Q:

11/1/2012 10
A 65 year-old woman with bronchiectasis and mycobacterium avium was referred to me. She had already had a partial immunology evaluation. Her IgG was 991 mg/dl with IgG subclasses 2 and 3 deficiency and absent pneumococcal antibody titers. IgA was 61 mg/dl, and IgM was 111 mg/dl. Incidentally, she also has chronic thrombocytopenia. I checked IL12 and IFN-gamma, both of which were less than 5 pg/ml. Do I need to do further laboratory tests for function or receptors? Do I need to treat her with IFN-gamma? If so, how do you recommend I proceed.

A:

Thank you for your inquiry.

I am forwarding your inquiry to Dr. Steven Holland at the National Institute of Health who is an internationally known expert in IL-12 and interferon gamma deficiency in mycobacterium infections. As soon as we hear from Dr. Holland, we will forward his response to you.

Thank you again for your inquiry.

Sincerely,
Phil Lieberman, M.D.

We received a response from Dr. Steven Holland regarding your Ask the Expert inquiry. Thank you again for your inquiry and we hope this response is helpful to you.

Sincerely,
Phil Lieberman, M.D.

Response from Dr. Steven Holland:
This is one of the most confusing areas in current immunology. However, let me try to address the confusion. The role of IFNg/IL-12 in control of nontuberculous mycobacteria is very well established for disseminated disease. However, in limited pulmonary disease (limited to the lung parenchyma) there has not been a persuasive demonstration of immunologic impairment. I have no idea what to make of serum cytokine levels, and there certainly are no criteria for them in this patient population. We know from the fact that patients with XLA or CVID do not get pulmonary NTM infections that antibody is not a very important player in susceptibility. So personally, I would reassure this patient that her NTM is likely not due to an underlying immune defect but is due to her underlying bronchiectasis. If she has destructive lung disease and is symptomatic, she should be treated with a multidrug regimen administered by someone with extensive experience. There are several centers around the country with expertise (National Jewish in Denver, UT Tyler, Stanford, NIH) and many others with experts on staff.

Now, in your patient's case, the only puzzle is why she has thrombocytopenia, since that is not part of the spectrum of pulmonary NTM disease. Has a bone marrow been done? Please feel free to contact me directly with any questions.

Steve Holland

AAAAI - American Academy of Allergy Asthma & Immunology