Saturday, July 9, 2011

The association between metal ions from hip resurfacing and reduced T-cell counts

J Bone Joint Surg Br. 2006 Apr;88(4):449-54.

Hart AJ, Hester T, Sinclair K, Powell JJ, Goodship AE, Pele L, Fersht NL, Skinner J.


Royal National Orthopaedic Hospital, Stanmore, UK.


We have studied the relationship between metal ion levels and lymphocyte counts in patients with metal-on-metal hip resurfacings. Peripheral blood samples were analysed for lymphocyte subtypes and whole blood cobalt and chromium ion levels in 68 patients (34 with metal-on-metal hip resurfacings and 34 with standard metal-on-polyethylene total hip replacements). All hip components were radiologically well-fixed and the patients were asymptomatic. Cobalt and chromium levels were significantly elevated in the patients with metal-on-metal hip resurfacings, compared with the patients with standard metal-on-polyethylene designs (p < 0.0001). There was a statistically significant decrease in the level of CD8(+) cells (T-cytotoxic/suppressor) (p = 0.005) in the metal-on-metal hip resurfacing group. A threshold level of blood cobalt and chromium ions was associated with reduced CD8(+) T-cell counts. We have no evidence that our patients suffered as a result of this reduced level of CD8(+) T-cells

[Added by Connie:  I published this study because it was a recent one that showed that there is a statistically significant decrease in the level of T cells in the metal on metal hip resurfacing group.

T cells or T lymphocytes belong to a group of white blood cells known as lymphocytes, and play a central role in cell-mediated immunity.

Cellular immunity protects the body by:
  1. activating antigen-specific cytotoxic T-lymphocytes that are able to induce apoptosis in body cells displaying epitopes of foreign antigen on their surface, such as virus-infected cells, cells with intracellular bacteria, and cancer cells displaying tumor antigens;
  2. activating macrophages and natural killer cells, enabling them to destroy pathogens; and
  3. stimulating cells to secrete a variety of cytokines that influence the function of other cells involved in adaptive immune responses and innate immune responses.

White blood cells fight infection. The white blood count (WBC) is part of a complete blood count (CBC) that is used to check your blood counts. There are several types of white blood cells. A differential test will show more detail about your white blood cell count:

Normal Adult Values
White Blood Cell Total4-11 k/ul
Note: Normal values will vary from laboratory to laboratory.

When you have a low white blood cell count there is an increased risk of infection. The level of risk depends on several factors:
  • How low your white blood count falls
  • How long your white blood count is low
  • Which type of low white blood cell count you have

Cancer /ˈkænsər/ ( listen) (medical term: malignant neoplasm) is a class of diseases in which a group of cells display uncontrolled growth, invasion that intrudes upon and destroys adjacent tissues, and sometimes metastasis, or spreading to other locations in the body via lymph or blood.
Researchers divide the causes of cancer into two groups: those with an environmental cause and those with a hereditary genetic cause. Cancer is primarily an environmental disease, though genetics influence the risk of some cancers.[1] Common environmental factors leading to cancer include: tobacco, diet and obesity, infections, radiation, lack of physical activity, and environmental pollutants.[1] These environmental factors cause or enhance abnormalities in the genetic material of cells.[2] Cell reproduction is an extremely complex process that is normally tightly regulated by several classes of genes, including oncogenes and tumor suppressor genes.

So, if your T cell counts are low due to the metal on metal hip implant, then it becomes difficult to fight off infection.  Infection is one of the causes of cancer....Make sense?]

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