Antibody-associated lymphotoxin in acute infection.

Five pediatric patients who were known to be previously healthy acutely developed lymphopenia during various viral or mycoplasma infections. In one case, fatal generalized varicella occurred and in another, severe toxic epidermal necrolysis ensued. To further investigate this phenomenon, a study was done to determine the incidence of and elucidate the pathogenesis of lymphopenia occurring during the acute phase of viral or mycoplasma infections. Acute and convalescent sera from patients with viral or mycoplasma infection and children immunized with live measles virus were screened for lymphocytotoxic activity against normal lymphocytes by the microcytotoxicity method of Terasaki and McClelland (1). Sera with lymphocytotoxic activity were found in 15 of 48 cases of viral infections, 4 of 22 mycoplasma infections, and 1 of 11 measles virus immunized persons. All those who had sera which were cytotoxic to lymphocytes in vitro had lymphopenia. The lymphocytotoxic activity resided in 19S fractions in 8 of 11 positive sera while the remaining 3 had activity both in 19S and 7S fractions and could be completely removed by absorption with antilight chain antiserum. The cytotoxic activities were all complement-dependent and were greater at 37 degrees C than at 4 degrees C. The significance of acute acquired immunologic deficiency due to the development of antibody-associated lymphotoxin (AbAL) during acute infections is discussed and five cases having more severe clinical manifestations are presented (Appendix).