Blood transfusions with high levels of contaminating soluble HLA-I correlate with levels of soluble CD8 in recipients' plasma; a new control factor in soluble HLA-I-mediated transfusion-modulated immunomodulation?
BACKGROUND
The cause of transfusion-related immunomodulation (TRIM) has proved tantalisingly elusive. An ever-growing body of evidence indicates that the infusion of large amounts of soluble and cell-associated antigens into a recipient can somehow induce TRIM. One soluble molecule that has been implicated in TRIM is soluble human leucocyte antigen I (sHLA-I). However, patients infused with large amounts of sHLA-I do not always and unambiguously experience TRIM. As soluble CD8 (sCD8) molecules have been shown to capable of binding membrane and soluble HLA-I molecules, we focused on sCD8 as a possible modulator of sHLA-I-mediated TRIM.


METHODS
To this aim we compared the up-regulation of circulating sCD8 in plasma from patients suffering from the same pathology, but chronically transfused with two different blood derivatives: pre- and post-storage leucodepleted red blood cells which contain low and high levels of contaminating sHLA-I, respectively.


RESULTS
Significantly larger amounts of sCD8 circulating molecules were detectable in the plasma of patients transfused with post-storage leucodepleted red blood cells whose supernatants contained significantly larger amounts of sHLA-I contaminating molecules.


CONCLUSIONS
With the limitation of indirect evidence, this report introduces a new facet of the bioactivity of sCD8 as a possible modulator of sHLA-I-mediated TRIM.
Department of Internal Medicine, I.R.C.C.S. "A.O.U. San Martino-IST" and University of Genoa, Genoa.
Massimo
M
Ghio
Department of Internal Medicine, I.R.C.C.S. "A.O.U. San Martino-IST" and University of Genoa, Genoa.
Paola
P
Contini
Department of Internal Medicine, I.R.C.C.S. "A.O.U. San Martino-IST" and University of Genoa, Genoa.
Gianluca
G
Ubezio
Department of Health Sciences, I.R.C.C.S. "A.O.U. San Martino-IST" and University of Genoa, Genoa.
Filippo
F
Ansaldi
Department of Internal Medicine, I.R.C.C.S. "A.O.U. San Martino-IST" and University of Genoa, Genoa.
Maurizio
M
Setti
Immunohematology and Transfusion Centre, Istituto Giannina Gaslini, Genoa, Italy.
Gino
G
Tripodi
D001793:Blood Preservation; D016827:CD8 Antigens / Q000097:blood* / Q000502:physiology; D018414:CD8-Positive T-Lymphocytes / Q000378:metabolism; D017707:Erythrocyte Transfusion / Q000009:adverse effects*; D015395:Histocompatibility Antigens Class I / Q000097:blood / Q000276:immunology*; D006801:Humans; D007165:Immunosuppression Therapy; D047589:Leukocyte Reduction Procedures; D010949:Plasma; D012995:Solubility; D017086:beta-Thalassemia / Q000097:blood / Q000628:therapy
D016827:CD8 Antigens; D015395:Histocompatibility Antigens Class I