HLA class I, II, and III polymorphism in Italian patients with sarcoidosis. The Pavia-Padova Sarcoidosis Study Group.

We studied the HLA polymorphisms (class I, II, and III) in 107 Italian patients with biopsy specimen-proven sarcoidosis in order to investigate the immunogenetic background of this disease. The mean age of onset of the disease was 36.08 +/- 12.4 years. Four patients (3.73 percent) were in radiologic stage 0, 38 patients (35.51 percent) were in radiologic stage I, 40 patients (37.38 percent) were in stage II, and 25 (23.36 percent) were in stage III. Thirty-eight patients (35.51 percent) had one or more extrapulmonary localization(s) of the disease. Positive association between sarcoidosis and HLA-B8 (chi 2 = 6.07, p = 0.0127, RR = 1.91) was confirmed. Regarding the age of onset of the disease, HLA-B35 was more frequent (chi 2 = 7.34, p = 0.0056, pc < 0.05, RR = 4.62) in patients with early onset of symptoms and/or signs, before the mean age of 36 years. With reference to the radiologic stage of the disease, HLA class II marker DR3 was more frequent in patients with stage I (chi 2 = 7.22, p = 0.0061, pc < 0.05, RR = 7.08). No significant relationship was found between sarcoidosis and HLA class III markers. These results seem to confirm an association of sarcoidosis with HLA classic genes and can sustain the hypothesis of a genetic heterogeneity of this disease.