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The purpose of this study was to determine whether benign hereditary leukopenia-neutropenia in Yemenites may be reflective of an absent or a lesser degree of chronic low grade inflammation that has been documented to exist in most apparently healthy subjects. The white blood cell count (WBCC), fibrinogen as well as high sensitivity C-reactive protein (hs-CRP) concentrations were determined in a group of apparently healthy individuals during their routine health screening program. These inflammatory biomarkers in a group of 82 Yemenite Jews were compared to those measured in a group of 1817 individuals whose parents immigrated to Israel from Central and East Europe, from countries surrounding the Mediterranean Sea as well as the Middle East. The two study groups were matched for possible confounding factors that may have an influence on the intensity of the microinflammatory response including age, gender, body mass index, components of the metabolic syndrome and the Ten Year Calculated Coronary Heart Disease Framingham Risk Score. The expected reduced WBCC was noted in the group of Yemenite Jews (6.99 +/- 1.64 versus 5.88 +/- 2.06 x 10(3)/microL cells, P = 0.001). However, they had significantly enhanced concentrations of hs-CRP, the respective values being 2.1 +/- 2 versus 1.4 +/- 2.4 mg/L in men (P = 0.002) and 2.5 +/- 2.2 versus 1.4 +/- 2.9 in women (P < 0.0005). An increased concentration of fibrinogen was found in the Yemenite Jews, although the difference was not statistically significant in men. Thus, the leukopenia-neutropenia in Yemenite Jews is probably not an expression of an absent or lesser degree of chronic low grade inflammation. These findings shed more light on the potential mechanisms that are responsible for the low WBCC in this particular ethnic group.

Benign familial (hereditary) leukopenia and neutropenia (BFLN) have been reported in some ethnic groups, including black Americans and Yemenite Jews. The bone-marrow response of 34 Yemenite Jews (with and without neutropenia) to an intravenous injection of 200 mg of hydrocortisone sodium succinate was studied and compared with the response of 18 healthy control subjects. The mean +/- SEM of the increments in polymorphonuclear cells (PMNs) following injection of hydrocortisone in Yemenite Jews (2,413 +/- 245/mm3 in neutropenic subjects and 2,187 +/- 343/mm3 in nonneutropenic subjects) were significantly lower than in the control subjects (4,431 +/- 467/mm3), without significant differences among the subgroups of the Yemenite Jews. The decreases in monocytes, lymphocytes, and eosinophils were similar in all groups. No correlation was found between baseline PMN levels and the increments following hydrocortisone administration. These results suggest a lowered bone-marrow response to hydrocortisone in subjects with BFLN, indicating some defect in PMNs release from the bone-marrow storage pool to the peripheral blood. It seems that this defect characterizes all members of the ethnic group, whether they have "overt" neutropenia or not.

Benign familial leukopenia (BFL) is a hereditary phenomenon, encountered in several ethnic groups. Subjects bearing BFL are believed to be affected by bacterial infection in no greater incidence than normal subjects. In our study we investigated a group of subjects with BFL during an acute bacterial infection in comparison to subjects without BFL with the same infection. We found that the subjects with BFL had no absolute leukocytosis during the infection. Nevertheless, they reacted similarly to the other subjects in regard to their temperature and heart rate; however, they were hospitalized for fewer days than subjects without BFL. We conclude that BFL is a benign phenomenon, requiring neither specific treatment as such, nor more aggressive therapy during infection. The benign course of an acute bacterial infection in BFL indicates that perhaps the number of WBC's that are normally recruited during an infection in normal subjects highly exceeds that which is necessary.

Benign neutropenia is often found among healthy Yemenite Jews. An assessment was made of the magnitude of labor-induced leukocytosis in 44 Yemenite Jewish women, by comparing their hematological values during labor with those of 27 non-Yemenite women. A statistically significant difference was found in the absolute counts of the white blood cells (WBC) during delivery between the two groups, the values being lower among Yemenite Jews [10,291 +/- 422] vs. [11,759 +/- 630] X 10(9)/1) and similar findings were detected among their infants. The low WBC counts in the Yemenite group at parturition were also associated with significantly lower plasma cortisol levels (Yemenite group: 33.7 +/- 3.5 micrograms/dl; controls: 49.3 X 2.9 micrograms/dl). A correlation was found between serum cortisol levels and the magnitude of leukocytosis in both groups of women and their infants. These results suggest that a low basal corticosteroid output may contribute to the low white blood cell counts detected in some ethnic groups like the Yemenite Jews.