CD107a Mobilization (Sendout)

Test Utility: This test is ordered as part of the workup for hyperinflammatory syndromes such as hemophagocytic lymphohistiocytosis (HLH). This test should be ordered concurrently or after Hyperinflammatory Screening Labs have been obtained (CBC with diff, ferritin, fibrinogen, triglycerides, LDH, and D-dimer).

The following are consistent with, but not specific for, a diagnosis of HLH:

-Elevated sIL-2R, CXCL-9, and IL-18
-Elevated sCD163
-Reduced NK function (or cell surface expression of CD107alpha)
-Reduced perforin, SAP, or XIAP

Test Description: This employs flow cytometry to evaluate natural killer (NK) cell function/degranulation using surface expression of CD107alpha (also called LAMP-1 [lysosomal-associated membrane protein 1]). Mononuclear cells from the peripheral blood are stimulated with K562 target cells which induce degranulation. Tagged anti-CD107a is present with the cells during the stimulation period. After a 6-hour incubation at 37°C, the cells are surface-stained with NK cell markers (as well as CD3 and CD8). If the NK cells have been degranulated, CD107a will be expressed on the effector surface and will be detected by flow cytometry and reported as percent expression and mean channel fluorescence (MCF). Sample viability is assessed by flow cytometry using 7-AAD. Samples with a cellular viability of >=80% are reported. Samples with a cellular viability of 75-79% will be run and assessed for reportability.

Ordering Requirements: Laboratory Medicine Resident (LMR) approval is required for the Hyperinflammatory Lab Panel to help ensure that when this panel is indicated, collections are timed appropriately to meet stability limits for Perforin/Granzyme B (Sendout) [RPERGB] and CD107a Mobilization (Sendout) [RCD107].

Collection Note: Limited specimen stability. Samples must be received at Cincinnati Children’s Hospital Lab within 24 hours of collection, on days that align with Cincinnati Lab's run schedule. Time blood collections accordingly. Failure to follow collection guidelines may result in test cancellations.

Collection Timing:

• Collect samples Monday through Wednesday only due to Cincinnati's run schedule and the short stability window. Avoid collections on Thursday/Friday, weekends, holidays, or the day before a holiday.
• Samples must be received by the performing lab within 24 hours of collection. Recommended to collect between 10:00 a.m. and 1:00 p.m. to ensure delivery within the stability limit.

Sample Requirements: 2 x 4 mL DARK GREEN (Na Heparin) tubes (see exception below)

• Also Accepted: 2 x 6 mL YELLOW TOP (ACD) tubes
• Volume Note: If the patient’s absolute lymphocyte count (ALC) is available, call 513-636-4685 or use the "Customized Volumes by ALC" sheet to obtain the precise amount of blood required for this assay. If the ALC is not available, 8 mL blood in Sodium Heparin (Dark Green) is the general requirement and should be sufficient for patients who are not lymphopenic. For counts below 200 cells/mcL, consider waiting until count increases.
• Lab: If Epic Order Question "Does patient have a low Absolute Lymphocyte Count (ALC)" indicates "YES - ADDITIONAL BLOOD IS REQUIRED," draw 2 x 10 mL Na Heparin (Dark Green) tubes.
• Expedite transport to the lab. Sample must be received in lab no later than 2:00 p.m. for same-day shipment.

FHCC: Forward samples to UW-MT immediately via Delivery Express courier. Call UW-MT Sendouts team to notify them of an incoming sample for same-day shipment.

UW-MT SPS: Store whole blood specimens at ambient temperature. Notify Sendouts immediately upon receipt of sample. Samples must be shipped same-day.

FHCC SPS: Send samples to UW-MT immediately via Delivery Express courier. Call UW-MT Sendouts team at 206-598-3423 to notify them of an incoming sample for same-day shipment.

Sendouts:

• Order Cincinnati Children's Test: 2905400
• Complete a Cincinnati Children's Diagnostic Immunology Laboratory requisition.
• Samples must arrive at Cincinnati within 24 hours of collection. Ship samples at ambient temperature to the address below, Monday through Wednesday only, using FedEx First Overnight priority.
  • CCHMC CDBI Laboratories
  • 3333 Burnet Ave
  • DIL Room R2328
  • Cincinnati, OH 45229
• Document the FedEx Tracking Number on the requisition and notify Cincinnati DIL of an incoming sample by faxing to: 513-636-3861.

Stability: Ambient (required): 24 hours; Refrigerated: Unacceptable; Frozen: Unacceptable.

Reject Due to: Frozen, clotted, hemolyzed, or centrifuged specimens. Specimen collected in an unacceptable anticoagulant. Specimens received >24 hrs after collection.