Specialist referral unearths wide spectrum of adult primary immune deficiencies

By Liam Davenport, MedWire Reporter

The range of adult primary immune deficiencies is considerable and the majority of patients are diagnosed only after specialist referral, conclude Canadian scientists who identified two novel patient groups with humoral abnormalities.

Recognizing the diversity of deficiencies among patients, Christos Tsoukas, from McGill University Health Center in Quebec, and colleagues recommend: "During the initial evaluation of patients with suspected primary immune deficiencies, the causative microbial agent should trigger a pattern of clinical investigations that follows a particular arm of the immune system.

"For instance, individuals with defects in humoral immunity are more prone to bacterial infections, whereas severe viral or fungal infections are frequently noted with T-cell defects."

Out of 381 patient referrals for suspected immune deficiency to a specialist center for the diagnosis and care of adults with primary immune deficiencies, 55% were referred by allergists, otorhinolaryngologists, and pulmonologists, while 17% came from family practitioners and internists.

The diagnosis of immune deficiency was confirmed in 244 of the study group, of whom 167 had European Society for Immunodeficiencies and the Pan-American Group for Immunodeficiency (ESID/PAGID)-defined primary immune deficiency. A further 43 had a novel or undefined deficiency, and 34 had a secondary immune deficiency. A total of 201 patients were newly diagnosed, giving a referral accuracy of 53%.

The most frequently occurring primary immune deficiencies were common variable immune deficiency, immunoglobulin A (IgA) deficiency, hypogammaglobulinemia with infections other than those meeting the variable common deficiency criteria, and idiopathic CD4+ T lymphopenia, in 43%, 15%, 10%, and 8% of patients, respectively.

Some patients did not fit the ESID/PAGID criteria, and had hypogammaglobulinemia with less frequent or nonrecurrent and mild bacterial infections, none requiring IgG replacement therapy, and pronounced B-cell lymphocytopenia. These were divided into 17 patients who were older than common variable immune deficiency patients but had similar IgG levels, and 12 patients with a median age over 65 years, a history of recurrent bacterial infections, low B-cell numbers, and borderline normal serum Ig levels.

The team also reports in the American Journal of Medicine that initial referral was made for chronic sinusitis, chronic bronchitis, and recurrent pneumonia, in 14%, 5%, and 5% of patients, respectively. Interestingly, only one-third of patients had undergone quantitative serum Ig assessment prior to referral.

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