Wiskott-Aldrich syndrome: histopathologic findings in the lymph nodes and spleens of 15 patients

A personalized approach to lymphoproliferations in patients with inborn errors of immunity

Biopsies from patients with inborn error of immunity (IEI) may pose a diagnostic challenge due to the abnormal anatomy of their lymphoid organs and the tendency for the development of lymphoproliferations in various organs, some of which may lead to the wrong impression of malignant lymphoma which may prompt aggressive unnecessary treatment. In this article we will review typical histologic findings in various IEI's described in the literature and discuss the appropriate approach to the diagnosis of lymphoproliferations in these patients by presenting illustrative cases.

An Autopsy Case of Wiskott-Aldrich Syndrome Revealing "FDC-Only Lymphoid Follicles" in Lymphoid Tissue: A Morphologic Correlate of Defective Immune Synapse

Wiskott-Aldrich Syndrome (WAS) is an inherited disorder characterized by the classical triad of eczema, micro-thrombocytopenia, and immune deficiency. This disease affects the hematopoietic cells to a variable extent. The spectrum of clinical and laboratory data for WAS has been well described in the literature though there is a paucity of its histopathologic and immunohistochemical correlates. The current case describes the autopsy findings of this rare entity in an 8-year old male child with specific recognition of altered histology noticed in the lymphoreticular tissues. The predominant morphological finding in lymphoid tissue was atretic hyalinized germinal centers labeled as "the follicular dendritic cell (FDC)-only lymphoid follicles." Immunohistochemistry revealed a reduction in germinal-center B-cells, T-follicular helper cells, attenuated mantle zone, FDC proliferation, and paracortical plasmacytosis. This case highlights the crippled immune cell population in WAS, ultimately leading to the morphology of atretic follicles rich in FDCs.

Molecular Tuning of Actin Dynamics in Leukocyte Migration as Revealed by Immune-Related Actinopathies

Motility is a crucial activity of immune cells allowing them to patrol tissues as they differentiate, sample or exchange information, and execute their effector functions. Although all immune cells are highly migratory, each subset is endowed with very distinct motility patterns in accordance with functional specification. Furthermore individual immune cell subsets adapt their motility behaviour to the surrounding tissue environment. This review focuses on how the generation and adaptation of diversified motility patterns in immune cells is sustained by actin cytoskeleton dynamics. In particular, we review the knowledge gained through the study of inborn errors of immunity (IEI) related to actin defects. Such pathologies are unique models that help us to uncover the contribution of individual actin regulators to the migration of immune cells in the context of their development and function.

Primary immunodeficiencies associated with eosinophilia

Background

Eosinophilia is not an uncommon clinical finding. However, diagnosis of its cause can be a dilemma once common culprits, namely infection, allergy and reactive causes are excluded. Primary immunodeficiency disorders (PID) are among known differentials of eosinophilia. However, the list of PIDs typically reported with eosinophilia is small and the literature lacks an inclusive list of PIDs which have been reported with eosinophilia. This motivated us to review the literature for all PIDs which have been described to have elevated eosinophils as this may contribute to an earlier diagnosis of PID and further the understanding of eosinophilia.

Methods

A retrospective PubMed, and Google Scholar search using the terms “eosinophilia” and “every individual PID” as classified by Expert Committee of the International Union of Immunological Societies with the limit of the English language was performed. Results were assessed to capture case(s) which reported eosinophilia in the context of PID conditions. Absolute eosinophil counts (AEC) were retrieved from manuscripts whenever reported.

Results

In addition to the typical PID conditions described with eosinophilia, we document that MHC class II deficiency, CD3γ deficiency, STAT1 deficiency (AD form), Kostmann disease, cyclic neutropenia, TCRα deficiency, Papillon-Lefevre syndrome, CD40 deficiency, CD40L deficiency, anhidrotic ectodermal dysplasia with immune deficiency, ataxia-telangiectasia, common variable immunodeficiency disorders (CVID), Blau syndrome, CARD9 deficiency, neonatal onset multisystem inflammatory disease or chronic infantile neurologic cutaneous and articular syndrome (NOMID/CINCA), chronic granulomatous disease, MALT1 deficiency and Roifman syndrome have been noted to have elevated eosinophils. Severe eosinophilia (>5.0 × 10⁹/L) was reported in Omenn syndrome, Wiskott Aldrich syndrome, ADA deficiency, autoimmune lymphoproliferative syndrome, immunodysregulation polyendocrinopathy enteropathy X-linked, STAT3 deficiency, DOCK8 deficiency, CD40 deficiency, MHC II deficiency, Kostmann disease, Papillon-Lefevre syndrome, and CVID.

Conclusions

This literature review shows that there is an extensive list of PIDs which have been reported with eosinophilia. This list helps clinicians to consider an extended differential diagnoses when tasked with exclusion of PID as a cause for eosinophilia.

Electronic supplementary material

The online version of this article (doi:10.1186/s13223-016-0130-4) contains supplementary material, which is available to authorized users.

Abnormalities of follicular helper T-cell number and function in Wiskott-Aldrich syndrome

Wiskott-Aldrich syndrome protein (WASp) is a hematopoietic-specific regulator of actin nucleation. Wiskott-Aldrich syndrome (WAS) patients show immunodeficiencies, most of which have been attributed to defective T-cell functions. T follicular helper (Tfh) cells are the major CD4(+) T-cell subset with specialized B-cell helper capabilities. Aberrant Tfh cells activities are involved in immunopathologies such as autoimmunity, immunodeficiencies, and lymphomas. We found that in WAS patients, the number of circulating Tfh cells was significantly reduced due to reduced proliferation and increased apoptosis, and Tfh cells were Th2 and Th17 polarized. The expression of inducible costimulator (ICOS) in circulating Tfh cells was higher in WAS patients than in controls. BCL6 expression was decreased in total CD4(+) T and Tfh cells of WAS patients. Mirroring the results in patients, the frequency of Tfh cells in WAS knockout (KO) mice was decreased, as was the frequency of BCL6(+) Tfh cells, but the frequency of ICOS(+) Tfh cells was increased. Using WAS chimera mice, we found that the number of ICOS(+) Tfh cells was decreased in WAS chimera mice, indicating that the increase in ICOS(+) Tfh cells in WAS KO mice was cell extrinsic. The data from in vivo CD4(+) naive T-cell adoptive transfer mice as well as in vitro coculture of naive B and Tfh cells showed that the defective function of WASp-deficient Tfh cells was T-cell intrinsic. Consistent findings in both WAS patients and WAS KO mice suggested an essential role for WASp in the development and memory response of Tfh cells and that WASp deficiency causes a deficient differentiation defect in Tfh cells by downregulating the transcription level of BCL6.

Eosinophilia Associated with Disorders of Immune Deficiency or Immune Dysregulation

Increased serum eosinophil levels have been associated with multiple disorders of immune deficiency or immune dysregulation. Although primary immunodeficiency diseases are rare, it is important to consider these in the differential diagnosis of patients with eosinophilia. In this review, the clinical features, laboratory findings, diagnosis, and genetic basis of disease of several disorders of immune deficiency or dysregulation are discussed. The article includes autosomal dominant hyper IgE syndrome, DOCK8 deficiency, phosphoglucomutase 3 deficiency, ADA-SCID, Omenn syndrome, Wiskott-Aldrich syndrome, Loeys-Dietz syndrome, autoimmune lymphoproliferative syndrome, immunodysregulation, polyendocrinopathy, enteropathy, X-linked syndrome, Comel-Netherton syndrome, and severe dermatitis, multiple allergies, and metabolic wasting syndrome.

Origins of tumor-associated macrophages and neutrophils

Tumor-associated macrophages (TAMs) and tumor-associated neutrophils (TANs) can control cancer growth and exist in almost all solid neoplasms. The cells are known to descend from immature monocytic and granulocytic cells, respectively, which are produced in the bone marrow. However, the spleen is also a recently identified reservoir of monocytes, which can play a significant role in the inflammatory response that follows acute injury. Here, we evaluated the role of the splenic reservoir in a genetic mouse model of lung adenocarcinoma driven by activation of oncogenic Kras and inactivation of p53. We found that high numbers of TAM and TAN precursors physically relocated from the spleen to the tumor stroma, and that recruitment of tumor-promoting spleen-derived TAMs required signaling of the chemokine receptor CCR2. Also, removal of the spleen, either before or after tumor initiation, reduced TAM and TAN responses significantly and delayed tumor growth. The mechanism by which the spleen was able to maintain its reservoir capacity throughout tumor progression involved, in part, local accumulation in the splenic red pulp of typically rare extramedullary hematopoietic stem and progenitor cells, notably granulocyte and macrophage progenitors, which produced CD11b(+) Ly-6C(hi) monocytic and CD11b(+) Ly-6G(hi) granulocytic cells locally. Splenic granulocyte and macrophage progenitors and their descendants were likewise identified in clinical specimens. The present study sheds light on the origins of TAMs and TANs, and positions the spleen as an important extramedullary site, which can continuously supply growing tumors with these cells.

Extramedullary hematopoiesis generates Ly-6C(high) monocytes that infiltrate atherosclerotic lesions

BACKGROUND

Atherosclerotic lesions are believed to grow via the recruitment of bone marrow-derived monocytes. Among the known murine monocyte subsets, Ly-6C(high) monocytes are inflammatory, accumulate in lesions preferentially, and differentiate. Here, we hypothesized that the bone marrow outsources the production of Ly-6C(high) monocytes during atherosclerosis.

METHODS AND RESULTS

Using murine models of atherosclerosis and fate-mapping approaches, we show that hematopoietic stem and progenitor cells progressively relocate from the bone marrow to the splenic red pulp, where they encounter granulocyte macrophage colony-stimulating factor and interleukin-3, clonally expand, and differentiate to Ly-6C(high) monocytes. Monocytes born in such extramedullary niches intravasate, circulate, and accumulate abundantly in atheromata. On lesional infiltration, Ly-6C(high) monocytes secrete inflammatory cytokines, reactive oxygen species, and proteases. Eventually, they ingest lipids and become foam cells.

CONCLUSIONS

Our findings indicate that extramedullary sites supplement the hematopoietic function of the bone marrow by producing circulating inflammatory cells that infiltrate atherosclerotic lesions.

The spatial and developmental relationships in the macrophage family

A classic study in 1968 proposed that bone marrow-dwelling promonocytes differentiate to monocytes, which then intravasate, circulate, and, on tissue entry, differentiate to sessile macrophages. Since then, understanding of the macrophage family relationship has undergone substantial enhancement and occasional revision. It is currently recognized that in addition to their role in the bone marrow, hematopoietic progenitors circulate and give rise to their descendants in extramedullary niches. Monocytes, of which there are several subsets, are not merely circulating macrophage precursors but participate in the immune response in their own right. Macrophages are highly heterogeneous and, as recent studies indicate, can arise in the absence of a monocyte intermediate. These spatial and developmental relationships reveal a complex interactive network and underscore the importance of context in evaluating biological systems. The observations have significant implications for how we image, target, and treat disease.

The thrombocytopenia of WAS: a familial form of ITP?

In the first report of the concurrent immunodeficiency, thrombocytopenia, and eczema that we now call the Wiskott-Aldrich Syndrome (WAS), Alfred Wiskott asked whether it could be a familial form of Werlhof's disease (now called ITP). This review summarizes what is known about platelet production, consumption, and function in clinical and murine WAS. Both platelet production and consumption are affected by WASP deficiency. Likely molecular mechanisms have been identified for the former process, but remain problematic for the latter. Recent data in a murine model suggest that WASP deficiency could increase both the incidence of antiplatelet antibodies and susceptibility to their enhancement of platelet consumption. Wiskott's original speculation about the relationship between WAS and ITP may need to be reconsidered.

Formation and function of the lytic NK-cell immunological synapse

The natural killer (NK)-cell immunological synapse is the dynamic interface formed between an NK cell and its target cell. Formation of the NK-cell immunological synapse involves several distinct stages, from the initiation of contact with a target cell to the directed delivery of lytic-granule contents for target-cell lysis. Progression through the individual stages is regulated, and this tight regulation underlies the precision with which NK cells select and kill susceptible target cells (including virally infected cells and cancerous cells) that they encounter during their routine surveillance of the body.

Morphologic and immunohistochemical evaluation of splenic hematopoietic proliferations in neoplastic and benign disorders

Spleen is a common site of extramedullary hematopoiesis. Extramedullary hematopoiesis seen in non-neoplastic conditions can occasionally be extensive and raise concerns for a myeloid neoplasm. We compared the morphologic and immunohistochemical features of splenic hematopoietic proliferations seen in neoplastic myeloid disorders (eg chronic myeloproliferative disorders, myelodysplastic/myeloproliferative disorders and acute myeloid leukemias) to extramedullary hematopoiesis seen in a variety of reactive conditions. In all, 80 spleen specimens were reviewed. The presence of each marrow-derived lineage, dysplasia and immunohistochemical results were evaluated (CD34, CD117, myeloperoxidase, CD68, p53, TdT, CD42b and hemoglobin). Neoplastic hematopoietic proliferations in chronic myeloproliferative disorders are characterized by trilineage hematopoiesis with significant dysplasia in all cell lineages. Acute myeloid leukemia showed an increase in immature forms, which were highlighted by immunohistochemistry. Reactive extramedullary hematopoiesis showed variability in histologic features. Post-bone marrow transplant and thrombotic thrombocytopenic purpura/hemolytic-uremic syndrome spleens showed extramedullary hematopoiesis with some morphologic features of immaturity, which could simulate chronic myeloproliferative disorder. However, they lacked characteristic immunohistochemical features of neoplastic myeloid disorders such as positivity for CD34 or CD117.

WASP- mice exhibit defective immune responses to influenza A virus, Streptococcus pneumoniae, and Mycobacterium bovis BCG

OBJECTIVE

To quantify the immune response of WASP- mice to three different pathogens: influenza A virus, Streptococcus pneumoniae, and Mycobacterium bovis.

METHODS

Primary and secondary T-cell responses to influenza A virus were quantified via tetramer assays. Viral clearance from lung was also measured. Lethality of intranasal inoculation with luminescent S. pneumoniae was assessed by dose escalation and direct luminescence imaging. After intravenous inoculation with M. bovis, residual mycobacteria in lung, liver, and spleen were measured by standard culture methods.

RESULTS

The reduced secondary T-cell response to influenza A virus correlates with a relative but not absolute loss of splenic T and B cells similar to that seen in clinical Wiskott-Aldrich Syndrome (WAS), and slower clearance of virus from lung. The reduced magnitude of the secondary T-cell response correlates with a progressive loss of influenza-specific T cells after primary inoculation. WASP- mice show an increased susceptibility to lethal pneumonia after intranasal inoculation with S. pneumoniae, which is among the most frequent causes of clinical complications in WAS patients. WASP- mice clear M. bovis bacille Calmette-Guerin (BCG) more slowly from lung, liver, and spleen. Bone marrow-derived macrophages, however, show normal ex vivo cytokine secretion in response to M. bovis.

CONCLUSIONS

These results demonstrate that WASP- mice are functionally immunodeficient in regard to three different pathogens, and provide relevant end points for the study of treatment modalities in this model. They also suggest a specific physiologic mechanism, failure to accumulate memory T cells, for at least one of the defective immune responses.

Wiskott-Aldrich syndrome protein deficiency leads to reduced B-cell adhesion, migration, and homing, and a delayed humoral immune response

The Wiskott-Aldrich syndrome protein (WASp) is mutated in the severe immunodeficiency disease Wiskott-Aldrich syndrome (WAS). The function of B cells and the physiologic alterations in WAS remain unclear. We show that B cells from WAS patients exhibited decreased motility and had reduced capacity to migrate, adhere homotypically, and form long protrusions after in vitro culture. WASp-deficient murine B cells also migrated less well to chemokines. Upon antigen challenge, WASp-deficient mice mounted a reduced and delayed humoral immune response to both T-cell-dependent and -independent antigens. This was at least in part due to deficient migration and homing of B cells. In addition, the germinal center reaction was reduced in WASp-deficient mice. Thus, WASp is crucial for optimal B-cell responses and plays a pivotal role in the primary humoral immune response.

Wiskott-Aldrich syndrome

Wiskott-Aldrich syndrome (WAS) is an X-linked immunodeficiency characterized by thrombocytopenia with small platelets, eczema, recurrent infections, autoimmune disorders, IgA nephropathy, and an increased incidence of hematopoietic malignancies. The identification of the responsible gene, WASP (Wiskott-Aldrich Syndrome Protein), revealed clinical heterogeneity of the syndrome, and showed that X-linked thrombocytopenia without, or with only mild immunodeficiency and eczema, is also caused by mutations of WASP. The study of WASP and its mutations demonstrates how a single gene defect can cause multiple and complex clinical symptoms.

Actin cytoskeletal function is spared, but apoptosis is increased, in WAS patient hematopoietic cells

Mutations in the Wiskott-Aldrich syndrome protein (WASP) have been hypothesized to cause defective actin cytoskeletal function. This resultant dysfunction of the actin cytoskeleton has been implicated in the pathogenesis of Wiskott-Aldrich syndrome (WAS). In contrast, it was found that stimulated actin polymerization is kinetically normal in the hematopoietic lineages affected in WAS. It was also found that the actin cytoskeleton in WAS platelets is capable of producing the hallmark cytoarchitectural features associated with activation. Further analysis revealed accelerated cell death in WAS lymphocytes as evidenced by increased caspase-3 activity. This increased activity resulted in accelerated apoptosis of these cells. CD95 expression was also increased in these cells, suggesting an up-regulation in the FAS pathway in WAS lymphocytes. Additionally, inhibition of actin polymerization in lymphocytes using cytochalasin B did not accelerate apoptosis in these cells. This suggests that the accelerated apoptosis observed in WAS lymphocytes was not secondary to an underlying defect in actin polymerization caused by mutation of the WAS gene. These data indicate that WASP does not play a universal role in signaling actin polymerization, but does play a role in delaying cell death. Therefore, the principal consequence of mutations in theWAS gene is to accelerate lymphocyte apoptosis, potentially through up-regulation of the FAS-mediated cell death pathway. This accelerated apoptosis may ultimately give rise to the clinical manifestations observed in WAS.

Spontaneous Apoptosis in Lymphocytes From Patients With Wiskott-Aldrich Syndrome: Correlation of Accelerated Cell Death and Attenuated Bcl-2 Expression

Wiskott-Aldrich syndrome (WAS) is an X-linked recessive disorder characterized by thrombocytopenia, eczema, and a progressive deterioration of immune function. WAS is caused by mutations in an intracellular protein, WASP, that is involved in signal transduction and regulation of actin cytoskeleton rearrangement. Because immune dysfunction in WAS may be due to an accelerated destruction of lymphocytes, we examined the susceptibility to apoptosis of resting primary lymphocytes isolated from WAS patients in the absence of exogenous apoptogenic stimulation. We found that unstimulated WAS lymphocytes underwent spontaneous apoptosis at a greater frequency than unstimulated normal lymphocytes. Coincident with increased apoptotic susceptibility, WAS lymphocytes had markedly attenuated Bcl-2 expression, whereas Bax expression did not differ. A negative correlation between the frequency of spontaneous apoptosis and the level of Bcl-2 expression was demonstrated. These data indicate that accelerated lymphocyte destruction by spontaneous induction of apoptosis may be one pathogenic mechanism by which the progressive immunodeficiency in WAS patients develops.

Spontaneous Apoptosis in Lymphocytes From Patients With Wiskott-Aldrich Syndrome: Correlation of Accelerated Cell Death and Attenuated Bcl-2 Expression

Wiskott-Aldrich syndrome (WAS) is an X-linked recessive disorder characterized by thrombocytopenia, eczema, and a progressive deterioration of immune function. WAS is caused by mutations in an intracellular protein, WASP, that is involved in signal transduction and regulation of actin cytoskeleton rearrangement. Because immune dysfunction in WAS may be due to an accelerated destruction of lymphocytes, we examined the susceptibility to apoptosis of resting primary lymphocytes isolated from WAS patients in the absence of exogenous apoptogenic stimulation. We found that unstimulated WAS lymphocytes underwent spontaneous apoptosis at a greater frequency than unstimulated normal lymphocytes. Coincident with increased apoptotic susceptibility, WAS lymphocytes had markedly attenuated Bcl-2 expression, whereas Bax expression did not differ. A negative correlation between the frequency of spontaneous apoptosis and the level of Bcl-2 expression was demonstrated. These data indicate that accelerated lymphocyte destruction by spontaneous induction of apoptosis may be one pathogenic mechanism by which the progressive immunodeficiency in WAS patients develops.

The spleen in the Wiskott-Aldrich syndrome: histopathologic abnormalities of the white pulp correlate with the clinical phenotype of the disease

The Wiskott-Aldrich syndrome (WAS) is a X-linked hematologic disorder characterized by thrombocytopenia, eczema, and immunodeficiency of variable severity. Reported here are the results of a morphologic, morphometric, and immunophenotypic analysis of splenic lymphoid tissue in 12 WAS patients with documented molecular defect and with different disease severity. Spleens from 29 age-matched patients with different diseases were used as controls. Paraffin-embedded tissue (from all cases) and fresh-frozen samples (from 5 WAS patients and 4 control subjects) were used to study the different white pulp compartments by classic morphologic, immunophenotyping, and image analysis techniques. Data were statistically analyzed by both parametric and nonparametric tests. Spleens from WAS patients showed a significant depletion of the total white pulp (p = 0.0008), T cell (p < 0.05), and B cell (p = 0.0002) areas and marginal zone (MZ) thickness (p < 0.0001). Among WAS patients, a negative correlation was found between the score of severity of the disease and all variables considered (Spearman's rank correlation coefficient, r = -0.79, r = -0.73, r = -0.68, and r = -0.56, respectively). In conclusion, this study shows that in WAS a general depletion of the splenic white pulp occurs, supporting the evidence that WAS is characterized by a combined immune defect. The significant reduction of the MZ may explain the inability of WAS patients to mount a response to T-independent antigens.

Follicular bronchitis/bronchiolitis

Nineteen open lung biopsies demonstrating follicular bronchitis/bronchiolitis were reviewed with special attention to clinical manifestations. Morphologically, follicular bronchitis/bronchiolitis was represented by coalescent reactive germinal centers adjacent to airways in the absence of clinical or pathologic evidence of chronic obstructive pulmonary disease or bronchiectasis. Three clinicopathologic groups were identified: 1) patients with collagen vascular diseases, especially rheumatoid arthritis and Sjögren's syndrome; 2) patients with a familial form of the disease or with immunodeficiency syndromes; and 3) a heterogeneous group of patients with frequent peripheral blood eosinophilia, suggesting a hypersensitivity reaction. Prognosis was related to age at the time of biopsy and, to some extent, to the clinical group. Steroid therapy had inconsistent effects in all groups identified. The differential diagnosis of lymphoid lesions in the lung is also discussed.

Malignant lymphoma in patients with the Wiskott-Aldrich syndrome

The type and incidence of malignant lymphoma developing in patients with the Wiskott-Aldrich syndrome being followed at the National Cancer Institute (NCI) between the years 1966 and 1982 was evaluated. Histologic material from lymphoid tissue was available for review on 24 of the 50 Wiskott-Aldrich patients followed by the Metabolism Branch of the NCI. In 17 patients, specimens were obtained by biopsy performed for diagnosis of lymphoid mass lesions, and in 16 patients autopsy specimens were reviewed. In 9 of the 24 patients a diagnosis of malignant lymphoma was made. A distinct preponderance of non-Hodgkin's lymphoma (NHL) over Hodgkin's disease (HD) with a ratio 8:1 was observed, and the overall incidence of malignant lymphoma in all 50 patients was 18%. The most common histologic subtype of NHL was large cell immunoblastic. In all but one patient the diagnosis of lymphoma was made antemortem, most often presenting in extranodal sites or the brain. Involvement of peripheral lymph nodes was conspicuous by its absence. Immunoperoxidase staining for kappa and lambda chain immunoglobulin and lysozyme was negative in the four cases studied, failing to provide supportive evidence for a B-cell or true histiocytic origin for the tumor cells. Histologic subtypes of lymphoma commonly observed in childhood, such as Burkitt's lymphoma and lymphoblastic lymphoma, were not observed. Despite treatment with combination chemotherapy in some patients, there were no long-term remissions and median survival was less than one year following the diagnosis of lymphoma.