Coccidioides immitis spherule

Spherusol ® is a skin test antigen indicated for the detection of delayed-type hypersensitivity to Coccidioides immitis in individuals with a history of pulmonary coccidioidomycosis. Spherusol ® is approved for use in individuals 18-64 years of age. The use of Spherusol ® to detect delayed-type hypersensitivity responses in a general population with unknown exposure to C. immitis has not been evaluated. Persons with acute or disseminated coccidioidomycosis may not develop a delayed-type hypersensitivity response to Spherusol ®. Persons with immunodeficiency and a history of coccidioidomycosis may not develop a delayed-type hypersensitivity response to Spherusol ®.

In individuals with a history of pulmonary coccidioidomycosis Spherusol ® is thought to elicit a cellular immune reaction to C. immitis, as evidenced by a delayed-type hypersensitivity (DTH) response to Coccidioidin. The general mechanism of the DTH response is based on the interaction of antigen with CD 4 and CD 8 lymphocytes followed by the secretion of interleukins and other lymphokines from macrophage cells. The release of effector molecules causes endothelial cells lining the blood vessels to become permeable and allows fibrinogen to escape into the surrounding tissue where it is converted to fibrin. The deposition of fibrin and the accumulation of T-cells and monocytes within the extracellular spaces cause the tissue to swell and become indurated. This process is usually detectable in 18 hours and peaks at 48 hours.

A single 0.1 mL intradermal injection. Induration at injection site to be evaluated 48 hours after administration. Preparation for Administration Spherusol ® is a clear, colorless sterile solution for intradermal administration. Parenteral drug products should be inspected visually for particulate matter and discoloration prior to administration, whenever solution and container permit. If any of these conditions exists, the skin test antigen should not be administered. Administration: Spherusol ® is administered as a 0.1 mL dose by intradermal injection to the volar surface of the forearm using a tuberculin syringe (0.5 or 1.0 mL) and a ½ inch 26-27 gauge needle. The needle should be inserted bevel side up in the skin at a 15-20 degree angle. Intradermal injection of 0.1 mL Spherusol ® will result in a bleb 5-10 mm in diameter at the injection site.

A severe allergic reaction (e.g., anaphylaxis) to Spherusol ®, or any component of Spherusol ® or other coccidioidin products is a contraindication to administration. Severe allergic reaction (e.g., anaphylaxis) to Spherusol ®, or any component of Spherusol ® or other coccidioidin products.

WARNING The expected response to Spherusol ® is a local area of inflammation at the site of the skin test. The reaction is usually dime to quarter size reaching maximum diameter between 24 and 48 hours. Larger accelerated reactions can occur, which may require treatment with local cold compresses and anti-inflammatory medication. Acute hypersensitivity reactions and anaphylaxis have occurred following the administration of other skin test antigens and may occur in individuals following the administration of Spherusol ®. Patients receiving beta-blocking drugs may be refractive to the usual dose of epinephrine in cases of hypersensitivity. Any condition or agent that impairs or attenuates delayed type hypersensitivity reactions, including infections and use of immunosuppressive drugs, can potentially cause a false negative reaction to Spherusol ®.

The most commonly reported local adverse reactions were itching and swelling (>75%) and pain (>15%) within 7 days of administration. To report SUSPECTED ADVERSE REACTIONS, contact Nielsen Biosciences, Inc. at (855) 855-1212 or Food and Drug Administration (FDA) at 1-800-332-1088 or www.vaers.hhs.gov.

Corticosteroids and immunosuppressive agents may suppress the response to the skin test. Corticosteroids and Immunosuppressives Corticosteroids and Immunosuppressive agents may suppress the response to the skin test. Pharmacologic doses of corticosteroids may suppress the response to skin test antigens after two weeks of therapy. The mechanism of suppression is thought to involve a decrease in monocytes and lymphocytes, particularly T-cells. The normal DTH response usually returns to pre-treatment levels within several weeks after steroid therapy is discontinued. The use of Spherusol ® has not been evaluated during or following the use of corticosteroids or immunosuppressive agents.

Store refrigerated at 2° to 8°C (35° to 46°F). Do not freeze.