Primary selective deficiency of immunoglobulin M

Selective IgM Deficiency: Evidence, Controversies, and Gaps

Selective Immunoglobulin M deficiency (SIgMD) has been recently included in the inborn errors of immunity (IEI) classification by the International Union of Immunological Societies Expert Committee. The understanding of SIgMD is still extremely limited, especially so in cases of SIgMD in the pediatric population. The epidemiology of SIgMD in the pediatric population is still unknown. The pathogenesis of SIgMD remains elusive, and thus far no genetic nor molecular basis has been clearly established as a definitive cause of this primary immunodeficiency. Recurrent respiratory infections represent the main clinical manifestations in children, followed by allergic and autoimmune diseases. No conclusive data on the correct therapeutic management of SIgMD are available. Although, for most SIgMD patients, Ig replacement therapy is not required, it may be recommended for patients with significantly associated antibody deficiency and recurrent or severe infections. Prophylactic antibiotics and the prompt treatment of febrile illness are crucial. There is insufficient evidence on the prognosis of this condition. Therefore, further studies are required to define the disease trajectories and to increase our understanding of the molecular mechanisms underlying SIgMD in order to facilitate a better clinical, immunological, and prognostic characterization of the condition and develop tailored therapeutic management strategies.

Selective IgM Deficiency: Clinical and Laboratory Features of 17 Patients and a Review of the Literature

PURPOSE

Primary selective IgM deficiency (sIgMD) is a primary immunodeficiency with unclear pathogenesis and a low number of published cases.

METHODS

We reviewed clinical and laboratory manifestations of 17 sIgMD patients. Serum IgM, IgG, and its subclasses, IgA, IgE, antibodies against tetanus toxoid, pneumococcal polysaccharides and Haemophilus influenzae type b, isohemagglutinins, and T and B lymphocyte subsets, expressions of IgM on B cells and B lymphocyte production of IgM were compared with previously reported case reports and a small series of patients, which included 81 subjects in total.

RESULTS

We found that some patients in our cohort (OC) and published cases (PC) had increased IgE levels (OC 7/15; PC 21/37), decreased IgG4 levels (OC 5/14), very low titers of isohemagglutinins (OC 8/8; PC 18/21), increased transitional B cell counts (OC 8/9), decreased marginal zone B cell counts (OC 8/9), and increased 21^low B cell counts (OC 7/9). Compared with the PC (20/20), only two of five OC patients showed very low or undetectable production of IgM after stimulation. A majority of the patients had normal antibody production to protein and polysaccharide antigens, basic lymphocyte subset counts, and expression of surface IgM molecules on B cells.

CONCLUSIONS

Low IgM levels are associated with various immunopathological disorders; however, pathogenic mechanisms leading to decreased IgM serum level in selective IgM deficiency remain unclear. Moreover, it is difficult to elucidate how strong these associations are and if these immunopathological conditions are primary or secondary.

Pediatric selective IgM immunodeficiency

Objective. Limited information exists on features of pediatric Selective IgM immunodeficiency (SIgMID). Previously published pediatric cases and 2 new cases are reviewed. Methods. English literature from PubMed and references from relevant articles were reviewed. Previously reported cases and 2 new cases from an allergy/immunology practice were analyzed. Results. Forty-nine reported cases of SIgMID presented with respiratory infections (77.6%), gastrointestinal disease (16.3%), skin disease (12.2%), and meningitis (8.2%). Mean serum IgM level was 16.5 ± 13.8 mg/dL. Two patients were identified with SIgMID among 6300 active pediatric patients (0.03%) presenting with asthma, vasomotor rhinitis, and recurrent respiratory infections. In the 51 cases reported, none developed lymphoproliferative disease nor evolved into panhypogammaglobulinemia; four fatalities were reported. Conclusions. The prevalence of SIgMID in our pediatric population was 0.03%. In general, respiratory infections are the common comorbid conditions. Death and autoimmune disease are uncommon complications of pediatric SIgMID.

Selective IgM immunodeficiency: retrospective analysis of 36 adult patients with review of the literature

OBJECTIVE

To review and compare previously reported cases of selective IgM immunodeficiency (SIgMID) with the largest adult cohort obtained from a retrospective analysis of an allergy and immunology practice.

DATA SOURCES

Publications were selected from the English-only PubMed database (1966-2005) using the following keywords: IgM immunodeficiency alone and in combination with celiac disease, autoimmune disease, malignancy, and infection. Bibliographic references of relevant articles were used.

STUDY SELECTION

Reported adult SIgMID cases were reviewed and included in a comparative database against our cohort.

RESULTS

Previously described patients with SIgMID include 155 adults and 157 patients of unspecified age. Thirty-six adult patients were identified with SIgMID from a database of 13,700 active adult patients (0.26%, 1:385). The mean +/- SD serum IgM level was 29.74 +/- 8.68 mg/dL (1 SD). The mean +/- SD age at the time of diagnosis of SIgMID was 55 +/- 13.5 years. Frequency of presenting symptoms included the following: recurrent upper respiratory tract infections, 77%; asthma, 47%; allergic rhinitis, 36%; vasomotor rhinitis, 19%; angioedema, 14%; and anaphylaxis, 11%. Serologically, 13% of patients had positive antinuclear antibodies (ANAs), 5% had serologic evidence of celiac disease, and nearly all had non-AB blood type. Patients also had low levels of IgM isohemagglutinins. No patients developed lymphoproliferative disease or panhypogammaglobulinemia, and none died of life-threatening infections, malignancy, or fulminant autoimmune-mediated diseases during a mean follow-up period of 3.7 years.

CONCLUSIONS

The prevalence of SIgMID in our adult population was 0.26% and may be more common than previously thought. Non-life-threatening respiratory disorders were common comorbid conditions.

Multiple recurrent hordeola associated with selective IgM deficiency

An external hordeolum is an acute, suppurative inflammation of the glands of Zeis and sweat glands or hair follicles most commonly caused by staphylococci, usually in the setting of a chronic blepharitis.(1) We report a case of a boy with unilateral multiple recurrent hordeola in association with selective IgM deficiency.