Therapeutic Parasite Reduction or Removal of Harmful Materials

Yanyun Wu, MD, PhD

Chief Medical Officer

Conflict of Interest

• None

Puget Sound Blood Center is now Bloodworks Northwest After 70 years Puget Sound Blood Center is changing our name!

November 20, 2015, ASFA regional Meeting

Cases Case 1

A 53-year-old male resident of Connecticut was admitted to ER in July. He recently had a week-long camping trip.

He presented with high fevers (40 C), shaking chill, weakness, and fatigue. He had severe hemolytic anemia (Hct of 21%)/pancytopenia (platelet count of 33K), with signs of disseminated intravascular coagulation, acute renal failure, and respiratory failure. He was intubated and transferred to ICU overnight.

There was no history of splenectomy or immunodeficiency.

Cases Case 2 • 60 year old woman with a prolonged hospital stay

(7 months) due to multiple medical and surgical issues.

• For the last week, patient has been spiking temp of 39 to 40 C.

• Significant DAT negative hemolytic anemia (Hct of 27%)

• She received transfusion of 4 units RBC 4 weeks ago. And she has a history of splenectomy

Kyle Noskoviak, M.D., and Elizabeth Broome, M.D. N Engl J Med 2008; 358:e19April 24, 2008DOI: 10.1056/NEJMicm070903

N Engl J Med 2012;366:2397-407.

Human babesiosis summary

Causative pathogen: protozoal parasite in phylum Apicomplexa

Target tissue: red blood cells

Transmission:

Ixodid ticks (Ixodes scapularis)

Blood transfusion

Perinatal/transplacental

Diagnosis: epidemiology, symptoms, microscopy, PCR, antibody

Treatment: atovaquone/azithromycin or clindamycin/quinine, exchange transfusion

Courtesy of Dr. Peter Krause, Yale

Babesia species causing human infection

US

• B. microti

• B. duncani

• B. divergens-like

Vannier and Krause, N. Engl. J. Med., 2012

Courtesy of Dr. Peter Krause, Yale

Europe • B. divergens • B. venatorum • B. microti

Asia • B. microti-like • K01

Year

Nu

mb

er c

ases

Babesiosis in the US 1986-2011

0

100

200

300

400

500

600

700

800

900

1000

1100

86 87 88 89 90 91 92 93 94 95 96 97 98 99 00 01 02 03 04 05 06 07 08 09 10 11

Courtesy of Dr. Peter Krause, Yale

One of the most common infections of free-living animals worldwide and an emerging infection in humans

Human babesiosis

• Require both a competent vertebrate and nonvertebrate host to maintain transmission cycles

• Transmitted by ixodid ticks to their vertebrate hosts

• Replicate in the vertebrate hosts’ red blood cells

Vannier E and Krause PJ. New Engl J Med, 2012

Transmission of Babesia microti by the Ixodes scapularis Tick

Courtesy of Dr. Peter Krause, Yale

Trophozoite

Merozoite

Pre-gametocyte

Gametes fuse

in the gut

Zygote enters

gut epithelium

Sporoblasts/Sporozoites

in salivary glands

Life cycle of Babesia microti

Courtesy of Dr. Peter Krause, Yale

Life cycle of Babesia microti

Babesiosis

Babesiosis clinical manifestations

1. Asymptomatic infection 2. Viral-like illness Fever, chills, sweats, headache, fatigue 3. Severe illness and death (5-21%) >50, asplenic, HIV, malignancy, blood transfusion recipients • Persistent, relapsing illness HIV/AIDS, malignancy, asplenic, immunosuppressive drugs • The incubation period is usually 1–3 weeks

Courtesy of Dr. Peter Krause, Yale

Babesiosis: persistent parasitemia

(DNA)

Krause, Spielman, Telford, et al., New Engl J Med, 1998

Courtesy of Dr. Peter Krause, Yale

Transfusion transmitted babesiosis

• Symptoms delayed as long as 1 week to 6 months after transfusion

• Symptoms similar to those of tick-transmitted disease but often more severe because blood recipients are often immunocompromised

• Mortality rate ranges from about 10% to 21%

Courtesy of Dr. Peter Krause, Yale

Babesiosis in highly immunocompromised patients

Clinical characteristic Cases

(n=14)

Controls

(n=46)

P value

Median number of antibiotic courses

(range)

4 (2-10) 1 <0.001

Median number hospital admissions

(range)

1.5 (0-4) 1 (0-1) <0.001

Median weeks of therapy (range) 13 (4-

102)

1 (0.5-1.5) <0.001

Number with complications (percent) 8 (57) 2 (4) <0.001

Number with fatal infection (percent) 3 (21) 0 <0.02

Krause, Gewurz, Hill, et al. Clin Inf Dis, 2008

Courtesy of Dr. Peter Krause, Yale

Babesiosis in highly immunocompromised patients • People suffering from broad-based immunosuppression are at risk of persistent relapsing Babesia microti infection

• Adaptive immunity (B and T cell) are important for resolution of infection

• These patients generally require anti-babesial therapy for at least 6 weeks, including 2 weeks after babesia are no longer detected on blood smear

Courtesy of Dr. Peter Krause, Yale

General approach to diagnosis

Epidemiology

Medical history

Physical examination

Laboratory testing

Courtesy of Dr. Peter Krause, Yale

Specific laboratory diagnosis

Microbial detection

Blood smear

Polymerase chain reaction

Small rodent inoculation

Antibody detection

IFA

Immunoblot

ELISA

Courtesy of Dr. Peter Krause, Yale

Diagnostic algorithm for babesiosis

Cunha et al, Clinical Infectious Diseases® 2015;60(5):827–9

Diagnosis

Cunha et al, Clinical Infectious Diseases® 2015;60(5):827–9

Treatment of babesiosis caused by Babesia microti

Mild illness Atovaquone (PO) + azithromycin (PO) Administration for 7-10 days

Severe illness Clindamycin (IV or PO) + quinine (PO) Administration for 7-10 days

Persistent or relapsing illness Atovaquone (PO) + azithromycin (PO) OR Clindamycin (IV or PO) + quinine (PO) Administration for at least 6 wks, including 2 wks after parasites are no longer detected on blood smear

Courtesy of Dr. Peter Krause, Yale

Babesiosis

Babesiosis

• What are we removing?

• What are we adding back?

• Have we changed patient outcome?

• Give me the proof!

• Show me the data!

Babesiosis

Readings: 1. Dorman et al, TRANSFUSION Volume 40, March 2000 2. Spaete et al, Journal of Clinical Apheresis 24:97–105 (2009)

Babesiosis

Dorman et al, TRANSFUSION Volume 40, March 2000

Dorman et al, TRANSFUSION Volume 40, March 2000

Dorman et al, TRANSFUSION Volume 40, March 2000

Dorman et al, TRANSFUSION Volume 40, March 2000

Dorman et al, TRANSFUSION Volume 40, March 2000

Summary

• 15 males (63%)

• The mean age: 56 years (SD 16; range, 25–77)

• The mean pretransfusion hemoglobin: 8.1 g/dl (SD 2.5; range, 4.7–13.7).

• The mean preRCE or preWBE level of parasitemia was 18% (SD 14; range, 1.6–60)

• The mean postExchange level of parasitemia was 3.6% (SD 3.8; range, 0.1–13.8) with a median of 2%

• Fifteen (63%) of the 24 patients were asplenic

• Two of four who died were asplenic, and a third was reported to have necrotic splenic lesions on postmortem exam

Babesiosis

Spaete J et al, J Clin Apher. 2009;24(3):97-105.

Babesiosis

Babesiosis

Harmful Materials:

• Parasite: from RBC only?

• Cytokine?

• Free Heme

• Others?

ASFA guideline: Rationale for therapeutic apheresis

1. First, it helps to lower the level of parasitemia by physically removing the infected RBCs from the blood stream and replacing them with noninfected RBCs. Because babesia organisms do not have an exo-erthrocytic phase, removal of RBC-associated parasites might be very effective.

2. Second, by removal of rigid infected cells, RBC exchange could decrease obstruction in the microcirculation and tissue hypoxia caused by adherence of RBCs to vascular endothelium.

3. Finally, the hemolytic process produces vasoactive compounds, including a variety of cytokines (including INF-g, TNF-a, IL-1, IL-6), nitric oxide and thromboplastin substances, which can promote renal failure and DIC. RBC exchange may help to remove the proinflammatory cytokines.

Babesiosis

Shaio MF et al. Am J Trop Med Hyg. (1998)

Babesiosis

Shaio MF et al. Am J Trop Med Hyg. (1998)

Krause PJ, et al. Trends in Parasitology, 2007;23:605-610.

Courtesy of Dr. Peter Krause, Yale

Pathogenesis

Excessive erythrocyte cytoadherence: Additionally, erythrocytes infected with some babesia species

undergo membrane changes that cause these erythrocytes to adhere to the vascular endothelium Excessive pro-inflammatory cytokine production During a babesia infection, inflammatory cytokines including tumor

necrosis factor a (TNF-a) and interleukin 6, and adhesion molecules such as Eselectin, intracellular adhesion molecule 1 and vascular-cell adhesion molecule 1 are upregulated

While moderate synthesis of these factors may be protective,

excessive upregulation may result in severe babesiosis

Krause PJ, Daily J, Telford SR, et al. Trends Parasitol, 2007

Sloan et al, Journal of Clinical Apheresis 00:00–00 (2014)

• Cytoadherence most thoroughly studied in B. bovis infection

• Cattle infected by B. bovis die from encephalopathy as erythrocytes obstruct brain blood vessels.

• B. bovis encephalopathy similar to human P. falciparum cerebral malaria

• Cytoadherence is beneficial for the parasite as it delays or prevents filtering/removal of infected RBCs by the spleen.

Erythrocyte cytoadherence

Courtesy of Dr. Peter Krause, Yale

Pro-inflammatory cytokines

• Severe disease occurs without erythrocyte cytoadherence for B. microti, suggesting other pathogenic mechanisms.

• Pro-inflammatory cytokines such as TNF-α and IFN-γ protect the host against B. microti infection but if produced in excess may cause severe symptoms and complications.

Courtesy of Dr. Peter Krause, Yale

Babesiosis

• When do you start or stop?

• How to exchange?

• Patient consent?

• Others?

Babesiosis

Ziggy Vote

1. Agree with ASFA Category? 2. More Study?

a. RCT? b. CT? c. Registry?

3. What kind of exchange? a. RBC b. RBC+ Plasma? c. Whole Blood?