Hypogammaglobulinémies primitives découvertes à l’âge adulte

A case of disseminated blastomycosis in Vermont

Blastomyces dermatitides is increasingly found in Canada along the St. Lawrence River. However, there are only rare reports of this disease in New England. We describe a case of disseminated blastomycosis in a patient from northern Vermont who acquired the fungus while gardening.

Diagnostic strategy for patients with hypogammaglobulinemia in rheumatology

The discovery of hypogammaglobulinemia, which is defined as a plasmatic level of immunoglobulin (Ig) under 5 g/L is rare in clinical practice. However, the management of immunodepressed patients in rheumatology, sometimes due to the use of immunosuppressive treatments such as anti-CD20 in chronic inflammatory rheumatisms, increases the risk of being confronted to this situation. The discovery of hypogammaglobulinemia in clinical practice, sometimes by chance, must never be neglected and requires a rigorous diagnosis approach. First of all, in adults, secondary causes, in particular lymphoid hemopathies or drug-related causes (immunosuppressors, antiepileptics) must be eliminated. A renal (nephrotic syndrome) or digestive (protein-losing enteropathy) leakage of Ig is also possible. More rarely, it is due to an authentic primary immunodeficiency (PID) discovered in adulthood: common variable immunodeficiency (CVID) which is the most frequent form of PID, affects young adults between 20 and 30 years and can sometimes trigger joint symptoms similar to those in rheumatoid arthritis; or Good syndrome, which associates hypogammaglobulinemia, thymoma and recurrent infections around the age of 40 years. In most cases, after confirming hypogammaglobulinemia on a second test, biological examinations and thoracic-abdominal-pelvic CT scan will guide the diagnosis, after which the opinion of a specialist can be sought depending on the findings of the above examinations. At the end of this review, we provide a decision tree to guide the clinician confronted to an adult-onset hypogammaglobulinemia.

Common variable immunodeficiency associated with inflammatory bowel disease and type I diabetes

Common variable immunodeficiency (CVID) is a heterogeneous group of primary immunodeficiency disorders characterized by defective antibody production, low levels of serum immunoglobulins and increased susceptibility to infection. The patient was a 39-year-old male who was admitted to the gastroenterology department with a two week history of diarrhea, blunt abdominal pain below the umbilicus, prolonged febrile state, loss of appetite and loss of body weight of 18 kg during the previous six months. Screening tests of serum immunoglobulins showed decreased concentrations of three types of immunoglobulins: IgA < 0.24 g/L, IgM < 0.18 g/L and IgG < 1.55 g/L. Lymphocytes immunophenotypisation revealed inversed CD4⁺/8⁺ T cells ratio, 0.31 and absence of plasma cells (CD138 negative). Colonoscopy showed a rectal mucosa like cobblestones with multiple longitudinal and serpentinous ulceration, without involvement of other segments of the colon and the small intestine. Histopathology revealed aphtous ulcerative lesions, transmural inflammation with multiple lymphoid aggregates and benign lymphoid nodular hyperplasia of the small intestine. Plasma cells were absent from the lamina propria. Magnetic resonance imaging of a perianal fistula demonstrated a trans-sphicteric type. This case is specific because of the three illnesses associated and only one case of an association of diabetes mellitus type I and immunodeficiency reported thus far.

[Late onset of primary immune deficiencies]

Primary immune deficiencies (PID) are characterized by a failure of the immune system that is not explained by any infectious, neoplastic, or iatrogenic cause. The diagnosis of PID should be considered in cases of severe or recurrent infections but also in cases with granulomatosis, autoimmune diseases, hemophagocytic syndrome, lymphoproliferative disorders, or even some solid tumors. The onset of PID may be late, most often in adulthood. Nonetheless, late onset may also mean in the first years rather than months of life or in adolescence rather than early childhood. In adults, the diagnosis of PID cannot be considered before acquired immunodeficiencies--far more frequent--are ruled out. Factors affecting the late onset of PID are not known.

Common variable immunodeficiency. Old questions are getting clearer

Common variable immunodeficiency (CVID) is a heterogeneous entity characterized by an impaired ability to produce antibodies. The failure is localized in partially mature B lymphocytes, though T lymphocyte abnormalities are occasionally present. This deficiency affects antibody synthesis and class switch from IgD and IgM, to IgG and IgA. CVID is related to selective IgA deficiency, and both abnormalities may coincide in one same family, and evolve from one to another in the same patient. The symptoms generally manifest in adults, but can occur at any age, even in infancy. Recurrent bacterial infections or pneumonias are frequent, and may be complicated by gastrointestinal problems, granulomas, autoimmune disorders or malignancies. A defect in memory B cells seems to condition the clinical severity. Recently, several mutations in genes encoding for molecules (CD19, TACI, ICOS) involved in B cell survival and isotype switch have been identified in patients with CVID. Nevertheless, genetic abnormalities have been found in less than 25 % of cases with CVID; the underlying mechanism thus remains unknown in the majority of CVID patients, and research in this field must continue.

Diagnostic des déficits immunitaires primitifs à l’âge adulte

The molecular bases of approximately one hundred primary immune deficiencies (PID) have been identified over the last 15 years. In adults, the diagnosis of PID cannot be evoked before ruling out acquired immunodeficiencies, which are far more frequent. The search for specific PIDs may be oriented by the type of agent responsible for severe and/or recurrent infection. More rarely, other clinical manifestations such as granulomatosis, autoimmune manifestations, hemophagocytic syndrome, lymphoproliferation, or solid tumors may also lead to the identification of PID.