What Works When Treating Granulomatous Disease in Genetically Undefined CVID? A Systematic Review

The biological basis for current treatment strategies for granulomatous disease in common variable immunodeficiency

PURPOSE OF REVIEW

The pathogenesis of granulomatous disease in common variable immunodeficiency (CVID) is still largely unknown, which hampers effective treatment. This review describes the current knowledge on the pathogenesis of granuloma formation in CVID and the biological basis of the current treatment options.

RECENT FINDINGS

Histological analysis shows that T and B cells are abundantly present in the granulomas that are less well organized and are frequently associated with lymphoid hyperplasia. Increased presence of activation markers such as soluble IL-2 receptor (sIL-2R) and IFN-ɣ, suggest increased Th1-cell activity. Moreover, B-cell abnormalities are prominent in CVID, with elevated IgM, BAFF, and CD21low B cells correlating with granulomatous disease progression. Innate immune alterations, as M2 macrophages and neutrophil dysregulation, indicate chronic inflammation. Therapeutic regimens include glucocorticoids, DMARDs, and biologicals like rituximab.

SUMMARY

Our review links the biological context of CVID with granulomatous disease or GLILD to currently prescribed therapies and potential targeted treatments.

Granulomas in Common Variable Immunodeficiency Display Different Histopathological Features Compared to Other Granulomatous Diseases

Granulomatous disease affects up to 20% of patients with Common Variable Immunodeficiency (CVID). Granulomas are comprised of highly activated immune cells, and emerge in response to antigenic triggers. In CVID granulomas however, the underlying pathophysiology is unclear and the specific trigger remains unknown. Granuloma formation in CVID is often compared to sarcoidosis, although clinical context and prognosis differ, suggesting a different pathogenesis. The aim of this study was to investigate if the cellular organization and proteomics of granulomas in CVID is different from other granulomatous diseases. Therefore, tissue slides from formaldehyde fixed paraffin embedded biopsies obtained from patients with CVID, sarcoidosis, tuberculosis and foreign-material induced pseudo-sarcoidosis were stained with hematoxylin and eosin and assessed for histopathological characteristics. Targeted spatial protein analysis was performed, and immune fluorescent multiplex assays were used to analyze the cellular organization. Histological analysis revealed that CVID granulomas were smaller, less circumscribed, with fewer multinucleated giant cells and minimal fibrosis compared to the other granulomatous diseases. Spatial protein analysis showed that granulomas in all diseases expressed CD68, CD11c, CD44, CD127, and PD-L1. However in CVID, reduced expression of the fibrosis-related protein fibronectin, but enrichment of CD163, CD3 and FAPα inside CVID granulomas was observed. Immunofluorescence analysis conformed a different cellular organization in CVID granulomas with increased influx of neutrophils, macrophages, T and B lymphocytes. In conclusion, granulomas in CVID display a different histological and cellular organization with increased influx of myeloid and lymphoid cells, compared to sarcoidosis, tuberculosis and pseudo-sarcoidosis, indicating a distinct pathogenesis underlying granuloma formation.

Clinical and experimental treatment of primary humoral immunodeficiencies

Selective IgA deficiency (sIgAD), common variable immunodeficiency (CVID), and transient hypogammaglobulinemia of infancy (THI) are the most frequent forms of primary antibody deficiencies. Difficulties in initial diagnosis, especially in the early childhood, the familiar occurrence of these diseases, as well as the possibility of progression to each other suggest common cellular and molecular patomechanism and a similar genetic background. In this review, we discuss both similarities and differences of these three humoral immunodeficiencies, focusing on current and novel therapeutic approaches. We summarize immunoglobulin substitution, antibiotic prophylaxis, treatment of autoimmune diseases, and other common complications, i.e. cytopenias, gastrointestinal complications, and granulomatous disease. We discuss novel therapeutic approaches such as allogenic stem cell transplantation and therapies targeting-specific proteins, dependent on the patient's genetic defect. The diversity of possible therapeutics models results from a great heterogeneity of the disease variants, implying the need of personalized medicine approach as a future of primary humoral immunodeficiencies treatment.

[Principles of the diagnostics of inborn errors of immunity]

Inborn errors of immunity (IEI) are a heterogeneous group of nearly 500 diseases characterized by a congenital dysfunction of the immune system. The vast majority of IEIs are rare diseases but all IEIs share a cumulative prevalence of 1:1200-1:2000. In addition to a pathological susceptibility to infections, IEIs can also present with lymphoproliferative, autoimmune or autoinflammatory manifestations. There is often an overlap with classical rheumatic and inflammatory disease patterns. Therefore, a basic knowledge of the clinical presentation and the diagnostics of IEIs is also relevant for the practicing rheumatologist.

Treatment of inflammatory complications in common variable immunodeficiency (CVID): current concepts and future perspectives

INTRODUCTION

Patients with Common variable immunodeficiency (CVID) have a high frequency of inflammatory complications like autoimmune cytopenias, interstitial lung disease and enteropathy. These patients have poor prognosis and effective, timely and safe treatment of inflammatory complications in CVID are essential, but guidelines and consensus on therapy are often lacking.

AREAS COVERED

This review will focus on current medical treatment of inflammatory complications in CVID and point out some future perspectives based on literature indexed in PubMed. There are a number of good observational studies and case reports on treatment of specific complications but randomized controlled trials are scarce.

EXPERT OPINION

In clinical practice, the most urgent issues that need to be addressed are the preferred treatment of GLILD, enteropathy and liver disease. Treating the underlying immune dysregulation and immune exhaustion in CVID is an alternative approach that potentially could alleviate these and other organ-specific inflammatory complications. Therapies of potential interest and wider use in CVID include mTOR-inhibitors like sirolimus, JAK-inhibitors like tofacitinib, the monoclonal IL-12/23 antibody ustekinumab, the anti-BAFF antibody belimumab and abatacept. For all inflammatory complications, there is a need for prospective therapeutic trials, preferably randomized controlled trials, and multi-center collaborations with larger cohorts of patients will be essential.

Granulomatous inflammation in inborn errors of immunity

Granulomas have been defined as inflammatory infiltrates formed by recruitment of macrophages and T cells. The three-dimensional spherical structure typically consists of a central core of tissue resident macrophages which may merge into multinucleated giant cells surrounded by T cells at the periphery. Granulomas may be triggered by infectious and non-infectious antigens. Cutaneous and visceral granulomas are common in inborn errors of immunity (IEI), particularly among patients with chronic granulomatous disease (CGD), combined immunodeficiency (CID), and common variable immunodeficiency (CVID). The estimated prevalence of granulomas in IEI ranges from 1%-4%. Infectious agents causing granulomas such Mycobacteria and Coccidioides presenting atypically may be 'sentinel' presentations for possible underlying immunodeficiency. Deep sequencing of granulomas in IEI has revealed non-classical antigens such as wild-type and RA27/3 vaccine-strain Rubella virus. Granulomas in IEI are associated with significant morbidity and mortality. The heterogeneity of granuloma presentation in IEI presents challenges for mechanistic approaches to treatment. In this review, we discuss the main infectious triggers for granulomas in IEI and the major forms of IEI presenting with 'idiopathic' non-infectious granulomas. We also discuss models to study granulomatous inflammation and the impact of deep-sequencing technology while searching for infectious triggers of granulomatous inflammation. We summarize the overarching goals of management and highlight the therapeutic options reported for specific granuloma presentations in IEI.

High Inborn Errors of Immunity Risk in Patients with Granuloma

OBJECTIVE

Granuloma etiology includes infections, vasculitis, chemicals, malignancies, lymphoproliferative disorders, and immunological diseases. We hypothesized that patients with granuloma have an underlying primary immunodeficiency disease (PIDD).

PATIENTS AND METHODS

We retrospectively enrolled 82 patients with immunological evaluation among 294 biopsy-proven granuloma patients (0- to 20-year-old). At the same time frame, we followed up with 1910 patients in the same age group.

RESULTS

Out of 82 patients, male/female ratio was 45/37. Median age at symptom onset was 5 years (28 days-17.4 years), age of granuloma at diagnosis was 8.6 years (36 days-19.4 years). Common symptoms at disease onset were fever (23.2%), lymphadenopathy (19.6%), abdominal pain (12.2%), and cough (12.2%). Granuloma was frequent in lymph nodes (26.8%), skin (19.5%), lung (13.4%), and bone (11%). Common infectious agents isolated were Mycobacterium spp. (23.2%) and EBV (4.9%). We document PIDD in 76.8% (63/82) of patients. 49.4% (40/81) of immunologically evaluated granuloma patients had hypogammaglobulinemia. Granuloma rate in pediatric PIDD was 3.3%(63/1910). Patients with multiple granulomas (n = 16) had a PIDD diagnosis. Lung involvement was three times more in PIDD. Brain involvement was only seen in PIDD. Fibroadipose tissue and liver involvement were more frequent in patients without documented PIDD and patients whose evaluation was not completed. The mortality rate in PIDD with granuloma was 15.9%, whereas there was no mortality in patients without PIDD.

CONCLUSION

As documented here, even in a university hospital, the immunologic evaluation ratio is about one-third. We showed high PIDD frequency in children with granuloma, and higher mortality in PIDD with granuloma. Thus, an immunologic evaluation performed meticulously by immunologists is a must for accurate diagnosis and decision of individualized therapeutic options.

The pediatric common variable immunodeficiency - from genetics to therapy: a review

Common variable immunodeficiency (CVID) is the most prevalent antibody deficiency, characterized by remarkable genetic, immunological, and clinical heterogeneity. The diagnosis of pediatric CVID is challenging due to the immaturity of the immune response and sustained actively developing antibody affinity to antigens and immunological memory that may overlap with the inborn error of immunity. Significant progress has been recently done in the field of immunogenetics, yet a paucity of experimental and clinical studies on different systemic manifestations and immunological features of CVID in children may contribute to a delayed diagnosis and therapy. In this review, we aimed at defining the variable epidemiological, etiological, and clinical aspects of pediatric CVID with special emphasis on predominating infectious and non-infectious phenotypes in affected children.

CONCLUSION

While pediatric CVID is a multifaceted and notorious disease, increasing the pediatricians' awareness of this disease entity and preventing the diagnostic and therapeutic delay are needed, thereby improving the prognosis and survival of pediatric CVID patients.

WHAT IS KNOWN

• CVID is an umbrella diagnosis characterized by complex pathophysiology with an antibody deficiency as a common denominator. • It is a multifaceted disease characterized by marked genetic, immunological, and clinical heterogeneity..

WHAT IS NEW

• The diagnosis of pediatric CVID is challenging due to the immaturity of innate and adaptive immune response. • Increasing the pediatricians' awareness of CVID for the early disease recognition, timely therapeutic intervention, and improving the prognosis is needed.