Moreover, primary immunodeficiencies are only one category. Secondary immunodeficiencies due to medications, malignancies or aging are not uncommon either. Many popular medications, such as certain anticonvulsants, may lead to potentially reversible antibody deficiencies. It’s unreasonable to assume a rheumatologist without additional training can identify a secondary immunodeficiency alone, but referral to a clinical immunologist with expertise certainly can help.
You Might Also Like
Explore This IssueAugust 2018
Also By This Author
Autoimmunity is incompatible with immunodeficiency.
It seems counterintuitive that an underactive immune system may lead to autoimmune manifestations. But this is a gross simplification of how our bodies work. The immune system is extraordinarily intricate and when one facet of the immune system does not work properly, it may very well trigger another facet to overcompensate.3 A classic example is early classical complement pathway deficiencies, which can trigger systemic lupus erythematosus (SLE) and SLE-like diseases.
In fact, from the clinical immunologist’s point of view, all autoimmune rheumatologic disease is on the same continuum as immunodeficiency. Unchecked and indiscriminate inflammation may predispose to recurrent or severe infections and other manifestations of immune deficiency. Some clinical data suggest that for a subset of patients with severe, uncontrolled rheumatoid arthritis, immunomodulatory treatment may, on balance, actually reduce the risk of recurrent infections.4
Immunodeficiency is a laboratory diagnosis.
As a clinical immunologist, this bugs me the most. Many labs can be ordered to assess the integrity of the immune system. But these are only a means to supplement clinical suspicions. Many patients in my clinic don’t have laboratory abnormalities but clearly have otherwise unexplainable immune problems, for which I provide treatment as best as I can. On the other side of the spectrum, I often see patients whose referring providers have identified laboratory abnormalities but have no clinical manifestations concerning for immunodeficiency.
Complicating matters is that qualitative deficits may be the primary drivers of many immunodeficiencies. In specific antibody deficiency, for example, the levels of immunoglobulins are within normal limits, but antibody titers demonstrate poor response to antigens. Conversely, patients may have low CD4 helper T cell counts but no appreciable qualitative defects causing clinical symptoms. I manage these patients conservatively, with the understanding that lab values should not dictate the quality of care.
Although I welcome all the business that comes to my clinic with abnormal lab values, this is a decidedly unwelcome hassle for patients and expenditure for the healthcare system at large. I would strongly encourage rheumatologists and others to focus on taking detailed histories and documenting infections, rather than ordering panels of screening labs beyond the widely available, cheap and meaningful IgG, IgA and IgM levels, as well as the complete blood count with differential.
Treatment for immunodeficiencies are limited and ineffective.