Immunological Laboratory, Kaunas Medical University Hospital, Lithuania

Key words: Staphylococcus aureus, Streptococcus pyogenes, lymphocyte immunophenotyping, T lymphocytes, grampositive cocci, superantigen.

Summary. A retrospective study of 176 immunologically tested patients admitted to Kaunas Medical University Hospital during 1997–2000 was performed. All patients had positive bacteriological culture test result confirming an infectious etiology of the disease. Our results showed that majority of immunological parameters were dependent on such non-specific factors as intensity and localization of the inflammatory process, an overall functional status of the patient, and the number of the disease exacerbation episodes during the last year before admission. In contrast to this, the absolute number of CD4 lymphocytes, the relative amount of HLA-DR positive lymphocytes and the index of neutrophil latex phagocytosis were exceptionally dependent on the species of the causative microorganism, in particular on superantigen producing cocci. In this case, the HLA-DR positive lymphocyte amount and the neutrophil phagocytosis index were significantly higher. In addition, the CD4/CD8 lymphocyte ratio (the immunoregulatory index) was significantly lower in this group.

As much as those findings are concordant with the signs of excessive immune activation, we conclude that they reflect a possible superantigenic action of the disease causing bacteria. Therefore, a need for immunomodulating therapy during the infections caused by species able to produce superantigens is confirmed.

Received 14 September 2001, accepted 5 December 2001.