Th1 predominance and perforin expression in minor salivary glands from patients with primary Sjogren's syndrome

Objectives of this study were to examine the cytokine and perforin mRNA exp ression in minor salivary glands from patients with primary Sjogren's syndr ome (pSS), searching for possible correlation with clinical parameters and to identify the dominant cytokine pattern in the different groups. Oral muc osa biopsy samples from 42 pSS patients were studied. Total RNA was analyse d by normalized RT-PCR using oligo-dT as the RT primer and IL-2, IFN-gamma, IL-12, IL-18, IL-4, IL-10, TGF-beta, TNF-alpha and perforin-specific prime rs for amplification. Results were analysed taking into account: (1) biopsy grade I to IV (Chisholm's classification); (2) diagnosis of either definit e pSS (n = 30) or probable pSS (n = 12), following the European classificat ion criteria (ECC), and (3) length of disease evolution from the beginning of symptoms to the time of biopsy, using an arbitrary cut-off point of 12 m onths. This studied showed that Th1-related cytokines (IL-2, IFN-gamma, IL- 12, IL-18, TNF-alpha) and perforin were present in most samples. IL-4 (Th2) was totally absent but other Th2 and regulatory cytokines (IL-10, TGF-beta ) were detected in the majority of samples. No Significant differences were found between definite and probable pSS nor between grades II, III, IV and fibrous tissue biopsies. A statistically significant increase of IL-2 (P = 0.012) and IFN-gamma (P = 0.019) was observed in samples from patients wit h longer disease evolution, whereas the two Th1-inducer cytokines IL-12 and IL-18 were equally and highly expressed in all samples. In conclusion, a p redominant Th1 pattern of cytokines was observed in all pSS samples, irresp ective of biopsy classification. In addition, a significant increase of Th1 cytokine expression frequency was associated with longer disease evolution . (C) 1999 Academic Press.