How useful is serum 1, 3-β-D-glucan in diagnosing Pneumocystis jiroveci pneumonia and invasive fungal disease?

Serum 1, 3-β-D-glucan (BG) is highly accurate for Pneumocystis jiroveci pneumonia (PJP), but only moderately accurate for diagnosing invasive fungal disease (IFD).

For PJP, a meta-analysis of studies looking at the performance of BG found a pooled sensitivity of 96%, specificity of 84% and area under receiver operating characteristic curve (AUC-ROC) of 0.96. 1 Thus, a negative BG essentially rules out PJP.

For IFD (primarily invasive candidiasis or aspergillosis), data based on 3 separate meta-analyses came to similar conclusions with a pooled sensitivity and specificity of ~80% and AUC-ROC of ~0.89 each.1-3 In some of the studies,2,3 the sensitivity of BG for IFD was between 50% to 60% which makes it difficult to exclude IFD when BG is normal.

Remember that BG may be false-positive in a variety of situations, including patients receiving immunological preparations (eg albumin or globulins), use of membranes and filters made from cellulose in hemodialysis, and use of cotton gauze swabs/packs/pads and sponges during surgery. 1 In addition, although BG is a component of the cell wall of most fungi, there are some exceptions including Zygomycetes and cryptococci.

Bonus pearl: Did you know that BG assay is based on Limulus amoebocyte lysate, extracted from amoebocytes of horseshoe crab species? 3

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References

  1. Onishi A, Sugiyama D, Kogata Y, et al. Diagnostic accuracy of serum 1,3-β-D-glucan for Pneumocystis jiroveci pneumonia, invasive candidiasis, and invasive aspergillosis: systematic review and meta-analysis. J Clin Microbiol 2012;50:7-15. https://www.ncbi.nlm.nih.gov/pubmed/22075593
  2. He S, Hang JP, Zhang L, et al. A systematic review and meta-analysis of diagnostic accuracy of serum 1,3–β-D-glucan for invasive fungal infection: focus on cutoff levels. J Microbiol Immunol Infect 2015;48:351-61. https://www.ncbi.nlm.nih.gov/pubmed/25081986
  3. Karageogopoulos DE, Vouloumanou EK, Ntziora F, et al. β-D-glucan assay for the diagnosis of invasive fungal infections: a meta-analysis. Clin Infect Dis 2011;52:750-69. https://academic.oup.com/cid/article/52/6/750/361658/

 

How useful is serum 1, 3-β-D-glucan in diagnosing Pneumocystis jiroveci pneumonia and invasive fungal disease?

When should I consider prophylaxis for Pneumocystis pneumonia (PCP) in my patient on prednisone?

It is generally recommended that patients on ≥20 mg of daily prednisone (or its equivalent) for ≥1 month be considered for PCP prophylaxis. 1

Couple of studies in 1990s helped define the dose and duration of corticosteroids (CS) that should prompt PCP prophylaxis. A Mayo Clinic study of patients without AIDS found that a median daily CS dose of 30 mg of prednisone or equivalent—with 25% of patients receiving as little as 16 mg of prednisone daily— was associated with PCP.The median duration of CS therapy before PCP was 12 weeks. A similar study found a mean CS dose of 33 mg of prednisone or equivalent with mean duration of 7 months (range 1-154 months) among patients with PCP without AIDS. 3

A 2018 retrospective study4  of patients with rheumatic diseases receiving prolonged high-dose CS therapy (≥30 mg prednisone for ≥4 weeks) found that PCP prophylaxis with trimethoprim/sulfamethoxazole (TMP/STX) resulted in 93% reduction in the incidence of PCP with an overall number needed to treat (NNT) of 52. It was suggested that PCP prophylaxis could be discontinued in patients receiving < 15 mg of prednisone daily.

Bonus Pearl: Did you know that TMP/STX may be given either as double-strength 3x/week or single-strength daily? 5,6

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References

1. Limper AH, Knox KS, Sarosi SA, et al. An official American Thoracic Society statement: Treatment of fungal infections in adult pulmonary and critical care patients. Am J Respir Crit Care Med 2011;183:96-128. https://www.ncbi.nlm.nih.gov/pubmed/21193785

2. Yale SH, Limper AH. Pneumocystis carinii pneumonia in patients without acquired immunodeficiency syndrome: associated illness and prior corticosteroid therapy. Mayo Clin Proc 1996;71:5-13. https://www.sciencedirect.com/science/article/abs/pii/S0025619611649148

3. Arend SM, Kroon FP, van’t Wout JW. Pneumocystis carinii pneumonia in patients without AIDS, 1980 through 1993: An analysis of 78 cases. Arch Intern Med 1995;155:2436-2441. https://www.ncbi.nlm.nih.gov/pubmed/7503602

4. Park JW, Curtis JR, Moon J, et al. Prophylactic effect of trimethoprim-sulfamethoxazole for Pneumocystis pneumonia in patients with rheumatic diseases exposed to prolonged high-dose glucocorticoieds. Ann Rheum Dis 2018;77:664-9. https://www.ncbi.nlm.nih.gov/pubmed/29092853

5. Anevlavis S, Kaltsas K, Bouros D. Prophylaxis for pneumocystis pneumonia (PCP) in non-HIV infected patients. PNEUMON 2012;25, October-December.http://www.pneumon.org/assets/files/789/file483_273.pdf

6. Stern A, Green H, Paul M, Leibovici L. Prophylaxis for pneumocystis pneumonia (PCP) in non-HIV immunocompromised patients (Review). Cochrane data of Systematic Reviews 2014, issue 10. DOI: 10.1002/14651858.CD005590.pub3. https://www.ncbi.nlm.nih.gov/pubmed/25269391

 

When should I consider prophylaxis for Pneumocystis pneumonia (PCP) in my patient on prednisone?

In my patient with a serious infection, when should I worry about a primary immunodeficiency disorder?

You may consider a primary immunodeficiency disorder (PID) when 2 or more of the following “warning signs” are present: 1

  • ≥ 4 ear infections in 1 year
  • ≥ 2 serious sinus infections in 1 year
  • ≥ 2 pneumonias in 1 year
  • Recurrent, deep skin or organ abscesses
  • Persistent thrush in mouth or persistent fungal infection on the skin
  • ≥ 2 deep-seated infections, including septicemia
  • ≥ 2 months on antibiotics with little effect
  • Need for IV antibiotics to clear infections
  • Failure of an infant to gain weight or grow normally
  • Family history of primary immunodeficiency

Other infectious conditions that may be a clue to PID include those in unusual locations (eg, pneumococcal arthritis) or caused by unusual pathogens (eg, Pneumocystis jirovecii).

Among non-infectious conditions, history of granulomas in multiple organs, early-onset eczema refractory to therapy, and autoimmunity (eg, autoimmune cytopenias, autoimmune thyroiditis, celiac disease, vitiligo, type I diabetes mellitus) may also be potential clues.2

But before you embark on searching for PID,  rule out local barrier disorders of the skin or mucosa (eg, foreign body, bronchiectasis, cystic fibrosis) and secondary causes of immunodeficiency (eg, HIV), syndromes of protein loss/deficiency (eg, cirrhosis, nephrotic syndrome, malnutrition), splenectomy, malignancy, and medications (eg, steroids, chemotherapy, tumor necrosis factor inhibitors).2

Final Fun Fact: Did you know that PID affects 1 in 1,200 people in the US? 3

References:

  1. Arkwright PD, Gennery AR. Ten warning signs of primary immunodeficiency: a new paradigm is needed for the 21st century. Ann N Y Acad Sci 2011; 1238:7-14 http://onlinelibrary.wiley.com/doi/10.1111/j.1749-6632.2011.06206.x/abstract
  2. Hausmann O, Warnatz K. Immunodeficiency in adults a practical guide for the allergist. Allergo J Int. 2014; 23: 261–268 https://link-springer-com.ezp-prod1.hul.harvard.edu/article/10.1007/s40629-014-0030-4
  3. Boyle JM, Buckley RH. Population prevalence of diagnosed primary immunodeficiency diseases in the United States. J Clin Immunol 2007; 27:497  https://link.springer.com/article/10.1007/s10875-007-9103-1

 

Contributed by Yousef Badran, MD, Mass General Hospital, Boston, MA.

In my patient with a serious infection, when should I worry about a primary immunodeficiency disorder?

When should I consider Pneumocystis jirovecii pneumonia (PCP) prophylaxis in my non-HIV patient?

The most significant risk factor for PCP prophylaxis is defect in cell-mediated immunity including high-dose glucocorticoid (HDGC, ≥20 mg of prednisone daily) treatment1.  A systematic review concluded that at a PCP rate of 6.2% in control groups, PCP prophylaxis with trimethoprim/sulfamethoxazole (TMP/STX) is highly effective (85% risk reduction) in non-HIV patients with acute leukemia or solid organ/autologous bone marrow  transplantation (number needed to treat 19)2.

Other Indications for PCP prophylaxis include1:

  1. HDGC treatment for ≥1month plus another cause of immunocompromise.
  2. Combination of immunosuppressive drugs, such as tumor-necrosing factor- α inhibitors plus HDGC or other immunosuppression.
  3. Polymyositis/dermatomyositis with interstitial pulmonary fibrosis on glucocorticoids.
  4. Certain primary immunodeficiencies (eg idiopathic CD4-lymphopenia, hyper-IgM syndrome).
  5. Granulomatosis with polyangiitis (Wegener’s) on methotrexate and HDGC
  6. Rheumatologic diseases on HDGC and a second immunosuppressive drug
  7. T-cell depleting agents (eg, fludarabine)
  8. Severe malnutrition

TMP/STX may be given either as double-strength 3x/week or single-strength daily1,2.

 

References

  1. Anevlavis S, Kaltsas K, Bouros D. Prophylaxis for pneumocystis pneumonia (PCP) in non-HIV infected patients. PNEUMON 2012;25, October-December.
  2. Stern A, Green H, Paul M, Leibovici L. Prophylaxis for pneumocystis pneumonia (PCP) in non-HIV immunocompromised patients (Review). Cochrane data of Systematic Reviews 2014, issue 10. DOI: 10.1002/14651858.CD005590.pub3. 
When should I consider Pneumocystis jirovecii pneumonia (PCP) prophylaxis in my non-HIV patient?

My patient with autoimmune hepatitis has been on less than 20 mg of prednisone daily for the past month and now complains of dyspnea. What is the dose of prednisone that should make me worry about Pneumocystis jirovecii pneumonia (PCP) in her?

The risk of infection in patients on glucocorticoids (GCs) is likely determined not only by the dose and duration of treatment but also by the nature of the underlying disease requiring GC therapy (eg, asthma, autoimmune disease, malignancy),   use of additional immunosuppressants, as well as individual host sensitivity to the effects of GCs1,2.  For these reasons, it is often difficult to determine how much GCs will be too much for a specific patient when discussing opportunistic infections such as PCP in patients without HIV infection.

In patients with an autoimmune disease such as ours, as little as 12 mg/day of prednisone on presentation or as few as 5 days of GC therapy has been associated with PCP3.  Because the critical amount of immunosuppression necessary for PCP to cause disease is unclear4, and autoimmunity is often associated with T-cell dysregulation5, it is prudent to consider PCP in the differential of diagnosis of dyspnea (along with fever or pulmonary infiltrates if present) in this patient despite not receiving “high” doses of prednisone daily.  It is also important to remember that many cases of PCP occur during GC taper4.

 

References

  1. Lionakis MS, Kontoyiannis DP. Glucocorticoids and invasive fungal infections. Lancet 2003;362:1828-38.
  2. Youssef J, Novosad SA, Winthrop KL. Infection risk and safety of corticosteroids. Rheum Dis Clin N Am 2016; 42; 157-176.
  3. Yale SH, Limper AH. Pneumocystis carinii pneumonia in patients without acquired immunodeficiency syndrome: associated illness and prior corticosteroid therapy. Mayo Clin Proc 1996;71:5-13.
  4. Sepkowitz KA, Brown AE, Armstrong D. Pneumocystis carinii pneumonia without acquired immunodeficiency syndrome. Arch Intern Med 1995;1125-28.
  5. Arkwright PD, Abinun M, Cant AJ. Autoimmunity in human immunodeficiency diseases. Blood 2002;99:2694-2707.
My patient with autoimmune hepatitis has been on less than 20 mg of prednisone daily for the past month and now complains of dyspnea. What is the dose of prednisone that should make me worry about Pneumocystis jirovecii pneumonia (PCP) in her?