Thank you for your inquiry.
Isolated IgM “syndrome” has highly variable manifestations and causes. Many patients are asymptomatic and others can suffer from severe infections. Since IgM is no contained in immunoglobulin replacement preparations, it was at one time considered not indicated in patients with isolated IgM deficiency. However, there is evidence that IgM replacement therapy can be helpful in patients who have diminished IgG responses to immunization with pneumococcus (see abstract copied below). Therefore it can be considered a reasonable therapy (see abstract below).
Since your patient has had an episode of pneumococcal pneumonia and a poor response to Pneumovax, he would, in my opinion, qualify for treatment with immunoglobulin replacement therapy.
Thank you again for your inquiry and we hope this response is helpful to you.
Yel L; Ramanuja S; Gupta S
Clinical and immunological features in IgM deficiency.
Int Arch Allergy Immunol. 2009; 150(3):291-8 (ISSN: 1423-0097)
Yel L; Ramanuja S; Gupta S
Division of Basic and Clinical Immunology, Department of Medicine, University of California, Irvine, CA 92697, USA.
Background: IgM deficiency is a dysgammaglobulinemia characterized by isolated low levels of serum IgM. Patients with IgM deficiency may exhibit various clinical manifestations. However, IgM deficiency still remains to be explored with regard to diagnosis and treatment.
Methods: Through a retrospective chart review, we investigated the clinical and immunological features of 15 symptomatic adult IgM-deficient patients who were referred to our immunology clinics over a 4-year period.
Results: The patients were comprised of 6 males and 9 females, with a mean age of 57.2 years. On initial evaluation, 12 patients (80%) presented with susceptibility to infections, 5 (33%) had atopic manifestations such as asthma and allergic rhinitis, 3 (20%) had both infections and atopy, 4 patients (28%) had fibromyalgia-like symptoms, 3 (20%) had autoimmune manifestations, and 1 patient had lymphoma. The mean serum IgM level was 27.4 mg/dl (range 14-39). Impaired specific antibody response to pneumococcal antigens in 5 out of 11 studied patients (45%) appeared to be a notable association. Subtle abnormalities in IgG subclasses, lymphocyte subsets and in vitro proliferative lymphocyte responses were observed. Five patients who were treated with intravenous immunoglobulin responded very well.
Conclusion: We propose that a thorough immunological evaluation including specific antibody responses be undertaken in patients with IgM deficiency. IgM-deficient patients who present with recurrent/severe infections may benefit from immunoglobulin treatment particularly in the presence of impaired pneumococcal antibody responses.
Phil Lieberman, M.D.