Leukopenia, leukoagglutinins, and low IgM in a family with severe febrile illnesses

Challenges in investigating patients with isolated decreased serum IgM: The SIMcal study

The clinical consequences of isolated decreased serum immunoglobulin (Ig)M are not sufficiently known. Therefore, it is difficult to determine the clinical policy following such a finding. Only few reported IgM‐deficient patients fulfil the European Society for Immunodeficiencies (ESID) diagnostic criteria for selective IgM deficiency (true sIgMdef), or their diagnosis is uncertain due to insufficient laboratory data (possible sIgMdef). Decreased serum IgM is often incidentally found in asymptomatic adults. The objective of our study was to further characterize true sIgMdef and to compare the European data collected through the ESID Registry community (tertiary centres) to our previously published Dutch cohort (secondary centre). Fifteen centres (12 countries) participated with 98 patients. Patients were excluded if serum IgM was only determined once (n = 14), had normalized (n = 8), or if they also had other immunological abnormalities (n = 15). Ten patients (5 adults) completely fulfilled the ESID criteria for true sIgMdef. Age‐matched cut‐off values varied widely between centres; when using the ESID diagnostic protocol reference values, only six patients (five adults) had true sIgMdef. Because of these small numbers, further analyses were performed in patients with true or possible sIgMdef (13 adults, 48 children). Respiratory infections were commonly reported at presentation (adults 54%, children 60%). Symptomatic adults had lower serum IgM levels (mean 0.27 g/L, 95% CI 0.22‐0.31) than those without symptoms (mean 0.33 g/L, 95% CI 0.30‐0.36; P = 0.02). To be able to explore the clinical consequences of true sIgMdef, we should fully analyse and accurately describe those patients in whom a decreased serum IgM is found.

Truly selective primary IgM deficiency is probably very rare

Isolated decreased serum-immunoglobulin (Ig)M has been associated with severe and/or recurrent infections, atopy and autoimmunity. However, the reported high prevalence of clinical problems in IgM-deficient patients may reflect the skewed tertiary centre population studied so far. Also, many papers on IgM deficiency have included patients with more abnormalities than simply IgM-deficiency. We studied truly selective primary IgM deficiency according to the diagnostic criteria of the European Society for Immunodeficiencies (ESID) (true sIgMdef) by reviewing the literature (261 patients with primary decreased serum-IgM in 46 papers) and analysing retrospectively all patients with decreased serum-IgM in a large teaching hospital in 's-Hertogenbosch, the Netherlands [1 July 2005-23 March 2016; n = 8049 IgM < 0·4 g/l; n = 2064 solitary (IgG+IgA normal/IgM < age-matched reference)]. A total of 359 of 2064 (17%) cases from our cohort had primary isolated decreased serum-IgM, proven persistent in 45 of 359 (13%) cases; their medical charts were reviewed. Our main finding is that true sIgMdef is probably very rare. Only six of 261 (2%) literature cases and three of 45 (7%) cases from our cohort fulfilled the ESID criteria completely; 63 of 261 (24%) literature cases also had other immunological abnormalities and fulfilled the criteria for unclassified antibody deficiencies (unPAD) instead. The diagnosis was often uncertain (possible sIgMdef): data on IgG subclasses and/or vaccination responses were lacking in 192 of 261 (74%) literature cases and 42 of 45 (93%) cases from our cohort. Our results also illustrate the clinical challenge of determining the relevance of a serum sample with decreased IgM; a larger cohort of true sIgMdef patients is needed to explore fully its clinical consequences. The ESID online Registry would be a useful tool for this.

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.

Transient T-cell abnormality in a selective IgM-immunodeficient patient with Brucella infection

We describe here one 9-year-old female patient with an unusual form of selective IgM and CD4+ (OKT4+) helper/inducer T-cell immunodeficiency associated with Brucella infection. During the acute phase of Brucella infection, the percentage of infection. During the acute phase of Brucella infection, the percentage of peripheral blood lymphocytes (PBL) displaying OKT3+, OKT11+, and OKT4A+ phenotypes was decreased, and that of the OKT8+ cell was increased. These phenotypic T-cell abnormalities disappeared after antibiotic therapy in a 5-week period. However, the marked deficiency of CD4+ T cells and the IgM deficiency present during the acute phase of illness remained after recovery from illness. In vitro immunoglobulin production experiments during the acute phase of illness demonstrated that the patient's T cells lacked the capacity to provide helper/inducer function for normal B-cell differentiation to secrete IgM. The patient's T cells were also shown to possess IgM-specific suppressor cell activity on normal B- and T-cell differentiations. Thus impaired T-cell function was shown to be responsible for IgM-deficient antibody production. Defective interleukin 2 receptor expression and production by the patient's PBL in response to mitogenic stimulation also were present, indicating a severe defect in the patient's T-cell function.

Selective immunoglobulin M deficiency associated with disseminated molluscum contagiosum

A 16-year-old girl with disseminated molluscum contagiosum (MC) was found to have a very low level of serum IgM, elevated levels of IgG and IgA, and a high level of IgE. She had normal numbers of peripheral blood IgM+, IgG+ and IgA+ B-lymphocytes but their terminal differentiation into plasma cells could not be induced by pokeweed mitogen (PWM) in vitro. On the other hand, the patient's T-cells showed normal helper functions in the PWM system and normal interferon (IFN) production in vitro. However, the IgM+ B-cells can be induced to differentiate into IgM secreting cells by Epstein-Barr virus (EBV), suggesting that the genetic mechanism for synthesis of the component immunoglobulin proteins is present. T-cell functions were impaired, as shown by delayed type cutaneous hypersensitivity (DTH) and mitogen response. The data suggest that the selective IgM deficiency of the patient is due mainly to defects in B-cells at the terminal differentiation stage, but immunological abnormalities are present in both B and T-cell systems. Neutrophil functions examined were normal. MC was treated by intravenous injection of IFN without any side effects; however, no clinical improvement was achieved.

Selective partial IgM deficiency: functional assessment of T and B lymphocytes in vitro

Seven patients with selective IgM deficiency (SIgMD) were studied for cell surface immunoglobulin (SmIg), T-cell subpopulations, and immunoglobulin (Ig) synthesis in vitro by peripheral blood lymphocytes (PBL). Serum IgM levels were less than 25 mg/dl, while IgA, IgG, and IgD were within normal levels. The patients had respiratory or urinary tract infections and two were diagnosed as having systemic lupus erythematosus (SLE). T/B-cell ratios in PBL were within normal ranges. Percentage ratios of B cells bearing SmIg were normal in five patients and decreased in two; however, normal values were seen after 7 days of culture in the presence of PWM. OKT4/OKT8 ratios decreased in five of seven patients, in whom two were due to a decrease in OKT4 and two to an increase in OKT8 cells. One showed a decrease in OKT4 and an increase in OKT8. Analysis of lymphocyte function for Ig synthesis in vitro, using a coculture of counterpart T and B cells from healthy individuals and patients with SIgMD, revealed that the increased function of IgM isospecific suppressor T cells (Ts) was responsible for the IgM deficiency in all seven patients.

Severe selective IgM deficiency

Among the primary antibody deficiency syndromes, severe selective IgM deficiency (also previously known as type V dysgammaglobulinaemia) is rare, and the majority of previous reports have indicated a fatal outcome. Three adult patients who were found to have a persistently low serum IgM are described. This deficiency was not obviously related to their presenting illness; in two of the patients, who were investigated in detail, it appeared to be of no immediate consequence.