Complications of mumps infection, islet-cell antibodies, and HLA

Class II major histocompatibility complex and organ specific autoimmunity in man

T helper lymphocytes only recognize the antigen to which they are directed if it is 'presented' to them by a cell expressing the same class II major histocompatibility complex (MHC) antigen as themselves. Since the target cells of most organ specific autoimmune diseases do not normally express class II MHC proteins on their surface, any cell specific surface antigens they possess may never have been presented, and therefore immunological tolerance to them may not exist. The target cells in several organ specific autoimmune diseases have been shown to express class II MHC aberrantly and this expression may have allowed presentation of such cell specific surface antigens to potentially autoreactive T helper lymphocytes. It has therefore been proposed that aberrant expression of class II MHC antigens may be an initiating factor in certain autoimmune diseases.

Islet cell antibodies and the development of diabetes mellitus in relation to mumps infection and mumps vaccination

Islet cell antibodies were investigated in 127 non-diabetic children after mumps infection and in four out of seven children who developed diabetes mellitus shortly after active mumps vaccination. Twenty-one of the children who had mumps and all four vaccinated children who were tested had islet cell cytoplasmic antibodies. In contrast, islet cell surface antibodies were detected in 43 out of 68 patients with mumps infection and in 32 out of 44 patients with other viral diseases. All but one mumps-infected child and all the other viral infected patients investigated did not develop diabetes mellitus. The mumps-infected ICA positive children did not show those HLA-frequencies associated with Type 1 diabetes.