include the thrombocytosis associated with sJIA, a chronic generalized activation of the immune system, leading to elevations of fibrinogen and sIL-2R, low platelet count associated with SLE, and more acute inflammation associated with KD. Therefore, individual diagnostic criteria are required, and they all differ from the diagnostic criteria for HLH, which are based on a previously non-activated immune system (Ahn et al., J Rheumatol 44:996-1003, 2017; Han et al., Ann Rheum Dis 75:e44, 2016; Ravelli et al., Ann Rheum Dis 75:481-489, 2016; Borgia et al., Arthritis Rheumatol 70:616-624, 2018; Henter et al., Pediatr Blood Cancer 48:124-131, 2007). This helps to explain why the HLH diagnostic criteria do not perform well in MAS.The initial treatment remains high-dose steroids and IVIG followed by the use of a calcineurin inhibitor for resistant cases. IVIG can be used if there is a concern about malignancy to wait for appropriate investigations or with steroids. Interluekin-1 inhibition is now the next therapy if there is a failure to respond to steroids and calcineurin inhibitors. Advances in understanding the mechanisms leading to MAS, which has been greatly aided by the use of mouse models of MAS and advances in genome sequencing, offer a bright future for more specific therapies. More recent therapies are directed to specific cytokines involved in the pathogenesis of MAS and can lead to decreases in the morbidity and mortality associated with MAS. These include therapies directed to inhibiting the JAK/STAT pathway and/or specific cytokines, interleukin-18 and gamma interferon, which are currently being studied in MAS. These more specific therapies may obviate the need for nonspecific immunosuppressive therapies including high-dose prolonged steroids, calcineurin inhibitors, and etoposide.

Severe COVID-19-Induced Hemophagocytic Lymphohistiocytosis

We reported a case of secondary hemophagocytic lymphohistiocytosis (HLH), a rare and life-threatening condition, which was suspected to have been triggered by a severe case of coronavirus disease 2019 (COVID-19). A 50-year-old man with a past medical history of ulcerative colitis with recent pancolitis status post colectomy and ileostomy two weeks before presentation presented to the emergency department with one week of subjective fevers, weakness, watery diarrhea, and decreased oral intake. A CT scan showed fluid in the rectum and post-surgical changes from his recent colectomy along with diffuse reticulonodular opacities of the lungs. His COVID-19 reverse transcriptase-polymerase chain reaction (RT-PCR) test was positive. Over the subsequent days, the patient's condition worsened as he developed worsening acute hypoxic respiratory failure with diffuse lymphadenopathy, splenomegaly, worsening cytopenias, and increased ferritin of >100,000 ng/ml on hospital day six. Hematology oncology was consulted and he was started on empiric steroid therapy followed by etoposide. However, his condition continued to worsen, and eventually, the patient passed away on hospital day eight.

Diagnosis and Management of Autoimmune Hemolytic Anemias

Autoimmune hemolytic anemia (AIHA) is usually categorized, as other immune-mediated cytopenias, in so-called benign hematology, and it is consequently managed in various settings, namely, internal medicine, transfusion centers, hematology and, more rarely, onco-hematology departments [...].

Direct antiglobulin test-negative autoimmune hemolytic anemia in a patient with β-thalassemia minor during pregnancy: A case report

BACKGROUND

Severe refractory anemia during pregnancy can cause serious maternal and fetal complications. If the cause cannot be identified in time and accurately, blind symptomatic support treatment may cause serious economic burden. Thalassemia minor pregnancy is commonly considered uneventful, and the condition of anemia rarely progresses during pregnancy. Autoimmune hemolytic anemia (AIHA) is rare during pregnancy with no exact incidence available.

CASE SUMMARY

We report the case of a 30-year-old β-thalassemia minor multiparous patient experiencing severe refractory anemia throughout pregnancy. We monitored the patient closely, carried out a full differential diagnosis, made a diagnosis of direct antiglobulin test-negative AIHA, and treated her with prednisone and intravenous immunoglobulin. The patient gave birth to a healthy full-term baby.

CONCLUSION

Coombs-negative AIHA should be suspected in cases of severe hemolytic anemia in pregnant patients with and without other hematological diseases.

Immune Phenomena in Myeloid Neoplasms: An "Egg or Chicken" Question

Immune phenomena are increasingly reported in myeloid neoplasms, and include autoimmune cytopenias/diseases and immunodeficiency, either preceding or complicating acute myeloid leukemia, myelodysplastic syndromes (MDS), chronic myeloproliferative neoplasms, and bone marrow failure (BMF) syndromes. Autoimmunity and immunodeficiency are the two faces of a dysregulated immune tolerance and surveillance and may result, along with contributing environmental and genetic factors, in an increased incidence of both tumors and infections. The latter may fuel both autoimmunity and immune activation, triggering a vicious circle among infections, tumors and autoimmune phenomena. Additionally, alterations of the microbiota and of mesenchymal stem cells (MSCs) pinpoint to the importance of a permissive or hostile microenvironment for tumor growth. Finally, several therapies of myeloid neoplasms are aimed at increasing host immunity against the tumor, but at the price of increased autoimmune phenomena. In this review we will examine the epidemiological association of myeloid neoplasms with autoimmune diseases and immunodeficiencies, and the pivotal role of autoimmunity in the pathogenesis of MDS and BMF syndromes, including the paroxysmal nocturnal hemoglobinuria conundrum. Furthermore, we will briefly examine autoimmune complications following therapy of myeloid neoplasms, as well as the role of MSCs and microbiota in these settings.

Two Cases of Pancytopenia with Coombs-Negative Hemolytic Anemia after Chimeric Antigen Receptor T-Cell Therapy

BACKGROUND

Chimeric antigen receptor (CAR) T-cells are changing the therapeutic landscape of hematologic malignancies. Severe side effects include cytokine release syndrome (CRS) and immune effector cell-associated neurotoxicity syndrome (ICANS), but prolonged cytopenia has also been reported. The underlying mechanism for prolonged cytopenia is poorly understood so far.

CASES

Severe pancytopenia with grade 2-3 anemia was marked 2-3 months after treatment. Laboratory evaluation revealed undetectable levels of haptoglobin with increased reticulocyte counts. Coomb's tests were negative, no schistocytes were detected on blood smear, and infectious causes were ruled out. Increased erythropoiesis without lymphoma infiltration was noted on bone marrow biopsy. A spontaneous increase in haptoglobin and hemoglobin levels was observed after several weeks. For one patient, peripheral CAR-T levels were monitored over time. We observed a decline at the same time as hemoglobin levels began to rise, implying a potential causality.

CONCLUSION

To our knowledge, we describe the first two cases of Coombs-negative hemolytic anemia after CAR-T treatment for B-cell lymphoma. We encourage routine monitoring for hemolytic anemia after CAR-T treatment and also encourage further investigations on the underlying mechanism.