Effect of Zinc Supplementation on Adenosine Deaminase Activity in Leprosy.

Serum Adenosine Deaminase (ADA) acts as marker of cellular immunity and its activity is found to be altered in various diseases in which there is a cell mediated immune response (CMI) including leprosy. The role of zinc is well established in the development and maintainence of immunocompetence and its supplementation activates the immune response in particular Tlymphocytes and monocytes in several ways. The aim of the study was planned to evaluate the effect of nutritional zinc supplementation on cell mediated immune response by investigating the pre and post intervention serum ADA levels after oral zinc sulphate supplementation in leprosy patients. A total of 49 cases, 30 Tuberculoid Leprosy (TT) and 19 Lepromatous Leprosy (LL) patients, within the age group of 25-60 years were enrolled in the study along with 30 age matched healthy controls. Serum ADA was estimated in all the subjects before and after (2 months and 4 months) oral zinc supplementation. Pre intervention serum ADA level was observed to be significantly increased in both the TT and LL (p<0.001) groups as compared to controls, revealing raised immunological activity in the patients. After oral zinc sulphate supplementation serum ADA re-evaluation was done in 38 cases. A highly significant (p < 0.001 ) rise in ADA level was registered in the post intervention period (4 months supplementation) in TT cases with a moderately significant (p< 0.05) increase in LL cases, indicating the ability of oral zinc therapy to affectively alter the cell mediated immune response in leprosy.

The Changes of Cell Mediated Immunity Correlated with Severity of Head Injury

Severe head injury results in the suppression of cellular immunity associated with dysfunctioning of effector lymphocytes, such as helper T cells(CD4) (and cytotoxic T cells(CD8). Despite progress in the management of increased intracranial pressure following head injury, infection remains the most common complication and the primary cause of prolonged hospitalization and death. This study attempts to assess the cellular immune function following head injury according to the degree of severity, and to establish the clinically available parameters of cell mediated immune(CMI) function, which can then be used for coherent prediction of infection risk. Eighteem head injury patients without severe systemic injury, who divided into three subgroups depending on the severity of head injury, were estimated with the use of CMI multitest kit(Merieux Institute, France) to test delayed-type hypersensitivity(DTH) and enumerated the circulating lymphocyte subpopulation(pan T-cell marker CD3, helper T cell marker CD4, cytotoxic T cell marker CD8 and B-cell marker CD19) on the 1st, 7th, and 21th day of injury. Patients were monitored for evidence of infection for this period. Fourteen patients had no reaction to any antigens of the DTH skin test(anergy) and the remaining four patients had also some degree of anergy. Seven patients became infected and all of them were anergic. There were significant decrease of circulating effector T lymphocytes, both CD4-positive and CD8-positive cells, within 24 hours of injury in the mild as well as the moderate and severe head injury group. CD4-positive cells were nearly completely recovered by the 7th day of injury. CD8-positive cells had sustained significant decrease even after 3 weeks of injury. There was no significant change in pan T-cells(CD3-positive cells) and B-cells(CD19-positive cells). The results suggest that DTH skin test and effector T cell enumeration are both relatively simple and highly sensitive parameters for monitoring CMI function. Especially, anergy of DTH skin test can be used for indicator to predict risk of infection. Mild as well as moderate and severe head injuries may result in the suppression of cellular immunity associated with the dysfunctioning of effector T cell.